Measurement system and machine tool

Abstract

This measurement system is capable of moving a machining head and a stage on which a workpiece is placed, and comprises: an optical device that is used for correcting the spatial accuracy of a machine tool that machines the workpiece using a tool detachably attached to a spindle of the machining head, and includes an optical member that emits measurement light toward a reflection member; and a rotation device that is capable of rotating the optical member around a rotation axis. The optical device is calibrated on the basis of a light reception result from a light reception device that receives, via the optical member, return light from the reflection member irradiated with the measurement light from the optical member having a first angle as the rotation angle, and a light reception result from the light reception device that receives, via the optical member, return light from the reflection member irradiated with the measurement light from the optical member after the rotation angle is changed to a second angle by the rotation device.

Description

Measurement System and Machine Tool

[0001] The present invention relates to the technical fields of, for example, machine tools and measurement systems used in machine tools.

[0002] Patent Document 1 describes an example of a measurement system. Suppressing deterioration of the measurement accuracy of such a measurement system is cited as an example of a technical problem.

[0003] German Utility Model No. 202004007647

[0004] According to a first aspect, there is provided a measurement system used for correcting the spatial accuracy of a machine tool that processes a workpiece with a tool detachably attached to the spindle of a machining head, wherein at least one of a stage for placing the workpiece and the machining head is movable, the measurement system including an optical device that includes an optical member that emits measurement light toward a reflecting member, and a rotating device that is rotatable around a rotation axis, the measurement light being emitted from the optical member whose rotation angle around the rotation axis is a first angle toward the reflecting member, and the measurement light being irradiated from the reflecting member, the first light reception result being the light reception result of a light reception device that receives the returned light through the optical member, and the measurement light being emitted from the optical member whose rotation angle around the rotation axis has changed from the first angle to a second angle toward the reflecting member by control of the rotating device by a control device, and the measurement light being irradiated from the reflecting member, the second light reception result being the light reception result of the light reception device that receives the returned light through the optical member, and the optical device being calibrated based on the first light reception result and the second light reception result.

[0005] According to a second aspect, there is provided a machine tool including the measurement system provided by the first aspect.

[0006] According to a third embodiment, a measurement system is provided for use in a machine tool in which at least one of a stage on which a workpiece is placed and a machining head is movable, and the workpiece is machined with a tool detachably attached to the spindle of the machining head, the measurement system comprising a spherical member which is at least a part of which is a spherical optical element, and an optical member which emits measurement light toward a third reflecting member via the spherical member, and an optical device which is detachably attached to the spindle in place of the tool, and a light receiving device which receives the reflected light from the third reflecting member which has been irradiated with the measurement light, and the machine tool is adjusted based on the result of receiving the reflected light by the light receiving device.

[0007] According to a fourth embodiment, a measurement system is provided for use in a machine tool in which at least one of a stage on which a workpiece is placed and a machining head is movable, and the workpiece is machined with a tool detachably attached to the spindle of the machining head, the measurement system comprising an optical device disposed within the machine tool, which includes a spherical member that is at least a part of which is a spherical optical element, and an optical member that emits measurement light toward a third reflecting member via the spherical member, and a light receiving device that receives the reflected light from the third reflecting member that has been irradiated with the measurement light, wherein the machine tool is adjusted based on the result of receiving the reflected light by the light receiving device.

[0008] According to the fifth aspect, a machine tool is provided that includes a measuring system provided according to the third or fourth aspect.

[0009] Figure 1 is a block diagram showing the system configuration of the machining system in the first embodiment. Figure 2 is a block diagram showing the system configuration of the machine tool in the first embodiment. Figure 3 is a perspective view showing the external appearance of the machine tool in the first embodiment. Figure 4 is a cross-sectional view showing the configuration of the machining head in the first embodiment. Figure 5 is a block diagram showing the system configuration of the measurement system in the first embodiment. Figure 6 is a cross-sectional view showing the machining head to which the measurement device (particularly the measurement unit and measurement head) in the first embodiment is attached. Figure 7 is a cross-sectional view showing the configuration of the measurement light source and the light receiving device. Figure 8 is a cross-sectional view showing the configuration of the optical device. Figure 9 is a cross-sectional view showing the configuration of the rotating device. Figure 10 is a cross-sectional view showing the injection optical member before rotation around the rotation axis and the injection optical member after rotation around the rotation axis. Figure 11A is a top view showing a plurality of reference members, and Figure 11B is a side view showing a plurality of reference members. Figure 12 is a flowchart showing the flow of the first spatial accuracy correction operation for calculating the movement error that occurs in the translational movement of at least one of the machining head and the stage. Figure 13 shows the movement error in the machine coordinate system. Figure 14 is a flowchart showing the flow of a second spatial accuracy correction operation for calculating the movement error that occurs in the rotational movement of at least one of the machining head and the stage. Figure 15 shows the movement error in the machine coordinate system. Figure 16 is a conceptual perspective view showing a measuring device (measuring head) that performs a first modified example of the spatial accuracy correction operation. Figures 17A and 17B are graphs showing the calculation results of the distance between the measurement point and the reference member. Figure 18 is a conceptual perspective view showing a measuring device (measuring head) that performs a second modified example of the spatial accuracy correction operation. Figure 19 shows the spatial accuracy calculated by the second modified example of the spatial accuracy correction operation. Figure 20 shows the spatial accuracy calculated by interpolation. Figure 21 is a cross-sectional view showing a spherical member and an injection optical member that rotates around the center of the spherical member as the center of rotation. Figure 22A is a cross-sectional view showing an example where the optical path of the measurement light is not shifted in a direction intersecting the direction of propagation of the measurement light between the polarizing beam splitter and the spherical member, while Figures 22B and 22C are cross-sectional views showing examples where the optical path of the measurement light is shifted in a direction intersecting the direction of propagation of the measurement light between the polarizing beam splitter and the spherical member.Figure 23 is a cross-sectional view showing an ejection optical element rotating around a spherical member. Figure 24 is a cross-sectional view showing the configuration of an optical device used to perform a calibration operation. Figure 25 is a flowchart showing the flow of the calibration operation. Figure 26 is a cross-sectional view showing a rotating ejection optical element. Figure 27 is a cross-sectional view showing the optical device provided in the measuring head. Figure 28A shows the result of receiving the reflected light (intensity) by the light receiving device when the measurement light transmitted through the half mirror is not illuminating the reference member, and Figure 28B shows the result of receiving the reflected light (intensity) by the light receiving device when the measurement light transmitted through the half mirror is illuminating the reference member. Figures 29A and 29B conceptually show calibration determination information that can be used to determine whether or not to perform a calibration operation, which is generated based on the result of receiving the reflected light from the half mirror. Figure 30 is a cross-sectional view showing the configuration of the optical device provided in the measuring head of the second embodiment. Figure 31A is a cross-sectional view showing an example where the optical path of the measurement light is not misaligned in the direction intersecting the direction of propagation of the measurement light between the polarizing beam splitter and the spherical member, and Figure 31B is a cross-sectional view showing an example where the optical path of the measurement light is misaligned in the direction intersecting the direction of propagation of the measurement light between the polarizing beam splitter and the spherical member. Figure 32 is a cross-sectional view showing the configuration of the light receiving device provided in the measurement head of the third embodiment. Figure 33 is a cross-sectional view showing the configuration of the optical device provided in the measurement head of the third embodiment. Figure 34 is a cross-sectional view showing the configuration of the light receiving device provided in the measurement head of the fourth embodiment. Figure 35 is a cross-sectional view showing the configuration of the optical device provided in the measurement head of the fourth embodiment. Figure 36 is a cross-sectional view showing the configuration of the light receiving device provided in the measurement head of the fifth embodiment. Figure 37 is a cross-sectional view showing the configuration of the optical device provided in the measurement head of the fifth embodiment. Figure 38 is a cross-sectional view showing the configuration of the light receiving device provided in the measurement head of the sixth embodiment. Figure 39 is a cross-sectional view showing the configuration of the optical device provided in the measurement head of the sixth embodiment. Figure 40 is a cross-sectional view showing the configuration of the optical device included in the measuring head of the seventh embodiment. Figure 41 is a cross-sectional view showing the configuration of the light receiving device included in the measuring head of the eighth embodiment. Figure 42 is a cross-sectional view showing the configuration of the optical device included in the measuring head of the eighth embodiment.Figure 43 is a cross-sectional view showing the configuration of the optical device provided in the measuring head of the ninth embodiment. Figure 44 is a cross-sectional view conceptually showing an ejection optical member that rotates around a rotation axis in the ninth embodiment. Figure 45 is a cross-sectional view showing the configuration of the optical device provided in the measuring head of the tenth embodiment. Figure 46 is a cross-sectional view conceptually showing an ejection optical member that rotates around a rotation axis in the tenth embodiment. Figure 47 is a cross-sectional view showing the respective arrangement positions of the measuring head and the reference member in the eleventh embodiment. Figures 48A to 48D are cross-sectional views showing the configuration of the spherical member in the twelfth embodiment. Figure 49 is a cross-sectional view showing the configuration of the spherical member in the thirteenth embodiment. Figure 50 is a cross-sectional view showing the configuration of the optical device provided in the measuring head of the fourteenth embodiment. Figure 51 is a cross-sectional view showing the incident position of the reflected light on the end face of the terminal portion of the optical transmission member. Figure 52 is a cross-sectional view showing the configuration of the optical device provided in the measuring head of the fifteenth embodiment. Figure 53 is a cross-sectional view showing the incident position of the reflected light on the end face of the terminal portion of the optical transmission member. Figure 54 is a block diagram showing the system configuration of the optical processing machine in the 16th embodiment. Figure 55 is a block diagram showing the system configuration of the measuring instrument in the 17th embodiment.

[0010] The following describes embodiments of the measurement system and machine tool with reference to the drawings. In the following, embodiments of the measurement system and machine tool will be described using a machining system SYS capable of machining a workpiece W, which is an example of an object.

[0011] In the following explanation, the positional relationships of the various components constituting the machining system SYS will be described using a machine coordinate system, which is an XYZ orthogonal coordinate system defined by the mutually orthogonal X, Y, and Z axes. For the sake of explanation, in the following explanation, the X-axis and Y-axis directions of the machine coordinate system are horizontal (i.e., predetermined directions in the horizontal plane), and the Z-axis direction of the machine coordinate system is vertical (i.e., a direction perpendicular to the horizontal plane, and essentially an up-and-down direction). Furthermore, the rotational directions (in other words, tilt directions) around the X, Y, and Z axes may be referred to as the θX direction, θY direction, and θZ direction, respectively.

[0012] Furthermore, in the following explanation, unless otherwise specified, the X-axis, Y-axis, and Z-axis refer to the X-axis, Y-axis, and Z-axis in the machine coordinate system, respectively.

[0013] (1) Machining System SYS in the First Embodiment First, the machining system SYS in the first embodiment will be described. In the following description, the machining system SYS in the first embodiment will be referred to as "machining system SYSa".

[0014] (1-1) Configuration of the SYS Processing System First, the configuration of the SYSa processing system in the first embodiment will be described.

[0015] (1-1-1) Overall Configuration of Machining System SYS First, the overall configuration of the machining system SYSa in the first embodiment will be described with reference to Figure 1. Figure 1 is a block diagram showing an example of the system configuration of the machining system SYSa in the first embodiment.

[0016] As shown in Figures 1 and 2, the machining system SYSa comprises a machine tool 1 and a measurement system 2. Note that the device including at least a part of the measurement system 2 and the machine tool 1 may be referred to as the machine tool. The machining system SYSa may also be referred to as the machine tool. In other words, the machine tool 1 may comprise at least a part of the measurement system 2. Note that the machining system SYSa may comprise the machine tool 1 and a part of the measurement system 2.

[0017] Machine tool 1 is a device capable of processing a workpiece W, which is the object to be processed. For this reason, machine tool 1 may also be called a processing device. The configuration of machine tool 1 will be described in detail later with reference to Figures 2 to 4.

[0018] The measurement system 2 is a measuring device used in the machine tool 1. For example, the measurement system 2 may be used to adjust the machine tool 1. Specifically, the measurement results from the measurement system 2 may be used to adjust the machine tool 1. In this case, the machine tool 1 may be adjusted by the measurement system 2. The machine tool 1 may be adjusted based on the measurement results of the object MT measured by the measurement system 2.

[0019] In the first embodiment, the adjustment of the machine tool 1 may include correction (in other words, calibration) of the spatial accuracy of the machine tool 1. In this case, the measurement system 2 may be used for correction of the spatial accuracy of the machine tool 1. The measurement results from the measurement system 2 may be used for correction of the spatial accuracy of the machine tool 1. The spatial accuracy of the machine tool 1 may be corrected based on the measurement results from the measurement system 2.

[0020] As will be described later, the measurement system 2 may measure the spatial accuracy of the machine tool 1 in order to correct its spatial accuracy (i.e., adjust the machine tool 1). In other words, the measurement system 2 may be used to measure the spatial accuracy of the machine tool 1. In this case, the spatial accuracy of the machine tool 1 may be corrected based on the measurement result of the spatial accuracy of the machine tool 1 by the measurement system 2.

[0021] The spatial accuracy of machine tool 1, the measurement of the spatial accuracy of machine tool 1, and the correction of the spatial accuracy of machine tool 1 will be described in detail later, so a detailed explanation is omitted here.

[0022] (1-1-2) Configuration of Machine Tool 1 Next, the configuration of the machine tool 1 will be described with reference to Figures 2 and 3. Figure 2 is a block diagram showing the system configuration of the machine tool 1 in the first embodiment. Figure 3 is a perspective view showing the external appearance of the machine tool 1 in the first embodiment.

[0023] As shown in Figures 2 and 3, the machine tool 1 comprises a machining head 11, a head drive system 12, a head position measuring device 13 (not shown in Figure 3), a stage device 14, a tool changing device 15 (not shown in Figure 3), and a machining control device 16 (not shown in Figure 3). Note that Figure 3 shows an example where the machine tool 1 is a vertical machine tool. However, the machine tool 1 is not limited to a vertical machine tool. The machine tool 1 may be any well-known machine tool such as a grinding machine or an electrical discharge machine. For example, the machine tool 1 may be a horizontal machine tool or a composite machine tool.

[0024] The machining head 11 is a machining device capable of machining a workpiece W. The machining head 11 may also be simply referred to as the head. Because the machining head 11 moves, as will be described later, the machining head 11 may also be referred to as the moving head. The machining head 11 comprises a spindle 111 and a head housing 112. The machining head 11 will be described below with reference to Figures 2 to 3, as well as Figure 4. Figure 4 is a cross-sectional view showing the configuration of the machining head 11. The machining head 11 may also be referred to as the spindle head.

[0025] As shown in Figures 2 to 4, the main spindle 111 is a member that can rotate around the rotation axis RX. In this case, the main spindle 111 may be a member that extends along the rotation axis RX. That is, the main spindle 111 may be a member that has a longitudinal shape along the rotation axis RX. In the example shown in Figures 3 to 4, the rotation axis RX of the main spindle 111 is parallel to the Z axis. However, the main spindle 111 may rotate around a rotation axis RX that intersects the Z axis. The rotation axis RX that intersects the Z axis may include a rotation axis RX that is perpendicular to the Z axis, or a rotation axis RX that is inclined with respect to the Z axis. The main spindle 111 may also be called a spindle.

[0026] As shown in Figure 4, a tool 113 (i.e., a machining tool) for machining the workpiece W can be attached to the spindle 111. Specifically, as shown in Figures 3 and 4, the spindle 111 is equipped with a mounting device 1111 for attaching the tool 113. The tool 113 is attached to the spindle 111 via the mounting device 1111. The tool 113 attached to the mounting device 1111 is removable from the mounting device 1111. In other words, the tool 113 is detachably attached to the spindle 111. The mounting device 1111 may also be called a mounting mechanism, a detachable device, or a detachable mechanism.

[0027] Furthermore, the state in the first embodiment that "the first object is attached to (or provided with, hereinafter the same as) the second object" may include at least one of the following states: "the first object is directly attached to the second object (i.e., the first object is attached to the second object so that the first object and the second object are in contact)" and "the first object is indirectly attached to the second object (i.e., the first object is attached to the second object without the first object and the second object being in contact)." The state that "the first object is indirectly attached to the second object" may also include the state that "the first object is attached to the second object via a third object different from the first and second objects."

[0028] In the example shown in Figures 3 and 4, the spindle 111 is equipped with a mounting device 1111 having a hole 1112 (for example, a tapered hole) formed at the tip of the spindle 111 (specifically, the tip on the workpiece W side) into which the tool 113 is fitted (or inserted). In this case, the tool 113 is attached to the spindle 111 by fitting (or inserting) the shank 1131 of the tool 113, which has a shape complementary to the hole 1112, into the hole 1112 of the mounting device 1111. The mounting device 1111 may hold the tool 113 attached to the mounting device 1111. In this case, the mounting device 1111 may be equipped with at least one of the following to hold the tool 113: a mechanical chuck, an electrostatic chuck, a hydraulic chuck, or a vacuum suction chuck.

[0029] When the spindle 111 rotates with the tool 113 attached to it, the tool 113 also rotates around the rotation axis RX. As a result, the rotating tool 113 comes into contact with the workpiece W, and the workpiece W is machined. In this way, the machine tool 1 (particularly the machining head 11) can machine the workpiece W using the spindle 111 and the tool 113. In other words, the machine tool 1 (particularly the machining head 11) can machine the workpiece W using the tool 113 attached to the spindle 111.

[0030] The head housing 112 is a housing that accommodates at least a portion of the spindle 111. The head housing 112 may house at least a portion of the spindle 111 in a housing space formed inside the head housing 112. At least a portion of the spindle 111 housed in the head housing 112 may be supported by the head housing 112 via bearing members (e.g., bearings) not shown.

[0031] Again, in Figures 2 and 3, the head drive system 12 is capable of moving the machining head 11. The head drive system 12 may also be called a drive device. The head drive system 12 may be capable of moving the machining head 11 along at least one of the X-axis, Y-axis, and Z-axis. In other words, the head drive system 12 may be capable of moving the machining head 11 along at least one of the translational axes, such as the translational axis along the X-axis, the translational axis along the Y-axis, and the translational axis along the Z-axis. Movement along at least one of the translational axes, such as the translational axis along the X-axis, the translational axis along the Y-axis, and the translational axis along the Z-axis may be called translational movement. Furthermore, in the following description, the translational axis along the X-axis, the translational axis along the Y-axis, and the translational axis along the Z-axis will be referred to as translational axis (X), translational axis (Y), and translational axis (Z), respectively. Furthermore, in the following explanation, unless otherwise specified, the translation axis may mean at least one of the translation axis (X), translation axis (Y), and translation axis (Z).

[0032] The head drive system 12 may be capable of moving the machining head 11 along at least one of the θX direction, θY direction, and θZ direction, in addition to or instead of at least one of the translation axis along the X-axis, the Y-axis, and the Z-axis. In other words, the head drive system 12 may be capable of rotating the machining head 11 around at least one of the rotation axis along the X-axis, the Y-axis, and the Z-axis, in addition to or instead of moving the machining head 11 along at least one of the translation axis along the X-axis, the Y-axis, and the Z-axis. Movement along at least one of the θX direction (direction around the rotation axis along the X-axis), the θY direction (direction around the rotation axis along the Y-axis), and the θZ direction (direction around the rotation axis along the Z-axis) may be referred to as rotational movement. Furthermore, in the following description, the rotation axis around the X axis, the rotation axis around the Y axis, and the rotation axis around the Z axis will be referred to as rotation axis (X), rotation axis (Y), and rotation axis (Z), respectively. Also, in the following description, unless otherwise specified, rotation axis may mean at least one of rotation axis (X), rotation axis (Y), and rotation axis (Z). Note that the operation of moving the machining head 11 along the rotation direction around the rotation axis may be considered equivalent to the operation of changing the orientation of the machining head 11.

[0033] In the example shown in Figure 3, the head drive system 12 is capable of moving the machining head 11 along the translation axis (X) and the translation axis (Z), respectively. In this case, the head drive system 12 may include, for example, a column 121 which is a wall-shaped member extending upward along the Z axis from the bed 140 which is the base of the stage device 14 described later, an X guide member 122 attached to (or formed on) the column 121 and extending along the X axis, an X block member 123 attached to the X guide member 122 and movable along the X guide member 122, a servo motor 124 which generates a driving force to move the X block member 123, a Z guide member 125 attached to (or formed on) the X block member 123 and extending along the Z axis, a Z block member (not shown in Figure 2) attached to the Z guide member 125 and movable along the Z guide member 125, and a servo motor 126 which generates a driving force to move the Z block member. The machining head 11 (particularly the head housing 112) may be attached to the Z-block member. As a result, the machining head 11 moves along the translation axis (X) in accordance with the movement of the X-block member 123, and moves along the translation axis (Z) in accordance with the movement of the Z-block member.

[0034] When the head drive system 12 moves the machining head 11, the relative positional relationship between the machining head 11 and the stage 141 (and furthermore, the workpiece W placed on the stage 141) changes. As a result, the relative positional relationship between the machining position where the machining head 11 performs machining and the workpiece W changes. In other words, the machining position moves relative to the workpiece W. The machine tool 1 may machine the workpiece W while moving the machining head 11. Specifically, the machine tool 1 may set the machining position to a desired position on the workpiece W by moving the machining head 11, and then machine the desired position on the workpiece W. However, if the machining position can be set to a desired position on the workpiece W by moving the stage 141 (described later), the machine tool 1 may machine the workpiece W without moving the machining head 11.

[0035] The head position measuring device 13 is capable of measuring the position of the machining head 11. An example of the head position measuring device 13 is an encoder. Another example of the head position measuring device 13 is a distance meter (for example, an interferometer). The head position measuring device 13 may also be called a position measuring sensor.

[0036] The stage apparatus 14 comprises a bed 140, a stage 141, a stage drive system 142, and a stage position measuring device 143. The stage 141 and the stage drive system 142 are supported by the bed 140.

[0037] A workpiece W is placed on the stage 141. For this reason, the stage 141 may also be called a mounting device. The stage 141 is capable of supporting the workpiece W placed on it. The stage 141 may also be capable of holding the workpiece W placed on it. In this case, the stage 141 may be equipped with at least one of the following for holding the workpiece W: a mechanical chuck, an electrostatic chuck, and a vacuum suction chuck.

[0038] The stage 141 is positioned so as to face the machining head 11 (particularly the spindle 111). In the example shown in Figure 1, the stage 141 is positioned below the machining head 11 (particularly the spindle 111). However, the stage 141 may be positioned at a location other than below the machining head 11 (particularly the spindle 111).

[0039] The stage drive system 142 is capable of moving the stage 141. The stage drive system 142 may also be referred to as a drive device. The stage drive system 142 may be capable of moving the stage 141 along, for example, at least one of the X axis, Y axis, and Z axis. In other words, the stage drive system 142 may be capable of moving the stage 141 along, for example, the translation axis (X), the translation axis (Y), and the translation axis (Z).

[0040] The stage drive system 142 may be capable of moving the stage 141 along at least one of the θX, θY, and θZ directions, in addition to or instead of at least one of the translation axis (X), translation axis (Y), and translation axis (Z). In other words, the stage drive system 142 may be capable of rotating the stage 141 around at least one of the rotation axis (X), rotation axis (Y), and rotation axis (Z), in addition to or instead of moving the stage 141 along at least one of the translation axis (X), translation axis (Y), and translation axis (Z). The operation of moving the stage 141 along the rotation direction around at least one of the rotation axis (X), rotation axis (Y), and rotation axis (Z) may be considered equivalent to the operation of changing the orientation of the stage 141.

[0041] In the example shown in Figure 3, the stage drive system 142 moves the stage 141 along the translation axis (Y) and rotates the stage 141 around the rotation axis (X) and rotation axis (Z), respectively. In this case, the stage drive system 142 may include, for example, a Y-guide member 1421 attached to (or formed on) the bed 140 and extending along the Y-axis, a trunnion (Y-block member) 1422 attached to the Y-guide member 1421 and movable along the Y-guide member 1421, a servo motor 1423 that generates a driving force to move the trunnion 1422, a cradle 1424 attached to the trunnion 1422 and rotatable around the rotation axis (X) relative to the trunnion 1422, and a servo motor (not shown) that generates a driving force to rotate the cradle 1424. The stage 141 may be attached to the cradle 1424 so as to be rotatable around the rotation axis (Z) relative to the cradle 1424 using the driving force generated by the servo motor (not shown). As a result, the stage 141 moves along the translation axis (Y) in accordance with the movement of the trunnion 1422, rotates around the rotation axis (X) in accordance with the rotation of the cradle 1424, and also rotates around the rotation axis (Z). In this case, the rotation axis (X) may be referred to as the A axis, and the rotation axis (Z) may be referred to as the C axis.

[0042] When the stage drive system 142 moves the stage 141, the relative positional relationship between the machining head 11 and the stage 141 (and furthermore, the workpiece W placed on the stage 141) changes. As a result, the relative positional relationship between the machining position where the machining head 11 performs machining and the workpiece W changes. In other words, the machining position moves relative to the workpiece W. The machine tool 1 may machine the workpiece W while moving the stage 141. Specifically, the machine tool 1 may set the machining position to a desired position on the workpiece W by moving the stage 141, and then machine the desired position on the workpiece W. However, if the machining position can be set to a desired position on the workpiece W by moving the machining head 11 as described above, the machine tool 1 may machine the workpiece W without moving the stage 141.

[0043] The stage position measuring device 143 can measure the position of the stage 141. An example of the stage position measuring device 143 is an encoder. Another example of the stage position measuring device 143 is a distance meter (for example, an interferometer). The stage position measuring device 143 may also be called a position measuring sensor.

[0044] The tool changing device 15 is a device capable of changing the tool 113 attached to the spindle 111. For example, the tool changing device 15 may include a first storage device (in other words, the first storage bin) in which at least one tool 113 is stored, and a first transfer device (in other words, the first transfer member) capable of taking out a desired tool 113 from the first storage device. As an example of the first storage device, at least one of a magazine and a turret can be given. As an example of the first transfer device, at least one of a changer arm, a robot arm (particularly, a robot arm to which an end effector capable of holding the tool 113 is attached), and a drone (particularly, a drone to which an end effector capable of holding the tool 113 is attached) can be given. The tool changing device 15 may take out one tool 113 to be attached to the spindle 111 from the first storage device using the first transfer device, and attach the taken-out one tool 113 to the spindle 111. That is, the tool changing device 15 may function as an attachment device capable of attaching the tool 113 to the spindle 111. The tool changing device 15 may remove the tool 113 attached to the spindle 111 from the spindle 111 using the first transfer device, and store the removed tool 113 in the first storage device. That is, the tool changing device 15 may function as a removal device capable of removing the tool 113 from the spindle 111. Incidentally, the tool changing device 15 may simply be referred to as a changing device. Incidentally, an automatic tool changer (ATC: Automatic Tool Changer) used in a machining center or the like may be used as the tool changing device 15.

[0045] As will be described in detail later, in the first embodiment, a measuring head 22 provided by the measuring system 2 can be attached to the spindle 111 instead of the tool 113. In this case, the tool changer 15 may be a device that can replace the measuring head 22 attached to the spindle 111. For example, the tool changer 15 may include a second storage device (in other words, a second storage compartment) that stores at least one measuring head 22, and a second transport device (in other words, a second transport member) that can take out a desired measuring head 22 from the second storage device. An example of the second storage device is at least one of a magazine and a turret. An example of the second transport device is at least one of a change arm, a robot arm (in particular a robot arm fitted with an end effector capable of holding the tool 113), and a drone (in particular a drone fitted with an end effector capable of holding the tool 113). The tool changing device 15 may use a second transport device to retrieve one measuring head 22 to be attached to the spindle 111 from the second storage device and attach the retrieved measuring head 22 to the spindle 111. In other words, the tool changing device 15 may function as a mounting device capable of attaching the measuring head 22 to the spindle 111. The tool changing device 15 may use a second transport device to remove the measuring head 22 attached to the spindle 111 from the spindle 111 and store the removed measuring head 22 in the second storage device. In other words, the tool changing device 15 may function as a removal device capable of removing the measuring head 22 from the spindle 111. Since the tool changing device 15 is not limited to the tool 113 and can replace the measuring head 22, it may simply be called a replacement device.

[0046] Furthermore, at least one measuring head 22 may be stored in a third storage device provided by the machine tool 1 separately from the tool changing device 15, in addition to or instead of the second storage device provided by the tool changing device 15. An example of the third storage device is a stand (storage area) on which at least one measuring head 22 can be placed. In this case, the tool changing device 15 may remove the tool 113 attached to the spindle 111, then the head drive system 12 may move the machining head 11 (spindle 111) to the third storage device, and then the measuring head 22 stored in the third storage device may be attached to the spindle 111. Alternatively, the head drive system 12 may move the machining head 11 (spindle 111) with the measuring head 22 attached to the spindle 111 to the third storage device, and the measuring head 22 may be removed (stored) in the third storage device, after which the tool changing device 15 may attach the tool 113 to the spindle 111.

[0047] Furthermore, if the measuring head 22 attached to the main spindle 111 is replaceable, the various cables connected to the measuring head 22 (for example, at least one of the optical fibers through which the measurement light ML and return light RL described later are transmitted, and the power cable that supplies power to the measuring head 22) may be routed in such a way that the cables are not cut due to at least one of the following: replacement of the measuring head 22 or movement of the main spindle 111 (measuring head 22) to which the measuring head 22 is attached. For example, the various cables connected to the measuring head 22 may have extra length to prevent them from being cut due to at least one of the following: replacement of the measuring head 22 or movement of the main spindle 111 (measuring head 22) to which the measuring head 22 is attached.

[0048] Further, the measurement head 22 may be stored in the first storage device that stores the tool 113. In this case, the tool changer 15 may take out one measurement head 22 to be attached to the spindle 111 from the first storage device using the first or second transfer device, and attach the taken-out one measurement head 22 to the spindle 111. The tool changer 15 may remove the measurement head 22 attached to the spindle 111 from the spindle 111 using the first or second transfer device, and store the removed measurement head 22 in the first storage device.

[0049] Also, in the above description, the machine tool 1 includes the tool changer 15, but the machine tool 1 may not include the tool changer 15. In this case, the processing system SYS may include the tool changer 15 separately from the machine tool 1.

[0050] The machining control device 16 controls the operation of the machine tool 1. For example, the machining control device 16 may control the operation of the machining head 11 (e.g., rotation of the spindle 111) included in the machine tool 1. For example, the machining control device 16 may control the operation of the head drive system 12 (e.g., movement of the machining head 11) included in the machine tool 1. For example, the machining control device 16 may control the operation of the stage drive system 142 (e.g., movement of the stage 141) included in the machine tool 1. For example, the machining control device 16 may control the operation of the tool changer 15 (i.e., replacement of the tool 113 and the measurement head 22 attached to the spindle 111) included in the machine tool 1.

[0051] As shown in FIG. 2, the machining control device 16 includes an arithmetic unit 161, a storage unit 162, and a communication unit 163. Further, the machining control device 16 may include an input device 164 and an output device 165. However, the machining control device 16 may not include at least one of the input device 164 and the output device 165. The arithmetic unit 161, the storage unit 162, the communication unit 163, the input device 164, and the output device 165 may be connected via a data bus not shown.

[0052] The arithmetic unit 161 is hardware that includes at least one circuit (for example, at least one of an electronic circuit and an electrical circuit). For this reason, the arithmetic unit 161 may be referred to as a circuit group. Furthermore, the machining control device 16 including the arithmetic unit 161 may also be referred to as a circuit group.

[0053] The arithmetic unit 161 includes at least one processor (i.e., one or more processors) as hardware. The processor may include, for example, a processor conforming to a von Neumann computer architecture. A processor conforming to a von Neumann computer architecture may include at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processor may also include, for example, a processor conforming to a non-von Neumann computer architecture. A processor conforming to a non-von Neumann computer architecture may include at least one of an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Circuit). The processor may be implemented by a group of circuits (e.g., at least one of an electronic circuit and an electrical circuit).

[0054] The arithmetic unit 161 reads a computer program 1621 which includes at least one computer program code and a computer program instruction. For example, the arithmetic unit 161 may read a computer program 1621 stored in a storage device 162. For example, the arithmetic unit 161 may read a computer program 1621 stored in a computer-readable and non-temporary recording medium using a recording medium reader (not shown) provided in the machining control device 16. The computer program 1621 read from the recording medium may be stored in the storage device 162. The arithmetic unit 161 may obtain (i.e., download or read) a computer program 1621 from a device (not shown) located outside the machining control device 16 via a communication device 163 (or other communication device). The downloaded computer program 1621 may be stored in the storage device 162.

[0055] The arithmetic unit 161 executes the loaded computer program 1621. As a result, a logical functional block for executing the processing that the machining control device 16 should perform (for example, the processing for controlling the machine tool 1 as described above) is realized within the arithmetic unit 161. In other words, the arithmetic unit 161, together with the storage device 162 on which the computer program 1621 is recorded (in other words, together with the storage device 162 and the computer program 1621 recorded in the storage device 162), can function as a controller or computer for realizing a logical functional block for executing the processing that the machining control device 16 should perform. That is, together with at least one processor in the arithmetic unit 161, the memory (recording medium) in the storage device 162, and the computer program 1621 are configured so that the machining control device 16 performs the processing that the machining control device 16 should perform (for example, the processing for controlling the machine tool 1 as described above).

[0056] The arithmetic unit 161 may include a single processor. In this case, the arithmetic unit 161 may use a single processor to perform the processing that the machining control device 16 should perform (for example, the processing for controlling the machine tool 1 as described above). For example, if the arithmetic unit 161 performs a first operation (for example, a first process which is part of the processing for controlling the machine tool 1) and a second operation (for example, a second process which is another part of the processing for controlling the machine tool 1), the arithmetic unit 161 may use a single processor to perform both the first and second operations. Alternatively, the arithmetic unit 161 may include multiple processors. In this case, the arithmetic unit 161 may use any one of the multiple processors to perform the processing that the machining control device 16 should perform (for example, the processing for controlling the machine tool 1 as described above). For example, if the arithmetic unit 161 includes a first and a second processor and performs the first and second operations, the arithmetic unit 161 may use any one of the first and second processors to perform the first and second operations, respectively. For example, the arithmetic unit 161 may perform a first operation using the first processor, or a second operation using the first processor, or a first operation using the second processor, or a second operation using the second processor.

[0057] The computing device 161 may implement a computational model that can be constructed by machine learning by executing a computer program 1621. An example of a computational model that can be constructed by machine learning is a computational model that includes a neural network (so-called artificial intelligence (AI)). In this case, the learning of the computational model may include learning the parameters of the neural network (for example, at least one of the weights and biases). The computing device 161 may control the machine tool 1 using the computational model. That is, the operation of controlling the machine tool 1 may include the operation of controlling the machine tool 1 using the computational model. Furthermore, the computing device 161 may implement a computational model that has been constructed by offline machine learning using training data. In addition, the computational model implemented in the computing device 161 may be updated by online machine learning on the computing device 161. Alternatively, the arithmetic unit 161 may control the machine tool 1 using an arithmetic model implemented in an external device (i.e., a device provided outside the machining control device 16) in addition to or instead of the arithmetic model implemented in the arithmetic unit 161.

[0058] Furthermore, the recording medium for recording the computer program 1621 executed by the arithmetic unit 161 may include at least one of the following: optical discs such as CD-ROM, CD-R, CD-RW, flexible disk, MO, DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, and Blu-ray (registered trademark); magnetic media such as magnetic tape; magneto-optical disks; semiconductor memory such as USB memory; and any other medium capable of storing a program. The recording medium may also include equipment capable of recording the computer program 1621 (for example, general-purpose or dedicated equipment on which the computer program 1621 is implemented in a state in which it can be executed in at least one form such as software and firmware). Furthermore, each process and function included in the computer program 1621 may be implemented by logical processing blocks realized within the arithmetic unit 161 (i.e., the processor) when the arithmetic unit 161 executes the computer program 1621, or by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit)) provided by the arithmetic unit 161, or in a form in which logical processing blocks and partial hardware modules that realize some elements of the hardware are mixed.

[0059] The storage device 162 includes at least one memory capable of storing desired data. In other words, the storage device 162 includes at least one memory containing desired data. The memory may be implemented by a group of circuits (for example, at least one of an electronic circuit and an electrical circuit). For example, the storage device 162 may store a computer program 1621 executed by the arithmetic unit 161. In this case, the storage device 162 (memory) may be used as the recording medium described above for recording the computer program 1621 executed by the arithmetic unit 161. The storage device 162 may temporarily store data that the arithmetic unit 161 temporarily uses when the arithmetic unit 161 is executing the computer program 1621. The storage device 162 may store data that the processing control device 16 stores long-term. Furthermore, the storage device 162 may include at least one of the following: RAM (Random Access Memory), ROM (Read Only Memory), hard disk drive, magneto-optical disk drive, SSD (Solid State Drive), and disk array device. In other words, the storage device 162 may include a non-temporary recording medium.

[0060] The communication device 163 can communicate with devices outside the machine tool 1 via a communication network (not shown).

[0061] The input device 164 is a device capable of receiving information input to the machining control device 16 from outside the machining control device 16. For example, the input device 164 may include an operating device (e.g., at least one of a keyboard, mouse, and touch panel) that can be operated by the user of the machining control device 16. For example, the input device 164 may include a recording medium reader capable of reading information recorded as data on a recording medium that can be attached externally to the machining control device 16.

[0062] Furthermore, the processing control device 16 can receive data from external devices via the communication device 163. In this case, the communication device 163 may function as an input device capable of receiving information input to the processing control device 16 from outside the processing control device 16.

[0063] The output device 165 is a device capable of outputting information to the outside of the processing control device 16. For example, the output device 165 may output information as an image. That is, the output device 165 may include a display device (so-called display) capable of displaying images. For example, the output device 165 may output information as sound. That is, the output device 165 may include an audio device (so-called speaker) capable of outputting sound. For example, the output device 165 may output information onto paper. That is, the output device 165 may include a printing device (so-called printer) capable of printing desired information onto paper. For example, the output device 165 may output information as data to a recording medium that can be attached externally to the processing control device 16.

[0064] Furthermore, the processing control device 16 can output information as data to external devices via the communication device 163. In this case, the communication device 163 may function as an output device capable of outputting information to the outside of the processing control device 16.

[0065] Furthermore, the machining control device 16 does not necessarily have to be located inside the machine tool 1. For example, the machining control device 16 may be located outside the machine tool 1 as a server or the like. In this case, the machining control device 16 and the machine tool 1 may be connected by a wired and / or wireless network (or a data bus and / or communication line). As a wired network, a network using a serial bus interface, such as at least one of IEEE 1394, RS-232x, RS-422, RS-423, RS-485, and USB, may be used. As a wired network, a network using a parallel bus interface may be used. As a wired network, a network using an Ethernet® compliant interface, such as at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T, may be used. As a wireless network, a network using radio waves may be used. An example of a network using radio waves is a network compliant with IEEE 802.1x (for example, at least one of wireless LAN and Bluetooth®). A network using infrared light may be used as the wireless network. A network using optical communication may be used as the wireless network. In this case, the processing control device 16 and the machine tool 1 may be configured to enable the transmission and reception of various types of information via the network. The processing control device 16 may also be able to transmit information such as commands and control parameters to the machine tool 1 via the network. The machine tool 1 may be equipped with a receiving device that receives information such as commands and control parameters from the processing control device 16 via the network. The machine tool 1 may be equipped with a transmitting device (i.e., an output device that outputs information to the processing control device 16) that transmits information such as commands and control parameters to the processing control device 16 via the network. Alternatively, a first control device that performs a part of the processing performed by the processing control device 16 may be provided inside the machine tool 1, while a second control device that performs another part of the processing performed by the processing control device 16 may be provided outside the machine tool 1.

[0066] (1-1-3) Configuration of Measurement System 2 Next, the configuration of the measurement system 2 will be described with reference to Figure 5. Figure 5 is a block diagram showing the system configuration of the measurement system 2 in the first embodiment.

[0067] As shown in Figure 5, the measurement system 2 comprises a measurement device 20 and a measurement control device 23.

[0068] The measuring device 20 is capable of measuring the object MT. For example, the measuring device 20 may be capable of measuring the characteristics of the object MT. The characteristics of the object MT may include, for example, the position of the object MT, the shape of the object MT, the distance between the measuring device 20 and the object MT, the direction of the object MT as seen from the measuring device 20, the reflectance of the object MT, the transmittance of the object MT, the temperature of the object MT, the internal structure of the object MT, and the surface roughness of the object MT.

[0069] In the following explanation, we will proceed using an example in which the measuring device 20 measures at least the position of the object to be measured MT. The position of the object to be measured MT may include the position of the surface of the object to be measured MT. The position of the surface of the object to be measured MT may include at least a portion of the surface of the object to be measured MT. Furthermore, the position of the object to be measured MT is not limited to the position of the surface of the object to be measured MT, but may include a portion of the position of the object to be measured MT. For example, the position of the object to be measured MT may include the position of the center of gravity of the object to be measured MT. Furthermore, the position of the object to be measured MT may mean the position of the object to be measured MT in the machine coordinate system used as a reference in the machining system SYSa (i.e., absolute position). Alternatively, the position of the object to be measured MT may mean the position of the object to be measured MT with respect to the measuring device 20 (i.e., relative position). Alternatively, the position of the object to be measured MT may mean the position of the object to be measured MT in the measurement coordinate system used by the measuring device 20, which will be described later, as a coordinate system different from the machine coordinate system.

[0070] As will be described in detail later, in the first embodiment, in order to measure the position of the object to be measured MT, the measuring device 20 measures the distance between the measuring device 20 and the object to be measured MT (for example, the distance between the measuring head 22, which will be described later, and the object to be measured MT), and the measuring control device 23 calculates the position of the object to be measured MT based on this distance. For this reason, the operation of measuring the position of the object to be measured MT can be considered to substantially mean the operation of measuring the distance from the measuring device 20 to the object to be measured MT, which is necessary for calculating the position of the object to be measured MT. In this case, the measuring device 20 (measuring system 2) can be considered to be used to measure (in other words, calculate) the distance from the measuring device 20 to the object to be measured MT.

[0071] An example of a measuring device 20 capable of measuring the distance between the measuring device 20 and the object to be measured MT is an interferometric measuring device. In the following description, an example of an interferometric measuring device will be described in which the measuring device 20 is an interferometric measuring device (in other words, the measuring device 20 measures distance using the principle of an interferometer). However, the measuring device 20 is not limited to an interferometer. Any distance measuring device capable of measuring the distance to the object to be measured MT may be used as the measuring device 20. An example of any distance measuring device capable of measuring the distance to the object to be measured MT is at least one of a TOF (Time Of Flight) sensor, a LiDAR (Light Detection And Ranging), a laser tracker, and a stereo camera.

[0072] The position of the surface of the object to be measured (MT) changes depending on the shape of the surface of the object to be measured (MT). For this reason, the operation of measuring the position of the object to be measured (MT) may be considered equivalent to the operation of measuring the shape of the object to be measured (MT). The shape of the object to be measured (MT) may include at least one of the one-dimensional shape, two-dimensional shape, and three-dimensional shape of the object to be measured (MT).

[0073] The object to be measured MT may include, for example, the workpiece W that the machining head 11 is machining. The object to be measured MT may include, for example, any object placed on the stage 141. Any object placed on the stage 141 may include, for example, the workpiece W. The object to be measured MT may include a reference member FM used in the spatial accuracy correction operation described later. The object to be measured MT may include, for example, the stage 141.

[0074] Furthermore, the same measuring device 20 may measure each of several different types of objects to be measured MT. Alternatively, several measuring devices 20 with different configurations may each measure several different types of objects to be measured MT. For example, a first measuring device 20 having the first configuration (for example, a first measuring device 20 having a first measuring head 22) may measure a first type of object to be measured MT (for example, a workpiece W). For example, a second measuring device 20 having a second configuration different from the first configuration (for example, a second measuring device 20 having a second measuring head 22 different from the first measuring head 22) may measure a second type of object to be measured MT different from the first type (for example, a reference member FM).

[0075] The measuring device 20 may be capable of measuring the object MT non-contact. The measuring device 20 may be capable of measuring the object MT optically. The measuring device 20 may be capable of measuring the object MT electrically. The measuring device 20 may be capable of measuring the object MT magnetically. The measuring device 20 may be capable of measuring the object MT thermally. The measuring device 20 may be capable of measuring the object MT acoustically. The measuring device 20 may be capable of measuring the object MT using a probe that physically contacts the object MT.

[0076] In the following explanation, we will proceed using an example in which the measuring device 20 can optically measure the object MT. In this case, the measuring device 20 may also be called an optical measuring device. Specifically, in the following explanation, we will proceed using an example in which the measuring device 20 measures the object MT by irradiating it with measurement light ML and receiving at least a portion of the light from the object MT that has been irradiated with measurement light ML. In the following explanation, the light from the object MT that has been irradiated with measurement light ML that is incident on the measuring device 20 (i.e., received by the measuring device 20) will be called "return light RL". In this case, the measuring device 20 (measuring system 2) may be considered to be used to irradiate the object MT with measurement light ML. The measuring device 20 (measuring system 2) may also be considered to be used to receive the return light RL from the object MT.

[0077] Furthermore, the light emitted from the object to be measured MT upon irradiation with the measurement light ML may include specularly reflected light generated at the object to be measured MT upon irradiation with the measurement light ML. The light emitted from the object to be measured MT upon irradiation with the measurement light ML may, in addition to or instead of specularly reflected light, include diffusely reflected light generated at the object to be measured MT upon irradiation with the measurement light ML. The light emitted from the object to be measured MT upon irradiation with the measurement light ML may, in addition to or instead of at least one of specularly reflected light and diffusely reflected light, include diffracted light generated at the object to be measured MT upon irradiation with the measurement light ML.

[0078] In the first embodiment, the measuring device 20 may include a measuring unit 21 and a measuring head 22 in order to optically measure the object MT to be measured. The measuring unit 21 may include a measuring light source 211 and a light receiving device 212. The measuring head 22 may include an optical device 221 and a rotating device 223. The configuration and operation of the measuring device 20 (i.e., the measuring unit 21 and the measuring head 22) will be described in detail later with reference to Figure 6, etc., but an overview will be briefly explained here. The measuring light source 211 provided in the measuring unit 21 is capable of generating measuring light ML. The measuring light ML generated by the measuring light source 211 is transmitted from the measuring unit 21 to the measuring head 22 via an optical transmission member 24 (see Figure 6), which will be described later. An example of the optical transmission member 24 is an optical system including a plurality of mirrors (i.e., a plurality of reflective members). In this case, the measurement light ML generated by the measurement light source 211 may be reflected sequentially by multiple mirrors and then incident on the measurement head 22. In other words, the measurement light ML generated by the measurement light source 211 may be transmitted spatially between the measurement unit 21 and the measurement head 22. The optical system that spatially transmits the measurement light ML generated by the measurement light source 211 between the measurement unit 21 and the measurement head 22 is not limited to multiple mirrors, and optical elements other than mirrors may be used. For the sake of explanation, in the following description, an example in which the optical transmission member 24 is an optical fiber will be described. The optical device 221 provided in the measurement head 22 irradiates the object to be measured MT with the measurement light ML transmitted from the measurement unit 21 to the measurement head 22. The rotating device 223 is capable of rotating the optical element of the optical device 221 that emits the measurement light ML toward the object to be measured MT around the rotation axis. In the following description, the optical component of the optical device 221 that emits the measurement light ML toward the object to be measured MT will be referred to as the ejection optical component 2210 (see Figure 8 below). As a result, the rotation of the optical component by the rotating device 223 changes the direction of emission of the measurement light ML from the measurement head 22. In this case, the measurement head 22 may also change the direction of emission of the measurement light ML from the measurement head 22 using the rotating device 223 so that the measurement light ML is irradiated onto the object to be measured MT located at a desired position.Furthermore, the optical device 221 (especially the ejection optical member 2210) receives the reflected light RL from the object to be measured MT, which is irradiated with the measurement light ML. The reflected light RL that has entered the optical device 221 (especially the ejection optical member 2210) is transmitted from the measurement head 22 to the measurement unit 21 via the optical transmission member 24. The light receiving device 212 of the measurement unit 21 receives the reflected light RL transmitted from the measurement head 22 to the measurement unit 21. In other words, the light receiving device 212 receives the reflected light RL via the measurement head 22. Specifically, the light receiving device 212 receives the reflected light RL via the optical device 221 (especially the ejection optical member 2210) of the measurement head 22. The result of the light receiving device 212 receiving the reflected light RL (i.e., the measurement result of the object to be measured MT by the measurement device 20) is output to the measurement control device 23. The optical component (for example, the ejection optical component 2210) may include at least one optical element. In this case, the optical element may be an existing element such as a reflective optical element like a mirror, a refractive optical element like a lens, or a polarizing element like a waveplate. The optical component may also be called a light-receiving optical component or an incident optical component, since it receives the reflected light RL from the object to be measured MT onto which the measurement light ML is irradiated. The optical component may also be called an optical system.

[0079] The measurement control device 23 controls the operation of the measurement system 2. For example, the measurement control device 23 may control the measurement device 20 to measure the object to be measured MT. Furthermore, as described above, since the measurement head 22 is attached to the machine tool 1 (for example, the spindle 111), the head drive system 12 of the machine tool 1 moves the measurement head 22. For this reason, the measurement control device 23 may control the machine tool 1 (particularly the head drive system 12) in cooperation with the machining control device 16 or independently of the machining control device 16 so that the measurement device 20 moves to a desired position. In other words, the measurement control device 23 may control the movement of the machining head 11 in cooperation with the machining control device 16 or independently of the machining control device 16. Furthermore, if the object to be measured MT moves together with the stage 141, the measurement control device 23 may control the machine tool 1 (particularly the stage drive system 142) in cooperation with the machining control device 16 or independently of the machining control device 16 so that the object to be measured MT moves to a desired position. In other words, the measurement control device 23 may control the movement of the stage 141 together with the processing control device 16 or independently of the processing control device 16.

[0080] Furthermore, because the measuring head 22 is attached to the machine tool 1 (spindle 111), the measuring control device 23 does not need to control the head drive system 12. In this case, the machining control device 16 may control the head drive system 12. Also, because the measuring head 22 is attached to the machine tool 1 (for example, the spindle 111), the machining control device 16 does not need to control the head drive system 12. In this case, the measuring control device 23 may control the head drive system 12. Also, the measuring control device 23 does not need to control the stage drive system 142. In this case, the machining control device 16 may control the stage drive system 142. Also, the machining control device 16 does not need to control the stage drive system 142. In this case, the measuring control device 23 may control the stage drive system 142.

[0081] In the first embodiment, the measurement control device 23 performs a spatial accuracy correction operation. The spatial accuracy correction operation is an operation to correct (in other words, calibrate) the spatial accuracy of the machine tool 1. In particular, the spatial accuracy correction operation is an operation to correct the spatial accuracy of the machine tool 1 based on the measurement result of the object MT measured by the measurement device 20 (i.e., the result of receiving the reflected light RL by the light receiving device 212). The operation to correct the spatial accuracy may include an operation to correct the spatial accuracy so that the spatial accuracy is higher than before the spatial accuracy correction. The spatial accuracy correction operation will be described in detail later with reference to Figure 10, etc., so the explanation here is omitted.

[0082] As mentioned above, the operation to correct the spatial accuracy of the machine tool 1 is one example of an operation to adjust the machine tool 1. In this case, the spatial accuracy correction operation may be considered as one example of an operation to adjust the machine tool 1 based on the measurement result of the object MT measured by the measuring device 20 (i.e., the result of receiving the return light RL by the light receiving device 212).

[0083] As shown in Figure 5, the measurement control device 23 includes an arithmetic unit 231, a storage device 232, and a communication device 233. Furthermore, the measurement control device 23 may also include an input device 234 and an output device 235. However, the measurement control device 23 does not have to include at least one of the input device 234 and the output device 235. The arithmetic unit 231, the storage device 232, the communication device 233, the input device 234, and the output device 235 may be connected via a data bus (not shown).

[0084] The arithmetic unit 231, storage device 232, communication device 233, input device 234, and output device 235 may each have the same characteristics as the arithmetic unit 161, storage device 162, communication device 163, input device 164, and output device 165 provided in the machining control device 16 described above. For this reason, the above-described descriptions of the machining control device 16, arithmetic unit 161, storage device 162, communication device 163, input device 164, and output device 165 can be reused as descriptions of the measurement control device 23, arithmetic unit 231, storage device 232, communication device 233, input device 234, and output device 235 by replacing the terms "machining control device 16", "arithmetic unit 161", "storage device 162", "communication device 163", "input device 164", "output device 165", and "machine tool 1" with the terms "measurement control device 23", "arithmetic unit 231", "storage device 232", "communication device 233", "input device 234", "output device 235", and "measurement system 2", respectively. Therefore, in order to avoid redundant explanations, detailed descriptions of the measurement control device 23, arithmetic unit 231, storage device 232, communication device 233, input device 234, and output device 235 will be omitted.

[0085] At least a portion of the processing performed by the measurement control device 23 may be performed by the machining control device 16. For example, as will be described in detail later, the machining control device 16 may perform at least a portion of the spatial accuracy correction operation performed by the measurement control device 23. Conversely, at least a portion of the processing performed by the machining control device 16 may be performed by the measurement control device 23.

[0086] The machining system SYSa may include a control device that can function as both a measurement control device 23 and a machining control device 16, instead of a measurement control device 23 and a machining control device 16. In other words, the machining system SYSa may include a control device that integrates the measurement control device 23 and the machining control device 16. For example, the machine tool 1 may include a control device that can function as both a measurement control device 23 and a machining control device 16, instead of a machining control device 16. In this case, the measurement system 2 may or may not include a measurement control device 23. As another example, the measurement system 2 may include a control device that can function as both a measurement control device 23 and a machining control device 16, instead of a measurement control device 23. In this case, the machine tool 1 may or may not include a machining control device 16. As yet another example, the machining system SYSa may include a control device that can function as both a measurement control device 23 and a machining control device 16, separate from the machine tool 1 and the measurement system 2. In this case, the machine tool 1 may or may not be equipped with a machining control device 16, and the measurement system 2 may or may not be equipped with a measurement control device 23.

[0087] (1-1-4) Measuring device 20 (especially the measuring unit 21 and the measuring head) Next, the measuring device 20 (especially the measuring unit 21 and the measuring head) provided in the measuring system 2 will be described in more detail.

[0088] (1-1-4-1) Mounting position of the measuring device 20 (especially the measuring unit 21 and the measuring head) First, the mounting position of the measuring device 20 (especially the measuring unit 21 and the measuring head) will be described in more detail with reference to Figure 6. Figure 6 is a cross-sectional view showing the machining head 11 to which the measuring device 20 (especially the measuring unit 21 and the measuring head 22) is attached.

[0089] As shown in Figure 6, the measuring device 20 is attached to the machining head 11. The measuring unit 21 and measuring head 22 of the measuring device 20 are each attached to the machining head 11. The measuring light source 211 and light receiving device 212 of the measuring unit 21 are each attached to the machining head 11. The optical device 221 and rotating device 223 of the measuring head 22 are each attached to the machining head 11.

[0090] However, at least a portion of the measuring light source 211 provided by the measuring unit 21 does not need to be attached to the processing head 11. At least a portion of the light receiving device 212 provided by the measuring unit 21 does not need to be attached to the processing head 11. At least a portion of the measuring unit 21 does not need to be attached to the processing head 11. At least a portion of the optical device 221 provided by the measuring head 22 does not need to be attached to the processing head 11. At least a portion of the rotating device 223 provided by the measuring head 22 does not need to be attached to the processing head 11. At least a portion of the measuring head 22 does not need to be attached to the processing head 11.

[0091] In the following, for the sake of explanation, we will describe an example in which at least the optical device 221 of the measuring head 22 of the measuring device 20 is attached to the processing head 11.

[0092] As shown in Figure 6, a measuring head 22 equipped with an optical device 221 may be attached to the machining head 11. Specifically, the measuring head 22 includes at least a head housing 220 that houses the optical device 221, and the head housing 220 may be attached to the machining head 11. Here, since the machine tool 1 is equipped with a machining head 11, the measuring head 22 equipped with the optical device 221 may be considered to be located inside the machine tool 1.

[0093] In the first embodiment, the measuring head 22 is attached to the spindle 111 of the machining head 11 instead of the tool 113. Specifically, the head housing 220 is attached to a mounting device 1111 provided on the spindle 111. In the example shown in Figure 6, since the spindle 111 is provided with a mounting device 1111 having a hole 1112, the head housing 220 is attached to the spindle 111 by fitting (or inserting) the shank 229, which corresponds to the protruding portion of the head housing 220 having a shape complementary to the hole 1112, into the hole 1112 of the mounting device 1111. The mounting device 1111 may also hold the head housing 220. In this case, the mounting device 1111 may be provided with at least one of the following to hold the head housing 220: a mechanical chuck, a hydraulic check, an electrostatic chuck, and a vacuum suction chuck. It should also be noted that since the measuring head 22 is equipped with an optical device 221, the optical device 221 may be considered to be attached to the spindle 111. The optical device 221 may be considered to be detachably attached to the spindle 111 in place of the tool 113.

[0094] The head housing 220 (i.e., the measuring head 22) attached to the mounting device 1111 is removable from the mounting device 1111. In other words, the head housing 220 (i.e., the measuring head 22) is detachably attached to the spindle 111. For example, when the measuring head 22 is attached to the spindle 111, the tool 113 is removed from the spindle 111. Conversely, when the tool 113 is attached to the spindle 111, the measuring head 22 is removed from the spindle 111. As described above, the attachment and removal of the measuring head 22 and the tool 113 are performed by the tool changer 15. However, the user of the machining system SYSa may manually perform at least one of the attachment and removal of the measuring head 22 to the spindle 111 and the attachment and removal of the tool 113 to the spindle 111.

[0095] The head housing 220 may house a rotating device 223 in addition to the optical device 221. In this case, the optical device 221 and the rotating device 223 may be considered to be attached to the machining head 11 (particularly the spindle 111). Alternatively, the optical device 221 may be considered to include the rotating device 223. In other words, a device including the optical device 221 and the rotating device 223 may be referred to as an optical device. In this case, the optical device including the optical device 221 and the rotating device 223 may be considered to be attached to the machining head 11 (particularly the spindle 111). However, the head housing 220 does not necessarily have to house the rotating device 223. In this case, the optical device 221 may be attached to the machining head 11, while the rotating device 223 may not be attached to the machining head 11.

[0096] However, the measuring head 22 may be attached to a different part of the machining head 11 than the spindle 111. Alternatively, the measuring head 22 may be attached to a different component than the machining head 11. The measuring head 22 may be provided at any position within the machine tool 1. The measuring head 22 may be provided at any position such that it can irradiate the object to be measured MT with measuring light ML transmitted from the measuring unit 21 to the measuring head 22 via the optical transmission member 24, and that it can supply the return light RL from the object to be measured MT to the measuring unit 21 via the optical transmission member 24. For example, the measuring head 22 may be attached to the head housing 112 of the machining head 11. The head housing 220 may be attached to the head housing 112 of the machining head 11. The head housing 220 may be attached to the machining head 11 at a position away from the rotation axis RX of the spindle 111 along a direction intersecting the rotation axis RX.

[0097] If the measuring head 22 is attached to a part of the machining head 11 different from the spindle 111, the measuring head 22 does not need to be removable from the machining head 11. In other words, the measuring head 22 does not need to be detachably attached to the machining head 11. The measuring head 22 may remain attached to the machining head 11 even during the machining period when the machining head 11 is machining the workpiece W using the tool 113. In fact, the measuring head 22 may always remain attached to the machining head 11. However, even if the measuring head 22 is attached to a part of the machining head 11 different from the spindle 111, the measuring head 22 may be detachably attached to the machining head 11.

[0098] The measuring head 22 may be mounted in a fixed position relative to the machining head 11. That is, the measuring head 22 may be mounted on the machining head 11 in such a way that the positional relationship between the machining head 11 and the measuring head 22 is fixed (i.e., does not change). The measuring head 22 may be directly fixed to the machining head 11. The measuring head 22 may be indirectly fixed to the machining head 11. For example, the measuring head 22 may be fixed to the other end of a support member, one end of which is directly fixed to the machining head 11. Both the state in which the measuring head 22 is directly fixed to the machining head 11 and the state in which the measuring head 22 is indirectly fixed to the machining head 11 correspond to the state in which the measuring head 22 is mounted in a fixed position relative to the machining head 11. When the measuring head 22 is mounted on the machining head 11, unless the measuring device 20 is equipped with a drive system for moving the measuring head 22 independently of the machining head 11, the positional relationship between the machining head 11 and the measuring head 22 is usually fixed. Furthermore, when the measuring head 22 is attached to the spindle 111 of the machining head 11, since the spindle 111 is rotatable around the rotation axis RX, the rotation of the spindle 111 may be locked using a mechanical fixing mechanism or the like when the measuring head 22 is attached to the spindle 111.

[0099] However, the measuring head 22 does not have to be mounted in a position where its positional relationship with the machining head 11 is fixed. The positional relationship between the machining head 11 and the measuring head 22 may be variable. The measuring device 20 may be equipped with a drive system for moving the measuring head 22 independently of the machining head 11. For example, this drive system may be configured to move the machining head 11 and the measuring head 22 relative to each other along the rotation axis RX. As described above, when the measuring head 22 is mounted on the head housing 112 of the machining head 11, the measuring head 22 may interfere with the machining of the workpiece W during the machining period when the machining head 11 is machining the workpiece W with the tool 113. Specifically, for example, if the measuring head 22 comes into contact with the workpiece W (or another object) before the tool 113 comes into contact with the workpiece W, the tool 113 will not be able to come into contact with the workpiece W, and as a result, the measuring head 22 will interfere with the machining of the workpiece W. Therefore, the positional relationship between the machining head 11 and the measuring head 22 during at least a portion of the measurement period in which the measuring device 20 measures the object MT may be different from the positional relationship between the machining head 11 and the measuring head 22 during at least a portion of the machining period in which the machining head 11 processes the workpiece W. For example, during at least a portion of the machining period, the positional relationship between the machining head 11 and the measuring head 22 may be set to a first relationship in which the measuring head 22 does not interfere with the machining of the workpiece W, and during at least a portion of the measurement period, the positional relationship between the machining head 11 and the measuring head 22 may be set to a second relationship different from the first relationship (for example, a second relationship in which the measuring device 20 can measure the object MT using the measuring head 22).

[0100] When the measuring head 22 is attached to the machining head 11, the measuring head 22 moves along with the movement of the machining head 11. In other words, the measuring head 22 moves in the same way as the machining head 11. For this reason, the head drive system 12 that moves the machining head 11 can be considered to function as a head drive system for moving the measuring head 22. In this case, the movement of the measuring head 22 changes the relative positional relationship between the measurement position where the measuring head 22 performs the measurement and the object to be measured MT. In other words, the measurement position moves relative to the object to be measured MT. The machine tool 1 may measure the object to be measured MT while moving the measuring head 22 by moving the machining head 11. Specifically, the machining system SYSa may measure the desired position of the object to be measured MT while setting the measurement position to a desired position on the object to be measured MT by moving the measuring head 22. However, if the object to be measured MT is the stage 141 or an object placed on the stage 141, the relative positional relationship between the measurement position where the measurement head 22 performs the measurement and the object to be measured MT will also change due to the movement of the stage 141. For this reason, if the measurement position can be set to a desired position on the object to be measured MT by moving the stage 141, the processing system SYSa may measure the object to be measured MT without moving the measurement head 22.

[0101] As shown in Figure 6, a measurement unit 21 may be attached to the machining head 11 in addition to or instead of the measurement head 22. Specifically, the measurement unit 21 may include a head housing 210, and the head housing 210 may be attached to the machining head 11. The measurement unit 21 may include a measurement light source 211 and a light receiving device 212 within the head housing 210. In other words, the measurement light source 211 and the light receiving device 212 may be housed within the head housing 210. In this case, the measurement light source 211 and the light receiving device 212 may be considered to be attached to the machining head 11. Here, since the machine tool 1 is equipped with a machining head 11, the measurement unit 21 may be considered to be located within the machine tool 1.

[0102] In the first embodiment, the measurement unit 21 may be attached to the head housing 112 of the machining head 11. That is, the head housing 210 of the measurement unit 21 may be attached to the head housing 112. The head housing 210 may be attached to the machining head 11 at a position away from the rotation axis RX of the spindle 111 along a direction intersecting the rotation axis RX. In the example shown in Figure 6, the measurement unit 21 (head housing 210) is attached to the side of the head housing 112. Since the measurement unit 21 is equipped with a measurement light source 211 and a light receiving device 212, the measurement light source 211 and the light receiving device 212 may be considered to be attached to the head housing 112.

[0103] When the measuring unit 21 is attached to the machining head 11, the measuring unit 21 moves along with the movement of the machining head 11. In other words, the measuring unit 21 moves in the same way as the machining head 11. For this reason, the head drive system 12 that moves the machining head 11 can be considered to function as a head drive system for moving the measuring unit 21.

[0104] However, the measurement unit 21 may be attached to a part of the machining head 11 different from the head housing 112. For example, the measurement unit 21 may be attached inside the machining head 11. For example, the measurement unit 21 may be housed inside the head housing 112 of the machining head 11. Alternatively, the measurement unit 21 may be attached to a component different from the machining head 11. The measurement unit 21 may be provided at any position within the machine tool 1. The measurement unit 21 may be provided at any position in which it can supply measurement light ML to the measurement head 22 via the optical transmission member 24, and can receive the return light RL transmitted from the measurement head 22 via the optical transmission member 24.

[0105] The measuring light source 211 of the measuring unit 21 may be attached to the spindle 111 of the machining head 11 in the same way as the optical device 221 described above. Specifically, the measuring light source 211 may be housed in the head housing 220 of the measuring head 22, and the head housing 220 housing the measuring light source 211 may be attached to the spindle 111. In this case, the measuring head 22 may be considered to be equipped with the measuring light source 211. Furthermore, the optical device 221 may be considered to include the measuring light source 211. In other words, a device including the optical device 221 and the measuring light source 211 may be referred to as an optical device. In this case, the optical device including the optical device 221 and the measuring light source 211 may be considered to be attached to the spindle 111 of the machining head 11.

[0106] A portion of the measuring light source 211 provided by the measuring unit 21 may be attached to the spindle 111 of the machining head 11, similar to the optical device 221 described above. Another portion of the measuring light source 211 provided by the measuring unit 21 may be attached to the head housing 112 of the machining head 11. Specifically, a portion of the measuring light source 211 may be housed in the head housing 220 of the measuring head 22, and the head housing 220 containing the portion of the measuring light source 211 may be attached to the spindle 111. In this case, the measuring head 22 may be considered to have a portion of the measuring light source 211, and the measuring unit 21 may be considered to have another portion of the measuring light source 211. Furthermore, the optical device 221 may be considered to include a portion of the measuring light source 211. In other words, a device including the optical device 221 and a portion of the measuring light source 211 may be referred to as an optical device. In this case, the optical device including the optical device 221 and a portion of the measuring light source 211 may be considered to be attached to the spindle 111 of the machining head 11.

[0107] In addition to or in place of at least a portion of the measurement light source 211 provided by the measurement unit 21, a light receiving device 212 provided by the measurement unit 21 may be attached to the spindle 111 of the machining head 11 in the same manner as the optical device 221 described above. Specifically, the light receiving device 212 may be housed in the head housing 220 of the measurement head 22, and the head housing 220 housing the light receiving device 212 may be attached to the spindle 111. In this case, the measurement head 22 may be considered to be equipped with the light receiving device 212. Furthermore, the optical device 221 may be considered to include the light receiving device 212. In other words, a device including the optical device 221 and the light receiving device 212 may be referred to as an optical device. In this case, the optical device including the optical device 221 and the light receiving device 212 may be considered to be attached to the spindle 111 of the machining head 11.

[0108] In addition to or instead of at least a portion of the measurement light source 211 provided by the measurement unit 21, a portion of the light receiving device 212 provided by the measurement unit 21 (for example, the interference optical system 213 in Figure 7, described later) may be attached to the spindle 111 of the machining head 11 in the same manner as the optical device 221 described above. Another portion of the light receiving device 212 provided by the measurement unit 21 (for example, the photodetector 214 in Figure 7, described later) may be attached to the head housing 112 of the machining head 11. Specifically, a portion of the light receiving device 212 may be housed in the head housing 220 of the measurement head 22, and the head housing 220 housing the portion of the light receiving device 212 may be attached to the spindle 111. In this case, the measurement head 22 may be considered to include a portion of the light receiving device 212, and the measurement unit 21 may be considered to include another portion of the light receiving device 212. Furthermore, the optical device 221 may be considered to include a portion of the light receiving device 212. In other words, a device including the optical device 221 and a portion of the light receiving device 212 may be referred to as an optical device. In this case, the optical device, including the optical device 221 and a part of the light receiving device 212, may be considered to be attached to the spindle of the spindle 111 of the machining head 11.

[0109] Alternatively, at least a portion of the measurement unit 21 may be provided at any location outside the machine tool 1. For example, at least a portion of the measurement light source 211 provided in the measurement unit 21 may be provided at any location outside the machine tool 1. At least a portion of the light receiving device 212 provided in the measurement unit 21 may be provided at any location outside the machine tool 1.

[0110] (1-1-4-2) Configuration of the Measurement Unit 21 Next, the configuration of the measurement unit 21 provided in the measurement device 20 will be described. In particular, the configuration of the measurement unit 21, which includes a measurement light source 211 and a light receiving device 212, will be described below with reference to Figure 7. Figure 7 is a cross-sectional view showing the configuration of the measurement light source 211 and the light receiving device 212.

[0111] The configuration of the measurement unit 21 shown in Figure 7 is merely an example, and the configuration of the measurement unit 21 is not limited to that shown in Figure 7. The measurement unit 21 may have any configuration as long as it transmits measurement light ML toward the measurement head 22, receives the return light RL transmitted from the measurement head 22, and can measure the position of the object to be measured MT from the result of receiving the return light RL.

[0112] As shown in Figure 7, the measurement light source 211 generates measurement light ML. The measurement light source 211 may include a laser capable of generating laser light as measurement light ML. The measurement light source 211 may include an optical comb light source capable of generating optical comb light as measurement light ML. The measurement light ML generated by the measurement light source 211 is emitted from the measurement light source 211 toward the light receiving device 212. In other words, the measurement light ML generated by the measurement light source 211 is incident on the light receiving device 212 from the measurement light source 211.

[0113] The measurement light ML incident on the light receiving device 212 is emitted from the light receiving device 212 toward the optical transmission member 24. In other words, the measurement light ML incident on the light receiving device 212 is incident on the optical transmission member 24 from the light receiving device 212. For this reason, in the first embodiment, the measurement light ML generated by the measurement light source 211 is transmitted from the measurement unit 21 toward the measurement head 22 via the light receiving device 212. However, the measurement light ML generated by the measurement light source 211 may be transmitted from the measurement unit 21 toward the measurement head 22 without passing through the light receiving device 212.

[0114] The light receiving device 212 includes an interference optical system 213 and a photodetector 214. The measurement light ML that enters the light receiving device 212 from the measurement light source 211 enters the interference optical system 213.

[0115] The interference optical system 213 is an optical system that splits the measurement light ML generated by the measurement light source 211 into a first measurement light ML transmitted from the measurement unit 21 to the measurement head 22 and a second measurement light ML used as a reference light. In the following description, the measurement light ML generated by the measurement light source 211, the first measurement light ML transmitted from the measurement unit 21 to the measurement head 22, and the second measurement light ML used as a reference light will be referred to as light source light SL, measurement light ML, and reference light RB, respectively, to distinguish these three types of measurement light ML from one another. The interference optical system 213 is further an optical system that interferes the return light RL from the object to be measured MT with the reference light RB.

[0116] Figure 7 shows an example of the configuration of an interference optical system 213 that splits the light source SL into a measurement light ML and a reference light RB, and interferes the return light RL with the reference light RB. However, the configuration of the interference optical system 213 is not limited to the configuration shown in Figure 7. The interference optical system 213 may have any configuration as long as it can split the light source SL into a measurement light ML and a reference light RB, and interfere the return light RL with the reference light RB.

[0117] As shown in Figure 7, the interference optical system 213 may include a polarizing beam splitter 2131, a mirror 2132, and a quarter-wave plate 2133. In the first embodiment, the mirror may be referred to as a reflective member or reflective element. The light source SL incident on the light receiving device 212 from the measurement light source 211 is incident on the polarizing beam splitter 2131. The polarizing beam splitter 2131 splits the light source SL incident on the polarizing beam splitter 2131 into measurement light ML and reference light RB. Specifically, the p-polarized light of the light source SL incident on the polarizing beam splitter 2131 is transmitted through the polarization separation surface of the polarizing beam splitter 2131 as measurement light ML. On the other hand, the s-polarized light of the light source SL incident on the polarizing beam splitter 2131 is reflected by the polarization separation surface of the polarizing beam splitter 2131 as reference light RB. Furthermore, the polarizing beam splitter is a polarization-separating type beam splitter. In addition to or instead of the polarizing beam splitter, other polarization-separating optical elements may be used.

[0118] The reference light RB reflected by the polarizing beam splitter 2131 is incident on the mirror 2132 via the quarter-wave plate 2133. The mirror 2132 reflects the reference light RB incident on it toward the polarizing beam splitter 2131. In particular, the mirror 2132 may retroreflect the reference light RB incident on it toward the polarizing beam splitter 2131. In this case, a retroreflective mirror may be used as the mirror 2132. Note that a retroreflective mirror may also be called a retroreflective member. The reference light RB reflected by the mirror 2132 is incident on the polarizing beam splitter 2131 via the quarter-wave plate 2133. Here, the reference light RB incident on the polarizing beam splitter 2131 via the quarter-wave plate 2133 is p-polarized due to reflection by the mirror 2132 and two transmissions by the quarter-wave plate 2133. Therefore, the reference light RB incident on the polarizing beam splitter 2131 via the quarter-wave plate 2133 passes through the polarization separation surface of the polarizing beam splitter 2131. The reference light RB that has passed through the polarizing beam splitter 2131 is incident on the photodetector 214.

[0119] On the other hand, the measurement light ML that has passed through the polarizing beam splitter 2131 is incident on the optical transmission member 24. In other words, the measurement light ML that has passed through the quarter-wave plate 2133 is transmitted from the measurement unit 21 to the measurement head 22 via the optical transmission member 24.

[0120] When the measurement light ML emitted from the measurement head 22 irradiates the object to be measured MT, as described above, the reflected light RL from the object to be measured MT is transmitted from the measurement head 22 to the measurement unit 21 via the optical transmission member 24. The reflected light RL transmitted from the measurement head 22 to the measurement unit 21 via the optical transmission member 24 is incident on the interference optical system 213. Specifically, the reflected light RL transmitted from the measurement head 22 to the measurement unit 21 via the optical transmission member 24 is incident on the polarizing beam splitter 2131. Here, as will be described in detail later, the reflected light RL is incident on the measurement unit 21 as s-polarized light. For this reason, the reflected light RL incident on the polarizing beam splitter 2131 is reflected by the polarization separation surface of the polarizing beam splitter 2131. The reflected light RL reflected by the polarization separation surface of the polarizing beam splitter 2131 is incident on the photodetector 214.

[0121] In this manner, the polarizing beam splitter 2131 emits a reference light RB and a return light RL toward the photodetector 214. As a result, the reference light RB emitted from the polarizing beam splitter 2131 and the return light RL emitted from the polarizing beam splitter 2131 interfere with each other. The photodetector 214 receives (in other words, detects) the interference light generated by the interference of the reference light RB and the return light RL. The result of the photodetector 214 receiving the interference light is output from the photodetector 214 to the measurement control device 23 as the result of the photodetector 212 receiving the return light RL (i.e., the measurement result of the measurement target object MT by the measurement device 20). In other words, in the first embodiment, the result of the photodetector 212 receiving the return light RL (i.e., the measurement result of the measurement target object MT by the measurement device 20) may include the result of the photodetector 214 receiving the interference light.

[0122] Furthermore, the device including the interference optical system 213 and the photodetector 214 may be referred to as an interference device. In this case, in the example shown in Figure 7, the measurement unit 21 includes a light receiving device 212 that includes the interference device. However, the measurement unit 21 may also include a light receiving device 212 that includes a part of the interference device but does not include other parts of the interference device. For example, the measurement unit 21 may include a light receiving device 212 that includes the photodetector 214 as part of the interference device but does not include the interference optical system 213, which is another part of the interference device. In this case, the interference optical system 213, which is another part of the interference device, may be provided by the measurement head 22. As another example, the measurement unit 21 may include a light receiving device 212 that includes the photodetector 214 and a part of the interference optical system 213 as part of the interference device but does not include other parts of the interference optical system 213, which is another part of the interference device. In this case, other parts of the interference optical system 213, which is another part of the interference device, may be provided by the measurement head 22.

[0123] (1-1-4-3) Configuration of the Optical Device 221 of the Measuring Head 22 Next, the configuration of the measuring head 22 of the measuring device 20 (in particular, the configuration of the optical device 221) will be described. First, the configuration of the optical device 221 of the measuring head 22 will be described with reference to Figure 8. Figure 8 is a cross-sectional view showing the configuration of the optical device 221.

[0124] The configuration of the optical device 221 shown in Figure 8 is merely an example, and the configuration of the optical device 221 is not limited to that shown in Figure 8. The optical device 221 may have any configuration as long as it can irradiate the object to be measured MT with measurement light ML and emit the return light RL from the object to be measured MT toward the measurement unit 21.

[0125] As shown in Figure 8, the optical device 221 may include an ejection optical member 2210 and a spherical member 222. The measurement light ML transmitted from the measurement unit 21 to the measurement head 22 via the optical transmission member 24 is incident on the ejection optical member 2210. The ejection optical member 2210 irradiates the object to be measured MT with the measurement light ML via the spherical member 222. Furthermore, the ejection optical member 2210 transmits the return light RL from the object to be measured MT from the measurement unit 21 to the measurement head 22 (particularly toward the light receiving device 212) via the optical transmission member 24.

[0126] The ejection optical member 2210 comprises a half-wave plate 2211, a polarizing beam splitter 2212, a quarter-wave plate 2213, a refractive optical system 2214, a quarter-wave plate 2215, a quarter-wave plate 2216, and a mirror 2217. For the purposes of the following explanation, the optical member (optical system) obtained by removing the refractive optical system 2214 from the ejection optical member 2210 will be referred to as the ejection optical member 2218. This is because, as will be explained in detail later, the ejection optical member 2218 is also an optical member that ejects the measurement light ML from the optical device 221 toward the object to be measured MT. The ejection optical member 2218 may also be referred to as the polarizing optical member.

[0127] The measurement light ML that enters the optical device 221 via the optical transmission member 24 (i.e., the ejection optical member 2210) enters the polarization beam splitter 2212 via the half-wave plate 2211. Here, as described above, the measurement light ML that enters the ejection optical member 2210 via the optical transmission member 24 is p-polarized. In this case, the measurement light ML that passes through the half-wave plate 2211 becomes s-polarized. Therefore, the polarization beam splitter 2212 is incident on the measurement light ML which is s-polarized.

[0128] The measurement light ML incident on the polarizing beam splitter 2212 is reflected by the polarization separation surface of the polarizing beam splitter 2212. The measurement light ML reflected by the polarizing beam splitter 2212 is incident on the spherical member 222 via the quarter-wave plate 2213 and the refractive optical system 2214. In other words, the polarizing beam splitter 2212 reflects the measurement light ML incident on the polarizing beam splitter 2212 via the half-wave plate 2211 toward the spherical member 222 so that the measurement light ML incident on the polarizing beam splitter 2212 via the half-wave plate 2211 is incident on the spherical member 222 via the quarter-wave plate 2213 and the refractive optical system 2214. To put it another way, the ejection optical member 2210 ejects the measurement light ML incident on the ejection optical member 2210 toward the spherical member 222.

[0129] The refractive optical system 2214 is positioned in the optical path of the measurement light ML between the ejection optical member 2218 and the spherical member 222. The refractive optical system 2214 is positioned in the optical path of the measurement light ML that enters the spherical member 222 from the ejection optical member 2218 through the refractive optical system 2214. The refractive optical system 2214 is an optical system that includes at least one lens. The refractive optical system 2214 may be aligned with respect to the spherical member 222 such that the focal point (in other words, the point of convergence) of the refractive optical system 2214 is located on the outer surface (in other words, the surface) of the spherical member 222. The refractive optical system 2214 may also be referred to as the refractive optical member.

[0130] The measurement light ML transmitted through the refractive optical system 2214 is incident on the spherical member 222. The spherical member 222 is at least partially a spherical optical element. In other words, the spherical member 222 is an optical member that includes a spherical optical element. The measurement light ML incident on the spherical member 222 via the refractive optical system 2214 is reflected by the spherical member 222. Specifically, the measurement light ML incident on the outer surface of the spherical member 222 via the refractive optical system 2214 is reflected by the outer surface of the spherical member 222. For this reason, at least a portion of the outer surface of the spherical member 222 may function as a reflective surface capable of reflecting the measurement light ML. The spherical member 222 reflects the measurement light ML incident on the outer surface of the spherical member 222 via the refractive optical system 2214 back towards the refractive optical system 2214. For example, the spherical member 222 may be a metal sphere that reflects the measurement light ML incident on the outer surface (surface) of the spherical member 222. In this case, the spherical member may be a metal sphere made of iron or steel. Furthermore, the spherical member 222 may be a member with a light-reflective film formed on its outer surface (surface). The light-reflective film may be a metal film such as aluminum. Furthermore, a portion of the outer surface (surface) of the spherical member 222 may be aspherical.

[0131] The measurement light ML reflected by the outer surface of the spherical member 222 is incident on the polarizing beam splitter 2212 via the refractive optical system 2214 and the quarter-wave plate 2213. In other words, the spherical member 222 reflects the measurement light ML incident on the spherical member 222 from the polarizing beam splitter 2212 via the quarter-wave plate 2213 and the refractive optical system 2214 toward the polarizing beam splitter 2212, so that the measurement light ML incident on the spherical member 222 from the polarizing beam splitter 2212 via the quarter-wave plate 2213 and the refractive optical system 2214 is incident on the polarizing beam splitter 2212 via the quarter-wave plate 2213 and the refractive optical system 2214.

[0132] Here, the measurement light ML incident on the polarizing beam splitter 2212 via the refractive optical system 2214 and the quarter-wave plate 2213 is p-polarized due to reflection by the spherical member 222 and two transmissions by the quarter-wave plate 2213. Therefore, the measurement light ML incident on the polarizing beam splitter 2212 via the refractive optical system 2214 and the quarter-wave plate 2213 passes through the polarization separation surface of the polarizing beam splitter 2212. The measurement light ML that has passed through the polarizing beam splitter 2212 is irradiated onto the object to be measured MT via the quarter-wave plate 2215. In other words, the ejection optical member 2210 ejects the measurement light ML from the spherical member 222 toward the object to be measured MT.

[0133] When the measurement light ML emitted from the ejection optical member 2210 is irradiated onto the object to be measured MT, as described above, the return light RL from the object to be measured MT is incident on the optical device 221 (particularly the ejection optical member 2210). Specifically, the return light RL from the object to be measured MT is incident on the polarizing beam splitter 2212 via the quarter-wave plate 2215. Here, the measurement light ML incident on the polarizing beam splitter 2212 via the quarter-wave plate 2215 is s-polarized due to reflection from the object to be measured MT and two transmissions through the quarter-wave plate 2215. Therefore, the measurement light ML incident on the polarizing beam splitter 2212 via the quarter-wave plate 2215 is reflected by the polarization separation surface of the polarizing beam splitter 2212. The measurement light ML reflected by the polarizing beam splitter 2212 is incident on the mirror 2217 via the quarter-wave plate 2216. In other words, the polarizing beam splitter 2212 reflects the reflected light RL that entered the polarizing beam splitter 2212 via the quarter-wave plate 2215 toward the mirror 2217, so that the reflected light RL that entered the polarizing beam splitter 2212 via the quarter-wave plate 2215 enters the mirror 2217 via the quarter-wave plate 2216.

[0134] Mirror 2217 reflects the reflected light RL incident on Mirror 2217. In particular, Mirror 2217 may retroreflect the reflected light RL incident on Mirror 2217. In this case, a retroreflective mirror may be used as Mirror 2217. The reflected light RL reflected by Mirror 2217 is incident on the polarizing beam splitter 2212 via the quarter-wave plate 2216. In other words, Mirror 2217 reflects the reflected light RL incident on Mirror 2217 from the polarizing beam splitter 2212 via the quarter-wave plate 2216 toward the polarizing beam splitter 2212, so that the reflected light incident on Mirror 2217 from the polarizing beam splitter 2212 via the quarter-wave plate 2216 is incident on the polarizing beam splitter 2212 via the quarter-wave plate 2216.

[0135] Here, the reflected light RL incident on the polarizing beam splitter 2212 via the quarter-wave plate 2216 is p-polarized due to reflection by the mirror 2217 and two transmissions through the quarter-wave plate 2216. Therefore, the reflected light RL incident on the polarizing beam splitter 2212 via the quarter-wave plate 2216 passes through the polarization separation surface of the polarizing beam splitter 2212. The reflected light RL that has passed through the polarizing beam splitter 2212 is incident on the optical transmission member 24 via the half-wave plate 2211. In other words, the reflected light RL that has passed through the polarizing beam splitter 2212 is converted to s-polarized by the half-wave plate 2211, and then transmitted via the optical transmission member 24 from the measurement head 22 to the measurement unit 21 (particularly towards the light receiving device 212). In other words, the reflected light RL that enters the polarizing beam splitter 2212 from the mirror 2217 via the quarter-wave plate 2216 passes through the polarizing beam splitter 2212 and enters the measurement unit 21 (particularly the light receiving device 212) via the half-wave plate 2211.

[0136] As a result, the light receiving device 212 receives the reflected light RL. That is, the light receiving device 212 receives the reflected light RL via the ejection optical member 2210. Note that the state in which "the light receiving device 212 receives the reflected light RL via the ejection optical member 2210" may also include the state in which "the light receiving device 212 receives the reflected light RL via all the optical elements included in the ejection optical member 2210 (in the example above, the half-wave plate 2211, the polarizing beam splitter 2212, the quarter-wave plate 2213, the refractive optical system 2214, the quarter-wave plate 2215, the quarter-wave plate 2216, and the mirror 2217)." The state in which "the light receiving device 212 receives the reflected light RL via the ejection optical member 2210" may also include the state in which "the light receiving device 212 receives the reflected light RL via some of the optical elements included in the ejection optical member 2210 (in the above example, some of the half-wave plate 2211, the polarizing beam splitter 2212, the quarter-wave plate 2213, the refractive optical system 2214, the quarter-wave plate 2215, the quarter-wave plate 2216, and the mirror 2217)." The state in which "the light receiving device 212 receives the reflected light RL via the ejection optical member 2210" may also include the state in which "the light receiving device 212 receives the reflected light RL via the optical element of the ejection optical member 2210 that is closest to the object to be measured MT (in the above example, the quarter-wave plate 2215)." The state in which "the light receiving device 212 receives the reflected light RL via the ejecting optical member 2210" may also include the state in which "the light receiving device 212 receives the reflected light RL via the optical element used to irradiate the object MT of the ejecting optical member 2210 with the measurement light ML."

[0137] (1-1-4-4) Configuration of the Rotating Device 223 of the Measuring Head 22 Next, the configuration of the rotating device 223 of the measuring head 22 will be described with reference to Figure 9. Figure 9 is a cross-sectional view showing the configuration of the rotating device 223.

[0138] Furthermore, the configuration of the rotating device 223 shown in Figure 9 is merely an example, and the configuration of the rotating device 223 is not limited to that shown in Figure 9. The rotating device 223 may have any configuration as long as the ejection optical member 2210 can be rotated around the rotation axis. In other words, the rotating device 223 may have any configuration as long as the ejection optical member 2218 and the refractive optical system 2214 can be rotated around the rotation axis.

[0139] As shown in Figure 9, the rotating device 223 may include a first support member 2231, a second support member 2232, a motor 2233, and a motor 2234.

[0140] The first support member 2231 supports the injection optical member 2210. In this case, the injection optical member 2210 may be attached to the first support member 2231.

[0141] The second support member 2232 supports the first support member 2231 so that the first support member 2231 can rotate around the first rotation axis RX1. For this reason, the second support member 2232 may support the first support member 2231 via bearing members such as bearings. The first support member 2231, supported by the second support member 2232, rotates around the first rotation axis RX1 using the power generated by the motor 2233 under the control of the measurement control device 23. As a result, the ejection optical member 2210 supported by the first support member 2231 also rotates around the first rotation axis RX1. In other words, the measurement control device 23 controls the rotation device 223 to rotate the ejection optical member 2210 around the first rotation axis RX1. In the example shown in Figure 9, the motor 2233 is provided on the first support member 2231, but it may also be provided on the second support member 2232 that supports the first support member 2231.

[0142] As a result, as shown in Figure 10, the rotation of the injection optical member 2210 around the first rotation axis RX1 by the rotating device 223 changes the emission direction (i.e., direction of travel) of the measurement light ML from the injection optical member 2210. Figure 10 shows the injection optical member 2210 before rotation around the first rotation axis RX1 (upper part of Figure 10) and the injection optical member 2210 after rotation around the first rotation axis RX1 (lower part of Figure 10), under the condition that the rotation axis (Y) is used as the first rotation axis RX1. In the example shown in Figure 10, the rotating device 223 rotates the injection optical member 2210 to change its state from one in which the injection optical member 2210 is irradiating the first object to be measured MT#1 with measurement light ML (upper part of Figure 10) to one in which the injection optical member 2210 is irradiating a second object to be measured MT#2, which is different from the first object to be measured MT#1, with measurement light ML (lower part of Figure 10).

[0143] The second support member 2232 is supported by the third support member 2201. However, the second support member 2232 may be supported by a support member different from the third support member 2201. The third support member 2201 may be a component that constitutes part of the head housing 220 of the measuring head 22. The third support member 2201 may be a component that connects to the head housing 220 of the measuring head 22. The third support member 2201 may be a component that constitutes part of the shank 229 (see Figure 6) of the head housing 220 that is attached to the spindle 111. The third support member 2201 may be a component that connects to the shank 229. In this case, the third support member 2201 may be attached directly or indirectly to the spindle 111. The third support member 2201 may be detachable from the spindle 111. Furthermore, since the third support member 2201 is detachable from the main shaft 111, the third support member 2201 may also be referred to as a detachable member.

[0144] The third support member 2201 supports the second support member 2232 so that it can rotate around a second rotation axis RX2 that intersects the first rotation axis RX1. For this reason, the third support member 2201 may support the second support member 2232 via bearing members such as bearings. The second support member 2232 supported by the third support member 2201 rotates around the second rotation axis RX2 using power generated by the motor 2234 under the control of the measurement control device 23. As a result, the ejection optical member 2210, which is indirectly supported by the second support member 2232 via the first support member 2231, also rotates around the second rotation axis RX2. In other words, the measurement control device 23 controls the rotation device 223 to rotate the ejection optical member 2210 around the second rotation axis RX2. As a result, although not shown in the diagram, the rotation of the injection optical member 2210 around the second rotation axis RX2 by the rotating device 223 changes the direction of emission of the measurement light ML from the injection optical member 2210.

[0145] In the example shown in Figure 9, the rotation axis (Y) is used as the first rotation axis RX1, and the rotation axis (Z) is used as the second rotation axis RX2. In other words, the rotation axis intersecting the rotation axis RX of the main spindle 111 is used as the first rotation axis RX1, and the rotation axis along the rotation axis RX of the main spindle 111 is used as the second rotation axis RX2. However, when the second support member 2232 rotates around the second rotation axis RX2, the first support member 2231 supported by the second support member 2232 also rotates around the second rotation axis RX2. Therefore, the rotation axis RX1 of the first support member 2231 also rotates around the second rotation axis RX2. In this case, it may be considered that the rotation axis RX1 of the first support member 2231 is a rotation axis along the XY plane.

[0146] Furthermore, if the second rotation axis RX2 is a rotation axis aligned with the rotation axis RX of the main spindle 111, the second rotation axis RX2 and the rotation axis RX of the main spindle 111 may or may not be coaxial.

[0147] When the rotation axis (Z) is used as the rotation axis RX2 of the second support member 2232, the rotation axis RX2 of the second support member 2232 becomes a rotation axis aligned with the rotation axis RX of the main shaft 111. In this case, the second support member 2232 may rotate around the rotation axis RX in conjunction with the rotation of the main shaft 111, in addition to or instead of rotating around the rotation axis RX2 using the power of the motor 2234. In this case, the rotating device 223 does not need to be equipped with the motor 2234. The third support member 2201 may fix the second support member 2232 without supporting it via a bearing member or the like so that the second support member 2232 can rotate around the second rotation axis RX2. In other words, the second support member 2232 may be fixed to the third support member 2201. In this case, as the spindle 111 rotates around the rotation axis RX, the third support member 2201, which is directly or indirectly connected to the spindle 111, rotates around the rotation axis RX, and as a result, the second support member 2232, which is fixed to the third support member 2201, may also rotate around the rotation axis RX.

[0148] When the rotation axis (Z) is used as the rotation axis RX2 of the second support member 2232, the rotation axis RX2 of the second support member 2232 may coincide with the rotation axis RX of the main spindle 111 along the Z axis. In other words, the rotation axis RX2 of the second support member 2232 may be coaxial with the rotation axis RX of the main spindle 111. Alternatively, the rotation axis RX2 of the second support member 2232 does not have to coincide with the rotation axis RX of the main spindle 111. In other words, the rotation axis RX2 of the second support member 2232 may be separated from the rotation axis RX of the main spindle 111 in a direction intersecting the rotation axis RX2 of the second support member 2232 (for example, a direction along the XY plane) (in other words, it may be offset).

[0149] Furthermore, the measurement system 2 may obtain a first measurement result by measuring the spatial accuracy of the machine tool 1 when the rotation axis RX2 of the second support member 2232 does not coincide with the rotation axis RX of the main spindle 111. In this case, the spatial accuracy of the machine tool 1 may be corrected based on the first measurement result. Alternatively, the measurement system 2 may obtain a second measurement result by measuring the spatial accuracy of the machine tool 1 when the rotation axis RX2 of the second support member 2232 coincides with the rotation axis RX of the main spindle 111. In this case, the spatial accuracy of the machine tool 1 may be corrected based on the second measurement result. If the measurement system 2 obtains both the first and second measurement results, the spatial accuracy of the machine tool 1 may be corrected based on the first and second measurement results.

[0150] The first axis of rotation RX1 is an axis of rotation that passes through (in other words, through, the same applies hereafter) the spherical member 222 at its center 222C. That is, the first axis of rotation RX1 is an axis of rotation that passes through the center 222C of the spherical member 222. In this case, the ejection optical member 2210 rotates around the first axis of rotation RX1 with the center 222C of the spherical member 222 as the center of rotation. However, the first axis of rotation RX1 may be an axis of rotation that passes through the spherical member 222 at a position away from the center 222C of the spherical member 222. The first axis of rotation RX1 may be an axis of rotation that does not pass through the spherical member 222. The first axis of rotation RX1 may be an axis of rotation that passes through a position away from the spherical member 222.

[0151] The second rotation axis RX2 is a rotation axis that passes through the spherical member 222 at its center 222C. In other words, the second rotation axis RX2 is a rotation axis that passes through the center 222C of the spherical member 222. In this case, the ejection optical member 2210 rotates around the second rotation axis RX2 with the center 222C of the spherical member 222 as the center of rotation. However, the second rotation axis RX2 may be a rotation axis that passes through the spherical member 222 at a position away from the center 222C of the spherical member 222. The second rotation axis RX2 may be a rotation axis that does not pass through the spherical member 222. The second rotation axis RX1 may be a rotation axis that passes through a position away from the spherical member 222.

[0152] The center 222C of the spherical member 222 may be used as the origin for distance measurement by the measurement system 2. The origin for distance measurement by the measurement system 2 (i.e., the center 222C of the spherical member 222) may be called the pivot point. However, a position other than the center 222C of the spherical member 222 may be set as the pivot point. For example, a point on the outer surface of the spherical member 222 may be set as the pivot point. For example, a point inside the spherical member 222 may be set as the pivot point. For example, a point located away from the spherical member 222 may be set as the pivot point. In the first embodiment, for the sake of explanation, an example in which the center 222C of the spherical member 222 is used as the pivot point will be described.

[0153] When the pivot point is defined in this way, the "distance between the measuring device 20 (measuring head 22) and the object to be measured MT" measured by the measuring system 2 may mean the distance between the pivot point and the object to be measured MT. For example, when the center 222C of the spherical member 222 is used as the pivot point as described above, the distance between the measuring device 20 (measuring head 22) and the object to be measured MT may mean the distance between the center 222C of the spherical member 222 and the object to be measured MT. Alternatively, the "distance between the measuring device 20 (measuring head 22) and the object to be measured MT" measured by the measuring system 2 may mean the distance between a position determined with respect to the pivot point (for example, a position fixed with respect to the pivot point) and the object to be measured MT. For example, when the center 222C of the spherical member 222 is used as the pivot point as described above, the distance between the measuring device 20 (measuring head 22) and the object to be measured MT may mean the distance between the spherical member 222 and the object to be measured MT. The distance between the measuring device 20 (measuring head 22) and the object to be measured MT may mean the distance between the outer surface of the spherical member 222 and the object to be measured MT.

[0154] When the pivot point is defined in this way, the components of the measuring device 20 may be aligned so that the rotation center of the injection optical member 2210 coincides with the pivot point. However, the components of the measuring device 20 do not have to be aligned so that the rotation center of the injection optical member 2210 coincides with the pivot point. The components of the measuring device 20 may be aligned so that the rotation center of the injection optical member 2210 does not coincide with the pivot point.

[0155] The third support member 2201 further supports the spherical member 222. However, as described above, the measurement light ML emitted from the ejection optical member 2210 is incident on the spherical member 222, and the spherical member 222 reflects the measurement light ML toward the ejection optical member 2210. For this reason, if the third support member 2201 supporting the spherical member 222 is located in the optical path of the measurement light ML, the measurement light ML will be blocked by the third support member 2201, and the measurement system 2 may not be able to measure the object MT using the measurement light ML. For this reason, the third support member 2201 may support the spherical member 222 at a position that does not overlap with the optical path of the measurement light ML incident on the spherical member 222 and the optical path of the measurement light ML reflected by the spherical member 222. The third support member 2201 may be positioned in a location that does not overlap with the optical path of the measurement light ML incident on the spherical member 222 and the optical path of the measurement light ML reflected by the spherical member 222.

[0156] The first support member 2231, the second support member 2232, and the third support member 2201 may have any shape as long as they satisfy the above-mentioned conditions. In the example shown in Figure 9, the third support member 2201 is a rod-shaped member having a longitudinal shape extending along the Z-axis. In this case, the third support member 2201 may be called a core. Furthermore, a spherical member 222 is attached to the -Z side end of the third support member 2201. On the other hand, the +Z side end of the third support member 2201 may be directly or indirectly connected to the head housing 220 or the shank 229. The second support member 2232 comprises a cylindrical member 2235 surrounding the third support member 2201, and a pair of support members 2236 that protrude -Z from a flange member constituting the -Z side end of the cylindrical member and are arranged to sandwich the first support member 2231 along a direction intersecting the Z-axis. The first support member 2231 is arranged to sandwich the spherical member 222 along a direction intersecting the Z axis and includes a pair of support members 2237 that are each supported by a pair of support members 2236 provided by the second support member 2232 so as to be rotatable around the first rotation axis RX1, and a support member 2238 that connects the pair of support members 2237 along a direction intersecting the Z axis and has an ejection optical member 2210 attached to its -Z side surface.

[0157] In the above description, the third support member 2201 supports the second support member 2232. However, the third support member 2201 may support the first support member 2231 in addition to or instead of supporting the second support member 2232. In addition to or instead of supporting the second support member 2232 so that the second support member 2232 can rotate around the second rotation axis RX2, the third support member 2201 may support the first support member 2231 so that the first support member 2231 can rotate around the first rotation axis RX1. In either case, the third support member 2201 may be considered to function as a support member for the rotating device 223 including the first support member 2231 and the second support member 2232.

[0158] Furthermore, in the above description, the first support member 2231 is rotatable around the first rotation axis RX1, and the second support member 2232 is rotatable around the second rotation axis RX2. However, the first support member 2231 may be rotatable around the second rotation axis RX2, or the second support member 2232 may be rotatable around the first rotation axis RX1. In other words, the first support member 2231 may be rotatable around either the first rotation axis RX1 or the second rotation axis RX2, or the second support member 2232 may be rotatable around the other of the first rotation axis RX1 or the second rotation axis RX2.

[0159] Furthermore, in the above description, the first support member 2231 supports the injection optical member 2210, the second support member 2232 supports the first support member 2231 so that the first support member 2231 can rotate around the first rotation axis RX1, and the third support member 2201 supports the second support member 2232 so that the second support member 2232 can rotate around the second rotation axis RX2. However, the second support member 2232 may support the injection optical member 2210, the first support member 2231 may support the second support member 2232 so that the second support member 2232 can rotate around either the first rotation axis RX1 or the second rotation axis RX2, and the third support member 2201 may support the first support member 2231 so that the first support member 2231 can rotate around either the first rotation axis RX1 or the second rotation axis RX2.

[0160] Furthermore, in the above description, one rotating device 223 comprises a first support member 2231 and a motor 2233 used to rotate the injection optical member 2210 around a first rotation axis RX1, and a second support member 2232 and a motor 2234 used to rotate the injection optical member 2210 around a second rotation axis RX2. However, the measuring device 20 may separately comprise a first rotating device including a first support member 2231 and a motor 2233 used to rotate the injection optical member 2210 around the first rotation axis RX1, and a second rotating device comprising a second support member 2232 and a motor 2234 used to rotate the injection optical member 2210 around a second rotation axis RX2. In this case, the measurement control device 23 may control the first rotating device to rotate the injection optical member 2210 around the first rotation axis RX1, or it may control the second rotating device to rotate the injection optical member 2210 around the second rotation axis RX2.

[0161] Furthermore, in the above description, the rotating device 223 rotates the injection optical member 2210 around the first rotation axis RX1 using motor 2233, and also rotates the injection optical member 2210 around the second rotation axis RX2 using motor 2234. However, the rotating device 223 may also use the same single motor (for example, either motor 2233 or 2234, or another motor) to rotate the injection optical member 2210 around the first rotation axis RX1 and also rotate the injection optical member 2210 around the second rotation axis RX2.

[0162] Furthermore, the above description describes an example in which the measuring head 22 is equipped with a rotating device 223 (for example, the rotating device 223 is housed in the head housing 220). However, the measuring head 22 does not have to be equipped with a rotating device 223. For example, the rotating device 223 does not have to be housed in the head housing 220. The rotating device 223 may be located outside the measuring head 22. In this case, the rotating device 223 outside the measuring head 22 may generate power to rotate the injection optical member 2210, and transmit the generated power from outside the measuring head 22 to the injection optical member 2210 inside the measuring head 22, thereby rotating the injection optical member 2210.

[0163] Furthermore, in the above description, the rotating device 223 is capable of rotatable the injection optical member 2210 around the first rotation axis RX1 and the second rotation axis RX2, respectively. In other words, the rotating device 223 is capable of rotatable the injection optical member 2210 around each of two different rotation axes. However, the rotating device 223 may be capable of rotatable the injection optical member 2210 around either the first rotation axis RX1 or the second rotation axis RX2, but not around the other of the first rotation axis RX1 or the second rotation axis RX2. In other words, the rotating device 223 may be capable of rotatable the injection optical member 2210 around a single rotation axis. Alternatively, the rotating device 223 may be capable of rotatable the injection optical member 2210 around the first rotation axis RX1, the second rotation axis RX2, and a third rotation axis intersecting the first rotation axis RX1 and the second rotation axis RX2. In other words, the rotating device 223 may be capable of rotating the ejection optical member 2210 around each of three different rotation axes.

[0164] (1-2) Spatial accuracy correction operation Next, the spatial accuracy correction operation performed by the measurement control device 23 will be explained.

[0165] (1-2-1) Overview of Spatial Accuracy Correction Operation As described above, the spatial accuracy correction operation is an operation to correct the spatial accuracy of the machine tool 1 based on the measurement results from the measuring device 20. The spatial accuracy may include movement errors (in other words, motion errors) that occur in the movement of at least one of the machining head 11 and the stage 141. That is, the spatial accuracy may include at least one of the movement errors that occur in the movement of the machining head 11 and the movement errors that occur in the movement of the stage 141. In this case, the spatial accuracy correction operation may include an operation to correct the movement error that occurs in the movement of at least one of the machining head 11 and the stage 141. The operation to correct the movement error may include an operation to correct the movement error so that the movement error is smaller compared to before the correction.

[0166] The movement error of the machining head 11 may include an error corresponding to the difference (i.e., deviation) between the actual position of the machining head 11 and the target position of the machining head 11 when the head drive system 12 moves the machining head 11 based on a drive control signal for controlling the head drive system 12 to move the machining head 11 (spindle 111) to a desired target position. In the following description, the drive control signal for controlling the head drive system 12 will be referred to as the head drive control signal. If the machining head 11 is capable of translational movement along the translation axis, the movement error of the machining head 11 may include an error corresponding to the difference (i.e., deviation) between the actual position of the machining head 11 and the target position of the machining head 11 when the head drive system 12 translates the machining head 11 along the translation axis based on a head drive control signal for controlling the head drive system 12 to move the machining head 11 to a desired target position. In other words, the movement error of the machining head 11 may include the movement error that occurs in the translational movement of the machining head 11. If the machining head 11 is rotatable around the rotation axis, the error may include the difference (i.e., deviation) between the actual position of the machining head 11 and the target position of the machining head 11 when the head drive system 12 rotates the machining head 11 around the rotation axis based on a head drive control signal for controlling the head drive system 12 to move the machining head 11 to a desired target position. In other words, the movement error of the machining head 11 may include the movement error that occurs in the rotational movement of the machining head 11.

[0167] The movement error of stage 141 may include an error corresponding to the difference (i.e., deviation) between the actual position of stage 141 and the target position of stage 141 when stage drive system 142 moves stage 141 based on a drive control signal for controlling stage drive system 142 to move stage 141 to a desired target position. In the following description, the drive control signal for controlling stage drive system 142 will be referred to as the stage drive control signal. If stage 141 is movable along the translation axis, the movement error of stage 141 may include an error corresponding to the difference (i.e., deviation) between the actual position of stage 141 and the target position of stage 141 when stage drive system 142 translates stage 141 along the translation axis based on a stage drive control signal for controlling stage drive system 142 to move stage 141 to a desired target position. In other words, the movement error of stage 141 may include the movement error that occurs in the translational movement of stage 141. If the stage 141 is rotatable around the axis of rotation, the movement error of the stage 141 may include an error corresponding to the difference (i.e., deviation) between the actual position of the stage 141 and the target position of the stage 141 when the stage drive system 142 rotates the stage 141 around the axis of rotation based on a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to a desired target position. In other words, the movement error of the stage 141 may include the movement error that occurs in the rotational movement of the stage 141.

[0168] Here, if a movement error occurs in the machining head 11 and this error is not corrected, even if the head drive system 12 moves the machining head 11 based on a head drive control signal used to control the head drive system 12 to move the machining head 11 to a desired target position, the machining head 11 may move to a position different from the desired target position due to the movement error. As a result, the machine tool 1 may not be able to move the machining head 11 accurately. Consequently, the machine tool 1 may not be able to machine the workpiece W placed on the stage 141 accurately. Furthermore, if a measuring head 22 is attached to the machining head 11 to measure the workpiece W, the measuring head 22 attached to the machining head 11 may not move accurately, so the measuring system 2 may not be able to properly measure the workpiece W (or any object MT to be measured) placed on the stage 141.

[0169] Similarly, if a movement error occurs in the stage 141 and this error is not corrected, even if the stage drive system 142 moves the stage 141 based on a stage drive control signal to move the stage 141 to a desired target position, the stage 141 may move to a position different from the desired target position due to the movement error. As a result, the machine tool 1 may not be able to move the stage 141 accurately. Consequently, the machine tool 1 may not be able to machine the workpiece W placed on the stage 141 accurately. Furthermore, if a measuring head 22 is attached to the machining head 11 to measure the workpiece W, the measuring system 2 may not be able to properly measure the workpiece W (or any object MT) placed on the stage 141.

[0170] Therefore, in the first embodiment, the machining system SYSa may move at least one of the machining head 11 and the stage 141 in such a way as to correct spatial accuracy by performing a spatial accuracy correction operation (for example, reducing or canceling out movement errors). In other words, the machining system SYSa may control the movement of the machining head 11 so that even if a movement error occurs in the machining head 11, the machining head 11 moves in the same way as if there were no movement error. The machining system SYSa may also control the movement of the stage 141 so that even if a movement error occurs in the stage 141, the stage 141 moves in the same way as if there were no movement error. As a result, when the head drive system 12 moves the machining head 11 based on a head drive control signal for controlling the head drive system 12 to move the machining head 11 to a desired position, the head drive system 12 can accurately move the machining head 11 to the desired position. For this reason, the machine tool 1 can move the machining head 11 with greater precision compared to when no spatial accuracy correction operation is performed. As a result, compared to when the spatial accuracy correction operation is not performed, the machine tool 1 can process the workpiece W with greater precision. Furthermore, when the measuring head 22 is attached to the machining head 11, the measuring system 2 can appropriately measure the workpiece W (or any object MT to be measured) placed on the stage 141 compared to when the spatial accuracy correction operation is not performed. Similarly, when the stage drive system 142 moves the stage 141 based on a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to a desired position, the stage drive system 142 can accurately move the stage 141 to the desired position. Therefore, compared to when the spatial accuracy correction operation is not performed, the machine tool 1 can move the stage 141 with greater precision. As a result, compared to when the spatial accuracy correction operation is not performed, the machine tool 1 can process the workpiece W with greater precision.Furthermore, when the measuring head 22 is attached to the machining head 11, the measuring system 2 can appropriately measure the workpiece W (or any object MT to be measured) placed on the stage 141, compared to when the spatial accuracy correction operation is not performed.

[0171] Furthermore, even if the machine tool 1 does not have a head drive system 12 (i.e., the machining head 11 does not move), as long as the machine tool 1 has a stage drive system 142 (i.e., the stage 141 moves), the measurement and control device 23 may calculate the movement error that occurs in the movement of the stage 141 by performing a spatial accuracy correction operation. Similarly, even if the machine tool 1 does not have a stage drive system 142 (i.e., the stage 141 does not move), as long as the machine tool 1 has a head drive system 12 (i.e., the machining head 11 moves), the measurement and control device 23 may calculate the movement error that occurs in the movement of the machining head 11 by performing a spatial accuracy correction operation.

[0172] The machining system SYSa may perform a spatial accuracy correction operation before the machine tool 1 begins machining the workpiece W. In this case, after the machine tool 1 has started machining the workpiece W, it can move at least one of the machining head 11 and the stage 141 with the spatial accuracy corrected by the spatial accuracy correction operation performed before the machine tool 1 began machining the workpiece W. As a result, the machine tool 1 can move the machining head 11 with high accuracy. In other words, the machine tool 1 can machine the workpiece W with high accuracy.

[0173] However, the machining system SYSa may perform spatial accuracy correction operations for at least a portion of the time while the machine tool 1 is machining the workpiece W. In other words, the machining system SYSa may perform spatial accuracy correction operations after the machine tool 1 has started machining the workpiece W. To put it another way, the machining system SYSa may perform spatial accuracy correction operations for at least a portion of the time between the time the machine tool 1 starts machining the workpiece W and the time the machine tool 1 finishes machining the workpiece W. Furthermore, the machining system SYSa may perform spatial accuracy correction operations after the machine tool 1 has finished machining the workpiece W.

[0174] Furthermore, the machine tool 1 may perform a first machining process and a second machining process different from the first machining process on the workpiece W. For example, the machine tool 1 may perform a first machining process (rough machining) with lower machining accuracy than the second machining process and a second machining process (fine machining) with higher machining accuracy than the first machining process on the workpiece W. As another example, the machine tool 1 may perform a first machining process and a second machining process equivalent to a finishing process on the workpiece W. In this case, the machining system SYSa may perform a spatial accuracy correction operation between the time the machine tool 1 finishes the first machining process and the time it starts the second machining process.

[0175] Furthermore, the machine tool 1 may process the workpiece W by alternately repeating the process of processing the workpiece W using the tool 113 and measuring the shape of the workpiece W using a shape measuring device (for example, a three-dimensional measuring device such as a 3D scanner, or a measuring device including a touch probe) so that the processed shape of the workpiece W becomes a desired shape. In this case, the period from when the machine tool 1 starts processing the workpiece W until when the machine tool 1 finishes processing the workpiece W may include the period during which the machine tool 1 alternately repeats the processing of the workpiece W and the measurement of the shape of the workpiece W. In this case, the processing system SYSa may perform a spatial accuracy correction operation for at least a portion of the period during which the machine tool 1 alternately repeats the processing of the workpiece W and the measurement of the shape of the workpiece W. As an example, the processing system SYSa may perform a spatial accuracy correction operation from when the machine tool 1 finishes processing the workpiece W until it starts measuring the shape of the workpiece W.

[0176] In the first embodiment, in order to correct the spatial accuracy, as shown in Figure 10, the measuring device 20 irradiates the reference member FM with measuring light ML and receives the reflected light RL from the reference member FM. Subsequently, the measurement control device 23 calculates the distance between the measuring device 20 and the reference member FM (for example, the distance between the pivot point and the reference member FM as described above) based on the measurement result from the measuring device 20 (i.e., the result of receiving the reflected light RL). Subsequently, the measurement control device 23 calculates the spatial accuracy based on the distance between the measuring device 20 and the reference member FM. The measurement control device 23 corrects the spatial accuracy based on the calculated spatial accuracy. A specific example of the operation of calculating the spatial accuracy based on the distance between the measuring head 22 and the reference member FM and correcting the spatial accuracy based on the calculated spatial accuracy will be described in detail later.

[0177] An example of the arrangement of the reference member FM is shown in Figures 11A and 11B. As shown in Figures 11A and 11B, in the first embodiment, at least one reference member FM is placed on the stage 141 and at least one of the workpiece W placed on the stage 141 (in other words, provided). Figures 11A to 11B show an example in which at least one reference member FM is placed on the stage 141 and at least one reference member FM is placed on the workpiece W placed on the stage 141. However, a reference member FM may be placed on the workpiece W while a reference member FM is not placed on the stage 141. A reference member FM may be placed on the stage 141 while a reference member FM is not placed on the workpiece W. At least one reference member FM may be placed on the datum of the workpiece W. The datum of the workpiece W is a reference part of the workpiece W. The datum of the workpiece W can also be said to be a reference part for machining the workpiece W. Furthermore, the datum of workpiece W can be said to be the reference point for measuring workpiece W.

[0178] Furthermore, if at least one reference member FM is placed on the datum of the workpiece W, the measurement control device 23 may, in addition to or instead of correcting spatial accuracy, calculate the position of the datum of the workpiece W (for example, the position of the part of the datum of the workpiece W where the reference member FM is placed) based on the calculation result of the distance between the measurement device 20 and the at least one reference member FM placed on the datum of the workpiece W (for example, the distance between the pivot point described above and the at least one reference member FM placed on the datum of the workpiece W). Moreover, if a plurality of (for example, at least three) reference members FM are placed on the datum of the workpiece W, as will be described later, the measurement control device 23 may, in addition to or instead of correcting spatial accuracy, calculate the positions of multiple parts of the datum of the workpiece W (for example, multiple parts where multiple reference members FM are each placed) based on the calculation result of the distance between the measurement device 20 and the plurality of reference members FM placed on the datum of the workpiece W (for example, the distance between the pivot point described above and the plurality of reference members FM placed on the datum of the workpiece W). Subsequently, the measurement and control device 23 may calculate the orientation of the workpiece W based on the calculation results of the positions of multiple parts of the workpiece W's datum.

[0179] In the first embodiment, a plurality of reference members FM may be arranged on at least one of the workpiece W and the stage 141. In the example shown in Figures 11A and 11B, at least four reference members FM are arranged on the workpiece W, and at least four reference members FM are arranged on the stage 141. However, three or fewer or five or more reference members FM may be arranged on the workpiece W. Three or fewer or five or more reference members FM may be arranged on the stage 141. However, a single reference member FM may be arranged on at least one of the workpiece W and the stage 141.

[0180] Multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that at least N (where N is a constant representing an integer of 1 or more) reference members FM are included within the measurement range of the measuring head 22, which is located at any position in the machine coordinate system. Multiple reference members FM may be arranged on the workpiece W and stage 141 such that at least N reference members FM are included within the measurement range of the measuring head 22, which moves within the machine coordinate system. The measurement range of the measuring head 22 may mean the range in which the measurement light ML can be irradiated by rotating the injection optical member 2210 using the rotating device 223 without moving the measuring head 22 (i.e., without moving the processing head 11 to which the measuring head 22 is attached). Also, "N" is a variable that indicates the minimum number of reference members FM included in the measurement range of the measuring head 22, and is typically a variable representing an integer of 1 or more. Also, N may be a variable representing an integer of 4 or more.

[0181] For example, multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that at least N first reference members FM are included within the measurement range of a measuring head 22 located at a first position in the machine coordinate system. Furthermore, multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that at least N second reference members FM are included within the measurement range of a measuring head 22 located at a second position different from the first position in the machine coordinate system. Note that at least N second reference members FM may be different from at least N first reference members FM. Alternatively, some of the at least N second reference members FM may be the same as some of the at least N first reference members FM. Alternatively, all of the at least N second reference members FM may be the same as all of the at least N first reference members FM.

[0182] As another example, the multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that, when the stage 141 is located at a third position in the machine coordinate system, at least N third reference members FM are included within the measurement range of the measurement head 22. Furthermore, the multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that, when the stage 141 is located at a fourth position different from the third position in the machine coordinate system, at least N fourth reference members FM are included within the measurement range of the measurement head 22. Note that the at least N fourth reference members FM may be different from the at least N third reference members FM. Alternatively, some of the at least N fourth reference members FM may be the same as some of the at least N third reference members FM. Alternatively, all of the at least N fourth reference members FM may be the same as all of the at least N third reference members FM.

[0183] One example of the variable N is 4. In this case, the multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that at least four reference members FM are included within the measurement range of the measuring head 22 located at a desired position in the machine coordinate system. The multiple reference members FM may be arranged on at least one of the workpiece W and stage 141 such that at least four reference members FM are included within the measurement range of the measuring head 22 moving within the machine coordinate system.

[0184] One reason why 4 is given as an example of variable N is that, as will be described later, the spatial accuracy correction operation uses the principle of multi-sided surveying. In this case, multiple lines are prepared connecting the measurement point MP, which coincides with the pivot point that serves as the origin of distance measurement, or which has a predetermined positional relationship with the pivot point, to the reference member FM. Based on the length of these lines (i.e., the distance between the measurement point MP and the reference member FM), the position of the measurement point MP is calculated, and the spatial accuracy is calculated based on the position of the measurement point MP. In the first embodiment, since not only the position of the measurement point MP but also the position of the reference member FM are unknown parameters, at least four reference members FM are required in order to set up the minimization problem described later. However, depending on the method of setting up the minimization problem, there may be three or fewer reference members FM.

[0185] In this case, when a reference member FM is placed on both the stage 141 and the workpiece W, the probability of at least N reference members FM being included within the measurement range of the measurement head 22 is higher compared to when the reference member FM is placed only on the stage 141 or only on the workpiece W.

[0186] The reference member FM may be directly positioned on the stage 141 or the workpiece W. Alternatively, the reference member FM may be positioned on the stage 141 or the workpiece W via a support member capable of supporting the reference member FM. In other words, the reference member FM may be indirectly positioned on the stage or the workpiece W via a support member. Specifically, the support member that supports the reference member FM may be directly positioned on the stage 141 or the workpiece W. An example of a support member capable of supporting the reference member FM is a jig. In the example shown in Figure 11B, each reference member FM is positioned on the stage 141 or the workpiece W via a rod-shaped support member. Note that the member including the reference member FM and the support member that supports the reference member FM may be referred to as the reference member FM. Note that the reference member FM may or may not be removable from the stage 141 or the workpiece W.

[0187] Multiple reference members FM may include at least two reference members FM each positioned at at least two different locations along the X-axis of the machine coordinate system. In other words, multiple reference members FM may include at least two reference members FM whose positions along the X-axis of the machine coordinate system are different from each other. To put it another way, multiple reference members FM may include at least two reference members FM that are spaced apart from each other along the X-axis of the machine coordinate system. For example, at least two reference members FM that are spaced apart from each other along the X-axis of the machine coordinate system may be positioned on the workpiece W. For example, at least two reference members FM that are spaced apart from each other along the X-axis of the machine coordinate system may be positioned on the stage 141. For example, at least one reference member FM positioned on the workpiece W and at least one reference member FM positioned on the stage 141 may be spaced apart from each other along the X-axis of the machine coordinate system.

[0188] Multiple reference members FM may include at least two reference members FM each positioned at at least two different locations along the Y-axis of the machine coordinate system. In other words, multiple reference members FM may include at least two reference members FM whose positions along the Y-axis of the machine coordinate system are different from each other. To put it another way, multiple reference members FM may include at least two reference members FM that are spaced apart from each other along the Y-axis of the machine coordinate system. For example, at least two reference members FM that are spaced apart from each other along the Y-axis of the machine coordinate system may be positioned on the workpiece W. For example, at least two reference members FM that are spaced apart from each other along the Y-axis of the machine coordinate system may be positioned on the stage 141. For example, at least one reference member FM positioned on the workpiece W and at least one reference member FM positioned on the stage 141 may be spaced apart from each other along the Y-axis of the machine coordinate system.

[0189] Multiple reference members FM may include at least two reference members FM each positioned at at least two different locations along the Z-axis of the machine coordinate system. In other words, multiple reference members FM may include at least two reference members FM whose positions along the Z-axis of the machine coordinate system are different from each other. To put it another way, multiple reference members FM may include at least two reference members FM that are spaced apart from each other along the Z-axis of the machine coordinate system. Because the Z-axis is vertical, multiple reference members FM may include at least two reference members FM with different heights. For example, at least two reference members FM with different heights may be placed on the workpiece W. For example, at least two reference members FM with different heights may be placed on the stage 141. For example, the height of at least one reference member FM placed on the workpiece W may be different from the height of at least one reference member FM placed on the stage 141.

[0190] The reference member FM may be a member having known properties. For example, the reference member FM may be a member having a known shape. For example, the reference member FM may be a member having known dimensions. For example, the reference member FM may be a member having a known reflectance (reflectance distribution). For example, the reference member FM may be a member having a known transmittance (transmittance distribution). For example, the reference member FM may be a reflective member capable of reflecting the incident measurement light ML. For example, the reference member FM may be a retroreflective member capable of retroreflecting the incident measurement light ML. The retroreflective member may be a corner cube. The retroreflective member may be an optical member (for example, it may be called a cat's eye or a spherical lens type retroreflective body) in which a reflective portion (for example, a highly reflective film such as aluminum) that reflects the incident measurement light ML is formed on at least a part of the outer surface (surface) of a member (for example, a ball lens) that is at least partly spherical and transmittance. The reference member FM may be an SMR (Spherically Mounted Retroreflectors) as an example of a retroreflective member. The reference member FM may also be called a reflector, a reflective member, or a retroreflective member. Furthermore, the reference member FM may also be called a target. For example, the reference member FM may be a marker. For example, the reference member FM may be an AR tag or a barcode.

[0191] The reference member FM may be a member having at least one feature point within the measurement range of the measurement head 22. Here, the state of having at least one feature point within the measurement range may mean that there is at least one feature point within the region of the surface of the reference member FM corresponding to the measurement range. The feature point may be a part of the reference member FM that satisfies the condition that the feature point is distinguishable from other parts of the reference member FM. For example, the feature point may be a part of the reference member FM that satisfies the condition that the characteristics of the feature point are distinguishable from the characteristics of other parts of the reference member FM. A vertex or corner of a region of the reference member FM that is distinguishable from other regions may be used as the feature point. A boundary of a region of the reference member FM that is distinguishable from other regions may be used as the feature point. When a reference member FM having at least one feature point within the measurement range of the measurement head 22 is used in this way, there is an advantage in that measurement errors can be reduced.

[0192] (1-2-2) Specific Flow of Spatial Accuracy Correction Operation Next, we will explain the specific flow of the spatial accuracy correction operation. As mentioned above, spatial accuracy includes at least one of the following: movement error caused by the translational movement of the machining head 11, movement error caused by the rotational movement of the machining head 11, and movement error caused by the translational movement of the stage 141 and movement error caused by the rotational movement of the stage 141. For the sake of explanation, below we will explain in order the first spatial accuracy correction operation for calculating the movement error caused by the translational movement of at least one of the machining head 11 and the stage 141, and the second spatial accuracy correction operation for calculating the movement error caused by the rotational movement of at least one of the machining head 11 and the stage 141.

[0193] (1-2-2-1) Specific flow of the first spatial accuracy correction operation for calculating the movement error that occurs in the translational movement of at least one of the machining head 11 and the stage 141 First, the first spatial accuracy correction operation for calculating the movement error that occurs in the translational movement of at least one of the machining head 11 and the stage 141 will be explained.

[0194] When calculating the movement error that occurs in the translational movement of the processing head 11, the measuring device 20 may rotate the injection optical member 2210 using the rotating device 223 to change the injection direction of the measurement light ML each time the processing head 11 translates and stops, thereby irradiating each of the at least N reference members FM included in the measurement range of the measuring head 22 with the measurement light ML. As a result, the measuring device 20 receives the return light RL from each of the at least N reference members FM each time the processing head 11 translates and stops. However, the measuring device 20 may sequentially rotate the injection optical member 2210 using the rotating device 223 while the processing head 11 is translating (specifically, while the processing head 11 is not stopped) to change the injection direction of the measurement light ML, thereby irradiating each of the at least N reference members FM included in the measurement range of the measuring head 22 with the measurement light ML. As a result, the measuring device 20 receives the reflected light RL from each of at least N reference members FM while the machining head 11 is moving in translation. The measuring control device 23 may calculate the movement error that occurs in the translational movement of the machining head 11 based on the results of receiving the reflected light RL from each of the at least N reference members FM, as an example of the spatial accuracy of the machine tool 1.

[0195] When calculating the movement error that occurs during the translational movement of the stage 141, the measuring device 20 may rotate the ejection optical member 2210 using the rotating device 223 to change the ejection direction of the measurement light ML each time the stage 141 translates and stops, thereby irradiating each of the at least N reference members FM included in the measurement range of the measuring head 22 with the measurement light ML. As a result, the measuring device 20 receives the return light RL from each of the at least N reference members FM each time the stage 141 translates and stops. However, the measuring device 20 may sequentially rotate the ejection optical member 2210 using the rotating device 223 while the stage 141 is translating (specifically, while the stage 141 is not stopped) to change the ejection direction of the measurement light ML, thereby irradiating each of the at least N reference members FM included in the measurement range of the measuring head 22 with the measurement light ML. In other words, the measuring device 20 may perform at least a portion of the movement of the processing head 11 or the stage 141 and at least a portion of the rotation of the injection optical member 2210 in parallel. As a result, the measuring device 20 receives the reflected light RL from each of at least N reference members FM while the stage 141 is moving in translation. The measuring control device 23 may calculate the movement error that occurs in the translational movement of the stage 141 based on the results of receiving the reflected light RL from each of the at least N reference members FM as an example of the spatial accuracy of the machine tool 1.

[0196] Furthermore, when calculating the movement error that occurs during translational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during translational movement), a workpiece W may be placed on the stage 141. For example, when calculating the movement error that occurs during translational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during translational movement), a workpiece W on which the reference member FM is placed may be placed on the stage 141. For example, when calculating the movement error that occurs during translational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during translational movement), a workpiece W without a reference member FM may be placed on the stage 141. When a workpiece W is placed on the stage 141, the measurement and control device 23 can calculate a movement error that includes an error component caused by the weight of the workpiece W. This is because, when a workpiece W is placed on the stage 141, compared to when the workpiece W is not placed on the stage 141, there is a possibility that a movement error will occur in the translational movement of the stage 141 on which the workpiece W is placed due to the weight of the workpiece W. However, when calculating the movement error that occurs in translational movement, it is not necessary for a workpiece W to be placed on the stage 141.

[0197] The following describes the flow of the first movement error correction operation for calculating the movement error that occurs in the translational movement of at least one of the machining head 11 and the stage 141, with reference to Figure 12. Figure 12 is a flowchart showing the flow of the first movement error correction operation for calculating the movement error that occurs in the translational movement of at least one of the machining head 11 and the stage 141.

[0198] As shown in Figure 12, first, the measurement control device 23 moves at least one of the machining head 11 and the stage 141 to the initial position within the machine coordinate system and then stops it at the initial position (step S101).

[0199] For example, the measurement control device 23 may move the machining head 11 to an initial head position, which is an example of an initial position. In this case, the machining control device 16, which controls the head drive system 12 under the control of the measurement control device 23, generates a head drive control signal to control the head drive system 12 to move the machining head 11 to the initial head position based on the initial head position in the machine coordinate system. Subsequently, under the control of the measurement control device 23, the machining control device 16 controls the head drive system 12 based on the generated drive control signal. As a result, the head drive system 12 moves the machining head 11 to the initial head position. As a result, the machining head 11 moves to the initial head position and then stops at the initial head position. However, at this point, the movement error of the machining head 11 has not been corrected, so the machining head 11 is not necessarily actually located at the initial head position (i.e., stopped). In other words, the actual position of the machining head 11 in the machine coordinate system does not necessarily coincide with the initial head position in the machine coordinate system.

[0200] The initial head position may be at the end of the range of movement in which the machining head 11 can move along the translation axis within the machine coordinate system. For example, the machining head 11 is movable along both the translation axis (X) and the translation axis (Z). In this case, the initial head position may be at the +X or - end of the range of movement in which the machining head 11 can move along the translation axis (X) within the machine coordinate system. The initial head position may be at the +Z or -Z end of the range of movement in which the machining head 11 can move along the translation axis (Z) within the machine coordinate system. Alternatively, the current position of the machining head 11 may be used as the initial head position. In this case, the measurement control device 23 does not necessarily have to move the machining head 11 in step S101. However, the initial head position is not limited to the positions exemplified herein.

[0201] The measurement control device 23 may move the stage 141 to an initial stage position, which is an example of an initial position. In this case, the machining control device 16, which controls the stage drive system 142 under the control of the measurement control device 23, generates a stage drive control signal to control the stage drive system 142 to move the stage 141 to the initial stage position based on the initial stage position in the machine coordinate system. Subsequently, under the control of the measurement control device 23, the machining control device 16 controls the stage drive system 142 based on the generated drive control signal. As a result, the stage drive system 142 moves the stage 141 to the initial stage position. Consequently, the stage 141 moves to the initial stage position and then stops at the initial stage position. However, at this point, the movement error of the stage 141 has not been corrected, so the stage 141 is not necessarily actually located at the initial stage position (i.e., stopped). In other words, the actual position of the stage 141 in the machine coordinate system does not necessarily coincide with the initial stage position in the machine coordinate system.

[0202] The initial stage position may be at the end of the range of movement in which the stage 141 can move along the translation axis within the machine coordinate system. For example, the stage 141 is movable along the translation axis (Y). In this case, the initial stage position may be at the +Y or -Y end of the range of movement in which the stage 141 can move along the translation axis (Y) within the machine coordinate system. Alternatively, the current position of the stage 141 may be used as the initial stage position. In this case, the measurement control device 23 does not necessarily have to move the stage 141 in step S101. However, the initial stage position is not limited to the positions exemplified herein.

[0203] Furthermore, if the measuring head 22 has been removed from the machining head 11, the measuring head 22 may be attached to the spindle 111 of the machining head 11 before or after at least one of the machining head 11 and the stage 141 moves in step S101. Similarly, if the measuring unit 21 has been removed from the machining head 11, the measuring unit 21 may be attached to the machining head 11 before or after at least one of the machining head 11 and the stage 141 moves in step S101.

[0204] Subsequently, the measurement control device 23 controls the measurement device 20 to irradiate at least four reference members FM with measurement light ML (step S102). Specifically, the measurement control device 23 changes the direction of emission of measurement light ML by controlling the rotating device 223 to rotate the emission optical member 2210 so that measurement light ML is emitted toward one reference member FM. As a result, the measurement device 20 irradiates one reference member FM with measurement light ML and receives the reflected light RL from the reference member FM. The measurement control device 23 repeats this operation for the number of reference members FM included in the measurement range of the measurement device 20. If the measurement range of the measurement device 20 includes at least five or more reference members FM, the measurement light ML may be irradiated toward each of four of those reference members FM and the reflected light RL from each reference member FM may be received.

[0205] For example, the measurement control device 23 may control the rotating device 223 so that the rotation angle of the injection optical member 2210 around the rotation axis RX1 is angle #111 and / or the rotation angle of the injection optical member 2210 around the rotation axis RX2 is angle #112. Angles #111 and #112 may be angles that satisfy the condition that "the measurement light ML ejected from the injection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #111 and / or whose rotation angle around the rotation axis RX2 is angle #112, can irradiate the reference member FM#11." Subsequently, the measurement control device 23 may control the measurement device 20 so that the measurement light ML is irradiated from the injection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #111 and / or whose rotation angle around the rotation axis RX2 is angle #112, toward the reference member FM#11. As a result, the light receiving device 212 may receive the reflected light RL from the reference member FM#11 via the output optical member 2210. Subsequently, the measurement control device 23 may acquire the light receiving result of the reflected light RL from the reference member FM#11 by the light receiving device 212.

[0206] Subsequently, the measurement control device 23 may control the rotation device 223 so that the rotation angle of the injection optical member 2210 around the rotation axis RX1 changes from angle #111 to angle #121 and / or the rotation angle of the injection optical member 2210 around the rotation axis RX2 changes from angle #112 to angle #122.Angles #121 and #122 may be angles that satisfy the condition that "the measurement light ML ejected from the injection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #121 and / or whose rotation angle around the rotation axis RX2 is angle #122, can irradiate a reference member FM#12 that is different from the reference member FM#11."Subsequently, the measurement control device 23 may control the measurement device 20 so that the measurement light ML is irradiated from the injection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #121 and / or whose rotation angle around the rotation axis RX2 is angle #122, toward the reference member FM#12. As a result, the light receiving device 212 may receive the reflected light RL from the reference member FM#12 via the output optical member 2210. Subsequently, the measurement control device 23 may acquire the light receiving result of the reflected light RL from the reference member FM#12 by the light receiving device 212.

[0207] Subsequently, the measurement control device 23 may control the rotation device 223 so that the rotation angle of the ejection optical member 2210 around the rotation axis RX1 changes from angle #121 to angle #131 and / or the rotation angle of the ejection optical member 2210 around the rotation axis RX2 changes from angle #122 to angle #132. Angles #131 and #132 may be angles that satisfy the condition that "the measurement light ML ejected from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #131 and / or whose rotation angle around the rotation axis RX2 is angle #132, can irradiate a reference member FM#13 that is different from reference members FM#11 to FM#12." Subsequently, the measurement control device 23 may control the measurement device 20 to irradiate measurement light ML toward the reference member FM#13 from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #131 and / or whose rotation angle around the rotation axis RX2 is angle #132. As a result, the light receiving device 212 may receive the reflected light RL from the reference member FM#13 via the ejection optical member 2210. Subsequently, the measurement control device 23 may acquire the light receiving result of the reflected light RL from the reference member FM#13 by the light receiving device 212.

[0208] Subsequently, the measurement control device 23 may control the rotation device 223 so that the rotation angle of the ejection optical member 2210 around the rotation axis RX1 changes from angle #131 to angle #141 and / or the rotation angle of the ejection optical member 2210 around the rotation axis RX2 changes from angle #132 to angle #142. Angles #141 and #142 may be angles that satisfy the condition that "the measurement light ML ejected from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #141 and / or whose rotation angle around the rotation axis RX2 is angle #142, can irradiate a reference member FM#14 that is different from reference members FM#11 to FM#13." Subsequently, the measurement control device 23 may control the measurement device 20 to irradiate measurement light ML toward the reference member FM#14 from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #141 and / or whose rotation angle around the rotation axis RX2 is angle #142. As a result, the light receiving device 212 may receive the reflected light RL from the reference member FM#14 via the ejection optical member 2210. Subsequently, the measurement control device 23 may acquire the light receiving result of the reflected light RL from the reference member FM#14 by the light receiving device 212.

[0209] In step S102, the measurement control device 23 may perform a global scan to identify the position of the reference member FM and control the measurement device 20 to irradiate the measurement light ML toward the identified position. The global scan may be an operation to identify the position of the reference member FM by scanning a global scan area corresponding to the measurement range of the measurement device 20 with the measurement light ML. In this case, during the period in which the global scan area is scanned with the measurement light ML, the light receiving device 212 will receive a high-intensity return light RL at the timing when the measurement light ML irradiates the reference member FM. For this reason, the measurement control device 23 may calculate the position of the reference member FM as the position where the measurement light ML was irradiated at a timing when the intensity of the return light RL received by the light receiving device 212 was higher than a predetermined threshold.

[0210] In step S102, the measurement control device 23 may, in addition to or instead of a global scan, determine the position of the reference member FM by performing a local scan and control the measurement device 20 to irradiate the measurement light ML toward the determined position. The local scan may be an operation in which the position of the reference member FM is determined by scanning a local scan area that is narrower than the measurement range of the measurement device 20 (in other words, narrower than the global scan area) with the measurement light ML. The local scan area may be an area that includes the position of the reference member FM determined in the global scan. In this case as well, the measurement control device 23 may calculate the position of the reference member FM as the position where the measurement light ML was irradiated at a timing when the intensity of the return light RL received by the light receiving device 212 was higher than a predetermined threshold.

[0211] Subsequently, the measurement and control device 23 determines whether or not to translate either the machining head 11 or the stage 141 (step S103). For example, if the number of translational movements of either the machining head 11 or the stage 141 is less than the required number of movements, the measurement and control device 23 may determine to move either the machining head 11 or the stage 141. For example, if the number of translational movements of either the machining head 11 or the stage 141 is equal to or greater than the required number of movements, the measurement and control device 23 may determine not to move either the machining head 11 or the stage 141. For example, if the distance (e.g., the sum of the distances) of translational movement of either the machining head 11 or the stage 141 is less than the required movement distance, the measurement and control device 23 may determine to move either the machining head 11 or the stage 141. For example, if the translational distance (e.g., the sum of the distances) of either the machining head 11 or the stage 141 exceeds the required movement distance, the measurement and control device 23 may determine that it will not move either the machining head 11 or the stage 141.

[0212] If the determination in step S103 determines that either the machining head 11 or the stage 141 should be moved (step S103: Yes), the measurement control device 23 translates either the machining head 11 or the stage 141 within the machine coordinate system (step S104). In step S104, the measurement control device 23 does not translate the machining head 11 and the stage 141 simultaneously. For example, in step S104, if the measurement control device 23 translates the machining head 11, it does not translate the stage 141 in parallel with the translation of the machining head 11. On the other hand, in step S104, if the measurement control device 23 translates the stage 141, it does not translate the machining head 11 in parallel with the translation of the stage 141. However, the measurement control device 23 may translate the machining head 11 and the stage 141 simultaneously in step S104.

[0213] In step S104, the measurement control device 23 may move the machining head 11 to a desired head position that has not yet been designated as a destination for the machining head 11. In step S104, the measurement control device 23 may move the stage 141 to a desired stage position that has not yet been designated as a destination for the stage 141.

[0214] Subsequently, the measurement control device 23 controls the measurement device 20 to irradiate at least four reference members FM with measurement light ML (step S102). As an example, a case will be described in which a reference member FM (for example, the first reference member FM) that was included in the measurement field of the measurement device 20 before the processing head 11 or stage 141 moved in step S104 is included in the measurement field of the measurement device 20 after the processing head 11 or stage 141 moved in step S104. In this case, the rotation device 223 may be controlled so that the rotation angle of the injection optical member 2210 around the rotation axis RX1 changes from angle #111 to angle #211 and / or the rotation angle of the injection optical member 2210 around the rotation axis RX2 changes from angle #112 to angle #212. Angles #211 and #212 may be angles that satisfy the condition that "the measurement light ML emitted from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #211 and / or whose rotation angle around the rotation axis RX2 is angle #212, can irradiate the first reference member FM." Subsequently, the measurement control device 23 may control the measurement device 20 to irradiate the measurement light ML from the ejection optical member 2210, whose rotation angle around the rotation axis RX1 is angle #211 and / or whose rotation angle around the rotation axis RX2 is angle #212, toward the first reference member FM. As a result, the light receiving device 212 may receive the return light RL from the first reference member FM via the ejection optical member 2210. Subsequently, the measurement control device 23 may acquire the light receiving result of the return light RL from the first reference member FM by the light receiving device 212. Thereafter, as already described above, the measurement control device 23 repeats the same operation for the number of reference members FM that are included in the measurement field of the measurement device 20 after the processing head 11 or stage 141 has moved in step S104.

[0215] On the other hand, if, as a result of the determination in step S103, it is determined that, for example, the processing head 11 and the stage 141 should not be moved (step S103: No), the measurement control device 23 calculates the actual position of the measurement point MP, which corresponds to the position where the measurement device 20 measured the reference member FM, based on the light reception result of the return light RL in step S102 (step S105). Specifically, the measurement control device 23 calculates the actual position of the measurement device 20 at the time the reference member FM was measured (for example, the position of the pivot point described above) as the actual position of the measurement point MP, based on the light reception result of the return light RL in step S102 (step S105).

[0216] As described above, the measuring device 20 receives reflected light RL from at least four reference members FM each time at least one of the machining head 11 and the stage 141 moves in step S101 or step S104. For this reason, the measuring control device 23 may calculate the position of the measuring point MP that moves with the movement of at least one of the machining head 11 and the stage 141. In other words, the measuring control device 23 calculates the position of the same number of measuring points MP (multiple measuring points MP) as the number of times at least one of the machining head 11 and the stage 141 has moved.

[0217] In the first embodiment, in step S105, the measurement control device 23 may first calculate the distance between each measurement point MP and each of the at least four reference members FM based on the reception result of the reflected light RL from each of the at least four reference members FM in order to calculate the position of each of the multiple measurement points MP. The measurement control device 23 may repeat this operation of calculating the distance as many times as there are measurement points MP (i.e., the number of times at least one of the machining head 11 and the stage 141 has moved). The distance between the measurement point MP and the reference member FM may be considered to be a value calculated based on the reception result of the reflected light RL from the reference member FM. Furthermore, because the distance between the measurement point MP and the reference member FM is calculated based on the reception result of the reflected light RL from the reference member FM, the reception result of the reflected light RL from the reference member FM may be considered to contain information regarding the distance between the measurement point MP and the reference member FM.

[0218] Furthermore, as described above, if the first rotation axis RX1 around which the ejection optical member 2210 rotates is located away from the center of the spherical member 222, the measurement control device 23 may correct the calculated distance between the measurement point MP and the reference member FM based on the distance between the first rotation axis RX1 and the center of the spherical member 222 (hereinafter, this distance will be referred to as the offset amount of the first rotation axis RX1) and the rotation angle of the ejection optical member 2210 at the time when measurement light ML is irradiated onto one reference member FM and the return light RL from one reference member FM is received. As an example, the measurement control device 23 may calculate a correction amount corresponding to the rotation angle of the injection optical member 2210 based on first correction information (e.g., a lookup table) that defines a correction amount for correcting the calculation result of the distance between the measurement point MP and a reference member FM, and which is determined based on the offset amount of the first rotation axis RX1, for each rotation angle of the injection optical member 2210, and then use the calculated correction amount to correct the calculation result of the distance between the measurement point MP and a reference member FM.

[0219] Furthermore, as described above, if the second rotation axis RX2 around which the ejection optical member 2210 rotates is located away from the center of the spherical member 222, the measurement control device 23 may correct the calculated distance between the measurement point MP and the reference member FM based on the distance between the second rotation axis RX2 and the center of the spherical member 222 (hereinafter, this distance will be referred to as the offset amount of the second rotation axis RX2) and the rotation angle of the ejection optical member 2210 at the time when measurement light ML is irradiated onto one reference member FM and the return light RL from the one reference member FM is received. As an example, the measurement control device 23 may calculate a correction amount corresponding to the rotation angle of the injection optical member 2210 based on second correction information (e.g., a lookup table) that defines a correction amount for each rotation angle of the injection optical member 2210, which is a correction amount for correcting the calculation result of the distance between the measurement point MP and a reference member FM and is determined based on the offset amount of the second rotation axis RX2, and then correct the calculation result of the distance between the measurement point MP and a reference member FM using the calculated correction amount.

[0220] Furthermore, as described above, if the rotation center of the injection optical member 2210 does not coincide with the pivot point, the measurement control device 23 may correct the calculated distance between the measurement point MP and the reference member FM based on the distance between the rotation center of the injection optical member 2210 and the pivot point (hereinafter, this distance will be referred to as the offset amount of the pivot point) and the rotation angle of the injection optical member 2210 at the time when measurement light ML is irradiated onto one reference member FM and the return light RL from the one reference member FM is received. As an example, the measurement control device 23 may calculate a correction amount corresponding to the rotation angle of the injection optical member 2210 based on third correction information (e.g., a lookup table) that defines a correction amount for correcting the calculated distance between the measurement point MP and the reference member FM, which is determined based on the offset amount of the pivot point, for each rotation angle of the injection optical member 2210, and then correct the calculated distance between the measurement point MP and the reference member FM using the calculated correction amount.

[0221] In addition to or instead of the measurement control device 23, a processing control device 16 (or other control device) may calculate the distance between each measurement point MP and each of the at least four reference members FM based on the reception result of the reflected light RL from the reference member FM. In this case, the processing control device 16 (or other control device) may obtain the reception result of the reflected light RL from the reference member FM from the measurement control device 23. Subsequently, the processing control device 16 (or other control device) may calculate the distance between each measurement point MP and each of the at least four reference members FM based on the acquired reception result.

[0222] Subsequently, the measurement control device 23 may calculate the positions of multiple measurement points MP based on the calculated distance. In the first embodiment, the measurement control device 23 may calculate the positions of multiple measurement points MP using the principle of polygonal surveying. Specifically, the measurement control device 23 may calculate the positions of multiple measurement points MP by solving a minimization problem using the principle of polygonal surveying. The minimization problem using the principle of polygonal surveying is a minimization problem for calculating the positions of multiple measurement points MP, which are unknown parameters, by using the distance between each measurement point MP and each reference member FM (the known side length of the polygon), calculated from the reception result of the reflected light RL, as a known parameter. Note that since polygonal surveying itself is a publicly known technique, a detailed explanation thereof will be omitted.

[0223] As a result, the measurement control device 23 can calculate the positions of multiple measurement points MP in the machine coordinate system, as shown in Figure 13, where the actual positions of the measurement points MP in the machine coordinate system (i.e., the positions calculated using the principle of multi-sided surveying) are indicated by black circles. The positions of the multiple measurement points MP shown in Figure 13 may be considered as the positions of multiple measurement points MP in the space in which at least one of the machining head 11 and the stage 141 moves along the translation axis. Furthermore, since the positions of the multiple measurement points MP are calculated based on the distance between each measurement point MP and each reference member FM, which is calculated based on the reception result of the reflected light RL from the reference member FM, the measurement control device 23 may be considered to be calculating the positions of multiple measurement points MP based on the reception result of the reflected light RL from the reference member FM.

[0224] In Figure 12 again, the measurement control device 23 then calculates the movement error that occurs in the translational movement of at least one of the machining head 11 and the stage 141 based on the actual positions of the multiple measurement points MP in the machine coordinate system calculated in step S105 (step S106). Here, the X position of one measurement point MP shown in Figure 13 indicates the actual X position of the measurement head 22 when the measurement device 20 (particularly the measurement head 22) is located at one measurement point MP. The Y position of one measurement point MP shown in Figure 13 indicates the actual Y position of the stage 141 when the measurement device 20 (particularly the measurement head 22) is located at one measurement point MP. The Z position of one measurement point MP shown in Figure 13 indicates the actual Z position of the measurement head 22 when the measurement device 20 (particularly the measurement head 22) is located at one measurement point MP. Furthermore, since the measuring head 22 is attached to the machining head 11, the X position of one measuring point MP shown in Figure 13 may be considered to represent the actual X position of the machining head 11 when the measuring device 20 (especially the measuring head 22) is positioned at one measuring point MP. Note that the tool center point (TCP) may be used as the position of the machining head 11. The Z position of one measuring point MP shown in Figure 13 may be considered to represent the actual Z position of the machining head 11 when the measuring device 20 (especially the measuring head 22) is positioned at one measuring point MP.

[0225] In this way, the measurement control device 23 can calculate the positions of the machining head 11 and the stage 141, respectively, when the measurement head 22 is positioned at the measurement point MP calculated in step S105. In this case, the measurement control device 23 may calculate the difference between the actual X position of the machining head 11 calculated from one measurement point MP and the commanded X position to which the machining head 11 should have been positioned when the measurement head 22 was positioned at one measurement point MP, as a movement error resulting from the translational movement of the machining head 11. The measurement control device 23 may also calculate the difference between the actual Y position of the stage 141 calculated from one measurement point MP and the commanded Y position to which the stage 141 should have been positioned when the measurement head 22 was positioned at one measurement point MP, as a movement error resulting from the translational movement of the stage 141. The measurement control device 23 may calculate the difference between the actual Z position of the machining head 11 calculated from a measurement point MP and the commanded Z position to which the machining head 11 should have been positioned when the measurement head 22 is positioned at a measurement point MP, as a movement error occurring in the translational movement of the machining head 11. Furthermore, since the movement error is calculated based on the position of each measurement point MP, which is calculated based on the reception result of the return light RL from the reference member FM, the measurement control device 23 may be considered to be calculating the movement error based on the reception result of the return light RL from the reference member FM.

[0226] The measurement control device 23 may repeat this operation for as many times as there are measurement points MP. As a result, as shown in Figure 13, the measurement control device 23 can calculate the movement error at each position in the machine coordinate system. In other words, the measurement control device 23 can calculate the movement error at each position in space where at least one of the machining head 11 and the stage 141 moves along the translation axis.

[0227] In addition to or instead of the measurement control device 23, a processing control device 16 (or other control device) may calculate the movement error based on the reception result of the reflected light RL from the reference member FM. In this case, the processing control device 16 (or other control device) may obtain from the measurement control device 23 the calculation result of the distance between the measurement device 20 located at each measurement point MP and each of the at least four reference members FM, or the reception result of the reflected light RL from the reference member FM. Subsequently, the processing control device 16 (or other control device) may calculate the movement error based on the acquired distance calculation result or the reception result of the reflected light RL.

[0228] Again in Figure 12, after the movement error has been calculated, the measurement control device 23 may correct the movement error based on the calculation result of the movement error (step S107). In other words, the measurement control device 23 may correct the spatial accuracy of the machine tool 1 based on the calculation result of the movement error (i.e., the calculation result of the spatial accuracy of the machine tool 1) (step S107).

[0229] In step S107, the measurement control device 23 may generate error correction information that can be used to correct movement errors (i.e., to correct the spatial accuracy of the machine tool 1). In other words, the operation to correct movement errors (i.e., to correct the spatial accuracy of the machine tool 1) may include the operation to generate error correction information. In this case, the machine tool 1 may move at least one of the machining head 11 and the stage 141 to correct the spatial accuracy (for example, to reduce or cancel out movement errors) based on the error correction information. In other words, the machine tool 1 may control the movement of the machining head 11 based on the error correction information so that the machining head 11 moves in the same way as if there were no movement errors in the machining head 11, even if there are movement errors in the machining head 11. The machine tool 1 may also control the movement of the stage 141 based on the error correction information so that the stage 141 moves in the same way as if there were no movement errors in the stage 141, even if there are movement errors in the stage 141. However, the measurement and control device 23 may control the machine tool 1 based on the calculation result of the movement error without generating error correction information, and move at least one of the machining head 11 and the stage 141 to correct the spatial accuracy (for example, to reduce or cancel out the movement error).

[0230] As an example, if a tool 113 is attached to the spindle 111 of the machining head 11, the machine tool 1 may machine the workpiece W using the tool 113 while moving at least one of the machining head 11 (particularly the tool 113 attached to the spindle 111 of the machining head 11) and the stage 141 in order to correct the spatial accuracy based on error correction information (for example, to reduce or cancel out movement errors). As another example, if a measuring head 22 is attached to the spindle 111 of the machining head 11, the machine tool 1 may measure the object to be measured MT using the measuring head 22 while moving at least one of the machining head 11 (particularly the measuring head 22 attached to the spindle 111 of the machining head 11) and the stage 141 in order to correct the spatial accuracy based on error correction information (for example, to reduce or cancel out movement errors).

[0231] Furthermore, the error correction information is information that can be used to control the machine tool 1. In this case, the measurement control device 23 may generate any information that can be used to control the machine tool 1 (for example, information for generating a control signal for at least one of the head drive system 12 and the stage drive system 142 of the machine tool 1 in the machining control device 16) based on the calculation result of the movement error. Alternatively, the measurement control device 23 may control the machine tool 1 without generating any information that can be used to control the machine tool 1 based on the calculation result of the movement error (for example, by generating a control signal for at least one of the head drive system 12 and the stage drive system 142 of the machine tool 1 and controlling with that control signal). Also, since the error correction information is generated based on the movement error calculated based on the reception result of the return light RL from the reference member FM, it may be considered that the measurement control device 23 generates error correction information (or any information that can be used to control the machine tool 1) based on the reception result of the return light RL from the reference member FM. Alternatively, the measurement and control device 23 may be considered to be controlling the machine tool 1 without generating any information that can be used to control the machine tool 1 based on the reception result of the return light RL from the reference member FM.

[0232] Error correction information may include correction values ​​for correcting the command position where the machining head 11 or stage 141 should have originally been located, in order to reduce or cancel out movement errors. Error correction information may include the position obtained by correcting the command position where the machining head 11 or stage 141 should have originally been located, in order to reduce or cancel out movement errors (i.e., the corrected command position). Error correction information may include correction values ​​for correcting the measurement results of the head position measuring device 13, which measures the position of the machining head 11, in order to reduce or cancel out movement errors. Error correction information may include correction values ​​for correcting the measurement results of the stage position measuring device 143, which measures the position of the stage 141, in order to reduce or cancel out movement errors. Error correction information may include machining path correction information for correcting the machining path that shows the machining path of the workpiece W by the machine tool 1. Error correction information and machining path correction information may include information obtained by correcting them in order to reduce or cancel out movement errors (i.e., the corrected machining path information). Error correction information may include measurement path correction information for correcting the measurement path that indicates the measurement path of the workpiece W by the measurement system 2 when the measurement system 2 measures the three-dimensional shape of the workpiece W. Error correction information may include information obtained by correcting the measurement path correction information to reduce or cancel out movement errors (i.e., corrected measurement path information). Error correction information may include drive correction information for correcting the drive control signal generated by the machining control device 16 to control the translational movement of at least one of the machining head 11 and the stage 141. Error correction information may include a signal obtained by correcting the drive control signal to reduce or cancel out movement errors (i.e., corrected drive control signal).

[0233] Furthermore, in addition to or instead of the measurement control device 23, the machining control device 16 (or other control device) may generate error correction information based on the calculation result of the movement error. Alternatively, the machining control device 16 (or other control device) may control the machine tool 1 without generating error correction information based on the calculation result of the movement error. In this case, the machining control device 16 (or other control device) may obtain the calculation result of the movement error, the calculation result of the distance, or the reception result of the reflected light RL from the measurement control device 23. Subsequently, the machining control device 16 (or other control device) may generate error correction information or control the machine tool 1 based on the obtained calculation result of the movement error, the calculation result of the distance, or the reception result of the reflected light RL.

[0234] (1-2-2-2) Specific flow of the second spatial accuracy correction operation for calculating the movement error occurring in the rotational movement of at least one of the machining head 11 and the stage 141 Next, the second spatial accuracy correction operation for calculating the spatial accuracy occurring in the rotational movement of at least one of the machining head 11 and the stage 141 will be described.

[0235] When calculating the spatial accuracy resulting from the rotational movement of the machining head 11, the measurement control device 23 may rotate the injection optical member 2210 using the rotating device 223 to change the injection direction of the measurement light ML each time the machining head 11 rotates and stops, thereby irradiating each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML. As a result, the measurement device receives the return light RL from each of the at least N reference members FM each time the machining head 11 rotates and stops. However, the measurement device 20 may sequentially rotate the injection optical member 2210 using the rotating device 223 while the machining head 11 is rotating (specifically, while the machining head 11 is not stopped) to change the injection direction of the measurement light ML, thereby irradiating each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML. In other words, the measuring device 20 may perform at least a portion of the movement (rotational movement) of the machining head 11 or stage 141 and at least a portion of the rotation of the injection optical member 2210 in parallel. As a result, the measuring device 20 receives the reflected light RL from each of at least N reference members FM while the machining head 11 is rotating. The measuring control device 23 may calculate the movement error that occurs in the rotational movement of the machining head 11 based on the results of receiving the reflected light RL from each of the at least N reference members FM as an example of the spatial accuracy of the machine tool 1.

[0236] When calculating the spatial accuracy resulting from the rotational movement of the stage 141, the measurement control device 23 may rotate the ejection optical member 2210 using the rotating device 223 to change the ejection direction of the measurement light ML each time the stage 141 rotates and stops, thereby irradiating each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML. As a result, the measurement device receives the return light RL from each of the at least N reference members FM each time the stage 141 rotates and stops. However, the measurement device 20 may sequentially rotate the ejection optical member 2210 using the rotating device 223 while the stage 141 is rotating (specifically, while the stage 141 is not stopped) to change the ejection direction of the measurement light ML, thereby irradiating each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML. As a result, the measuring device 20 receives the reflected light RL from each of at least N reference members FM while the stage 141 is rotating. The measuring control device 23 may calculate the movement error that occurs in the rotational movement of the stage 141 based on the results of receiving the reflected light RL from each of at least N reference members FM, as an example of the spatial accuracy of the machine tool 1.

[0237] Furthermore, when calculating the movement error that occurs during rotational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during rotational movement), a workpiece W may be placed on the stage 141. For example, when calculating the movement error that occurs during rotational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during rotational movement), a workpiece W on which the reference member FM is placed may be placed on the stage 141. For example, when calculating the movement error that occurs during rotational movement (for example, when the measuring device 20 irradiates a reference member FM with measuring light ML and receives the return light RL from the reference member FM in order to calculate the movement error that occurs during rotational movement), a workpiece W without a reference member FM may be placed on the stage 141. When a workpiece W is placed on the stage 141, the measurement and control device 23 can calculate a movement error that includes an error component due to the weight of the workpiece W. This is because, when a workpiece W is placed on the stage 141, compared to when the workpiece W is not placed on the stage 141, there is a possibility that a movement error will occur in the rotational movement of the stage 141 on which the workpiece W is placed due to the weight of the workpiece W. However, when calculating the movement error that occurs in rotational movement, it is not necessary for a workpiece W to be placed on the stage 141.

[0238] The following describes the flow of the second spatial accuracy correction operation for calculating the spatial accuracy that occurs during the rotational movement of at least one of the machining head 11 (measuring head 22) and the stage 141, with reference to Figure 14. Figure 14 is a flowchart showing the flow of the second spatial accuracy correction operation for calculating the spatial accuracy that occurs during the rotational movement of at least one of the machining head 11 and the stage 141.

[0239] As mentioned above, in the first embodiment, the stage 141 rotates while the machining head 11 does not. Therefore, the following description mainly concerns the operations for calculating the spatial accuracy resulting from the rotational movement of the stage 141. However, even when the machining head 11 rotates, the spatial accuracy resulting from the rotational movement of the machining head 11 may be calculated by performing the following operations.

[0240] As shown in Figure 14, first, the measurement control device 23 moves at least one of the machining head 11 and the stage 141 to an initial position within the machine coordinate system and then stops it at that initial position (step S201). Note that the operation of step S201 may be the same as the operation of step S101 in Figure 12 described above. For this reason, a detailed explanation of the operation of step S201 is omitted.

[0241] However, in step S201, the measurement control device 23 may correct the spatial accuracy resulting from the translational movement of at least one of the machining head 11 and the stage 141 based on the error correction information generated in the first spatial accuracy correction operation described above. However, the measurement control device 23 does not have to correct the spatial accuracy resulting from the translational movement of at least one of the machining head 11 and the stage 141 using the error correction information generated in the first spatial accuracy correction operation. In this case, the measurement control device 23 may use as the initial position a position calculated from one of the multiple measurement points MP calculated in the first spatial accuracy correction operation described above. In either case, in step S201 of the second spatial accuracy correction operation, an initial position that substantially reflects the calculation result of the movement error in the first spatial accuracy correction operation is used. For this reason, the information regarding the actual positions of the machining head 11 and the stage 141 that moved in step S201 is known information to the measurement control device 23.

[0242] Subsequently, the measurement control device 23 controls the measurement device 20 to irradiate at least three reference members FM with measurement light ML (step S202). Note that the operation of step S202 may be the same as the operation of step S102 in Figure 12 described above. For this reason, a detailed explanation of the operation of step S202 is omitted.

[0243] Subsequently, the measurement and control device 23 determines whether or not to translate at least one of the processing head 11 and the stage 141 (step S203). Note that the operation in step S203 may be the same as the operation in step S103 in Figure 12 described above. For this reason, a detailed explanation of the operation in step S203 is omitted.

[0244] If, as a result of the determination in step S203, it is determined that at least one of the machining head 11 and the stage 141 should be translated (step S203: Yes), the measurement control device 23 translates at least one of the machining head 11 and the stage 141 within the machine coordinate system (step S204). Note that the operation in step S204 may be the same as the operation in step S104 in Figure 12 described above. For this reason, a detailed explanation of the operation in step S204 is omitted.

[0245] However, in step S204, the measurement control device 23 may correct the spatial accuracy resulting from the translational movement of at least one of the machining head 11 and the stage 141 based on the error correction information generated in the first spatial accuracy correction operation described above. Alternatively, in the second movement calculation operation, the measurement control device 23 does not need to use the error correction information to correct the spatial accuracy resulting from the translational movement of at least one of the machining head 11 and the stage 141. In this case, the measurement control device 23 may use a position calculated from one of the multiple measurement points MP calculated in the first spatial accuracy correction operation described above as the desired head position, which is the destination of the machining head 11, and the desired stage position, which is the destination of the stage 141. In either case, in step S204 of the second spatial accuracy correction operation, the head position and stage position that substantially reflect the calculation result of the movement error in the first spatial accuracy correction operation are used. For this reason, the information regarding the actual positions of the machining head 11 and the stage 141 that moved in step S204 is known information to the measurement control device 23.

[0246] Subsequently, the measurement control device 23 controls the measurement head 22 so that the measurement light ML is irradiated onto at least three reference members FM (step S202).

[0247] On the other hand, if the determination in step S203 determines that the machining head 11 and the stage 141 should not be moved translationally (step S203: No), the measurement control device 23 determines whether or not to rotate the stage 141 (step S208). For example, if the number of rotational movements of the stage 141 is less than the required number of movements, the measurement control device 23 may determine to rotate the stage 141. For example, if the number of rotational movements of the stage 141 is equal to or greater than the required number of movements, the measurement control device 23 may determine not to rotate the stage 141. For example, if the distance the stage 141 has rotated (e.g., the sum of the distances) is less than the required distance, the measurement control device 23 may determine to rotate the stage 141. For example, if the distance the stage 141 has rotated (e.g., the sum of the distances) is equal to or greater than the required distance, the measurement control device 23 may determine not to rotate the stage 141.

[0248] If, as a result of the determination in step S208, it is determined that the stage 141 should be rotated (step S208: Yes), the measurement control device 23 rotates the stage 141 within the machine coordinate system (step S209).

[0249] Subsequently, the measurement control device 23 controls the measurement head 22 so that the measurement light ML is irradiated onto at least three reference members FM (step S202).

[0250] Thus, in the first embodiment, each time the stage 141 moves along the rotation axis and stops, the measurement control device 23 performs the first spatial accuracy correction operation described above. However, the second spatial accuracy correction operation may differ from the first spatial accuracy correction operation in which at least four reference members FM are irradiated with measurement light ML in step S102 of Figure 12, in that at least three reference members FM are irradiated with measurement light ML in step S202 of Figure 14.

[0251] On the other hand, if, as a result of the determination in step S208, for example, it is determined that the stage 141 should not be rotated (step S208: No), the measurement control device 23 calculates the actual positions of at least three reference members FM based on the reception result of the return light RL in step S202 (step S205). For example, as described above, since the information regarding the actual positions of the processing head 11 and the stage 141 is known information to the measurement control device 23, the measurement control device 23 may calculate the distance between the measurement head 22 and the reference member FM based on the reception result of the return light RL, and then calculate the position of the reference member FM by performing calculations based on the principle of triangulation using the calculated distance and the actual positions of the processing head 11 and the stage 141. The measurement control device 23 repeats this operation of calculating the position of the reference member FM for the number of reference member FMs. As a result, the measurement control device 23 can calculate the positions of at least three reference member FM under the condition that the rotation angles of the processing head 11 and the stage 141 are at a predetermined angle.

[0252] Furthermore, the measurement and control device 23 repeatedly calculates the positions of at least three reference members FM when the rotation angle of the stage 141 is at a predetermined angle, for each rotation angle of the stage 141. As a result, as shown in Figure 15, where the actual positions of the reference members FM in the machine coordinate system (i.e., positions calculated using the principle of triangulation) are indicated by black circles, the measurement and control device 23 can calculate the positions of the reference members FM in the machine coordinate system as they rotate along with the rotational movement of the stage 141.

[0253] In Figure 14 again, the measurement and control device 23 then calculates the spatial accuracy resulting from the rotational movement of at least one of the machining head 11 and the stage 141 based on the actual position of the reference member FM in the machine coordinate system calculated in step S205 (step S206). Here, the measurement and control device 23 can calculate the actual X rotation angle (i.e., the rotation angle around the rotation axis (X)) and the Z rotation angle (i.e., the rotation angle around the rotation axis (Z)) of the stage 141 based on the actual position of the reference member FM shown in Figure 15. As a result, the measurement and control device 23 may calculate the difference between the actual X rotation angle of the stage 141 and the commanded X rotation angle of the stage 141 as the spatial accuracy resulting from the rotational movement of the stage 141. The measurement and control device 23 may also calculate the difference between the actual Z rotation angle of the stage 141 and the commanded Z rotation angle of the stage 141 as the spatial accuracy resulting from the rotational movement of the stage 141.

[0254] Again in Figure 14, after the movement error has been calculated, the measurement control device 23 may correct the movement error based on the calculation result (step S207). In other words, the measurement control device 23 may correct the spatial accuracy of the machine tool 1 based on the calculation result of the movement error (i.e., the calculation result of the spatial accuracy of the machine tool 1) (step S207). Note that the operation of step S207 may be the same as the operation of step S107 in Figure 12 described above. For this reason, a detailed explanation of the operation of step S207 is omitted.

[0255] (1-2-3) The timing measurement control device 23 that performs the spatial accuracy correction operation may decide whether or not to perform the spatial accuracy correction operation (i.e., adjust the machine tool 1) based on the adjustment judgment conditions of the machine tool 1. In other words, the measurement control device 23 may decide the timing to perform the spatial accuracy correction operation based on the adjustment judgment conditions of the machine tool 1. In this case, if it is decided to perform the spatial accuracy correction operation (i.e., if it is decided to adjust the machine tool 1), the spatial accuracy correction operation may be performed (started). On the other hand, if the measurement control device 23 decides not to perform the spatial accuracy correction operation, it does not have to perform the spatial accuracy correction operation (it does not have to start it).

[0256] The adjustment decision conditions may include instructions from the user who wishes to perform a spatial accuracy correction operation. In this case, the user may input instruction information to the measurement control device 23 as an adjustment decision condition using the input device 234 provided by the measurement control device 23. For example, the measurement control device 23 may control an output device 235 that can function as a display device to display a GUI (Graphical User Interface) that can be used by the user to input instruction information to perform a spatial accuracy correction operation. If instruction information to perform a spatial accuracy correction operation is input using the input device 234, the measurement control device 23 may decide to perform the spatial accuracy correction operation. The user may also input instruction information to perform a spatial accuracy correction operation to the measurement control device 23 as an adjustment decision condition using the input device 164 provided by the machining control device 16.

[0257] The adjustment judgment conditions may include adjustment judgment parameters (conditions related to the adjustment judgment parameters) that can be used to determine whether or not to perform a spatial accuracy correction operation. In this case, the measurement control device 23 may decide to perform a spatial accuracy correction operation if the adjustment judgment parameters (adjustment judgment conditions) fall outside a predetermined adjustment judgment threshold. On the other hand, the measurement control device 23 may decide not to perform a spatial accuracy correction operation if the adjustment judgment parameters do not fall outside a predetermined adjustment judgment threshold. The adjustment judgment conditions may also be called adjustment judgment items.

[0258] Furthermore, the state in which "the adjustment judgment parameter falls outside the predetermined adjustment judgment threshold" may include the state in which "the adjustment judgment parameter exceeds the predetermined adjustment judgment threshold in a situation where it is desirable to perform spatial accuracy correction operation when the adjustment judgment parameter exceeds the predetermined adjustment judgment threshold." The state in which "the adjustment judgment parameter falls outside the predetermined adjustment judgment threshold" may include the state in which "the adjustment judgment parameter falls below the predetermined adjustment judgment threshold in a situation where it is desirable to perform spatial accuracy correction operation when the adjustment judgment parameter falls below the predetermined adjustment judgment threshold." The state in which "the adjustment judgment parameter does not fall outside the predetermined adjustment judgment threshold" may include the state in which "the adjustment judgment parameter falls below the predetermined adjustment judgment threshold in a situation where it is desirable to perform spatial accuracy correction operation when the adjustment judgment parameter exceeds the predetermined adjustment judgment threshold." The state in which "the adjustment judgment parameter does not fall outside the predetermined adjustment judgment threshold" may include the state in which "the adjustment judgment parameter exceeds the predetermined adjustment judgment threshold in a situation where it is desirable to perform spatial accuracy correction operation when the adjustment judgment parameter falls below the predetermined adjustment judgment threshold."

[0259] The adjustment judgment parameters may include parameters related to the environment of the machine tool 1.

[0260] The environment parameters for the machine tool 1 may include the temperature of the surrounding area (ambient temperature) of the machine tool 1. In this case, the measurement and control device 23 may obtain information regarding the ambient temperature of the machine tool 1 from a temperature sensor capable of detecting the ambient temperature of the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameters are outside the adjustment determination threshold if the ambient temperature of the machine tool 1 is too high (specifically, the ambient temperature of the machine tool 1 exceeds a first temperature threshold, which is an example of an adjustment determination threshold). The measurement and control device 23 may also determine that the adjustment determination parameters are outside the adjustment determination threshold if the ambient temperature of the machine tool 1 is too low (specifically, the ambient temperature of the machine tool 1 falls below a second temperature threshold, which is an example of an adjustment determination threshold and is lower than the first temperature threshold described above). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameters are not outside the adjustment determination threshold if the ambient temperature of the machine tool 1 is at an appropriate temperature (specifically, the ambient temperature of the machine tool 1 is below the first temperature threshold and above the second temperature threshold).

[0261] The environmental parameters for the machine tool 1 may include the humidity around the machine tool 1. In this case, the measurement and control device 23 may obtain information regarding the humidity around the machine tool 1 from a humidity sensor capable of detecting the humidity around the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameters fall outside the adjustment determination threshold if the humidity around the machine tool 1 is too high (specifically, the humidity around the machine tool 1 exceeds a first humidity threshold, which is an example of an adjustment determination threshold). The measurement and control device 23 may also determine that the adjustment determination parameters fall outside the adjustment determination threshold if the humidity around the machine tool 1 is too low (specifically, the humidity around the machine tool 1 falls below a second humidity threshold, which is an example of an adjustment determination threshold and is lower than the first humidity threshold described above). On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameter is not outside the adjustment judgment threshold when the humidity around the machine tool 1 is at a suitable humidity level (specifically, the humidity around the machine tool 1 is below the first humidity threshold and above the second humidity threshold).

[0262] The environmental parameters for the machine tool 1 may include vibrations around the machine tool 1. An example of vibration is vibration caused by an earthquake. In this case, the measurement and control device 23 may obtain information regarding vibrations around the machine tool 1 from a vibration sensor capable of detecting vibrations around the machine tool 1. An example of a vibration sensor is at least one of a displacement sensor and an acceleration sensor. Subsequently, the measurement and control device 23 may determine that the adjustment judgment parameter is outside the adjustment judgment threshold if the vibrations around the machine tool 1 are too large (specifically, the vibrations around the machine tool 1 exceed a first vibration threshold, which is an example of an adjustment judgment threshold). The state "vibrations around the machine tool 1 exceed the first vibration threshold" may include at least one of the following states: "the amplitude of vibrations around the machine tool 1 exceeds the first vibration threshold," "the frequency of vibrations around the machine tool 1 exceeds the first vibration threshold," and "the acceleration of vibrations around the machine tool 1 exceeds the first vibration threshold." On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameter is not outside the adjustment judgment threshold when the vibration around the machine tool 1 is below the permissible limit (specifically, the vibration around the machine tool 1 is below the first vibration threshold).

[0263] The adjustment judgment parameters may include parameters related to changes in the environment of the machine tool 1.

[0264] The parameters relating to the environmental changes of the machine tool 1 may include the amount of change in the temperature around the machine tool 1 (for example, the amount of change within a certain period). In this case, the measurement and control device 23 may obtain information regarding the temperature around the machine tool 1 from a temperature sensor capable of detecting the temperature around the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameters are outside the adjustment determination threshold if the temperature around the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in the temperature around the machine tool 1 exceeds a first temperature change threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameters are not outside the adjustment determination threshold if the amount of change in the temperature around the machine tool 1 is not so large (specifically, the amount of change in the temperature around the machine tool 1 is below the first temperature change threshold).

[0265] The parameters relating to environmental changes of the machine tool 1 may include the amount of change in humidity around the machine tool 1 (for example, the amount of change within a certain period). In this case, the measurement and control device 23 may acquire information regarding the humidity around the machine tool 1 from a humidity sensor capable of detecting the humidity around the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold if the humidity around the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in humidity around the machine tool 1 exceeds a first humidity change threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if the amount of change in humidity around the machine tool 1 is not so large (specifically, the amount of change in humidity around the machine tool 1 is below the first humidity change threshold).

[0266] The environment parameters for the machine tool 1 may include the amount of change in vibration around the machine tool 1. In this case, the measurement and control device 23 may acquire information regarding the vibration around the machine tool 1 from a vibration sensor capable of detecting vibration around the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment judgment parameter has fallen outside the adjustment judgment threshold if the vibration around the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in vibration around the machine tool 1 exceeds a first vibration change threshold, which is an example of an adjustment judgment threshold). The state "the amount of change in vibration around the machine tool 1 exceeds the first vibration change threshold" may include at least one of the following states: "the amount of change in the amplitude of vibration around the machine tool 1 exceeds the first vibration change threshold," "the amount of change in the frequency of vibration around the machine tool 1 exceeds the first vibration change threshold," and "the amount of change in the acceleration of vibration around the machine tool 1 exceeds the first vibration change threshold." On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameter is not outside the adjustment judgment threshold when the amount of change in vibration around the machine tool 1 is not so large (specifically, the amount of change in vibration around the machine tool 1 is below the first vibration change threshold).

[0267] The adjustment judgment parameters may include parameters related to the state of the machine tool 1.

[0268] The parameters relating to the state of the machine tool 1 may include the temperature of the machine tool 1. The temperature of the machine tool 1 may include the temperature of a predetermined part of the machine tool 1 or the temperature of a predetermined space within the machine tool 1. In this case, the measurement and control device 23 may obtain information regarding the temperature of the machine tool 1 from a temperature sensor capable of detecting the temperature of the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameters are outside the adjustment determination threshold if the temperature of the machine tool 1 is too high above an allowable limit (specifically, the temperature of the machine tool 1 exceeds a third temperature threshold, which is an example of an adjustment determination threshold). The measurement and control device 23 may also determine that the adjustment determination parameters are outside the adjustment determination threshold if the temperature of the machine tool 1 is too low above an allowable limit (specifically, the temperature of the machine tool 1 falls below a fourth temperature threshold, which is an example of an adjustment determination threshold and is lower than the third temperature threshold described above). On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameters are not outside the adjustment judgment thresholds when the temperature of the machine tool 1 is at an appropriate temperature (specifically, when the temperature of the machine tool 1 is below the third temperature threshold and above the fourth temperature threshold).

[0269] The parameters relating to the state of the machine tool 1 may include the humidity of the machine tool 1. The humidity of the machine tool 1 may include the humidity of a predetermined space within the machine tool 1. In this case, the measurement control device 23 may obtain information regarding the humidity of the machine tool 1 from a humidity sensor capable of detecting the humidity of the machine tool 1. Subsequently, the measurement control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold if the humidity of the machine tool 1 is too high above the allowable limit (specifically, the humidity of the machine tool 1 exceeds a third humidity threshold, which is an example of an adjustment determination threshold). The measurement control device 23 may also determine that the adjustment determination parameter is outside the adjustment determination threshold if the humidity of the machine tool 1 is too low above the allowable limit (specifically, the humidity of the machine tool 1 falls below a fourth humidity threshold, which is an example of an adjustment determination threshold and is lower than the third humidity threshold mentioned above). On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameters are not outside the adjustment judgment thresholds when the humidity of the machine tool 1 is at a suitable humidity level (specifically, when the humidity of the machine tool 1 is below the third humidity threshold and above the fourth humidity threshold).

[0270] The parameters relating to the state of the machine tool 1 may include the acceleration of at least one of the machining head 11 and stage 141 of the machine tool 1. In this case, the measurement and control device 23 may obtain information regarding the acceleration of at least one of the machining head 11 and stage 141 from a vibration sensor (e.g., an acceleration sensor) or a gyro sensor capable of detecting the acceleration of at least one of the machining head 11 and stage 141. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter has fallen outside the adjustment determination threshold when a relatively large impact is applied to at least one of the machining head 11 and stage 141 and the acceleration of at least one of the machining head 11 and stage 141 exceeds an allowable amount (specifically, when the acceleration of at least one of the machining head 11 and stage 141 exceeds a first acceleration threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if, because a relatively large impact has not been applied to at least one of the machining head 11 and the stage 141, the acceleration of at least one of the machining head 11 and the stage 141 has not exceeded the allowable limit (specifically, the acceleration of at least one of the machining head 11 and the stage 141 is below the first acceleration threshold).

[0271] The parameters relating to the state of the machine tool 1 may include vibrations of the machine tool 1. The vibrations of the machine tool 1 may include vibrations transmitted to the machine tool 1 from outside the machine tool 1. An example of vibrations transmitted to the machine tool 1 is vibrations caused by an earthquake. The vibrations of the machine tool 1 may also include vibrations occurring within the machine tool 1 itself. In this case, the measurement and control device 23 may acquire information regarding the vibrations of the machine tool 1 from a vibration sensor capable of detecting the vibrations of the machine tool 1. An example of a vibration sensor is at least one of a displacement sensor and an acceleration sensor. Subsequently, the measurement and control device 23 may determine that the adjustment judgment parameter is outside the adjustment judgment threshold if the vibrations of the machine tool 1 are too large (specifically, the vibrations of the machine tool 1 exceed a second vibration threshold, which is an example of an adjustment judgment threshold). The state "the vibration of machine tool 1 exceeds the second vibration threshold" may include at least one of the following states: "the amplitude of the vibration of machine tool 1 exceeds the second vibration threshold," "the frequency of the vibration of machine tool 1 exceeds the second vibration threshold," and "the acceleration of the vibration of machine tool 1 exceeds the second vibration threshold." On the other hand, the measurement and control device 23 may determine that the adjustment judgment parameter is not outside the adjustment judgment threshold when the vibration of machine tool 1 is below the permissible amount (specifically, the vibration of machine tool 1 is below the second vibration threshold).

[0272] The adjustment judgment parameters may include parameters related to changes in the state of the machine tool 1.

[0273] The parameters relating to the change in the state of the machine tool 1 may include the amount of change in the temperature of the machine tool 1 (for example, the amount of change within a certain period). In this case, the measurement and control device 23 may obtain information regarding the temperature of the machine tool 1 from a temperature sensor capable of detecting the temperature of the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold if the temperature of the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in the temperature of the machine tool 1 exceeds a second temperature change threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if the amount of change in the temperature of the machine tool 1 is not so large (specifically, the amount of change in the temperature of the machine tool 1 is below the second temperature change threshold).

[0274] The parameters relating to the change in the state of the machine tool 1 may include the amount of change in the humidity of the machine tool 1 (for example, the amount of change within a certain period). In this case, the measurement and control device 23 may obtain information regarding the humidity of the machine tool 1 from a humidity sensor capable of detecting the humidity of the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold if the humidity of the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in the humidity of the machine tool 1 exceeds a second humidity change threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if the amount of change in the humidity of the machine tool 1 is not so large (specifically, the amount of change in the humidity of the machine tool 1 is below the second humidity change threshold).

[0275] Parameters relating to the state of the machine tool 1 may include a change in the acceleration of at least one of the machining head 11 and stage 141 of the machine tool 1 (e.g., jerk). In this case, the measurement and control device 23 may obtain information regarding the acceleration of at least one of the machining head 11 and stage 141 from a vibration sensor (e.g., an acceleration sensor) or a gyro sensor capable of detecting the acceleration of at least one of the machining head 11 and stage 141. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold when a relatively large impact is applied to at least one of the machining head 11 and stage 141 and the acceleration of at least one of the machining head 11 and stage 141 changes significantly beyond an allowable amount (specifically, the change in the acceleration of at least one of the machining head 11 and stage 141 exceeds a first acceleration change threshold, which is an example of an adjustment determination threshold). On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if, because a relatively large impact has not been applied to at least one of the machining head 11 and the stage 141, the acceleration of at least one of the machining head 11 and the stage 141 has not changed significantly beyond the allowable limit (specifically, the change in acceleration of at least one of the machining head 11 and the stage 141 is below the first acceleration change threshold).

[0276] The parameters relating to the state of the machine tool 1 may include the amount of change in the vibration of the machine tool 1. In this case, the measurement and control device 23 may acquire information regarding the vibration of the machine tool 1 from a vibration sensor capable of detecting the vibration of the machine tool 1. Subsequently, the measurement and control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold when the vibration of the machine tool 1 has changed significantly beyond an allowable amount (specifically, the amount of change in the vibration of the machine tool 1 exceeds the second vibration change threshold, which is an example of an adjustment determination threshold). The state "the amount of change in the vibration of the machine tool 1 exceeds the second vibration change threshold" may include at least one of the following states: "the amount of change in the amplitude of the vibration of the machine tool 1 exceeds the second vibration change threshold", "the amount of change in the frequency of the vibration of the machine tool 1 exceeds the second vibration change threshold", and "the amount of change in the acceleration of the vibration of the machine tool 1 exceeds the second vibration change threshold". On the other hand, the measurement and control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold when the amount of change in the vibration of the machine tool 1 is not so large (specifically, the amount of change in the vibration of the machine tool 1 is below the second vibration change threshold).

[0277] The adjustment judgment parameters may include parameters related to elapsed time. The elapsed time may include at least one of the following: the total time (cumulative time) that the machine tool 1 has performed machining, and the total time (cumulative time) that the machine tool 1 has moved at least one of the machining head 11 and stage 141 in order to machine the workpiece W. The total time (cumulative time) that the machine tool 1 has moved at least one of the machining head 11 and stage 141 in order to machine the workpiece W may include at least one of the following: the total time (cumulative time) that the machine tool 1 has moved at least one of the machining head 11 and stage 141 while machining the workpiece W, and the total time (cumulative time) that the machine tool 1 has moved at least one of the machining head 11 and stage 141 when not machining the workpiece W. The elapsed time may include, starting from a predetermined reference time, the total time (cumulative time) that the machine tool 1 has spent machining, starting from a predetermined reference time, the total time (cumulative time) that the machine tool 1 has spent moving at least one of the machining head 11 and stage 141 to machine the workpiece W, and at least one of the time from the predetermined reference time to the present time. The predetermined reference time may include the time when the measurement control device 23 completed (in other words, finished) the previous spatial accuracy correction operation. In this case, the measurement control device 23 may determine that the adjustment determination parameter is outside the adjustment determination threshold if the elapsed time exceeds a first time threshold, which is an example of an adjustment determination threshold. On the other hand, the measurement control device 23 may determine that the adjustment determination parameter is not outside the adjustment determination threshold if the elapsed time falls below the first time threshold.

[0278] The adjustment determination condition may include at least one of the date, day of the week, and time. In this case, the measurement control device 23 may decide to perform a spatial accuracy correction operation if the current date is set as a date on which a spatial accuracy correction operation should be performed. On the other hand, the measurement control device 23 may decide not to perform a spatial accuracy correction operation if the current date is not set as a date on which a spatial accuracy correction operation should be performed. The measurement control device 23 may also decide to perform a spatial accuracy correction operation if the current day of the week is set as a day of the week on which a spatial accuracy correction operation should be performed. On the other hand, the measurement control device 23 may decide not to perform a spatial accuracy correction operation if the current day of the week is not set as a day of the week on which a spatial accuracy correction operation should be performed. The measurement control device 23 may also decide to perform a spatial accuracy correction operation if the current time is set as a time on which a spatial accuracy correction operation should be performed. On the other hand, if the current time is not set as the time for which spatial accuracy correction operation should be performed, the measurement control device 23 may decide not to perform spatial accuracy correction operation.

[0279] The adjustment judgment conditions may include conditions relating to the results of the first preliminary measurement operation. The first preliminary measurement operation may be the same as the spatial accuracy correction operation described above in that it includes an operation to measure the spatial accuracy of the machine tool 1. On the other hand, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that it does not include an operation to correct the spatial accuracy of the machine tool 1. In this case, the measurement control device 23 may control the measurement device 20 to repeat the operation of irradiating the reference member FM with measurement light ML and receiving the return light RL from the reference member FM with the light receiving device 212, while changing the rotation angle of the ejection optical member 2210 using the rotating device 223, similar to the case when performing the spatial accuracy correction operation. After that, the measurement control device 23 may calculate the movement error based on the result of receiving the return light RL by the light receiving device 212, similar to the case when performing the spatial accuracy correction operation. The calculated movement error may be used as an adjustment judgment condition (adjustment judgment parameter). Subsequently, the measurement control device 23 may determine that the adjustment judgment parameter falls outside the adjustment judgment threshold if the calculated movement error is greater than the allowable amount (specifically, the movement error exceeds the first movement error threshold, which is an example of an adjustment judgment threshold). On the other hand, the measurement control device 23 may determine that the adjustment judgment parameter does not fall outside the adjustment judgment threshold if the calculated movement error is not greater than the allowable amount (specifically, the movement error is below the first movement error threshold).

[0280] Alternatively, in the first preliminary measurement operation, the measurement control device 23 may, using the rotating device 223, perform the operation of irradiating the reference member FM with measurement light ML and receiving the return light RL from the reference member FM with the light receiving device 212 only once, without changing the rotation angle of the ejection optical member 2210. After that, the measurement control device 23 may calculate an index value that can be used to determine whether or not to perform a spatial accuracy correction operation based on the result of receiving the return light RL by the light receiving device 212. The calculated index value may be used as an adjustment determination condition (adjustment determination parameter). After that, the measurement control device 23 may determine whether or not the calculated index value falls outside the adjustment determination threshold.

[0281] However, the first preliminary measurement operation may be an operation that satisfies the condition that "the time required to perform the first preliminary measurement operation is shorter than the time required to perform the spatial accuracy correction operation described above." In other words, the first preliminary measurement operation may be a simpler operation than the spatial accuracy correction operation described above. Furthermore, as described above, since the spatial accuracy correction operation includes an operation to measure spatial accuracy (for example, the operation from step S101 to step S104 in Figure 12), the first preliminary measurement operation may be an operation that satisfies the condition that "the time required to perform the first preliminary measurement operation is shorter than the time required to perform the operation to measure spatial accuracy described above (for example, the operation from step S101 to step S104 in Figure 12)." For example, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that the number of times the measurement light ML is irradiated onto the reference member FM in the first preliminary measurement operation may be fewer than the number of times the measurement light ML is irradiated onto the reference member FM in the spatial accuracy correction operation. For example, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that the number of times the light receiving device 212 receives the return light RL from the reference member FM in the first preliminary measurement operation may be less than the number of times the light receiving device 212 receives the return light RL from the reference member FM in the spatial accuracy correction operation. For example, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that the number of times the return light RL reception results by the light receiving device 212 obtained in the first preliminary measurement operation may be less than the number of times the return light RL reception results by the light receiving device 212 obtained in the spatial accuracy correction operation. For example, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that the number of times the rotation angle of the ejection optical member 2210 is changed using the rotating device 223 in the first preliminary measurement operation may be less than the number of times the rotation angle of the ejection optical member 2210 is changed using the rotating device 223 in the spatial accuracy correction operation.For example, the first preliminary measurement operation may differ from the spatial accuracy correction operation described above in that the amount by which the rotation angle of the injection optical member 2210 is changed using the rotating device 223 in the first preliminary measurement operation (i.e., the amount of change in rotation angle) may be less than the amount by which the rotation angle of the injection optical member 2210 is changed using the rotating device 223 in the spatial accuracy correction operation (i.e., the amount of change in rotation angle). As an example, if the rotation angle of the injection optical member 2210 is changed from a first angle to a second angle using the rotating device 223 in the first preliminary measurement operation, and the rotation angle of the injection optical member 2210 is changed from a third angle to a fourth angle using the rotating device 223 in the spatial accuracy correction operation, then the difference between the first angle and the second angle (i.e., the amount of change in rotation angle in the first preliminary measurement operation) may be smaller than the difference between the third angle and the fourth angle (i.e., the amount of change in rotation angle in the spatial accuracy correction operation). Furthermore, if the rotation angle of the injection optical member 2210 is changed only multiple times, the amount by which the rotation angle of the injection optical member 2210 is changed may be the sum of the changes in the rotation angle over the multiple times. For example, the number of measurement points MP used in the first preliminary measurement operation may be less than the number of measurement points MP used in the spatial accuracy correction operation. The number of reference members FM to which the measurement light ML is irradiated in the first preliminary measurement operation may be less than the number of reference members FM to which the measurement light ML is irradiated in the spatial accuracy correction operation.

[0282] Alternatively, the measurement control device 23 may perform a modified version of the spatial accuracy correction operation described later (however, this does not necessarily include an operation to correct the spatial accuracy of the machine tool 1) as the first preliminary measurement operation. This is because the time required to perform the modified version of the spatial accuracy correction operation described later (however, this does not necessarily include an operation to correct the spatial accuracy of the machine tool 1) is shorter than the time required to perform the spatial accuracy correction operation described above (however, this does not necessarily include an operation to correct the spatial accuracy of the machine tool 1).

[0283] The measurement control device 23 may decide whether or not to perform the first preliminary measurement operation based on the above-described adjustment determination conditions (excluding conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter) before performing the first preliminary measurement operation. The operation of deciding whether or not to perform the first preliminary measurement operation based on the adjustment determination conditions (excluding conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter) may be the same as the operation of deciding whether or not to perform a spatial accuracy correction operation based on the adjustment determination conditions (excluding conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter). In other words, the explanation of the operation of deciding whether or not to perform a spatial accuracy correction operation based on the above-described adjustment determination conditions (excluding conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter) can be reused as an explanation of the operation of deciding whether or not to perform the first preliminary measurement operation based on the adjustment determination conditions (excluding conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter) by replacing the phrase "spatial accuracy correction operation" with the phrase "first preliminary measurement operation". Therefore, in order to avoid redundant explanations, the explanation of the operation to determine whether or not to perform the first preliminary measurement operation based on the adjustment determination conditions (excluding the conditions relating to the results of the first preliminary measurement operation; the same applies hereinafter) is omitted. Subsequently, if the measurement control device 23 decides to perform the first preliminary measurement operation based on the adjustment determination conditions, it may perform the first preliminary measurement operation and then decide whether or not to perform a spatial accuracy correction operation based on the adjustment determination conditions relating to the results of the first preliminary measurement operation. When the adjustment determination parameters described above are used as adjustment determination conditions, the adjustment determination threshold that is compared with the adjustment determination parameters to determine whether or not to perform the first preliminary measurement operation may be the same as or different from the adjustment determination threshold that is compared with the adjustment determination parameters to determine whether or not to perform a spatial accuracy correction operation.

[0284] Furthermore, the reference member FM to which the measurement light ML is irradiated in the first preliminary measurement operation may be the same as, or different from, the reference member FM to which the measurement light ML is irradiated in the spatial accuracy correction operation.

[0285] The measurement control device 23 may output information based on the adjustment judgment conditions. For example, the measurement control device 23 may output information based on the adjustment judgment conditions using the output device 235. As one example, the measurement control device 23 may output information indicating the adjustment judgment conditions. As another example, the measurement control device 23 may output information indicating the judgment result based on the adjustment judgment conditions. As yet another example, the measurement control device 23 may output information indicating that the adjustment judgment parameter is within the adjustment judgment threshold when the adjustment judgment parameter, which is an example of the adjustment judgment conditions, is within the adjustment judgment threshold. As yet another example, the measurement control device 23 may output information indicating that the adjustment judgment parameter is outside the adjustment judgment threshold when the adjustment judgment parameter, which is an example of the adjustment judgment conditions, is outside the adjustment judgment threshold. As yet another example, when a different adjustment judgment condition is used than the adjustment judgment parameter, the measurement control device 23 may output information indicating that the adjustment judgment conditions are met (i.e., that it has been decided to perform a spatial accuracy correction operation). As yet another example, when the adjustment judgment conditions are met, the measurement control device 23 may output information to suggest to the user that a spatial accuracy correction operation be performed. As a result, users can properly understand information regarding the adjustment judgment conditions.

[0286] (1-2-4) Modified Spatial Accuracy Correction Operation Next, we will explain modified spatial accuracy correction operation. Note that the following explanation will mainly describe operations that are different from the spatial accuracy correction operation described above. For this reason, unless otherwise specified, the same operations as the spatial accuracy correction operation described above may be performed in the following modified operations.

[0287] (1-2-4-1) First Modified Example of Spatial Accuracy Correction Operation As shown in Figure 16, a conceptual perspective view of a measuring device 20 (measuring head 22) that performs the first modified example of spatial accuracy correction operation, the measuring control device 23 may control the measuring device 20 so that each time the machining head 11 is moved by a predetermined distance along a translation axis (i.e., the measuring head 22 is moved by a predetermined distance), the measuring light ML is irradiated onto the same reference member FM and the return light RL from the reference member FM is received. In the example shown in Figure 16, the measuring control device 23 may control the measuring device 20 so that each time the machining head 11 (measuring head 22) is moved by a predetermined distance along the translation axis (X), the measuring light ML is irradiated onto the same reference member FM and the return light RL from the reference member FM is received.

[0288] Subsequently, the measurement control device 23 may calculate the distance between the measurement point MP, which corresponds to the position where the measurement device 20 measured the reference member FM, and the reference member FM, based on the reception result of the return light RL. Here, if there is no movement error in the translational movement of the machining head 11, the distance between the measurement point MP and the reference member FM changes linearly or proportionally with respect to the amount of movement of the machining head 11, as shown in Figure 17A, a graph showing the calculation result of the distance between the measurement point MP and the reference member FM. On the other hand, if there is a movement error in the translational movement of the machining head 11, the distance between the measurement point MP and the reference member FM will no longer change linearly with respect to the amount of movement of the machining head 11 (in other words, it will change nonlinearly) or will no longer be proportional, as shown in Figure 17B, a graph showing the calculation result of the distance between the measurement point MP and the reference member FM. For this reason, the measurement control device 23 may calculate the movement error occurring in the translational movement of the machining head 11 based on the relationship between the distance between the measurement point MP and the reference member FM and the amount of movement of the machining head 11. For example, as shown in Figure 17B, the measurement control device 23 may calculate, for each amount of movement of the machining head 11, the amount of deviation (so-called pitch error) of the actual distance between the measurement point MP and the reference member FM from the ideal distance between the measurement point MP and the reference member FM (that is, the distance between the measurement point MP and the reference member FM when no movement error occurs in the translational movement of the machining head 11, as the movement error that occurs in the translational movement of the machining head 11.

[0289] Furthermore, instead of moving the machining head 11 along one translation axis by a predetermined distance, the measurement control device 23 may control the measuring device 20 so that, each time the stage 141 is moved along one translation axis by a predetermined distance, the same reference member FM is illuminated with measurement light ML and the return light RL from the reference member FM is received. In this case, the measurement control device 23 may calculate the movement error that occurs in the translational movement of the stage 141 based on the relationship between the distance between the measurement point MP and the reference member FM and the amount of movement of the stage 141.

[0290] In the example described above, the machining head 11 moves along the translation axis (X) and the translation axis (Z), and the stage 141 moves along the translation axis (Y). In this case, the measurement control device 23 may calculate the movement error (e.g., pitch error) that occurs in the translational movement of the machining head 11 along the translation axis (X) based on the reception result of the return light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 moves along the translation axis (X) by a predetermined distance, or the measurement control device 23 may calculate the movement error (e.g., pitch error) that occurs in the translational movement of the machining head 11 along the translation axis (Z) based on the reception result of the return light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 moves along the translation axis (Z) by a predetermined distance, by irradiating the same reference member FM with measurement light ML. The measurement control device 23 may calculate the movement error (for example, pitch error) that occurs in the translational movement of the stage 141 along the translational axis (Y) based on the reception result of the return light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the stage 141 is moved a predetermined distance along the translational axis (Y).

[0291] In this first modified version of the spatial accuracy correction operation, a single reference member FM may be placed on at least one of the workpiece W and the stage 141 instead of multiple reference members FM. Even in this case, the measurement control device 23 can appropriately perform the first modified version of the spatial accuracy correction operation.

[0292] (1-2-4-2) Second Modified Example of Spatial Accuracy Correction Operation As shown in Figure 18, a conceptual perspective view of a measuring device 20 (measuring head 22) that performs a second modified example of spatial accuracy correction operation, the measuring control device 23 may control the measuring device 20 so that each time the machining head 11 (measuring head 22) or stage 141 is moved by a predetermined distance along the first translation axis, the measuring light ML is irradiated onto the same reference member FM and the return light RL from the reference member FM is received. In the example shown in Figure 18, the measuring control device 23 may control the measuring device 20 so that each time the machining head 11 (measuring head 22) is moved by a predetermined distance along the translation axis (X), the measuring light ML is irradiated onto the same reference member FM and the return light RL from the reference member FM is received.

[0293] Subsequently, the measurement control device 23 may calculate the orientation of the reference member FM from the measurement point MP corresponding to the position where the measurement device 20 measured the reference member FM, based on the reception result of the reflected light RL. For example, because the intensity of the reflected light RL increases when the measurement light ML is irradiated onto the reference member FM, the orientation at which the measurement light ML was emitted from the measurement head 22 at the timing when the intensity of the reflected light RL received by the light receiving device 212 is high may be calculated as the orientation of the reference member FM. The orientation at which the measurement light ML was emitted from the measurement head 22 can be calculated from the rotation angle of the ejection optical member 2210 by the rotating device 223. In the example shown in Figure 18, the angle θ between the second rotation axis RX2 (i.e., the Z axis) of the rotating device 223 and the axis along the direction of emission of the measurement light ML from the measurement head 22 is used as the orientation of the reference member FM. Subsequently, as shown in Figure 19, the measurement and control device 23 may calculate the motion trajectory of the machining head 11 or stage 141 along the first translation axis based on the calculation result of the orientation of the reference member FM.

[0294] Subsequently, the measurement control device 23 may control the measurement device 20 so that, each time the machining head 11 or stage 141 is moved a predetermined distance along a second translation axis different from the first translation axis, it irradiates the same reference member FM with measurement light ML and receives the return light RL from the reference member FM. Then, as shown in Figure 19, the measurement control device 23 may calculate the motion trajectory of the machining head 11 or stage 141 along the second translation axis based on the result of receiving the return light RL.

[0295] Subsequently, as shown in Figure 19, the measurement and control device 23 may calculate the deviation (so-called perpendicularity) from the perpendicularity between the axial average line of the motion trajectory of the machining head 11 or stage 141 along the first translation axis and the axial average line of the motion trajectory of the machining head 11 or stage 141 along the second translation axis as the spatial accuracy of the machine tool 1.

[0296] In the example described above, the machining head 11 moves along the translation axis (X) and the translation axis (Z), and the stage 141 moves along the translation axis (Y). In this case, the measurement control device 23 may calculate the deviation (so-called perpendicularity) from the perpendicularity between the axial average line of the motion trajectory of the machining head 11 along the translation axis (X) and the axial average line of the motion trajectory of the machining head 11 along the translation axis (Z), based on the reception result of the return light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 is moved a predetermined distance along the translation axis (X), and the return light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 is moved a predetermined distance along the translation axis (Z), as the spatial accuracy of the machine tool 1. The measurement control device 23 may calculate the deviation (so-called perpendicularity) from the perpendicularity between the axial average line of the motion trajectory of the machining head 11 along the translation axis (X) and the axial average line of the motion trajectory of the stage 141 along the translation axis (Y) as the spatial accuracy of the machine tool 1, based on the reception result of the reflected light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 is moved a predetermined distance along the translation axis (X), and the reception result of the reflected light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the stage 141 is moved a predetermined distance along the translation axis (Y). The measurement control device 23 may calculate the deviation (so-called perpendicularity) from the perpendicularity between the axial average line of the motion trajectory of the machining head 11 along the translation axis (Z) and the axial average line of the motion trajectory of the stage 141 along the translation axis (Y), based on the reception result of the reflected light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the machining head 11 is moved a predetermined distance along the translation axis (Z), and the reception result of the reflected light RL received by the light receiving device 212 by irradiating the same reference member FM with measurement light ML each time the stage 141 is moved a predetermined distance along the translation axis (Y), as the spatial accuracy of the machine tool 1.

[0297] When the second modification of the spatial accuracy correction operation is performed in this manner, a single reference member FM may be placed on at least one of the workpiece W and the stage 141 instead of multiple reference members FM. Even in this case, the measurement control device 23 can appropriately perform the second modification of the spatial accuracy correction operation.

[0298] (1-2-4-3) Third Modification of Spatial Accuracy Correction Operation When performing the third modification of the spatial accuracy correction operation, the measurement control device 23 may first perform the spatial accuracy correction operation described above on the first space of the machine coordinate system to calculate the actual position of the measurement point MP in the first space, as shown in Figure 20. In other words, the actual position of the measurement point MP in the first space may be calculated by performing the spatial accuracy correction operation described above, which includes moving at least one of the machining head 11 and the stage 141 in the first space of the machine coordinate system. As a result, as shown in Figure 20, the measurement control device 23 may calculate the spatial accuracy (movement error) in the first space based on the calculation result of the actual position of the measurement point MP in the first space.

[0299] Furthermore, as shown in Figure 20, the measurement control device 23 may estimate the position of measurement point MP in a second space different from the first space of the machine coordinate system based on the calculation result of the position of measurement point MP in the first space. For example, the measurement control device 23 may interpolate the position of measurement point MP in a second space different from the first space of the machine coordinate system based on the calculation result of the position of measurement point MP in the first space. As an example of interpolation, at least one of interpolation and extrapolation can be given. Subsequently, the measurement control device 23 may calculate the spatial accuracy (movement error) in the second space based on the estimation result (interpolation result) of the position of measurement point MP in the second space. Alternatively, the measurement control device 23 may estimate the spatial accuracy (movement error) in the second space based on the calculation result of the spatial accuracy (movement error) in the first space. For example, the measurement control device 23 may interpolate the spatial accuracy (movement error) in the second space based on the calculation result of the spatial accuracy (movement error) in the first space.

[0300] In this case, since it is no longer necessary to move the machining head 11 and stage 141 (and furthermore, to irradiate the reference member FM with measurement light ML) in order to calculate spatial accuracy in the second space of the machine coordinate system, the time required to calculate (and further correct) the spatial accuracy of a relatively large space within the machine coordinate system can be shortened.

[0301] (1-2-5) Technical effects that can be obtained by performing spatial accuracy correction operation using the measurement system 2 As described above, in the first embodiment, the measurement device 20 irradiates the object to be measured MT (for example, the reference member FM) with measurement light ML via the spherical member 222. In this case, the measurement accuracy of the measurement device 20 is improved compared to the case in which the spherical member 222 is not used. The technical reasons for this will be explained below.

[0302] First, let me explain the first technical reason. Figure 21 is a cross-sectional view showing a spherical member 222 and an injection optical member 2210 that rotates around the center 222C of the spherical member 222 as its pivot point. As shown in Figure 21, in the first embodiment, the rotating device 223 rotates the injection optical member 2210 in order to change the direction of emission of the measurement light ML emitted from the injection optical member 2210. On the other hand, the rotating device 223 does not need to rotate the spherical member 222 in order to change the direction of emission of the measurement light ML emitted from the injection optical member 2210. Even if the spherical member 222 is not rotated in this way, because the spherical member 222 has a spherical shape, the measurement light ML emitted from the injection optical member 2210 is reflected by the spherical outer surface of the spherical member 222, and the measurement light ML reflected by the spherical outer surface of the spherical member 222 returns to the injection optical member 2210. Therefore, in the first embodiment, the measuring device 20 does not need to rotate (i.e., move) the ejection optical member 2210 and the spherical member 222 in conjunction to change the direction of emission of the measurement light ML. As a result, compared to the case where it is necessary to rotate (i.e., move) the ejection optical member 2210 and the spherical member 222 (or any optical member such as a planar reflecting member that reflects the measurement light ML ejected from the ejection optical member 2210 back to the ejection optical member 2210) in conjunction, the possibility of the positional relationship between the ejection optical member 2210 and the spherical member 222 deviating from the ideal (in other words, the design) positional relationship is reduced. This is because, in the first embodiment, the rotating device 223 only needs to move (in this case rotate) the ejection optical member 2210 relative to the spherical member 222 while the spherical member 222 is fixed. Considering that a misalignment in the positional relationship between the injection optical element 2210 and the spherical element 222 could lead to a deterioration in the measurement accuracy of the measuring device 20, it is expected that the measurement accuracy of the measuring device 20 will be improved in the first embodiment.

[0303] Next, I will explain the second technical reason. As shown in Figure 21, the measuring device 20 irradiates the object to be measured MT (for example, the reference member FM) with measuring light ML via the spherical member 222. Here, as described above, if the center 222C of the spherical member 222 is used as the pivot point, even if the rotating device 223 rotates the ejection optical member 2210 around the center 222C of the spherical member 222 as the center of rotation, the pivot point (i.e., the center 222C of the spherical member 222) will remain in the same position. In other words, the pivot point, which corresponds to the origin of the "distance between the measuring device 20 (measuring head 22) and the object to be measured MT" measured by the measuring system 2, will remain in the same position. For this reason, even if the rotating device 223 rotates the ejection optical member 2210 around the center 222C of the spherical member 222 as the center of rotation, the possibility that the rotation of the ejection optical member 2210 will affect the measurement accuracy of the measuring device 20 will be small. In other words, even if the rotating device 2...

Claims

1. A measurement system used to correct the spatial accuracy of a machine tool in which at least one of a stage on which a workpiece is placed and a machining head is movable, and the workpiece is machined with a tool detachably attached to the spindle of the machining head, comprising: an optical device including an optical member that emits measurement light toward a reflective member; and a rotating device that can rotate the optical member about a rotation axis, wherein the optical device is calibrated based on a first light reception result, which is the light reception result of a light receiving device that receives the reflected light from the reflective member irradiated with the measurement light, when the measurement light is emitted toward the reflective member from the optical member at a rotation angle of a first angle about the rotation axis, and the reflected light is received by a light receiving device that receives the reflected light from the reflective member irradiated with the measurement light, when the rotation angle about the rotation axis changes from the first angle to a second angle by control of the rotating device by a control device, when the measurement light is emitted toward the reflective member from the optical member, and the reflected light is received by a light receiving device that receives the reflected light through the optical member.

2. The measurement system according to claim 1, wherein the reflective member rotates together with the optical member in accordance with the rotation of the optical member by the rotating device.

3. The measurement system according to claim 1 or 2, wherein the reflective member is removable from the optical path of the measurement light emitted from the optical member.

4. The measurement system according to any one of claims 1 to 3, wherein the reflective member includes a retroreflective member that retroreflects the measurement light incident on the reflective member.

5. The measurement system according to any one of claims 1 to 4, wherein the optical device includes a spherical member which is at least a part of a spherical optical element, the optical member emits the measurement light incident on the optical member toward the reflecting member via the spherical member, and emits the reflected light from the reflecting member which has been irradiated with the measurement light toward the light receiving device.

6. The measurement system according to claim 5, wherein the optical member emits the measurement light incident on the optical member toward the spherical member, and emits the measurement light from the spherical member that has been irradiated with the measurement light toward the reflecting member.

7. The measurement system according to claim 5 or 6, wherein the optical device includes a refractive optical system disposed in the optical path of the measurement light between the optical member and the spherical member, and the spherical member reflects the measurement light incident on the outer surface of the spherical member from the optical member via the refractive optical system toward the optical member from the outer surface toward the optical member via the refractive optical system.

8. The measurement system according to claim 5 or 6, wherein the measurement light incident from the optical member to the spherical member is incident into the interior of the spherical member via the outer surface of the spherical member, and the spherical member reflects the measurement light incident into the interior of the spherical member toward the optical member.

9. The measurement system according to claim 7, wherein the calibration of the optical device includes adjusting the position of the refractive optical system.

10. The measurement system according to any one of claims 5 to 9, wherein the calibration of the optical device includes adjusting the position of the spherical member.

11. The measurement system according to any one of claims 1 to 10, wherein the optical component includes a beam splitter.

12. The measurement system according to claim 1, wherein the reflective member includes a first reflective element positioned on the optical path of the measurement light emitted from the optical member having a rotation angle of a first angle around the rotation axis, and a second reflective element different from the first reflective element, positioned on the optical path of the measurement light emitted from the optical member having a rotation angle of a second angle around the rotation axis.

13. The measurement system according to claim 12, wherein the first reflecting element is a retroreflective element that retroreflects the measurement light incident on the first reflecting element, and the second reflecting element is a retroreflective element that retroreflects the measurement light incident on the second reflecting element.

14. The measurement system according to claim 12 or 13, wherein the first reflective element and the second reflective element are arranged on a circumference centered on the rotation axis.

15. The measurement system according to any one of claims 12 to 14, wherein the reflective member is a first reflective member, and the optical member includes a second reflective member different from the first reflective member, which reflects the measurement light incident on the optical member toward the first reflective member and reflects the reflected light from the first reflective member irradiated with the measurement light toward the light receiving device.

16. The measurement system according to any one of claims 12 to 14, wherein the optical member includes the terminal portion of an optical fiber through which the measurement light from the light source propagates, from which the measurement light is emitted.

17. The measurement system according to any one of claims 1 to 16, wherein the calibration of the optical device includes adjusting the position of the optical member.

18. The measuring system according to any one of claims 1 to 17, wherein the rotating device includes a first support member for supporting the optical member and a second support member for supporting the first support member such that the first support member is rotatable around the axis of rotation, and the calibration of the optical device includes adjusting the position of at least one of the first support member and the second support member.

19. The measurement system according to any one of claims 1 to 18, wherein the rotating shaft includes an axis that intersects with the rotating shaft of the main shaft.

20. The measuring system according to any one of claims 1 to 19, wherein the rotating shaft includes an axis along the rotation axis of the main shaft.

21. The measurement system according to any one of claims 5 to 10, wherein the rotating shaft intersects with the rotating shaft of the main shaft and includes a shaft that passes through the spherical member.

22. The measuring system according to any one of claims 5 to 10 or 21, wherein the rotating shaft is an axis along the rotating shaft of the main shaft and includes an axis passing through the spherical member.

23. The measurement system according to claim 21 or 22, wherein the rotating shaft passes through the center of the spherical member.

24. The measurement system according to any one of claims 1 to 23, wherein the rotation axis is a first rotation axis, the rotating device is capable of rotating the optical member around a second rotation axis intersecting the first rotation axis, the measurement light is emitted from the optical member at a rotation angle of a third angle around the second rotation axis toward the reflecting member, and the optical device is calibrated based on a third light reception result, which is the light reception result of the light receiving device that receives the reflected light from the reflecting member irradiated with the measurement light via the optical member, and a fourth light reception result, which is the light reception result of the light receiving device that receives the reflected light from the reflecting member irradiated with the measurement light via the optical member, as the rotation angle around the second rotation axis changes from a third angle to a fourth angle by the control device, and the optical device is calibrated based on the first light reception result and the second light reception result.

25. The measurement system according to claim 24, wherein the third light reception result and the fourth light reception result are the respective light reception results of the light receiving device, which receives the reflected light from the reflected light irradiated by the measurement light via the optical member, with the rotation angle of the optical member around the first rotation axis being the first angle, and the measurement light being emitted from the optical member at the third and fourth angles, respectively.

26. The measurement system according to claim 24 or 25, wherein, with the rotation angle around the first rotation axis being the second angle, the measurement light is emitted from the optical member with a rotation angle around the second rotation axis being the fifth angle toward the reflecting member, and the optical device is calibrated based on the fifth light reception result, which is the light reception result of the light receiving device that receives the reflected light from the reflecting member irradiated with the measurement light via the optical member, and the measurement light is emitted from the optical member with a rotation angle around the second rotation axis changing from the fifth angle to the sixth angle due to control of the rotation device by the control device, toward the reflecting member, and the optical device is calibrated based on the sixth light reception result, which is the light reception result of the light receiving device that receives the reflected light from the reflecting member irradiated with the measurement light via the optical member.

27. The measurement system according to any one of claims 24 to 26, wherein one of the first rotation axis and the second rotation axis is a rotation axis that intersects with the rotation axis of the main spindle, and the other is a rotation axis along the main spindle.

28. The measurement system according to any one of claims 24 to 27, wherein the rotating device includes a first rotating device capable of rotating the optical member around a first rotation axis and a second rotating device capable of rotating the optical member around a second rotation axis, and the control device controls the first rotating device and the second rotating device.

29. The measurement system according to any one of claims 24 to 28, wherein the reflective member includes a third reflective element positioned on the optical path of the measurement light emitted from the optical member having a rotation angle of a third angle around the second rotation axis, and a fourth reflective element positioned on the optical path of the measurement light emitted from the optical member having a rotation angle of a fourth angle around the second rotation axis.

30. The measurement system according to claim 29, wherein the third reflecting element is a retroreflective member that retroreflects the measurement light incident on the third reflecting element, and the fourth reflecting element is a retroreflective member that retroreflects the measurement light incident on the fourth reflecting element.

31. The measurement system according to claim 29 or 30, wherein the third reflective element and the fourth reflective element are arranged on a circumference centered on the second rotation axis.

32. The measurement system according to any one of claims 1 to 31, wherein the optical device is calibrated by the user based on the light reception result.

33. The measurement system according to any one of claims 1 to 31, wherein the control device calibrates the optical device based on the light reception result.

34. The measurement system according to any one of claims 1 to 31, wherein the optical device is calibrated based on the light reception result.

35. The measurement system according to any one of claims 1 to 34, wherein the light receiving device includes at least a part of an interference device that receives light by interfering the reflected light from the reflective member irradiated with the measurement light with a reference light.

36. The measurement system according to claim 35, wherein the light receiving device includes a part of the interferometer, and the optical member includes another part of the interferometer.

37. The measurement system according to claim 35 or 36, wherein the first light reception result includes a first ratio which is the ratio of the intensity of the reflected light received by the interfering device through the optical member when the measurement light is emitted from the optical member at a first angle toward the reflecting member, to the intensity of the reference light, and the second light reception result includes a second ratio which is the ratio of the intensity of the reflected light received by the interfering device through the optical member when the measurement light is emitted from the optical member at a second angle toward the reflecting member, to the intensity of the reference light, and the optical device is calibrated such that the first ratio and the second ratio are substantially the same.

38. The light receiving device includes at least a part of an interference device that receives light by interfering the reflected light from the reflective member irradiated with the measurement light with a reference light, wherein the first light receiving result includes a first ratio which is the ratio of the intensity of the reflected light received by the interference device via the optical member when the measurement light is emitted from the optical member at a first angle toward the reflective member, to the intensity of the reference light, wherein the second light receiving result includes a second ratio which is the ratio of the intensity of the reflected light received by the interference device via the optical member when the measurement light is emitted from the optical member at a second angle toward the reflective member, to the intensity of the reference light, wherein the third light receiving result includes a third ratio which is the ratio of the intensity of the reflected light received by the interference device via the optical member when the measurement light is emitted from the optical member at a third angle toward the reflective member, to the intensity of the reference light, The measurement system according to any one of claims 24 to 31, wherein the fourth light reception result includes a fourth ratio which is the ratio of the intensity of the reflected light received by the interferometer through the optical member to the intensity of the reference light, and the optical device is calibrated such that the first ratio, the second ratio, the third ratio, and the fourth ratio are substantially the same.

39. The measurement system according to any one of claims 1 to 38, wherein the control device calculates a first distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a first angle, based on the first light reception result, and calculates a second distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a second angle, based on the second light reception result, and the optical device is calibrated so that the first distance and the second distance are substantially the same.

40. The measurement system according to any one of claims 24 to 38, wherein the control device calculates a first distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a first angle, based on the first light reception result; calculates a second distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a second angle, based on the second light reception result; calculates a third distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a third angle, based on the third light reception result; and calculates a fourth distance, which is the distance between the optical device and the reflective member when the rotation angle of the optical member around the rotation axis is a fourth angle, based on the fourth light reception result, and the optical device is calibrated so that the first distance, the second distance, the third distance, and the fourth distance are substantially the same.

41. The measurement system according to any one of claims 1 to 40, wherein the optical device includes the light receiving device.

42. The measurement system according to any one of claims 1 to 41, wherein the optical device includes a light source that generates the measurement light, and the optical member emits the measurement light from the light source toward the reflecting member.

43. The measurement system according to any one of claims 1 to 42, wherein the optical device includes the rotating device.

44. The measurement system according to any one of claims 1 to 43, comprising the control device.

45. The measurement system according to any one of claims 1 to 44, wherein the reflective member is a first reflective member, the light receiving device is a first light receiving device, the measurement light is a first measurement light, and the calibrated optical device is attached to the spindle in place of the tool, and the spatial accuracy of the machine tool is corrected based on the result of receiving the reflected light from the third reflective member, which is generated when the second measurement light is irradiated from the optical device toward the third reflective member via the optical member, via the optical member, with the second light receiving device via the optical member.

46. ​​The measurement system according to any one of claims 5 to 10, wherein the reflective member is a first reflective member, the light receiving device is a first light receiving device, the measurement light is a first measurement light, the optical device includes a detachable member that supports the spherical member and is detachable from the main spindle, and instead of the tool, the calibrated optical device is attached to the main spindle via the detachable member, and the spatial accuracy of the machine tool is corrected based on the result of receiving the reflected light from the third reflective member, which is generated when a second measurement light incident on the optical member is irradiated toward the third reflective member via the spherical member supported by the detachable member attached to the main spindle, via the optical member and the spherical member, by the second light receiving device via the optical member and the spherical member.

47. The measurement system according to claim 45 or 46, wherein at least a portion of the second light receiving device is the same as at least a portion of the first light receiving device.

48. The measurement system according to any one of claims 45 to 47, comprising the second light receiving device.

49. The measurement system according to any one of claims 45 to 48, wherein the control device is a first control device, and the second measurement light is irradiated toward the third reflecting member via the optical member, whose rotation angle around the rotation axis is set by the control of the rotating device by the second control device.

50. The measurement system according to any one of claims 45 to 49, wherein the control device is a first control device, and the second control device corrects the spatial accuracy based on the reception result of the reflected light from the third reflecting member irradiated with the second measurement light, which is received by the second light receiving device.

51. The measurement system according to any one of claims 45 to 50, wherein the spatial accuracy of the machine tool is corrected based on the measurement results of the spatial accuracy.

52. The measurement system according to claim 51, wherein the control device is a first control device, the second control device measures the spatial accuracy based on the reception result of the reflected light from the third reflecting member to which the second measurement light received by the second light receiving device is irradiated, and the spatial accuracy of the machine tool is corrected based on the measurement result of the spatial accuracy.

53. The measurement system according to claim 49, 50, or 52, wherein the second control device is the same control device as the first control device.

54. The measurement system according to any one of claims 45 to 53, wherein the second measurement light is light having the same characteristics as the first measurement light.

55. The measurement system according to any one of claims 1 to 44, wherein the optical device is mounted on the spindle in place of the tool, the first light reception result and the second light reception result are acquired with the optical device mounted on the spindle, and the optical device mounted on the spindle is calibrated based on the first light reception result and the second light reception result.

56. The measurement system according to claim 55, wherein the spatial accuracy of the machine tool is corrected based on the result of receiving the reflected light from the third reflecting member via the optical member, which is generated when the measurement light is irradiated from the optical device mounted on the spindle to the third reflecting member via the optical member, via the optical member, by the light receiving device via the optical member.

57. The measuring system according to any one of claims 45 to 56, wherein the optical device is attached to the spindle in place of the tool by an exchange device.

58. The measurement system according to claim 57, wherein the optical device is stored in the exchange device, and the optical device stored in the exchange device is attached to the spindle in place of the tool by the exchange device.

59. The measurement system according to claim 57 or 58, wherein the machine tool is equipped with the exchange device.

60. The measurement system according to any one of claims 45 to 59, wherein the third reflective member is provided on the stage.

61. The measurement system according to any one of claims 1 to 60, wherein the spatial accuracy of the machine tool includes at least one of the movement error caused by the movement of the stage and the movement error caused by the movement of the machining head.

62. The measurement system according to any one of claims 1 to 61, wherein it is determined whether or not the optical device is calibrated based on the calibration determination conditions for the optical device.

63. The measurement system according to claim 62, wherein the control device determines whether or not to calibrate the optical device based on the calibration determination conditions.

64. The measurement system according to claim 62 or 63, wherein, when the calibration determination condition falls outside the threshold, the optical device emits the measurement light from the optical member toward the reflecting member, the light receiving device receives the reflected light, and the optical device is calibrated based on the first light receiving result and the second light receiving result.

65. The measurement system according to claim 64, wherein, when the calibration determination condition falls outside the threshold, the control device calibrates the optical device based on the first light reception result and the second light reception result.

66. The measurement system according to any one of claims 1 to 64, wherein the control device outputs information based on the calibration determination conditions of the optical device.

67. The measurement system according to any one of claims 1 to 66, wherein the control device outputs the information when the calibration determination condition falls outside the threshold.

68. The measurement system according to claim 66 or 67, wherein the information includes information indicating that the calibration determination conditions have been met.

69. The measurement system according to any one of claims 66 to 68, wherein the information includes information relating to a suggestion for calibration to the user.

70. The measurement system according to any one of claims 62 to 69, wherein the calibration determination conditions include the environment of the optical device and changes in the environment of the optical device.

71. The measurement system according to claim 70, wherein the environment of the optical device includes at least one of the temperature around the optical device and the humidity around the optical device.

72. The measurement system according to any one of claims 62 to 71, wherein the calibration determination condition includes the state of the optical device or a change in the state of the optical device.

73. The measurement system according to claim 72, wherein the state of the optical device includes at least one of the temperature of the optical device, the humidity of the optical device, and the acceleration of the optical device.

74. The measurement system according to any one of claims 62 to 73, wherein the calibration determination condition includes elapsed time.

75. The measurement system according to claim 74, wherein the elapsed time includes at least one of the time the measurement system was used to measure the spatial accuracy and the time elapsed since the previous calibration of the optical device.

76. The measurement system according to any one of claims 62 to 75, wherein the calibration determination condition includes at least one of date, day of the week, and time.

77. The measurement system according to any one of claims 62 to 76, wherein the calibration determination condition includes at least one of the following: a fifth light reception result, which is the light reception result of the light receiving device that receives the reflected light from the reflecting member irradiated with the measurement light via the optical member, and a value based on the fifth light reception result, wherein the measurement light is emitted from the optical member at a fifth angle of rotation around the rotation axis toward the reflecting member.

78. The measurement system according to claim 77, wherein the calibration determination condition includes at least one of the sixth light reception result and a value calculated based on the sixth light reception result, which is the light reception result of the light receiving device that receives the reflected light from the optical member, whose rotation angle has changed from the fifth angle to the sixth angle by the control device, and which emits the measurement light toward the reflecting member, and receives the reflected light from the reflecting member that has been irradiated with the measurement light via the optical member, and at least one of the fifth light reception result and a value calculated based on the fifth light reception result.

79. The measurement system according to claim 78, wherein the difference between the fifth angle and the sixth angle is greater than the difference between the first angle and the second angle.

80. The measurement system according to claim 78 or 79, wherein the number of times the rotation angle is changed in order to obtain the light reception result as the calibration determination condition is less than the number of times the rotation angle is changed in order to obtain the light reception result used for the calibration of the optical device.

81. The measurement system according to any one of claims 77 to 80, wherein the number of light reception results obtained as calibration judgment conditions is less than the number of light reception results obtained for the calibration of the optical device.

82. The measurement system according to any one of claims 77 to 81, wherein the calibration determination condition is a second calibration determination condition, and when the first calibration determination condition of the optical device falls outside the threshold, the measurement light is emitted from the optical member at the fifth angle toward the reflecting member, and the fifth light reception result is obtained by receiving the reflected light from the reflecting member that has been irradiated with the measurement light via the optical member.

83. The measurement system according to claim 82, wherein the first calibration determination condition includes at least one of the environment of the optical device, a change in the environment of the optical device, the state of the optical device, a change in the state of the optical device, elapsed time, date, day of the week, and time.

84. The measurement system according to any one of claims 1 to 83, wherein the reflective member reflects a first measurement light, which is a part of the measurement light incident on the reflective member from the optical member, toward the optical member, and the second measurement light, which is another part of the measurement light incident on the reflective member, passes through the reflective member, and the light receiving device receives the reflected light from the reflective member irradiated with the first measurement light via the optical member.

85. The measurement system according to claim 84, wherein the reflective member includes a half-mirror.

86. The measurement system according to claim 83 or 84, wherein the optical device is attachable to the spindle in place of the tool, and with the optical device attached to the spindle, the optical device emits the measurement light from the optical member toward the reflecting member, and the light receiving device receives the reflected light.

87. The measurement system according to any one of claims 83 to 86, wherein the reflective member is a first reflective member, the reflected light from the first reflective member is the first reflected light, the second measurement light transmitted through the first reflective member is incident on a third reflective member, the light receiving device receives the second reflected light, which is the reflected light from the third reflective member irradiated with the second measurement light, via the optical member, and the spatial accuracy of the machine tool is corrected based on the result of the light receiving device receiving the second reflected light.

88. A machine tool comprising a measuring system according to any one of claims 1 to 87.

89. A measuring system for use in a machine tool in which at least one of a stage on which a workpiece is placed and a machining head is movable, and the workpiece is machined with a tool detachably attached to the spindle of the machining head, comprising: a spherical member which is at least a part of which is a spherical optical element; an optical member which emits measuring light toward a third reflecting member via the spherical member, and an optical device which is detachably attached to the spindle in place of the tool; and a light receiving device which receives the reflected light from the third reflecting member which has been irradiated with the measuring light, and the machine tool is adjusted based on the result of receiving the reflected light by the light receiving device.

90. The measurement system according to claim 89, wherein the optical device includes a third support member that supports the spherical member and is detachable from the main shaft.

91. The measurement system according to claim 90, wherein the optical device includes a rotating device capable of rotating the optical member around a rotation axis, and the third support member supports the rotating device.

92. The measuring system according to claim 91, wherein the rotating device includes a first support member for supporting the optical member and a second support member for supporting the first support member such that the first support member is rotatable around the rotation axis, and the third support member supports at least one of the first support member and the second support member.

93. The measuring system according to claim 91 or 92, wherein the rotating shaft of the rotating device includes an axis that intersects with the rotating shaft of the main shaft.

94. The measuring system according to any one of claims 91 to 93, wherein the rotating shaft of the rotating device includes an axis along the axis of rotation of the main shaft.

95. The measuring system according to any one of claims 91 to 94, wherein the rotating shaft of the rotating device passes through the spherical member.

96. The measuring system according to claim 95, wherein the rotating shaft of the rotating device passes through the center of the spherical member.

97. The measurement system according to any one of claims 89 to 96, wherein the third reflective member is provided on the stage or the workpiece placed on the stage.

98. A measurement system according to any one of claims 91 to 97, comprising a control device for controlling the rotating device, wherein the third reflective member is provided on the stage or the workpiece placed on the stage, and the measurement light is emitted from the optical member, whose rotation angle around the rotation axis is a seventh angle, toward the third reflective member via the spherical member, and the machine tool is adjusted based on a seventh light reception result, which is the light reception result of the light receiving device that receives the return light from the third reflective member irradiated with the measurement light via the optical member, and an eighth light reception result, which is the light reception result of the light receiving device that receives the return light from the third reflective member irradiated with the measurement light, toward the third reflective member via the spherical member, as at least one of the stage and the processing head moves and the rotation angle of the optical member changes from a seventh angle to an eighth angle by control of the rotating device by the control device, and the machine tool is adjusted based on this result.

99. The device comprises a control device for controlling the rotating device, wherein each of the third reflective member, fourth reflective member, fifth reflective member, and sixth reflective member is provided on at least one of the stage and the workpiece placed on the stage, and the measurement light is emitted from the optical member, whose rotation angle around the rotation axis is seventh angle, toward the third reflective member via the spherical member, and the seventh light reception result is the light reception result of a light receiving device that receives the return light from the third reflective member irradiated with the measurement light via the optical member, and the measurement light is emitted from the optical member, whose rotation angle has changed from seventh to ninth angle by the control device for the rotating device, toward the fourth reflective member via the spherical member, and the ninth light reception result is the light reception result of a light receiving device that receives the return light from the fourth reflective member irradiated with the measurement light via the optical member, and the rotation angle has changed from ninth to first angle by the control device for the rotating device A measurement system according to any one of claims 91 to 98, wherein the machine tool is adjusted based on a 10th light reception result, which is the light reception result of the light receiving device that receives the reflected light from the 5th reflector irradiated with the measurement light, via the optical member, when the optical member has changed its rotation angle from the 10th angle to the 11th angle by the control device, when the optical member has changed its rotation angle from the 10th angle to the 11th angle, when the measurement light is emitted from the 6th reflector irradiated with the measurement light, via the spherical member, when the light receiving device that receives the reflected light from the 6th reflector irradiated with the measurement light, when the machine tool is adjusted based on the 11th light reception result, which is the light reception result of the light receiving device that receives the reflected light from the 6th reflector irradiated with the measurement light, via the optical member.

100. A measurement system for use in a machine tool in which at least one of a stage on which a workpiece is placed and a machining head is movable, and the workpiece is machined with a tool detachably attached to the spindle of the machining head, comprising: an optical device disposed within the machine tool, which includes a spherical member that is at least a part of which is a spherical optical element, and an optical member that emits measurement light toward a third reflecting member through the spherical member; and a light receiving device that receives the reflected light from the third reflecting member to which the measurement light is emitted from the optical member toward the third reflecting member through the spherical member, wherein the machine tool is adjusted based on the result of receiving the reflected light by the light receiving device.

101. The measurement system according to claim 100, further comprising a rotating device capable of rotating the optical member around a rotation axis.

102. The measurement system according to claim 101, wherein the optical device includes the rotating device, and the rotating device includes a first support member for supporting the optical member and a second support member for supporting the first support member such that the first support member is rotatable around the rotation axis.

103. The measuring system according to claim 101 or 102, wherein the rotating shaft of the rotating device includes a first shaft that penetrates the spherical member.

104. The measuring system according to claim 103, wherein the rotating shaft of the rotating device includes a second shaft that intersects the first shaft.

105. The measurement system according to claim 104, wherein the second axis penetrates the spherical member.

106. The measurement system according to claim 104 or 105, wherein at least one of the first axis and the second axis passes through the center of the spherical member.

107. A measurement system according to any one of claims 101 to 106, comprising a control device for controlling the rotating device, wherein the machine tool is adjusted based on the following: a 12th light reception result, which is the light reception result of a light receiving device that receives the return light from the third reflecting member irradiated with the measurement light, via the optical member, from the optical member whose rotation angle has changed from the 12th angle to the 13th angle due to the control device for the rotating device, and a 13th light reception result, which is the light reception result of a light receiving device that receives the return light from the third reflecting member irradiated with the measurement light, via the optical member, from which at least one of the stage and the processing head has moved, and the machine tool is adjusted based on the following:

108. The measurement system according to any one of claims 100 to 107, wherein the optical device is provided in a portion of the processing head different from the spindle.

109. The measurement system according to any one of claims 100 to 108, wherein the third reflective member is provided on the stage or the workpiece placed on the stage.

110. The device comprises a control device for controlling the rotating device, wherein each of the third reflective member, fourth reflective member, fifth reflective member, and sixth reflective member is provided on at least one of the stage and the workpiece placed on the stage, and the measurement light is emitted from the optical member, whose rotation angle around the rotation axis is seventh angle, toward the third reflective member via the spherical member, and the seventh light reception result is the light reception result of a light receiving device that receives the return light from the third reflective member irradiated with the measurement light via the optical member, and the measurement light is emitted from the optical member, whose rotation angle has changed from seventh to ninth angle by the control device for the rotating device, toward the fourth reflective member via the spherical member, and the ninth light reception result is the light reception result of a light receiving device that receives the return light from the fourth reflective member irradiated with the measurement light via the optical member, and the rotation angle has changed from ninth to tenth angle by the control device for the rotating device A measurement system according to any one of claims 100 to 109, wherein the machine tool is adjusted based on a 10th light reception result, which is the light reception result of the light receiving device that receives the reflected light from the 5th reflector irradiated with the measurement light via the optical member, from the optical member whose rotation angle has changed from a 10th angle to an 11th angle by the control device, from the optical member whose rotation angle has changed from a 10th angle to an 11th angle, the measurement light is emitted from the 6th reflector irradiated with the measurement light via the spherical member, from the optical member, and the light receiving device that receives the reflected light from the 6th reflector irradiated with the measurement light, from the light receiving device that receives the reflected light via the optical member.

111. The optical device is provided on the stage or on the workpiece placed on the stage, according to any one of claims 100 to 107.

112. The measurement system according to any one of claims 100 to 107 and 111, wherein the third reflective member is provided on the processing head.

113. The measurement system according to claim 112, wherein the third reflective member is provided on the main spindle of the machining head in place of the tool.

114. The optical device is a second optical device, the optical member is a second optical member, the spherical member is a second spherical member, the light receiving device is a second light receiving device, the measurement light is a second measurement light, the third optical device includes a third spherical member which is at least a part of which is a spherical optical element, and a third optical member which emits a third measurement light toward the third reflecting member via the third spherical member, the third measurement light is emitted from the third optical member toward the third reflecting member via the third spherical member, and the third light receiving device which receives the reflected light from the third reflecting member which has been irradiated with the third measurement light, the fourth optical device includes a fourth spherical member which is at least a part of which is a spherical optical element, and a fourth optical member which emits a fourth measurement light toward the third reflecting member via the fourth spherical member, The fourth optical device includes a fourth light receiving device that receives the reflected light from the third reflecting member to which the fourth measurement light is emitted from the fourth optical member toward the third reflecting member via the fourth spherical member, and a fifth spherical member that is at least a part of a spherical optical element, and a fifth optical member that emits the fifth measurement light toward the third reflecting member via the fifth spherical member, and the fifth light receiving device that receives the reflected light from the third reflecting member to which the fifth measurement light is emitted from the fifth optical member toward the third reflecting member via the fifth spherical member, and the second optical device, the third optical device, the fourth optical device, and the fifth optical device are provided on the stage and the workpiece placed on the stage,The measurement light is emitted from the second optical member toward the third reflective member via the second spherical member, and the 14th light-receiving result is the light-receiving result of the second light-receiving device that receives the reflected light from the third reflective member that has been irradiated with the measurement light via the second optical member, and the 15th light-receiving result is the light-receiving result of the third light-receiving device that receives the reflected light from the third reflective member that has been irradiated with the measurement light via the third spherical member, and the 4th light is emitted from the 4th optical member toward the front A measurement system according to any one of claims 111 to 113, wherein the machine tool is adjusted based on a 16th light reception result, which is the light reception result of a fourth light receiving device that receives the reflected light from the third reflecting member that has been irradiated with the measurement light via the fourth optical member, and a 17th light reception result, which is the light reception result of a fifth light receiving device that receives the reflected light from the third reflecting member that has been irradiated with the measurement light via the fifth spherical member, from the fifth optical member toward the third reflecting member.

115. The measurement system according to any one of claims 89 to 114, wherein the optical member emits the measurement light incident on the optical member toward the reflecting member via the spherical member, and emits the reflected light from the reflecting member irradiated with the measurement light toward the light receiving device.

116. The measurement system according to claim 115, wherein the optical member emits the measurement light incident on the optical member toward the spherical member, and emits the measurement light from the spherical member that has been irradiated with the measurement light toward the reflecting member.

117. The measurement system according to any one of claims 89 to 116, wherein the optical component includes a beam splitter.

118. The measurement system according to any one of claims 89 to 117, wherein the optical device includes a refractive optical system disposed in the optical path of the measurement light between the optical member and the spherical member, and the spherical member reflects the measurement light incident on the outer surface of the spherical member from the optical member via the refractive optical system toward the optical member from the outer surface toward the optical member via the refractive optical system.

119. The measurement system according to any one of claims 89 to 117, wherein the measurement light incident from the optical member to the spherical member is incident into the interior of the spherical member via the outer surface of the spherical member, and the spherical member reflects the measurement light incident into the interior of the spherical member toward the optical member.

120. The measurement system according to any one of claims 89 to 119, wherein the optical member comprises a polarizing beam splitter and at least one waveplate.

121. The optical member includes a polarizing beam splitter, a first half-wave plate, a first quarter-wave plate, a second quarter-wave plate, a third quarter-wave plate, and a seventh reflecting member, wherein the measurement light incident on the optical device is incident on the polarizing beam splitter via the first half-wave plate, and the polarizing beam splitter reflects the measurement light incident on the polarizing beam splitter via the first half-wave plate toward the spherical member, such that the measurement light incident on the polarizing beam splitter via the first half-wave plate is incident on the spherical member via the first quarter-wave plate. The spherical member reflects the measurement light incident on the spherical member from the polarizing beam splitter via the first quarter-wave plate toward the polarizing beam splitter, such that the measurement light incident on the spherical member from the polarizing beam splitter via the first quarter-wave plate is incident on the polarizing beam splitter via the first quarter-wave plate; the measurement light incident on the spherical member from the polarizing beam splitter via the first quarter-wave plate passes through the polarizing beam splitter and is incident on the third reflecting member via the second quarter-wave plate; and the reflected light from the third reflecting member irradiated with the measurement light is incident on the polarizing beam splitter via the second quarter-wave plate. The measurement system according to claim 120, wherein the polarizing beam splitter reflects the light that has been incident on the polarizing beam splitter via the second quarter-wave plate toward the seventh reflecting member such that the light that has been incident on the polarizing beam splitter via the second quarter-wave plate is incident on the seventh reflecting member via the third quarter-wave plate, the seventh reflecting member reflects the light that has been incident on the seventh reflecting member via the third quarter-wave plate such that the light that has been incident on the seventh reflecting member from the polarizing beam splitter via the third quarter-wave plate is incident on the polarizing beam splitter via the third quarter-wave plate, and the light that has been incident on the polarizing beam splitter from the seventh reflecting member via the third quarter-wave plate passes through the polarizing beam splitter and is incident on the light receiving device via the first half-wave plate.

122. The measurement system according to any one of claims 89 to 119, wherein the optical member includes a beam splitter, the beam splitter reflects the measurement light incident on the optical device toward the spherical member, the spherical member reflects the measurement light incident on the spherical member from the beam splitter toward the beam splitter, the beam splitter transmits the measurement light incident on the optical device from the spherical member toward the third reflecting member, the reflected light from the third reflecting member irradiated with the measurement light is incident on the beam splitter, the beam splitter reflects the reflected light incident on the beam splitter from the third reflecting member, and the reflected light reflected by the beam splitter is incident on the light receiving device.

123. The measurement system according to any one of claims 89 to 122, wherein the optical member includes an eighth reflecting member, the eighth reflecting member reflects a first measurement light, which is a part of the measurement light incident on the eighth reflecting member, toward the light receiving device, and transmits a second measurement light, which is another part of the measurement light incident on the reflecting member, toward the third reflecting member, and the light receiving device receives the reflected light from the third reflecting member, which is irradiated with the second measurement light, via the eighth reflecting member.

124. The measurement system according to claim 123, wherein the eighth reflective member includes a half mirror.

125. The measurement system according to any one of claims 89 to 124, further comprising a control device for adjusting the machine tool based on the light reception result.

126. The measurement system according to any one of claims 89 to 125, wherein the adjustment of the machine tool includes correction of the spatial accuracy of the machine tool.

127. The measurement system according to claim 126, comprising a control device for measuring the spatial accuracy of the machine tool based on the light reception result, wherein the spatial accuracy of the machine tool is corrected based on the measurement result of the spatial accuracy.

128. The measurement system according to claim 126 or 127, wherein the spatial accuracy of the machine tool includes at least one of the movement error caused by the movement of the stage and the movement error caused by the movement of the machining head.

129. The measurement system according to any one of claims 89 to 128, wherein it is determined whether or not the machine tool is adjusted based on the adjustment determination conditions for the machine tool.

130. The measurement system according to claim 129, further comprising a control device that determines whether or not to adjust the machine tool based on the adjustment determination conditions.

131. The measurement system according to claim 129 or 130, wherein, when the adjustment judgment condition falls outside the threshold, the optical device emits the measurement light from the optical member toward the third reflecting member via the spherical member, and the machine tool is adjusted based on the light receiving result by the light receiving device of the return light from the third reflecting member irradiated with the measurement light.

132. The measurement system according to claim 130, wherein, when the adjustment judgment condition falls outside the threshold, the optical device emits the measurement light from the optical member toward the third reflecting member via the spherical member, and the control device adjusts the machine tool based on the light receiving result of the return light from the third reflecting member irradiated with the measurement light by the light receiving device.

133. The measurement system according to claim 130, wherein the adjustment of the machine tool includes correction of the spatial accuracy of the machine tool, and when the adjustment determination condition falls outside a threshold, the optical device emits the measurement light from the optical member toward the third reflecting member via the spherical member, the control device measures the spatial accuracy of the machine tool based on the light receiving result of the return light from the third reflecting member irradiated with the measurement light by the light receiving device, and the spatial accuracy of the machine tool is corrected based on the measurement result of the spatial accuracy.

134. The measurement system according to any one of claims 89 to 133, comprising a control device that outputs information based on the adjustment determination conditions of the machine tool.

135. The measurement system according to any one of claims 89 to 134, further comprising a control device that outputs the information when the adjustment determination condition falls outside the threshold.

136. The measurement system according to claim 134 or 135, wherein the information includes information indicating that the adjustment determination conditions have been met.

137. The measurement system according to any one of claims 134 to 136, wherein the information includes information relating to a suggestion of the adjustment to the user.

138. The measurement system according to any one of claims 129 to 137, wherein the adjustment determination conditions include the environment of the machine tool and changes in the environment of the machine tool.

139. The measurement system according to claim 138, wherein the environment of the machine tool includes at least one of the temperature around the machine tool and the humidity around the machine tool.

140. The measurement system according to any one of claims 129 to 139, wherein the adjustment determination condition includes the state of the machine tool or a change in the state of the machine tool.

141. The measurement system according to claim 140, wherein the state of the machine tool includes at least one of the temperature of the machine tool, the humidity of the machine tool, and the acceleration of at least one of the stage and the machining head of the machine tool.

142. The measurement system according to any one of claims 129 to 141, wherein the adjustment determination condition includes elapsed time.

143. The measurement system according to claim 142, wherein the elapsed time includes at least one of the time the machine tool was used to process the workpiece and the time elapsed since the previous spatial accuracy correction.

144. The measurement system according to any one of claims 129 to 143, wherein the adjustment determination condition includes at least one of a date, a day of the week, and a time.

145. A measurement system according to any one of claims 129 to 144, comprising a rotating device capable of rotating the optical member around a rotation axis, wherein the adjustment determination condition includes at least one of a plurality of light reception results obtained by receiving the reflected light from the seventh reflecting member irradiated with the measurement light emitted from the optical member by the light receiving device at each of a plurality of rotation angles around the rotation axis, and a value calculated based on the plurality of light reception results.

146. The measurement system according to claim 145, wherein the seventh reflective member is the same reflective member as the third reflective member.

147. The measurement system according to claim 145 or 146, wherein the number of light reception results obtained as the adjustment judgment conditions is less than the number of light reception results used for the adjustment.

148. A measurement system according to any one of claims 145 to 147, wherein, at each of a plurality of rotation angles around the rotation axis, the machine tool is adjusted based on a plurality of light reception results obtained by the light receiving device from the reflected light from the third reflecting member to which the measurement light emitted from the optical member is irradiated, and the amount by which the rotation angle is changed to obtain the plurality of light reception results obtained as adjustment determination conditions is greater than the amount by which the rotation angle is changed to obtain the plurality of light reception results used for adjustment.

149. The measurement system according to claims 145 to 148, wherein, at each of a plurality of rotation angles around the rotation axis, the machine tool is adjusted based on a plurality of light reception results obtained by the light receiving device from the return light from the third reflecting member to which the measurement light emitted from the optical member has been irradiated, and the number of times the rotation angle is changed to obtain the plurality of light reception results obtained as adjustment determination conditions is less than the number of times the rotation angle is changed to obtain the plurality of light reception results used for the adjustment.

150. The measurement system according to any one of claims 145 to 149, wherein the adjustment determination condition is a second adjustment determination condition, and when the first adjustment determination condition of the optical device falls outside the threshold, the second adjustment determination condition is obtained by receiving a plurality of light reception results and a value based on the plurality of light reception results, for each of a plurality of rotation angles around the rotation axis, the light received by the light receiving device from the seventh reflecting member to which the measurement light emitted from the optical member has been irradiated.

151. The measurement system according to claim 150, wherein the first adjustment determination condition includes at least one of the environment of the machine tool, a change in the environment of the machine tool, the state of the machine tool, a change in the state of the machine tool, elapsed time, date, day of the week, and time.

152. A machine tool comprising a measuring system according to any one of claims 89 to 151.

153. The machine tool according to claim 152, wherein the machine tool is adjusted by the measurement system.

Images