Measurement system, machine tool, optical device, measurement method, computer program, and recording medium

Abstract

Provided is an optical device mounted to a spindle of a machining head in place of a tool detachably attached to the spindle in a machine tool which uses the tool to machine a workpiece while moving a stage for placing the workpiece and the machining head. This optical device comprises a direction change member which can change a travel direction of measurement light and a light reception unit which receives return light which is generated by illuminating each of a plurality of reference members with the measurement light having been changed in travel direction by the direction change member and returns from each of the plurality of reference members. The light reception unit receives the return light generated by illuminating with the measurement light each of: at least one from among the plurality of reference members that is disposed on the workpiece placed on the stage; and the workpiece placed on the stage or at least another one from among the plurality of reference members that is placed on the stage.

Description

Measurement system, machine tool, optical device, measurement method, computer program, and recording medium

[0001] The present invention relates to the technical fields of, for example, machine tools, and measurement systems, measurement methods, optical devices, measurement methods, computer programs, and recording media used in machine tools.

[0002] Patent Document 1 describes a machine tool that calculates movement errors that occur in the translational and rotational movements of first and second machine parts. In such a machine tool, a technical challenge is to appropriately calculate the movement errors.

[0003] U.S. Patent Publication No. 2018 / 0174317

[0004] According to a first aspect, in a machine tool that processes a workpiece using a tool detachably attached to the spindle of the machining head while moving at least one of a stage on which the workpiece is placed and a machining head, an optical device is provided that is attached to the spindle instead of the tool, and includes a direction changing member that can change the direction of propagation of measurement light, and a light receiving unit that receives return light from each of a plurality of reference members generated by irradiating each of the plurality of reference members with the measurement light whose direction of propagation has been changed by the direction changing member, and the light receiving unit receives the return light generated by irradiating the measurement light to at least one reference member among the plurality of reference members that is placed on the workpiece placed on the stage, and to each of the workpiece placed on the stage or at least one other reference member placed on the stage.

[0005] According to a second aspect, there is provided a measurement system used in a machine tool that processes a workpiece with a tool detachably attached to a spindle of a machining head while moving at least one of a stage on which a workpiece is placed and a machining head, the measurement system comprising: an optical device that is attached to the spindle instead of the tool and has a direction-changing member that can change the direction of propagation of measurement light, and that receives return light from each of the at least four reference members generated by irradiating each of the at least four reference members with the measurement light whose direction has been changed by the direction-changing member; and a calculation unit that calculates a position of the optical device based on the reception result of the return light from each of the at least four reference members by the optical device attached to the spindle, wherein the optical device receives the return light generated by irradiating the measurement light to at least one of the at least four reference members that is placed on the workpiece placed on the stage, and to each of the workpiece placed on the stage or at least three reference members that are placed on the stage.

[0006] According to a third aspect, there is provided a machine tool comprising the measurement system provided by the first aspect described above, the machining head, the stage, and a drive device that moves at least one of the machining head and the mounting device.

[0007] According to a fourth aspect, there is provided a measurement method used in a machine tool that processes a workpiece with a tool detachably attached to a spindle of a machining head while moving at least one of a stage on which a workpiece is placed and a machining head, the measurement method including: irradiating measurement light onto each of at least four reference members with an optical device attached to the spindle instead of the tool; receiving return light from each of the at least four reference members generated by irradiating the measurement light onto each of the at least four reference members with the optical device; and calculating a position of the optical device based on the reception result of the return light from each of the at least four reference members by the optical device, wherein each of the at least four reference members is placed on the workpiece placed on the stage or on the stage, and at least one of the at least four reference members is placed on the workpiece placed on the stage.

[0008] According to a fifth aspect, there is provided a computer program for causing a computer to execute the measurement method provided by the fourth aspect described above.

[0009] According to a sixth aspect, there is provided a recording medium on which the computer program provided by the fifth aspect described above is recorded.

[0010] According to a seventh aspect, in a machine tool that processes a workpiece using a tool detachably attached to the spindle of the machining head while moving at least one of a stage on which a workpiece is placed and a machining head, an optical device is provided that is attached to the spindle instead of the tool, and includes a direction changing member that can change the direction of propagation of measurement light, and a light receiving unit that receives return light from each of the at least four reference members generated by irradiating the measurement light, whose direction has been changed by the direction changing member, onto each of the at least four reference members, wherein the light receiving unit receives the return light generated by irradiating the measurement light onto at least one reference member that is placed on the workpiece placed on the stage, and onto each of the workpiece placed on the stage or at least three reference members that are placed on the stage, and the result of receiving the return light by the light receiving unit is used to calculate the position of the optical device.

[0011] According to an eighth aspect, there is provided a machine tool that processes a workpiece with a tool detachably attached to the spindle of the machining head while moving at least one of a stage on which the workpiece is placed and a machining head, and that is equipped with a calculation unit that is attached to the spindle in place of the tool and that calculates the position of the optical device based on the light reception results of an optical device that receives return light from each of at least four reference members generated by irradiating measurement light onto each of the at least four reference members, and the calculation unit calculates the position of the optical device based on the light reception results of the optical device of the return light generated by irradiating measurement light onto at least one reference member placed on the workpiece placed on the stage, and each of the workpiece placed on the stage or at least three reference members placed on the stage.

[0012] According to a ninth aspect, there is provided a measurement system used in a machine tool that processes a workpiece with a tool detachably attached to a spindle of a machining head while moving at least one of a stage on which a workpiece is placed and a machining head, the measurement system comprising: an optical device that receives return light from a reference member generated by irradiating measurement light onto a reference member each time the stage or the machining head moves to a plurality of different positions under a situation where the spindle is positioned in a first space other than a second space occupied by the workpiece placed on the stage; and a calculation unit that calculates a position relative to the spindle in the first space based on the result of receiving return light from the reference member received by the optical device each time the stage or the machining head moves to a plurality of different positions, and calculates a position relative to the spindle in the second space based on the calculated position relative to the spindle in the first space.

[0013] According to a tenth aspect, there is provided a measurement system used in a machine tool that processes a workpiece with a tool detachably attached to the spindle of the machining head while moving at least one of a stage on which the workpiece is placed and a machining head, the measurement system comprising: an optical device that is attached to the spindle instead of the tool and that receives return light from a reference member generated by irradiating measurement light onto the workpiece placed on the stage or a reference member placed on the stage; and a calculation unit that calculates the position of the optical device based on the temperature of at least one of the workpiece and the stage detected by a temperature detector that can detect the temperature of at least one of the workpiece and the stage, and the result of receiving the return light from the reference member by the optical device.

[0014] According to an eleventh aspect, there is provided a measurement system for use in a machine tool that processes a workpiece with a tool detachably attached to a spindle of a processing head while moving at least one of a stage on which a workpiece is placed and a processing head, the measurement system including: an optical device that is attached to the spindle instead of the tool and that receives return light from a reference member generated by irradiating the reference member with measurement light; and a calculation unit that calculates a position of the optical device based on a result of receiving the return light from the reference member by the optical device attached to the spindle, the optical device including a direction changer that can change the traveling direction of the measurement light. a reference member, the calculation unit controls the direction changing member so that the direction changing member changes the direction of travel of the measurement light to scan a first region where the measurement light can be irradiated with the measurement light; the optical device receives return light from the first region generated by scanning the first region with the measurement light; the calculation unit calculates the direction of the reference member from the optical device based on the result of receiving the return light from the first region by the optical device; and the calculation unit controls the direction changing member so that the measurement light is irradiated onto the reference member based on the direction of the reference member.

[0015] According to a twelfth aspect, there is provided a measurement system used in a machine tool that processes a workpiece with a tool detachably attached to a spindle of a machining head while moving at least one of a stage on which a workpiece is placed and a machining head, the measurement system comprising: an optical device that is attached to the spindle instead of the tool and has a direction changing member that can change the direction of propagation of measurement light, and that receives return light from each of at least four reference members that are arranged on at least one of the stage and the workpiece, the return light having been changed by the direction changing member, and a calculation unit that calculates the distance between the optical device and each of the at least four reference members based on the result of receiving the return light from each of the at least four reference members by the optical device, and generates information for controlling the machine tool based on the calculated distance.

[0016] According to the thirteenth aspect, there is provided a machine tool that processes a workpiece using a tool detachably attached to the spindle of the machining head while moving at least one of a stage on which a workpiece is placed and a machining head, the machine tool comprising an optical device that is attached to the spindle in place of the tool and that receives return light from at least four reference members generated by irradiating measurement light onto each of the at least four reference members and that is positioned on at least one of the stage and the workpiece, and a calculation unit that calculates the distance between the optical device and each of the at least four reference members based on the light reception results, and that controls at least one of the stage and the machining head based on a command value regarding the movement of at least one of the stage and the machining head and the calculated distance.

[0017] The functions and other advantages of the present invention will become apparent from the following detailed description of the preferred embodiments.

[0018] FIG. 1 is a perspective view showing the appearance of a processing system according to this embodiment. FIG. 2 is a block diagram showing the system configuration of the processing system according to this embodiment. FIG. 3 is a cross-sectional view showing the configuration of a processing head according to this embodiment. FIG. 4 is a cross-sectional view showing the configuration of a processing head according to this embodiment. FIG. 5 is a cross-sectional view showing a processing head to which a measurement device (particularly, a measurement head) according to this embodiment is attached. FIG. 6 is a cross-sectional view showing a processing head to which a measurement device (particularly, a measurement head) according to this embodiment is attached. FIG. 7 is a cross-sectional view showing an optical system that irradiates a measurement object with measurement light and receives return light from the measurement object. FIG. 8 is a cross-sectional view showing the structure of an optical system provided in a measurement head according to this embodiment. FIG. 9 is a cross-sectional view showing a reference member and a measurement head that measures the reference member. FIG. 10(a) is a top view showing multiple reference members, and FIG. 10(b) is a side view showing multiple reference members. Each of FIGS. 11(a) to 11(e) is a side view showing a measurement head that irradiates a reference member with measurement light. FIG. 12 is a flowchart showing the flow of a movement error calculation operation for calculating a movement error that occurs in the translational movement of at least one of the processing head and the stage. FIG. 13 schematically shows a measurement head that performs a global scan. FIG. 14 schematically shows a measurement head that performs a local scan. FIG. 15 shows a measurement coordinate system. FIG. 16 shows a measurement coordinate system that moves within the machine coordinate system as the stage moves. FIG. 17 shows three measurement points and four reference members. FIG. 18 shows the positions of the measurement points in the measurement coordinate system. FIG. 19 shows the positions of the measurement points in the machine coordinate system. FIG. 20 shows the movement error in the machine coordinate system. FIG. 21 is a flowchart showing the flow of a movement error calculation operation for calculating a movement error that occurs in the rotational movement of at least one of the processing head and the stage. FIG. 22 shows the positional relationship between the measurement head and the reference member. FIG. 23 shows the position of the reference member in the machine coordinate system. FIG. 24 shows the movement error in the machine coordinate system. FIG. 25 is a cross-sectional view showing the positional relationship between the stage, workpiece, and measurement head. Fig. 26 is a cross-sectional view showing the positional relationship between the stage, workpiece, and measurement head. Fig. 27 shows a movement error calculated by interpolation. Fig. 28 is a cross-sectional view showing the positional relationship between the stage, workpiece, and measurement head.FIG. 29 shows a movement error calculated by interpolation. FIG. 30 is a cross-sectional view showing the positional relationship between the stage, workpiece, and measurement head. FIG. 31 shows how the positions of measurement points in multiple spaces are combined. FIG. 32(a) shows the measurement head under a first condition in which no workpiece is placed on the stage, and FIG. 32(b) shows the measurement head under a second condition in which a workpiece is placed on the stage. FIGS. 33(a) and 33(b) are a top view and a side view, respectively, showing the datum and reference member of the workpiece. FIGS. 34(a) and 34(b) are a side view and a top view, respectively, showing the datum and reference member of the workpiece. FIGS. 35(a) and 35(b) show the datum points of the workpiece. FIGS. 36(a) and 36(b) show the datum points of the workpiece. FIG. 37 shows the datum points of the workpiece. FIG. 38 schematically shows the configuration of a machining system in a fourth modified example. FIG. 39 is a cross-sectional view showing an example of a measurement head provided in a processing system according to the fourth modified example. FIGS. 40(a) and 40(b) are cross-sectional views showing an example of a measurement head provided in a processing system according to the fourth modified example. FIG. 41 is a cross-sectional view showing the positional relationship between a measurement head and a reference member. FIGS. 42(a) and 42(b) are cross-sectional views showing a rotationally moving stage and a measurement head tracking a reference member disposed on the rotationally moving stage. FIG. 43 is a graph showing the distance between the measurement head and the reference member calculated from the return light of the reference member when the stage is rotationally moving, in correspondence with the movement trajectory of the reference member. FIG. 44 is a cross-sectional view showing a first specific example of a measurement head according to the seventh modified example. FIGS. 45(a) and 45(b) are cross-sectional views showing a second specific example of a measurement head according to the seventh modified example. FIGS. 46(a) and 46(b) are cross-sectional views showing a third specific example of a measurement head according to the seventh modified example. FIG. 47 is a cross-sectional view showing a fourth specific example of a measurement head according to the seventh modified example. Fig. 48 is a cross-sectional view showing a fifth specific example of the measurement head in the seventh modified example. Fig. 49 is a cross-sectional view showing a sixth specific example of the measurement head in the seventh modified example. Fig. 50 shows a pivot point located at a position away from the rotation axis of the spindle.51(a) to 51(c) are cross-sectional views showing how the posture of a spindle changes when the pivot point is located on the rotation axis of the spindle. 52(a) to 52(c) are cross-sectional views showing how the posture of a spindle changes when the pivot point is located at a position away from the rotation axis of the spindle. 53 is a cross-sectional view showing the configuration of a measurement device of a ninth modified example. 54 is a cross-sectional view showing the configuration of a first specific example of a measurement device in the ninth modified example. 55 is a cross-sectional view showing the configuration of a second specific example of a measurement device in the ninth modified example. 56 is a cross-sectional view showing the configuration of a third specific example of a measurement device in the ninth modified example. 57 is a cross-sectional view showing a measurement head that repeats unit measurement operations of irradiating a reference member with measurement light and receiving return light from the reference member. 58 is a cross-sectional view showing a measurement head that repeats unit measurement operations of irradiating a reference member with measurement light and receiving return light from the reference member. 59 is a block diagram showing the system configuration of a machining system of an eleventh modified example. FIG. 60 is a cross-sectional view showing a thermally expanding workpiece. FIGS. 61(a) to 61(d) are cross-sectional views showing an example of a temperature sensor. FIGS. 62(a) and 62(b) are cross-sectional views showing a workpiece placed on a stage via a support member. FIG. 63 is a cross-sectional view showing the positional relationship between the reference member FM and the measuring head and the processing head. FIG. 64 is a cross-sectional view showing the positional relationship between the reference member FM and the measuring head and the processing head. FIG. 65 is a block diagram showing the system configuration of a processing system in a twelfth modified example. FIG. 66 is a block diagram showing the system configuration of a processing system in a thirteenth modified example. FIG. 67 is a block diagram showing the system configuration of a processing system in a fourteenth modified example.

[0019] Hereinafter, embodiments of a measurement system, a machine tool, an optical device, a measurement method, a computer program, and a recording medium will be described with reference to the drawings. Hereinafter, the embodiments of the measurement system, the machine tool, the optical device, the measurement method, the computer program, and a recording medium will be described using a machining system SYS that can machine a workpiece W, which is an example of an object.

[0020] In the following description, the positional relationships of the various components constituting the machining system SYS will be described using a machine coordinate system, which is an XYZ Cartesian coordinate system defined by mutually orthogonal X-, Y-, and Z-axes. For ease of explanation, the following description will be given using an example in which the X- and Y-axis directions of the machine coordinate system are horizontal (i.e., predetermined directions within a horizontal plane) and the Z-axis direction of the machine coordinate system is vertical (i.e., a direction perpendicular to the horizontal plane, essentially an up-and-down direction). Furthermore, the rotation directions around the X-, Y-, and Z-axes (in other words, tilt directions) may be referred to as the θX direction, the θY direction, and the θZ direction, respectively.

[0021] In the following description, unless otherwise specified, the X-axis, Y-axis, and Z-axis refer to the X-axis in the machine coordinate system, the Y-axis in the machine coordinate system, and the Z-axis in the machine coordinate system, respectively.

[0022] (1) Configuration of the Machining System SYS in the Present Embodiment First, the configuration of the machining system SYS in the present embodiment will be described.

[0023] (1-1) Overall Configuration of Machining System SYS First, the overall configuration of the machining system SYS in this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the machining system SYS (particularly, machine tool 1) in this embodiment. Figure 2 is a block diagram showing an example of the system configuration of the machining system SYS in this embodiment.

[0024] As shown in Figures 1 and 2, the machining system SYS includes a machine tool 1 and a measurement system 2. Note that, to make the drawings easier to understand, the measurement system 2 is omitted from Figure 1. Therefore, Figure 1 may be considered to mainly show the external appearance of the machine tool 1. Furthermore, an apparatus including at least a part of the measurement system 2 and the machine tool 1 may be referred to as a machine tool. In other words, at least a part of the measurement system 2 may be included in the machine tool 1.

[0025] (1-1-1) Configuration of Machine Tool 1 The machine tool 1 is a processing device capable of processing a workpiece W. To process the workpiece W, the machine tool 1 is equipped with a processing head 11, a head drive system 12, a head position measuring device 13, a stage device 14, a tool exchange device 15, and a processing control device 16.

[0026] The machining head 11 is a machining device for machining the workpiece W. The machining head 11 includes a spindle 111 and a head housing 112. The machining head 11 will be described below with reference to FIGS. 3 and 4 in addition to FIGS. 1 and 2. FIGS. 3 and 4 are cross-sectional views showing the configuration of the machining head 11. The machining head 11 may be simply referred to as a head or a spindle head. While FIG. 1 shows a vertical machine tool as an example, the machine tool 1 is not limited to vertical machine tools. The machine tool 1 may be any well-known machine tool. For example, the machine tool 1 may be a horizontal machine tool or a combined machine tool.

[0027] As shown in Figures 1, 3, and 4, the main shaft 111 is a member that can rotate around a rotation axis RX. In this case, the main shaft 111 may be, for example, a member that extends along the rotation axis RX (i.e., a member having a longitudinal shape). In the example shown in Figure 1, the rotation axis RX of the main shaft 111 is parallel to the Z axis. However, the main shaft 111 may also rotate around a rotation axis RX that intersects the Z axis (for example, a rotation axis RX that is perpendicular to the Z axis or inclined with respect to the Z axis). The main shaft 111 may also be referred to as a spindle.

[0028] As shown in Fig. 4, a tool 113 for machining the workpiece W (i.e., a machining tool) can be attached to the spindle 111. Specifically, as shown in Figs. 3 and 4, the spindle 111 has an attachment portion 1111 for attaching the tool 113. The tool 113 is attached to the spindle 111 via the attachment portion 1111. The tool 113 attached to the attachment portion 1111 can be removed from the attachment portion 1111. In other words, the tool 113 is attached to the spindle 111 in a detachable manner.

[0029] In this embodiment, the state in which "a first object is attached to a second object" may include at least one of a state in which "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 a state in which "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 in which "the first object is indirectly attached to the second object" may also include a state in which "the first object is attached to the second object via a third object that is different from the first and second objects."

[0030] 3 and 4 , the spindle 111 is provided with a mounting portion 1111 at the tip of the spindle 111 (specifically, the tip on the workpiece W side), which has a hole 1112 (e.g., a tapered hole) formed therein into which the tool 113 is fitted (or inserted). In this case, a shank 1131 of the tool 113, which has a shape complementary to the hole 1112, is fitted (or inserted) into the hole 1112 of the mounting portion 1111, thereby mounting the tool 113 to the spindle 111. The mounting portion 1111 may hold the tool 113 mounted thereto. In this case, the mounting portion 1111 may include at least one of a mechanical chuck, an electrostatic chuck, a hydraulic chuck, a vacuum chuck, or the like to hold the tool 113.

[0031] 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, machining the workpiece W. 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.

[0032] The head housing 112 is a housing that houses the main shaft 111. The head housing 112 may house the main shaft 111 in a housing space formed inside the head housing 112. The main shaft 111 housed in the head housing 112 may be supported by the head housing 112 via a bearing member (for example, a bearing) not shown.

[0033] 1 and 2 , the head drive system 12 moves the machining head 11. The head drive system 12 may also be referred to as a drive device. The head drive system 12 may move the machining head 11, for example, along at least one of the X-axis, Y-axis, and Z-axis. That is, the head drive system 12 may move the machining head 11, for example, along at least one of the translational axes along the X-axis, Y-axis, and Z-axis. Movement along at least one of the translational axes along the X-axis, Y-axis, and Z-axis may also be referred to as translational movement. In the following description, the translational axes along the X-axis, Y-axis, and Z-axis will be referred to as the translational axis (X), the translational axis (Y), and the translational axis (Z), respectively. Furthermore, in the following description, unless otherwise specified, the translational axis may mean at least one of the translational axis (X), the translational axis (Y), and the translational axis (Z).

[0034] The head drive system 12 may move the machining head 11 along at least one of the θX direction, the θY direction, and the θZ direction, in addition to or instead of at least one of the translational axes along the X axis, the Y axis, and the Z axis. That is, in addition to or instead of moving the machining head 11 along at least one of the translational axes along the X axis, the Y axis, and the Z axis, the head drive system 12 may rotate the machining head 11 around at least one of the rotational axes along the X axis, the Y axis, and the Z axis. Movement along at least one of the θX direction (the direction around the rotational axis along the X axis), the θY direction (the direction around the rotational axis along the Y axis), and the θZ direction (the direction around the rotational axis along the Z axis) may also be referred to as rotational movement. In the following description, the rotational axis around the X axis, the rotational axis around the Y axis, and the rotational axis around the Z axis will be referred to as the rotational axis (X), the rotational axis (Y), and the rotational axis (Z), respectively. In the following description, unless otherwise specified, the rotation axis may refer to at least one of the rotation axis (X), the rotation axis (Y), and the rotation axis (Z). The operation of moving the machining head 11 in the rotation direction around the rotation axis may be considered equivalent to the operation of changing the attitude of the machining head 11.

[0035] 1 , the head drive system 12 moves the machining head 11 along both the translation axis (X) and the translation axis (Z). In this case, the head drive system 12 may include, for example, a column 121, which is a wall-like member extending upward along the Z axis from a bed 140, which is a base of a 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 that generates a driving force for moving 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 FIG. 1 ) attached to the Z guide member 125 and movable along the Z guide member 125, and a servo motor 126 that generates a driving force for moving the Z block member. The machining head 11 (particularly the head housing 112) may be mounted to a Z-block member such that the machining head 11 moves along the translational axis (X) in response to movement of the X-block member 123 and along the translational axis (Z) in response to movement of the Z-block member.

[0036] When the head drive system 12 moves the machining head 11, the relative positional relationship between the machining head 11 and a stage 141 (described later) (and further, 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 with respect 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 machine the desired position of the workpiece W while setting the machining position at the desired position of the workpiece W by moving the machining head 11. However, if the machining position can be set at the desired position of 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.

[0037] The head position measuring device 13 is capable of measuring the position of the processing head 11. An example of the head position measuring device 13 is an encoder.

[0038] The stage device 14 includes a bed 140, a stage 141, and a stage drive system 142. The stage 141 and the stage drive system 142 are supported by the bed 140.

[0039] The workpiece W is placed on the stage 141. For this reason, the stage 141 may be referred to as a placement device. The stage 141 is capable of supporting the workpiece W placed on the stage 141. The stage 141 may be capable of holding the workpiece W placed on the stage 141. In this case, the stage 141 may be equipped with at least one of a mechanical chuck, an electrostatic chuck, a vacuum chuck, or the like to hold the workpiece W.

[0040] The stage 141 is disposed at a position where it can face the machining head 11 (particularly, the spindle 111). In the example shown in Fig. 1, the stage 141 is disposed below the machining head 11 (particularly, the spindle 111). However, the stage 141 may be disposed at a position different from the position below the machining head 11 (particularly, the spindle 111).

[0041] The stage drive system 142 moves the stage 141. The stage drive system 142 may also be referred to as a drive device. The stage drive system 142 may move the stage 141, for example, along at least one of the X-axis, the Y-axis, and the Z-axis. In other words, the stage drive system 142 may move the stage 141, for example, along at least one of the translational axis (X), the translational axis (Y), and the translational axis (Z).

[0042] The stage drive system 142 may, for example, move the stage 141 along at least one of the θX direction, the θY direction, and the θZ direction in addition to or instead of at least one of the translational axis (X), the translational axis (Y), and the translational axis (Z). That is, in addition to or instead of moving the stage 141 along at least one of the translational axis (X), the translational axis (Y), and the translational axis (Z), the stage drive system 142 may rotate the stage 141 around at least one of the rotational axes (X), the rotational axis (Y), and the rotational axis (Z). Note that the operation of moving the stage 141 in a rotational direction around at least one of the rotational axes (X), the rotational axis (Y), and the rotational axis (Z) may be considered equivalent to an operation of changing the attitude of the stage 141.

[0043] 1 , the stage drive system 142 moves the stage 141 along a translation axis (Y) and rotates the stage 141 about each of the rotation axis (X) and the rotation axis (Z). 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 for moving the trunnion 1422, a cradle 1424 attached to the trunnion 1422 and rotatable about the rotation axis (X) relative to the trunnion 1422, and a servo motor (not shown) that generates a driving force for rotating the cradle 1424. The stage 141 may be attached to the cradle 1424 so as to be rotatable about 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 rotates around the rotation axis (Z). In this case, the rotation axis (X) may be referred to as the A-axis. The rotation axis (Z) may be referred to as the C-axis.

[0044] When the stage drive system 142 moves the stage 141, the relative positional relationship between the machining head 11 and the stage 141 (and further 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 with respect to the workpiece W. The machine tool 1 may machine the workpiece W while moving the stage 141. Specifically, the machine tool 1 may machine the desired position of the workpiece W while setting the machining position at the desired position of the workpiece W by moving the stage 141. However, if the machining position can be set at the desired position of the workpiece W by moving the above-mentioned machining head 11, the machine tool 1 may machine the workpiece W without moving the stage 141.

[0045] The position measurement device 143 is capable of measuring the position of the stage 141. An example of the position measurement device 143 is an encoder.

[0046] The tool changer 15 is a device capable of changing the tool 113 attached to the spindle 111. For example, the tool changer 15 may retrieve one tool 113 to be attached to the spindle 111 from a tool magazine (not shown) that stores a plurality of tools 113, and attach the retrieved tool 113 to the spindle 111. In other words, the tool changer 15 may function as an attachment device capable of attaching the tool 113 to the spindle 111. The tool changer 15 may remove the tool 113 attached to the spindle 111 from the spindle 111 and store the removed tool 113 in a tool magazine (not shown). In other words, the tool changer 15 may function as a removal device capable of removing the tool 113 from the spindle 111. Note that an automatic tool changer (ATC) used in a machining center or the like may be used as the tool changer 15.

[0047] 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) provided 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) provided 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) provided 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 attached to the spindle 111 and the measuring head 22) provided in the machine tool 1.

[0048] The machining control device 16 may include, for example, an arithmetic device and a storage device. The machining control device 16 including such an arithmetic device may be referred to as an arithmetic unit. The arithmetic device may include, for example, at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The storage device may include, for example, a memory. The machining control device 16 functions as a device that controls the operation of the machine tool 1 by the arithmetic device executing a computer program. This computer program is a computer program for causing the arithmetic device to perform (i.e., execute) the operations to be performed by the machining control device 16, which will be described later. In other words, this computer program is a computer program for causing the machining control device 16 to function so as to cause the machine tool 1 to perform the operations to be performed by the machining control device 16. The computer program executed by the arithmetic device may be recorded in a storage device (i.e., a recording medium) included in the machining control device 16, or may be recorded in any storage medium (e.g., a hard disk or a semiconductor memory) built into or externally attachable to the machining control device 16. Alternatively, the arithmetic unit may download the computer program to be executed from a device external to the processing control device 16 via a network interface. The processing control device 16 does not necessarily have to include a storage device.

[0049] The machining control device 16 does not have to be provided inside the machine tool 1. For example, the machining control device 16 may be provided as a server or the like outside the machine tool 1. 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 a communication line). As the wired network, for example, a network using a serial bus interface represented by at least one of IEEE1394, RS-232x, RS-422, RS-423, RS-485, and USB may be used. As the wired network, a network using a parallel bus interface may be used. As the wired network, a network using an interface compliant with Ethernet (registered trademark) represented by at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T may be used. As the 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 a wireless LAN and Bluetooth (registered trademark)). A network using infrared rays may be used as the wireless network. A network using optical communication may be used as the wireless network. In this case, the machining control device 16 and the machine tool 1 may be configured to be able to send and receive various information via the network. The machining control device 16 may also be able to send 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 machining 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 machining control device 16) that sends information such as commands and control parameters to the machining control device 16 via the network. Alternatively, a first control device that performs part of the processing performed by the machining 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 machining control device 16 may be provided outside the machine tool 1.

[0050] A computational model that can be constructed by machine learning may be implemented in the machining control device 16 by causing the computation device to execute a computer program. An example of a computational model that can be constructed by machine learning is a computational model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computational model may include learning of parameters of the neural network (e.g., at least one of a weight and a bias). The machining control device 16 may control the operation of the machine tool 1 using the computational model. In other words, the operation of controlling the operation of the machine tool 1 may include the operation of controlling the operation of the machine tool 1 using the computational model. Note that a computational model that has been constructed by offline machine learning using training data may be implemented in the machining control device 16. Furthermore, the computational model implemented in the machining control device 16 may be updated by online machine learning on the machining control device 16. Alternatively, the processing control device 16 may control the operation of the machine tool 1 using a computational model implemented in a device external to the processing control device 16 (particularly, a device provided outside the machine tool 1) in addition to or instead of the computational model implemented in the processing control device 16.

[0051] The recording medium for recording the computer program executed by the machining control device 16 may be at least one of a CD-ROM, CD-R, CD-RW, flexible disk, MO, optical disk such as DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, and Blu-ray (registered trademark), magnetic medium such as magnetic tape, magneto-optical disk, semiconductor memory such as USB memory, and any other medium capable of storing a program. The recording medium may also include a device capable of recording a computer program (for example, a general-purpose device or a dedicated device in which a computer program is implemented in an executable state in at least one of the forms of software and firmware). Furthermore, each process or function included in the computer program may be realized by a logical processing block realized within the processing control device 16 when the processing control device 16 (i.e., a computer) executes the computer program, or may be realized by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit)) provided in the processing control device 16, or may be realized in a form that combines logical processing blocks and partial hardware modules that realize some elements of the hardware.

[0052] (1-1-2) Configuration of Measurement System 2 The measurement system 2 is capable of measuring a measurement object. To measure the measurement object, the measurement system 2 includes a measurement device 20 and a measurement control device 24.

[0053] The measurement device 20 is capable of measuring a measurement object. For example, the measurement device 20 may be capable of measuring the characteristics of the measurement object. The characteristics of the measurement object may include, for example, at least one of the position of the measurement object, the shape of the measurement object, the distance between the measurement device 20 and the measurement object, the direction of the measurement object as seen from the measurement device 20, the reflectance of the measurement object, the transmittance of the measurement object, the temperature of the measurement object, the internal structure of the measurement object, and the surface roughness of the measurement object.

[0054] In the following description, an example will be given in which the measuring device 20 measures at least the position of the measurement object. The position of the measurement object may include the position of the surface of the measurement object. The position of the surface of the measurement object may include the position of at least a portion of the surface of the measurement object. The position of the measurement object may mean the position of the measurement object in a machine coordinate system used as a reference in the machining system SYS (i.e., absolute position). Alternatively, the position of the measurement object may mean the position of the measurement object with respect to the measuring device 20 (i.e., relative position). Alternatively, the position of the measurement object may mean the position of the measurement object in a measurement coordinate system (described below) used by the measuring device 20 as a coordinate system different from the machine coordinate system.

[0055] As will be described in detail later, in this embodiment, in order to measure the position of the measurement object, the measurement device 20 measures the distance between the measurement device 20 and the measurement object (specifically, the distance between the measurement head 22, which will be described later, and the measurement object), and the measurement control device 24 calculates the position of the measurement object based on this distance. Therefore, the operation of at least measuring the position of the measurement object may be considered to essentially mean the operation of measuring the distance from the measurement head 22 to the measurement object, which is necessary to calculate the position of the measurement object.

[0056] The position of the surface of the measurement object changes depending on the shape of the surface of the measurement object. Therefore, the operation of measuring the position of the measurement object may be considered equivalent to the operation of measuring the shape of the measurement object. The shape of the measurement object may include at least one of a one-dimensional shape, a two-dimensional shape, and a three-dimensional shape of the measurement object.

[0057] The measurement object may include, for example, a workpiece W to be machined by the machining head 11. The measurement object may include, for example, any object placed on the stage 141. The any object placed on the stage 141 may include, for example, the workpiece W. The measurement object may include a reference member FM used in the movement error calculation operation described below. The measurement object may include, for example, the stage 141.

[0058] The measurement device 20 may be capable of measuring the measurement object without contact. The measurement device 20 may be capable of measuring the measurement object optically. The measurement device 20 may be capable of measuring the measurement object electrically. The measurement device 20 may be capable of measuring the measurement object magnetically. The measurement device 20 may be capable of measuring the measurement object thermally. The measurement device 20 may be capable of measuring the measurement object acoustically. The measurement device 20 may be capable of measuring the measurement object using a probe that physically contacts the measurement object.

[0059] In the following description, an example will be given in which the measurement device 20 is capable of optically measuring a measurement object. In this case, the measurement device 20 may be referred to as an optical measurement device. Specifically, in the following description, an example will be given in which the measurement device 20 measures the measurement object by irradiating the measurement object with measurement light ML and receiving at least a portion of the light from the measurement object irradiated with the measurement light ML. The light from the measurement object irradiated with the measurement light ML is light from the measurement object that is generated by the irradiation of the measurement light ML. In the following description, the light from the measurement object irradiated with the measurement light ML that enters the measurement device 20 (i.e., is received by the measurement device 20) is referred to as "return light RL."

[0060] The light from the measurement object generated by irradiation with the measurement light ML may include specularly reflected light generated by the measurement object by irradiation with the measurement light ML. The light from the measurement object generated by irradiation with the measurement light ML may include, in addition to or instead of specularly reflected light, diffusely reflected light generated by the measurement object by irradiation with the measurement light ML. The light from the measurement object generated by irradiation with the measurement light ML may include diffracted light generated by the measurement object by irradiation with the measurement light ML in addition to or instead of at least one of specularly reflected light and diffusely reflected light.

[0061] In this embodiment, in order to optically measure the measurement object, the measurement device 20 may include, for example, a measurement light source 21, a measurement head 22, and an output interface 23. The configuration and operation of the measurement device 20 will be described in detail later, but a brief overview will be provided here. The measurement light source 21 is capable of generating measurement light ML. The measurement head 22 is attached to the processing head 11. That is, the measurement head 22 is disposed on the processing head 11. The measurement head 22 attached to the processing head 11 may be fixed to the processing head 11. The measurement head 22 attached to the processing head 11 may be detachable from the processing head 11. For simplicity of illustration, FIG. 1 does not illustrate the measurement head 22 attached to the processing head 11. However, the measurement head 22 attached to the processing head 11 is illustrated in FIGS. 5 and 6, etc., which will be used to later describe in detail the configuration and operation of the measurement device 20. The measurement head 22 irradiates the measurement light ML onto the measurement object. Furthermore, the measurement head 22 receives return light RL from the measurement object irradiated with the measurement light ML. The measurement head 22 may also be referred to as an optical device. The output interface 23 can output the measurement results of the measurement object by the measurement head 22 (i.e., the reception results of the return light RL from the measurement object) to the measurement control device 24.

[0062] The measurement device 20 does not have to include the measurement light source 21. For example, the measurement light source 21 may be a light source arranged outside the measurement device 20. For example, the measurement light source 21 may be arranged outside the machine tool 1. For example, the measurement light source 21 may be arranged outside the measurement system 2. For example, the measurement light source 21 may be arranged outside the measurement device 20 (typically, outside the measurement system 1) at a predetermined position inside the machine tool 1. An example of a predetermined position outside the measurement device 20 (typically, outside the measurement system 1) but inside the machine tool 1 is a predetermined position outside or inside a housing that houses at least one of the machining head 11, head drive system 12, stage device 14, and machining control device 16 of the machine tool 1. For example, the measurement light source 21 may be arranged at a predetermined position outside the measurement device 20 but inside the measurement system 2. An example of a predetermined position outside the measurement device 20 but inside the measurement system 2 is a predetermined position outside or inside a housing that houses the measurement control device 24 of the measurement system 2. In this case, the measurement head 22 of the measurement device 20 may irradiate the measurement object with measurement light ML generated by a measurement light source 21 disposed outside the measurement device 20 .

[0063] In this embodiment, as will be described in detail later, the measuring head 22 may be attachable to the spindle 111 of the machine tool 1. That is, in addition to the tool 113, the measuring head 22 provided in the measuring device 20 may be attached to the spindle 111. In this case, the tool changer 15 may function as an attachment device that can attach the measuring head 22 to the spindle 111. That is, the tool changer 15 may remove the measuring head 22 from a tool magazine (not shown) that stores the measuring head 22 in addition to the tool 113 (or from a head magazine (not shown) that stores the measuring head 22 and is different from the tool magazine that stores the tool 113), and attach the removed measuring head 22 to the spindle 111. Furthermore, the tool changer 15 may function as a removal device that can remove the measuring head 22 from the spindle 111. That is, the tool changer 15 may remove the measuring head 22 attached to the spindle 111 from the spindle 111, and store the removed measuring head 22 in a tool magazine (not shown) or a head magazine (not shown). The measurement head 22 does not have to be attached to the main shaft 111. For example, the measurement head 22 may be attached to the head housing 112.

[0064] The measurement control device 24 controls the operation of the measurement system 2. For example, the measurement control device 24 may control the measuring device 20 to measure the measurement object. Furthermore, because the measuring head 22 is attached to the machine tool 1 (particularly the spindle 111) as described above, the head drive system 12 of the machine tool 1 moves the measuring head 22. Therefore, the measurement control device 24 may control the machine tool 1 (particularly the head drive system 12) together with the machining control device 16 so that the measuring device 20 moves to a desired position. That is, the measurement control device 24 may control the movement of the machining head 11 together with the machining control device 16. Furthermore, when the measurement object moves together with the stage 141, the measurement control device 24 may control the machine tool 1 (particularly the stage drive system 142) together with the machining control device 16 so that the measurement object moves to a desired position. That is, the measurement control device 24 may control the movement of the stage 141 together with the machining control device 16.

[0065] Since the measurement head 22 is attached to the machine tool 1 (spindle 111), the measurement control device 24 does not have to control the head drive system 12. In this case, the processing control device 16 may control the head drive system 12. Since the measurement head 22 is attached to the machine tool 1 (spindle 111), the processing control device 16 does not have to control the head drive system 12. In this case, the measurement control device 24 may control the head drive system 12. Furthermore, the measurement control device 24 does not have to control the stage drive system 142. In this case, the processing control device 16 may control the stage drive system 142. Furthermore, the processing control device 16 does not have to control the stage drive system 142. In this case, the measurement control device 24 may control the stage drive system 142.

[0066] In this embodiment, the measurement control device 24 performs a movement error calculation operation. The movement error calculation operation may include an operation of calculating a movement error (in other words, a motion error) occurring in the movement of at least one of the machining head 11 and the stage 141 based on the measurement results of the measurement object by the measurement head 22. The movement error calculation operation may include an operation of generating information regarding the movement error occurring in the movement of at least one of the machining head 11 and the stage 141 as information for controlling the machine tool 1 based on the measurement results of the measurement object by the measurement head 22. The movement error calculation operation may include an operation of generating information for controlling the machine tool 1 (particularly, information different from the information regarding the movement error) based on the calculated movement error (information regarding the generated movement error). In this case, the measurement control device 24 may output the generated information to the machining control device 16. The machining control device 16 may control the machine tool 1 based on the information. The movement error calculation operation will be described in detail later with reference to FIG. 9 and the like, and therefore will not be described here. The movement error may also be referred to as a spatial accuracy error.

[0067] The measurement control device 24 that performs the movement error calculation operation may be referred to as a movement error calculation device, a calculation device, or an arithmetic device. The measurement system 2 including the measurement device 20 and the measurement control device 24 may be referred to as a movement error calculation system, a calculation system, or an arithmetic system. A system including the measurement control device 24 and a reference member FM (described later) used to perform the movement error calculation operation may be referred to as a movement error calculation system, a calculation system, or an arithmetic system. A system including the measurement control device 24 and the reference member FM may be referred to as the measurement system 2. A system including the reference member FM, the measurement device 20, and the measurement control device 24 may be referred to as a movement error calculation system, a calculation system, or an arithmetic system. A system including the reference member FM, the measurement device 20, and the measurement control device 24 may be referred to as the measurement system 2. A system including the measurement head 22 and the measurement control device 24 may be referred to as the measurement system 2.

[0068] The measurement control device 24 may include, for example, an arithmetic device and a storage device. Such a measurement control device 24 equipped with an arithmetic device may be referred to as a calculation unit. The arithmetic device may include, for example, at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The storage device may include, for example, a memory. The measurement control device 24 functions as a device that controls the operation of the measuring device 20 by the arithmetic device executing a computer program. Furthermore, as described above, when the measurement control device 24 controls at least a portion of the operation of the machine tool 1 (for example, at least one of the head drive system 12 and the stage drive system 142), the measurement control device 24 functions as a device that controls the operation of the machine tool 1 by the arithmetic device executing a computer program. However, when the measurement control device 24 does not need to control at least a portion of the operation of the machine tool 1, the measurement control device 24 does not need to function as a device that controls the operation of the machine tool 1. This computer program is a computer program for causing the arithmetic device to perform (i.e., execute) the operations to be performed by the measurement control device 24, which will be described later. In other words, this computer program is a computer program for causing the measurement control device 24 to function so as to cause the measuring device 20 (and further the machine tool 1) to perform the operations to be described later. The computer program executed by the arithmetic device may be recorded in a storage device (i.e., a recording medium) provided in the measurement control device 24, or may be recorded in any storage medium (e.g., a hard disk or semiconductor memory) that is built into the measurement control device 24 or that can be externally attached to the measurement control device 24. Alternatively, the arithmetic device may download the computer program to be executed from a device external to the measurement control device 24 via a network interface. Note that the measurement control device 24 does not necessarily have to include a storage device.

[0069] The measurement control device 24 does not have to be provided inside the measurement system 2. For example, the measurement control device 24 may be provided as a server or the like outside the measurement system 2. In this case, the measurement control device 24 and the measurement system 2 may be connected via a wired and / or wireless network (or a data bus and / or communication line). As the wired network, a network using a serial bus interface, such as at least one of IEEE1394, RS-232x, RS-422, RS-423, RS-485, and USB, may be used. As the wired network, a network using a parallel bus interface may be used. As the wired network, a network using an interface compliant with Ethernet (registered trademark), such as at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T, may be used. As the 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 (e.g., at least one of a wireless LAN and Bluetooth (registered trademark)). A network using infrared rays may be used as the wireless network. A network using optical communication may be used as the wireless network. In this case, the measurement control device 24 and the measurement system 2 may be configured to be able to send and receive various information via the network. The measurement control device 24 may also be able to send information such as commands and control parameters to the measurement system 2 via the network. The measurement system 2 may include a receiving device that receives information such as commands and control parameters from the measurement control device 24 via the network. The measurement system 2 may also include a transmitting device (i.e., an output device that outputs information to the measurement control device 24) that sends information such as commands and control parameters to the measurement control device 24 via the network. Alternatively, a first control device that performs part of the processing performed by the measurement control device 24 may be provided inside the measurement system 2, while a second control device that performs another part of the processing performed by the measurement control device 24 may be provided outside the measurement system 2.

[0070] At least a part of the processing performed by the measurement control device 24 may be performed by the processing control device 16. As an example, the processing control device 16 may perform at least a part of the movement error calculation operation performed by the measurement control device 24. Conversely, at least a part of the processing performed by the processing control device 16 may be performed by the measurement control device 24.

[0071] The machining system SYS may include a control device that can function as the measurement control device 24 and the machining control device 16, instead of the measurement control device 24 and the machining control device 16. That is, the machining system SYS may include a control device in which the measurement control device 24 and the machining control device 16 are integrated. As an example, the machine tool 1 may include a control device that can function as the measurement control device 24 and the machining control device 16, instead of the machining control device 16. In this case, the measurement system 2 may or may not include the measurement control device 24. As another example, the measurement system 2 may include a control device that can function as the measurement control device 24 and the machining control device 16, instead of the measurement control device 24. In this case, the machine tool 1 may or may not include the machining control device 16.

[0072] A computational model that can be constructed by machine learning may be implemented in the measurement control device 24 by the computation device executing a computer program. An example of a computational model that can be constructed by machine learning is a computational model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computational model may include learning of parameters of the neural network (e.g., at least one of a weight and a bias). The measurement control device 24 may use the computational model to control the operation of the measurement system 2. In other words, the operation of controlling the operation of the measurement system 2 may include the operation of controlling the operation of the measurement system 2 using the computational model. Note that a computational model that has been constructed by offline machine learning using teacher data may be implemented in the measurement control device 24. Furthermore, the computational model implemented in the measurement control device 24 may be updated by online machine learning on the measurement control device 24. Alternatively, the measurement control device 24 may control the operation of the measurement system 2 using a computational model implemented in a device external to the measurement control device 24 (particularly, a device provided outside the measurement system 2) in addition to or instead of the computational model implemented in the measurement control device 24.

[0073] The recording medium for recording the computer program executed by the measurement control device 24 may be at least one of the following: a CD-ROM, CD-R, CD-RW, a flexible disk, an MO, a DVD-ROM, a DVD-RAM, a DVD-R, a DVD+R, a DVD-RW, a DVD+RW, or an optical disk such as Blu-ray (registered trademark), a magnetic medium such as a magnetic tape, a magneto-optical disk, a semiconductor memory such as a USB memory, or any other medium capable of storing a program. The recording medium may also include a device capable of recording a computer program (for example, a general-purpose device or a dedicated device in which a computer program is implemented in an executable state in at least one form such as software or firmware). Furthermore, each process or function included in the computer program may be realized by a logical processing block realized within the measurement control device 24 when the measurement control device 24 (i.e., the computer) executes the computer program, or may be realized by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit)) provided in the measurement control device 24, or may be realized in a form that mixes logical processing blocks and partial hardware modules that realize some elements of the hardware.

[0074] The output device 25 is a device that outputs information to the outside of the measurement system 2. For example, the output device 25 may output information as an image. That is, the output device 25 may include a display device (a so-called display) capable of displaying an image. For example, the output device 25 may output information as sound. That is, the output device 25 may include an audio output device (a so-called speaker) capable of outputting sound. For example, the output device 25 may output information on paper. That is, the output device 25 may include a printing device (a so-called printer) capable of printing desired information on paper. For example, the output device 25 may output information as data to a recording medium that can be externally attached to the measurement system 2. For example, the output device 25 may output (i.e., transmit) information as data via a communication line. That is, the output device 25 may function as a communication device. Note that the measurement system 2 does not necessarily have to include the output device 25.

[0075] (1-2) Configuration of the Measuring Device 20 (Measuring Head 22) Next, the structure of the measuring device 20 will be described in more detail with reference to Fig. 5. Fig. 5 is a cross-sectional view showing the machining head 11 to which the measuring device 20 (particularly the measuring head 22) is attached.

[0076] As shown in FIG. 5 , the measurement head 22 is attached to the machining head 11. Specifically, the measurement head 22 includes a head housing 221, and the head housing 221 is attached to the machining head 11. In the example shown in FIG. 5 , the measurement head 22 is attached to the spindle 111 of the machining head 11. That is, the measurement head 22 is attached to the spindle 111 instead of the tool 113. Specifically, the head housing 221 is attached to an attachment portion 1111 provided on the spindle 111. In the example shown in FIG. 5 , the spindle 111 includes an attachment portion 1111 having a hole 1112 formed therein. Therefore, the shank 220, which corresponds to the protruding portion of the head housing 221 and has a shape complementary to the hole 1112, is fitted (or inserted) into the hole 1112 of the attachment portion 1111, thereby attaching the head housing 221 to the spindle 111. The attachment portion 1111 may hold the head housing 221. In this case, the mounting portion 1111 may include at least one of a mechanical chuck, a hydraulic chuck, an electrostatic chuck, a vacuum chuck, and the like to hold the head housing 221 .

[0077] The head housing 221 (i.e., the measurement head 22) attached to the attachment portion 1111 is detachable from the attachment portion 1111. That is, the head housing 221 (i.e., the measurement head 22) is detachably attached to the spindle 111. For example, when the measurement head 22 is attached to the spindle 111, the tool 113 is detached from the spindle 111. On the other hand, when the tool 113 is attached to the spindle 111, the measurement head 22 is detached from the spindle 111. As described above, the attachment and detachment of the head housing 221 and the attachment and detachment of the tool 113 are performed by the tool exchange device 15. However, an operator of the machining system SYS may manually perform at least one of the attachment and detachment of the measurement head 22 to the spindle 111 and the attachment and detachment of the tool 113 to the spindle 111.

[0078] However, the measurement head 22 may be attached to a part of the machining head 11 that is different from the spindle 111. The measurement head 22 may be attached to a part of the machining head 11 that is different from the spindle 111, as long as the measurement head 22 is capable of measuring the object to be measured. For example, as shown in FIG. 6 , which is a cross-sectional view showing the machining head 11 to which the measurement device 20 (particularly the measurement head 22) is attached, the measurement head 22 may be attached to the head housing 112 of the machining head 11. The head housing 221 may be attached to the head housing 112 of the machining head 11. The head housing 221 may be attached to the machining head 11 at a position separated from the rotation axis RX of the spindle 111 along a direction intersecting the rotation axis RX. In the example shown in FIG. 6 , the head housing 221 is attached to the side of the head housing 112.

[0079] When the measurement head 22 is attached to a part of the machining head 11 that is different from the spindle 111, the measurement head 22 does not have to be detachable from the machining head 11. In other words, the measurement head 22 does not have to be detachably attached to the machining head 11. The measurement head 22 may remain attached to the machining head 11 even during the machining period in which the machining head 11 uses the tool 113 to machine the workpiece W. The measurement head 22 may remain attached to the machining head 11 at all times. However, even when the measurement head 22 is attached to a part of the machining head 11 that is different from the spindle 111, the measurement head 22 may be detachably attached to the machining head 11.

[0080] The measurement head 22 may be attached at a fixed position relative to the processing head 11. In other words, the measurement head 22 may be attached to the processing head 11 so that the positional relationship between the processing head 11 and the measurement head 22 is fixed (i.e., does not change). The measurement head 22 may be attached by being directly fixed to the processing head 11. The measurement head 22 may be attached by being indirectly fixed to the processing head 11. For example, the measurement head 22 may be fixed to a support member, one side of which is directly fixed to the processing head 11, the other side of which is directly fixed to the processing head 11. Both a state in which the measurement head 22 is directly fixed to the processing head 11 and a state in which the measurement head 22 is directly fixed to the processing head 11 correspond to a state in which the measurement head 22 is attached at a fixed position relative to the processing head 11. Note that when the measurement head 22 is attached to the processing head 11, the positional relationship between the processing head 11 and the measurement head 22 is usually fixed unless the measurement device 20 is equipped with a drive system for moving the measurement head 22 independently of the processing head 11. Furthermore, when the measurement head 22 is attached to the main shaft 111 of the processing head 11, since the main shaft 111 is rotatable around the rotation axis RX, the rotation of the main shaft 111 may be locked using a mechanical fixing mechanism or the like when the measurement head 22 is attached to the main shaft 111.

[0081] However, the measurement head 22 does not have to be attached at a position where its positional relationship with the machining head 11 is fixed. The positional relationship between the machining head 11 and the measurement head 22 may be variable. The measuring device 20 may be equipped with a drive system for moving the measurement head 22 independently of the machining head 11. For example, this drive system may be configured to move the machining head 11 and the measurement head 22 relatively along the rotation axis RX. As described above, when the measurement head 22 is attached to the head housing 112 of the machining head 11, the measurement head 22 may interfere with the machining of the workpiece W during the machining period in which the machining head 11 machines the workpiece W with the tool 113. Specifically, for example, if the measurement 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 contact the workpiece W, and as a result, the measurement head 22 will interfere with the machining of the workpiece W. Therefore, the positional relationship between the machining head 11 and the measurement head 22 during at least a portion of the measurement period in which the measuring device 20 measures the measurement object may be different from the positional relationship between the machining head 11 and the measurement head 22 during at least a portion of the processing period in which the machining head 11 processes the workpiece W. For example, during at least a portion of the processing period, the positional relationship between the machining head 11 and the measurement head 22 may be set to a first relationship in which the measurement head 22 does not interfere with the processing of the workpiece W, and during at least a portion of the measurement period, the positional relationship between the machining head 11 and the measurement 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 measurement object using the measurement head 22).

[0082] At this time, if the positional relationship between the machining head 11 and the measurement head 22 is variable, the measurement control device 24 may use the head position measurement device 13 to measure the movement amounts of the machining head 11 and the measurement head 22 along the rotation axis RX. Furthermore, the measurement control device 24 may measure the movement error along this movement axis in advance, and reflect this pre-measured movement error when calculating the movement error of the machine tool 1 by performing the movement error calculation operation described above.

[0083] Furthermore, the drive system for moving the measurement head 22 is not limited to the rotation axis RX, but may be configured to move the processing head 11 and the measurement head 22 relative to each other along a direction different from the direction along the rotation axis RX.

[0084] When the measurement head 22 is attached to the machining head 11, the measurement head 22 also moves as the machining head 11 moves. In other words, the measurement head 22 moves in the same manner as the machining head 11. For this reason, the head drive system 12 that moves the machining head 11 may be considered to function as a head drive system for moving the measurement head 22. In this case, the movement of the measurement head 22 changes the relative positional relationship between the measurement position where the measurement head 22 performs measurement and the measurement object. In other words, the measurement position moves with respect to the measurement object. The machine tool 1 may measure the measurement object while moving the measurement head 22 by moving the machining head 11. Specifically, the machining system SYS may measure the desired position of the measurement object while setting the measurement position at a desired position of the measurement object by moving the measurement head 22. However, if the measurement object 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 measurement and the measurement object also changes with the movement of the stage 141. Therefore, if the measurement position can be set at the desired position of the measurement object by moving the stage 141, the processing system SYS may measure the measurement object without moving the measurement head 22.

[0085] When the measurement head 22 is attached to the spindle 111, the measurement head 22 may also rotate about the rotation axis RX in accordance with the rotation of the spindle 111. In this case, the measurement control device 24 may previously determine a movement error that accompanies the rotational movement of the spindle 111, and may reflect this previously measured movement error when calculating the movement error of the machine tool 1 by performing the movement error calculation operation described above.

[0086] The measurement head 22 further includes an optical system 222. The optical system 222 is housed in an internal storage space of the head housing 221. Therefore, the optical system 222 is attached to the processing head 11 via the head housing 221. When the optical system 222 is housed in the head housing 221 in this manner, unwanted substances (e.g., cutting chips, cutting fluid, etc.) generated by processing the workpiece W are prevented from adhering to the optical system 222.

[0087] The measurement head 22 may include a measurement light source 21. For example, the measurement light source 21 may be housed in the internal space of the head housing 221. In this case, the measurement light source 21 may be considered to constitute part of the optical system 222. The measurement light source 21 may not be attached to the machining head 11, or may be attached to a part of the machining head 11 that is different from the main shaft 111. When the measurement device 202 includes multiple measurement light sources 21 (for example, measurement light sources 21#1 and 21#2, which will be described later), at least one of the multiple measurement light sources 21 may not be attached to the machining head 11, or may be attached to a part of the machining head 11 that is different from the main shaft 111.

[0088] The optical system 222 is used to irradiate the measurement light ML from the measurement light source 21 onto the measurement object. Furthermore, the optical system 222 is used to receive the return light RL from the measurement object. Specifically, as shown in FIG. 7 , which is a cross-sectional view showing the optical system 222 that irradiates the measurement light ML onto the measurement object and receives the return light RL from the measurement object, the measurement light ML generated by the measurement light source 21 enters the optical system 222 from the measurement light source 21 via an optical transmission member (not shown), such as an optical fiber. The optical system 222 emits the measurement light ML that has entered the optical system 222 toward the measurement object. In other words, the optical system 222 irradiates the measurement light ML onto the measurement object.

[0089] When the measurement light ML is irradiated onto the measurement object, light resulting from the irradiation of the measurement light ML is emitted from the measurement object. The light resulting from the irradiation of the measurement light ML may include reflected light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include scattered light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include transmitted light of the measurement light ML irradiated onto the measurement object. The light resulting from the irradiation of the measurement light ML may include diffracted light of the measurement light ML irradiated onto the measurement object.

[0090] At least a portion of the light generated by the irradiation of the measurement light ML is incident on the optical system 222 as return light RL from the measurement object. Specifically, a light component of the light generated by the irradiation of the measurement light ML that travels along the optical path of the measurement light ML is incident on the optical system 222 as return light RL. In this case, the optical path of the measurement light ML that is emitted from the optical system 222 and incident on the measurement object may be the same as the optical path of the return light RL that is emitted from the measurement object and incident on the optical system 222. In other words, the optical path of the measurement light ML between the optical system 222 and the measurement object may be the same as the optical path of the return light RL between the optical system 222 and the measurement object. As an example, when the measurement light ML is perpendicularly incident on the measurement object, the return light RL may be light that is mainly composed of specularly reflected light of the measurement light ML. However, when the measurement light ML is perpendicularly incident on the measurement object, the return light RL may include light other than the specularly reflected light of the measurement light ML (for example, at least one of the diffusely reflected light, scattered light, transmitted light, and diffracted light of the measurement light ML). As another example, when the measurement light ML is obliquely incident on the measurement object (in other words, non-perpendicularly incident), the return light RL may be light mainly composed of the diffusely reflected light of the measurement light ML. However, when the measurement light ML is obliquely incident on the measurement object, the return light RL may include light other than the diffusely reflected light of the measurement light ML (for example, at least one of the specularly reflected light, scattered light, transmitted light, and diffracted light of the measurement light ML).

[0091] The structure of the optical system 222 that irradiates the measurement object with the measurement light ML and receives the return light RL will now be described in more detail with reference to Fig. 8. Fig. 8 is a cross-sectional view showing the structure of the optical system 222.

[0092] As shown in FIG. 8, the optical system 222 includes a beam splitter 2221, a beam splitter 2222, a photodetector (measurement unit) 2223, a beam splitter 2224, a mirror 2225, a photodetector (measurement unit) 2226, a mirror 2227, and a galvanometer mirror 2228.

[0093] As will be described in detail later in a ninth modified example, at least one of the measurement light source 21, the beam splitter 2221, the beam splitter 2222, the photodetector 2223, the beam splitter 2224, the mirror 2225, and the photodetector 2226 does not have to be housed in the head housing 221. In other words, at least one of the measurement light source 21, the beam splitter 2221, the beam splitter 2222, the photodetector 2223, the beam splitter 2224, the mirror 2225, and the photodetector 2226 does not have to be attached to the machining head 11, or may be attached to a part of the machining head 11 that is different from the main shaft 111. At least one of the measurement light source 21, the beam splitter 2221, the beam splitter 2222, the photodetector 2223, the beam splitter 2224, the mirror 2225, and the photodetector 2226 may be housed in a housing different from the head housing 221 attached to the spindle 111 of the machining head 11. In this case, the housing different from the head housing 221 does not have to be attached to the machining head 11, or may be attached to a part of the machining head 11 different from the spindle 111, or may be attached outside or inside a housing that houses at least one of the machining head 11, the head drive system 12, the stage device 14, the measurement device 20, the machining control device 16, and the measurement control device 24 of the machine tool 1. Note that at least one of the measurement light source 21, the beam splitter 2221, the beam splitter 2222, the photodetector 2223, the beam splitter 2224, the mirror 2225, and the photodetector 2226 is not limited to being located inside the machine tool 1, and may be arranged outside the machine tool 1.

[0094] The measurement light ML from the measurement light source 21 is incident on the beam splitter 2221. In this embodiment, two measurement light sources 21 (specifically, measurement light sources 21#1 and 21#2) generate two measurement light sources ML, respectively, and these two measurement light sources ML are incident on the beam splitter 2221. For this reason, the measurement device 20 includes a measurement light source 21#1 and a measurement light source 21#2. The two measurement light sources 21 may each emit two measurement light sources ML that are phase-synchronized and coherent with each other. However, the measurement device 20 may also include a single measurement light source 21.

[0095] The two measurement light sources 21 have different oscillation frequencies. Therefore, the two measurement light sources 21 respectively emit two measurement light beams ML with different frequencies. When the measurement light source 21 generates pulsed light as the measurement light beam ML, the two measurement light beams ML respectively emit two measurement light beams ML with different pulse frequencies (e.g., the number of pulsed light beams per unit time, which is the reciprocal of the emission period of the pulsed light beam). As an example, the measurement light source 21#1 may emit measurement light beams ML with a pulse frequency of 25 GHz, and the measurement light source 21#2 may emit measurement light beams ML with a pulse frequency of 25 GHz+α (e.g., +100 kHz). In the following description, the measurement light beams ML generated by the measurement light source 21#1 will be referred to as "measurement light beams ML#1," and the measurement light beams ML generated by the measurement light source 21#2 will be referred to as "measurement light beams ML#2." However, the two measurement light sources 21 may have the same oscillation frequency.

[0096] The measurement light source 21 includes an optical frequency comb light source. The optical frequency comb light source is a light source that can generate light containing frequency components equally spaced on the frequency axis (hereinafter referred to as an "optical frequency comb") as pulsed light. In this case, the measurement light source 21 emits pulsed light containing frequency components equally spaced on the frequency axis as the measurement light ML. However, the measurement light source 21 may include a light source other than the optical frequency comb light source.

[0097] The two measurement beams ML#1 and ML#2 incident on the beam splitter 2221 are emitted toward the beam splitter 2222. In other words, the beam splitter 2221 emits the measurement beams ML2#1 and ML#2 incident on the beam splitter 2221 from different directions in the same direction (i.e., the direction in which the beam splitter 2222 is disposed).

[0098] The beam splitter 2222 emits measurement light ML#1-1, which is a part of measurement light ML#1 that is incident on the beam splitter 2222, toward the photodetector 2223. The beam splitter 2222 emits measurement light ML#1-2, which is another part of measurement light ML#1 that is incident on the beam splitter 2222, toward the beam splitter 2224. The beam splitter 2222 emits measurement light ML#2-1, which is a part of measurement light ML2#2 that is incident on the beam splitter 2222, toward the photodetector 2223. The beam splitter 2222 emits measurement light ML#2-2, which is another part of measurement light ML#2 that is incident on the beam splitter 2222, toward the beam splitter 2224.

[0099] The measurement beams ML#1-1 and ML#2-1 emitted from the beam splitter 2222 are incident on the photodetector 2223. The photodetector 2223 receives the measurement beams ML#1-1 and ML#2-1. The photodetector 2223 receives and detects the measurement beams ML#1-1 and ML#2-1. Note that the state in this embodiment where "an object receives light" may also mean the state where "light is incident on an object." Therefore, the state in this embodiment where "an object receives light" may also mean the state where "an object capable of detecting light receives light" or the state where "an object not capable of detecting light receives light." In particular, the photodetector 2223 receives and detects interference light generated by interference between the measurement beams ML#1-1 and ML#2-1. The operation of receiving the interference light generated by the interference between the measurement light ML#1-1 and the measurement light ML#2-1 may be considered equivalent to the operation of receiving the measurement light ML#1-1 and the measurement light ML#2-1. The detection result by the photodetector 2223 (i.e., the reception result of the interference light) is output to the measurement control device 24 via the output interface 23 as part of the measurement result of the measurement device 20.

[0100] The measurement beams ML#1-2 and ML#2-2 emitted from the beam splitter 2222 are incident on the beam splitter 2224. The beam splitter 2224 emits at least a portion of the measurement beam ML#1-2 incident on the beam splitter 2224 toward the mirror 2225. The beam splitter 2224 emits at least a portion of the measurement beam ML#2-2 incident on the beam splitter 2224 toward the mirror 2227.

[0101] Measurement light ML#1-2 emitted from beam splitter 2224 is incident on mirror 2225. Measurement light ML#1-2 incident on mirror 2225 is reflected by the reflecting surface of mirror 2225 (the reflecting surface may also be referred to as a reference surface). Specifically, mirror 2225 reflects measurement light ML#1-2 incident on mirror 2225 toward beam splitter 2224. That is, mirror 2225 emits measurement light ML#1-2 incident on mirror 2225 as measurement light ML#1-3, which is its reflected light, toward beam splitter 2224. Measurement light ML#1-3 emitted from mirror 2225 is incident on beam splitter 2224. Beam splitter 2224 emits measurement light ML#1-3 incident on beam splitter 2224 toward beam splitter 2222. The measurement beams ML#1-3 emitted from the beam splitter 2224 are incident on the beam splitter 2222. The beam splitter 2222 emits the measurement beams ML#1-3 incident on the beam splitter 2222 toward the photodetector 2226.

[0102] On the other hand, measurement light ML#2-2 emitted from beam splitter 2224 toward mirror 2227 is incident on galvanometer mirror 2228 via mirror 2227. Galvanometer mirror 2228 can change the traveling direction of measurement light ML#2-2 emitted from galvanometer mirror 2228 toward the measurement object so as to change the irradiation position of measurement light ML (measurement light ML#2-2 in this case) on the measurement object. For this reason, galvanometer mirror 2228 may be referred to as a direction changing member or direction changing device. Galvanometer mirror 2228 may include scanning mirror 22281, which may also be referred to as a reflecting member or deflecting member. Scanning mirror 22281 is a tilt-angle variable mirror that can change the angle with respect to the optical path of measurement light ML#2-2 incident on scanning mirror 22281. The scanning mirror 22281 can change the angle with respect to the optical path of the measurement light ML#2-2 incident on the scanning mirror 22281 by rotating about a rotation axis that intersects with the optical path on the incident side of the measurement light ML#2-2 incident on the scanning mirror 22281. Note that the scanning mirror 22281 may tilt or oscillate about the rotation axis that intersects with the optical path on the incident side of the measurement light ML#2-2 incident on the scanning mirror 22281. The scanning mirror 22281 may be able to change the traveling direction of the measurement light ML#2-2 by rotating about a first rotation axis that intersects with the optical path on the incident side of the measurement light ML#2-2 incident on the scanning mirror 22281 so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the X-axis. The scanning mirror 22281 may be capable of changing the traveling direction of the measurement light ML#2-2 by rotating about a second rotation axis that intersects the optical path on the incident side of the measurement light ML#2-2 incident on the scanning mirror 22281 and intersects the first rotation axis, so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the Y axis. Alternatively, the galvanometer mirror 2228 may include, as the scanning mirror 22281, a first scanning mirror that is capable of changing the traveling direction of the measurement light ML#2-2 by rotating about the first rotation axis, so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the X axis, and a second scanning mirror that is capable of changing the traveling direction of the measurement light ML#2-2 by rotating about the second rotation axis, so that the irradiation position of the measurement light ML#2-2 on the measurement object changes along the Y axis.In this case, the second rotation axis of the second scanning mirror may be in a twisted relationship with the first rotation axis of the first scanning mirror.

[0103] The galvanometer mirror 2228 may change the traveling direction of the measurement light ML#2-2 starting from a pivot point PV of the galvanometer mirror 2228. The pivot point PV may be a virtual point on the reflecting surface of the scanning mirror 22281. Note that if the galvanometer mirror 2228 includes multiple scanning mirrors 22281, the pivot point PV may be a virtual point on the reflecting surface of one of the multiple scanning mirrors 22281 that is closest to the measurement object on the optical path of the measurement light ML#2-2. For example, the pivot point may be the center point of the reflecting surface of the scanning mirror 22281. For example, the pivot point may be the point where the measurement light ML#2-2 enters the scanning mirror 22281. The pivot point PV may be the point where the measurement light ML#2-2 exits the scanning mirror 22281. The pivot point PV may be a point on the rotation axis of the scanning mirror 22281.

[0104] The pivot point PV does not have to be a virtual point on the reflecting surface of the scanning mirror 22281. For example, the pivot point PV may be a virtual point that serves as a reference (starting point) for calculating the distance to the measurement object. In this case, as an example, the pivot point PV may be a point on the reflecting surface of the scanning mirror 22281 or a predetermined point of the optical system 222. There may also be multiple pivot points PV. For example, there may be a pivot point PV for each plane scanned by the measurement light ML#2-2. For example, if the galvanometer mirror 2228 includes a first scanning mirror and a second scanning mirror as described above, the pivot point with respect to the XZ plane may be on the first rotation axis of the first scanning mirror, and the pivot point with respect to the YZ plane may be on the second rotation axis of the second scanning mirror. The pivot point PV may also be referred to as a reference point or a measurement reference point because it can be said to be the reference of the measurement device 20 (measurement head 22).

[0105] Because the galvanometer mirror 2228 can change the irradiation position of the measurement light ML#2-2 on the measurement object in this way, the measurement device 20 can sequentially irradiate multiple parts of the measurement object with the measurement light ML#2-2. As a result, the measurement device 20 can measure multiple parts of the measurement object relatively quickly. In other words, the measurement device 20 is capable of multi-point measurement of the measurement object. Note that the multiple parts to which the measurement light ML#2-2 is sequentially irradiated do not have to be arranged in order along a predetermined direction on the measurement object.

[0106] The measurement head 22 irradiates the measurement object with measurement light ML#2-2, which is parallel light. In this case, the optical system 222 may be designed so that the measurement light ML#2-2 emitted from the galvanometer mirror 2228 is parallel light. However, as will be described later in a fourth modified example, the measurement head 22 may also irradiate the measurement object with measurement light ML#2-2, which is convergent light. In this case, the optical system 222 may be equipped with a focusing optical system that focuses the measurement light ML#2-2 emitted from the galvanometer mirror 2228. An fθ lens is an example of a focusing optical system.

[0107] When the measurement light ML is irradiated onto the measurement object, return light RL, which is at least a portion of the light generated by irradiating the measurement light ML onto the measurement object, is emitted from the measurement object. The return light RL is incident on the optical system 222 (specifically, the galvanometer mirror 2228). As described above, the return light RL is a light component that travels along the optical path of the measurement light ML among the light generated by irradiating the measurement light ML. Therefore, between the optical system 222 (particularly the galvanometer mirror 2228) and the measurement object, the optical path of the return light RL may overlap with the optical path of the measurement light ML#2-2. In other words, between the optical system 222 and the measurement object, the optical path of the return light RL and the optical path of the measurement light ML#2-2 may be coaxial. For example, the galvanometer mirror 2228 may irradiate the measurement light ML#2-2 onto the measurement object so that the measurement light ML#2-2 is perpendicularly incident on the measurement object. When measurement light ML#2-2 is perpendicularly incident on the measurement object, the optical path of return light RL typically overlaps with the optical path of measurement light ML#2-2 between optical system 222 and the measurement object. However, galvanometer mirror 2228 may irradiate measurement light ML#2-2 onto the measurement object so that measurement light ML#2-2 is obliquely incident on the measurement object. Even in this case, as described above, the optical path of return light RL, which is mainly composed of diffusely reflected light of measurement light ML, overlaps with the optical path of measurement light ML#2-2 between optical system 222 and the measurement object.

[0108] The return light RL incident on the galvanometer mirror 2228 is incident on the photodetector 2226 via the galvanometer mirror 2228, the mirror 2227, and the beam splitters 2224 and 2222. Therefore, the photodetector 2226 may be considered to receive the return light RL via the galvanometer mirror 2228.

[0109] As described above, in addition to the return light RL, the measurement light ML#1-3 is incident on the photodetector 2226. That is, the return light RL that travels toward the photodetector 2226 via the measurement object, and the measurement light ML#1-3 that travels toward the photodetector 2226 without traveling through the measurement object, are incident on the photodetector 2226. Note that the measurement light ML#1-3 that travels toward the photodetector 2226 is used as the reference light RB. For this reason, in the following description, the measurement light ML#1-3 that travels toward the photodetector 2226 is referred to as the reference light RB. The photodetector 2226 receives the reference light RB and the return light RL. The photodetector 2226 receives and detects the reference light RB and the return light RL. In particular, the photodetector 2226 receives and detects the interference light generated by the interference between the reference light RB and the return light RL. The operation of receiving the interference light generated by the interference between the reference light RB and the return light RL is equivalent to the operation of receiving the reference light RB and the return light RL. The detection result of the photodetector 2226 (i.e., the reception result of the interference light) is output to the measurement control device 24 via the output interface 23 as part of the measurement result of the measurement device 20.

[0110] The measurement control device 24 acquires the detection results of the photodetector 2223 and the detection results of the photodetector 2226 via the output interface 23. The measurement control device 24 generates measurement data of the measurement object based on the detection results of the photodetector 2223 and the detection results of the photodetector 2226 (i.e., the measurement results of the measurement device 20).

[0111] In this embodiment, as described below, the measurement control device 24 may first calculate the distance between the measurement head 22 and the measurement object based on the detection results of the photodetector 2223 and the detection results of the photodetector 2226. That is, the measurement control device 24 may generate measurement data related to the distance between the measurement head 22 and the measurement object. Furthermore, the measurement control device 24 may calculate the position of the measurement object based on the distance between the measurement head 22 and the measurement object. That is, the measurement control device 24 may generate measurement data related to the position of the measurement object. Furthermore, the measurement control device 24 may calculate the shape of the measurement object based on the position of the measurement object (in particular, the positions of each of the multiple parts of the measurement object). That is, the measurement control device 24 may generate measurement data related to the shape of the measurement object.

[0112] Specifically, since the pulse frequency of measurement light ML#1 is different from the pulse frequency of measurement light ML#2, the pulse frequency of measurement light ML#1-1 is different from the pulse frequency of measurement light ML#2-1. Therefore, the interference light between measurement light ML#1-1 and measurement light ML#2-1 is interference light in which pulse light appears in synchronization with the timing when the pulse light constituting measurement light ML#1-1 and the pulse light constituting measurement light ML2#2-1 simultaneously enter the photodetector 2223. Similarly, the pulse frequency of reference light RB is different from the pulse frequency of return light RL. Therefore, the interference light between reference light RB and return light RL is interference light in which pulse light appears in synchronization with the timing when the pulse light constituting reference light RB and the pulse light constituting return light RL simultaneously enter the photodetector 2226. Here, the position (position on the time axis) of the pulsed light of interference light detected by the photodetector 2226 varies depending on the positional relationship between the measurement head 22 and the measurement object (that is, essentially, the positional relationship between the processing head 11 and the measurement object). This is because the interference light detected by the photodetector 2226 is interference light between the return light RL that travels toward the photodetector 2226 via the measurement object and the reference light RB that travels toward the photodetector 2226 without passing through the measurement object. On the other hand, the position (position on the time axis) of the pulsed light of interference light detected by the photodetector 2223 does not vary depending on the positional relationship between the measurement head 22 and the measurement object (that is, essentially, the positional relationship between the processing head 11 and the measurement object). For this reason, it can be said that the time difference between the pulsed light of interference light detected by the photodetector 2226 and the pulsed light of interference light detected by the photodetector 2223 indirectly indicates the positional relationship between the measurement head 22 and the measurement object. Specifically, it can be said that the time difference between the pulsed light of interference light detected by the photodetector 2226 and the pulsed light of interference light detected by the photodetector 2223 indirectly indicates the distance between the measurement head 22 and the measurement object in the direction along the optical path of the measurement light ML emitted from the optical system 222 (i.e., the direction along the traveling direction of the measurement light ML). Therefore, the measurement control device 24 can calculate the distance between the measurement head 22 and the measurement object in the direction along the optical path of the measurement light ML emitted from the optical system 222, based on the time difference between the pulsed light of interference light detected by the photodetector 2226 and the pulsed light of interference light detected by the photodetector 2223.

[0113] Furthermore, because the irradiation position of measurement light ML#2-2 on the measurement object is determined by the drive state of the galvanometer mirror 2228, the measurement control device 24 can calculate the direction of the irradiated portion from the measurement head 22 (e.g., the direction of the irradiated portion from the pivot point PV) based on information related to the drive state of the galvanometer mirror 2228. That is, the measurement control device 24 can calculate the direction in which measurement light ML#2-2 is emitted from the measurement head 22 as the direction of the irradiated portion from the measurement head 22 based on information related to the drive state of the galvanometer mirror 2228. An example of the information related to the drive state of the galvanometer mirror 2228 is information related to the rotation angle of the scanning mirror 22281 included in the galvanometer mirror 2228. Here, the galvanometer mirror 2228 may be provided with a rotation angle detector for detecting the rotation angle of the scanning mirror 22281. Such a rotation angle detector may be, for example, at least one of a rotary encoder and an angle detection device that irradiates light onto the scanning mirror 22281 and optically detects its angle. Furthermore, under conditions in which the movement error described above has been corrected, the measurement control device 24 can identify the position of the measurement head 22 in the machine coordinate system using the head position measurement device 13 that can measure the position of the machining head 11 to which the measurement head 22 is attached. As a result, the measurement control device 24 can calculate the position of the irradiated portion in the machine coordinate system (e.g., its position in a three-dimensional coordinate space) based on the distance between the measurement head 22 and the irradiated portion, the direction of the irradiated portion from the measurement head 22, and the position of the measurement head 22 in the machine coordinate system. In other words, the measurement control device 24 can generate measurement data that indicates the position of the irradiated portion in the machine coordinate system.

[0114] The measurement head 22 may irradiate multiple portions of the measurement object with the measurement light ML#2-2. For example, the galvanometer mirror 2228 may change the irradiation position of the measurement light ML#2-2 on the measurement object so that the measurement head 22 irradiates multiple portions of the measurement object with the measurement light ML#2-2. For example, at least one of the processing head 11 (measurement head 22) and the stage 141 may move so that the measurement head 22 irradiates multiple portions of the measurement object with the measurement light ML#2-2. When the measurement light ML#2-2 irradiates multiple portions of the measurement object, the measurement control device 24 can generate measurement data indicating the positions of the multiple portions of the measurement object. As a result, the measurement control device 24 can generate measurement data indicating the shape of the measurement object based on the measurement data indicating the positions of the multiple portions. For example, the measurement control device 24 can generate measurement data indicating the shape of the measurement object by calculating a three-dimensional shape composed of virtual planes (or curved surfaces) connecting the multiple portions whose positions have been identified as the shape of the measurement object.

[0115] In this manner, the measurement apparatus 20 can measure the measurement object by irradiating the measurement light ML onto the measurement object and receiving the return light RL from the measurement object irradiated with the measurement light ML. In particular, in the example described above, the measurement apparatus 20 can measure the measurement object by receiving interference light between the return light RL and the reference light RB. For this reason, the measurement apparatus 20 may be considered to be an interferometric measurement apparatus. However, the measurement apparatus 20 does not have to be an interferometric measurement apparatus as long as it can measure the measurement object. For example, the measurement apparatus 20 may be a triangulation measurement apparatus. The measurement apparatus 20 may be a stereo measurement apparatus. The measurement apparatus 20 may be a phase-shift measurement apparatus. The measurement apparatus 20 may be a confocal measurement apparatus. The measurement apparatus 20 may be a ToF (Time of Flight) measurement apparatus. The measuring device 20 may be a frequency modulated continuous wave (FMCW) type measuring device.

[0116] (2) Movement Error Calculation Operation Next, the movement error calculation operation performed by the measurement control device 24 will be described.

[0117] (2-1) Overview of the Movement Error Calculation Operation As described above, the movement error calculation operation is an operation for calculating a movement error that occurs in the movement of at least one of the processing head 11 and the stage 141, based on the measurement results by the measurement head 22. As described above, the measurement head 22 receives the interference light between the reference light RB and the return light RL, and therefore the movement error calculation operation may be considered to be an operation for calculating a movement error that occurs in the movement of at least one of the processing head 11 and the stage 141, based on the reception result of the interference light between the reference light RB and the return light RL.

[0118] For example, 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 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, and the target position of the machining head 11. In the following description, the drive control signal for controlling the head drive system 12 is referred to as the head drive control signal. If the machining head 11 is translationally movable along a 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 when the head drive system 12 translates the machining head 11 along the translation axis based on the head drive control signal for controlling the head drive system 12 to move the machining head 11 to a desired target position, and the target position of the machining head 11. In other words, the movement error of the machining head 11 may include a movement error that occurs during the translational movement of the machining head 11. If the machining head 11 is rotatable about the rotation 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 when the head drive system 12 rotates the machining head 11 about 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, and the target position of the machining head 11. In other words, the movement error of the machining head 11 may include a movement error that occurs during the rotational movement of the machining head 11.

[0119] 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 when the stage drive system 142 moves the stage 141 based on a drive control signal for controlling the stage drive system 142 to move the stage 141 to a desired target position, and the target position of the stage 141. In the following description, the drive control signal for controlling the stage drive system 142 is referred to as a stage drive control signal. If the stage 141 is movable along a translation axis, the movement error may include an error corresponding to the difference (i.e., deviation) between the actual position of the stage 141 when the stage drive system 142 translates the stage 141 along the translation axis based on a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to a desired target position, and the target position of the stage 141. In other words, the movement error of the stage 141 may include a movement error that occurs during the translational movement of the stage 141. If the stage 141 is rotatable around the rotation axis, the stage 141 may include an error corresponding to the difference (i.e., deviation) between the actual position of the stage 141 when the stage drive system 142 rotates the stage 141 around the rotation axis based on a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to a desired target position, and the target position of the stage 141. In other words, the movement error of the stage 141 may include a movement error that occurs during the rotational movement of the stage 141.

[0120] Here, if the movement error of the machining head 11 is not corrected under conditions in which the movement error of the machining head 11 occurs, even if 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 target position, the movement error may cause the machining head 11 to move to a position different from the desired target position. For this reason, the machine tool 1 may not be able to move the machining head 11 with precision. As a result, the machine tool 1 may not be able to accurately machine the workpiece W placed on the stage 141. Furthermore, if the measurement head 22 or the measurement head 22d-1 described below is attached to the machining head 11, the measurement head 22 or the measurement head 22d-1 attached to the machining head 11 may not move with precision, and therefore the measurement system 2 may not be able to properly measure the workpiece W placed on the stage 141.

[0121] Similarly, if a movement error of the stage 141 occurs but the movement error of the stage 141 is not corrected, even if 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 target position, the movement error may cause the stage 141 to move to a position different from the desired target position. Therefore, the machine tool 1 may not be able to move the stage 141 with precision. As a result, the machine tool 1 may not be able to accurately machine the workpiece W placed on the stage 141. Furthermore, if the measurement head 22 or a measurement head 22d-1 (described later) is attached to the machining head 11, the measurement system 2 may not be able to properly measure the workpiece W placed on the stage 141.

[0122] Therefore, in the present embodiment, the machining system SYS may calculate a movement error by performing a movement error calculation operation, and move at least one of the machining head 11 and the stage 141 to correct (e.g., cancel) the movement error. That is, even when a movement error of the machining head 11 occurs, the machining system SYS may control the movement of the machining head 11 so that the machining head 11 moves in the same way as when no movement error of the machining head 11 occurs. Even when a movement error of the stage 141 occurs, the machining system SYS may control the movement of the stage 141 so that the stage 141 moves in the same way as when no movement error of the stage 141 occurs. As a result, when the head drive system 12 moves the machining head 11 based on the 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. Therefore, the machine tool 1 can move the machining head 11 with higher precision than when the movement error calculation operation is not performed. As a result, the machine tool 1 can machine the workpiece W with higher precision than when the movement error calculation operation is not performed. Furthermore, when the measurement head 22 or a measurement head 22d-1 described later is attached to the machining head 11, the measurement system 2 can properly measure the workpiece W placed on the stage 141, compared to when the movement error calculation 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, the machine tool 1 can move the stage 141 with higher precision than when the movement error calculation operation is not performed. As a result, the machine tool 1 can machine the workpiece W with higher precision than when the movement error calculation operation is not performed. Furthermore, when the measurement head 22 or a measurement head 22d-1 described later is attached to the machining head 11, the measurement system 2 can properly measure the workpiece W placed on the stage 141, compared to when the movement error calculation operation is not performed.

[0123] The machining system SYS may perform a movement error calculation operation before the machine tool 1 starts machining the workpiece W. In this case, after starting machining the workpiece W, the machine tool 1 can move at least one of the machining head 11 and the stage 141 so as to correct (e.g., cancel out) the movement error calculated in the movement error calculation operation. This allows the machine tool 1 to move the machining head 11 with high precision. In other words, the machine tool 1 can machine the workpiece W with high precision.

[0124] However, the machining system SYS may perform the movement error calculation operation during at least a portion of the period during which the machine tool 1 is machining the workpiece W. In other words, the machining system SYS may perform the movement error calculation operation after the machine tool 1 starts machining the workpiece W. In yet other words, the machining system SYS may perform the movement error calculation operation during at least a portion of the period from when the machine tool 1 starts machining the workpiece W until when the machine tool 1 finishes machining the workpiece W. Furthermore, the machining system SYS may perform the movement error calculation operation after the machine tool 1 finishes machining the workpiece W.

[0125] In this embodiment, to calculate the movement error, as shown in FIG. 9 , the measurement head 22 irradiates the reference member FM with measurement light ML and receives return light RL from the reference member FM. Thereafter, the measurement control device 24 calculates the distance between the measurement head 22 and the reference member FM based on the measurement result by the measurement head 22 (i.e., the reception result of the interference light between the reference light RB and the return light RL). Thereafter, the measurement control device 24 calculates the movement error based on the distance between the measurement head 22 and the reference member FM. Note that a specific example of the operation of calculating the movement error based on the distance between the measurement head 22 and the reference member FM will be described in detail later.

[0126] An example of the arrangement of the reference member FM is shown in Figures 10(a) and 10(b). As shown in Figures 10(a) and 10(b), in this embodiment, at least one reference member FM is arranged on the workpiece W placed on the stage 141. Furthermore, at least one reference member FM may be arranged on the stage 141. However, the reference member FM does not have to be arranged on the stage 141. In the following explanation, as an example, an example will be described in which the reference member FM is arranged on each of the workpiece W and the stage 141. It is to be noted that the reference member FM does not have to be arranged on the workpiece W placed on the stage 141.

[0127] Furthermore, in this embodiment, a plurality of reference members FM may be arranged on the workpiece W and the stage 141. In the example shown in Figures 10(a) and 10(b), 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 less or five or more reference members FM may be arranged on the workpiece W. Three or less or five or more reference members FM may be arranged on the stage 141.

[0128] The multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least N (where N is a constant indicating an integer greater than or equal to 1) reference members FM are included within the measurement range of the measurement head 22 located at any position within the machine coordinate system. The multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least N reference members FM are included within the measurement range of the measurement head 22 moving within the machine coordinate system. The measurement range of the measurement head 22 may refer to an area that can be scanned by the measurement light ML whose traveling direction is changed by the galvanometer mirror 2228. Furthermore, "N" is a variable indicating the minimum number of reference members FM included in the measurement range of the measurement head 22, and is typically a variable indicating an integer greater than or equal to 1. Furthermore, N may also be a variable indicating an integer greater than or equal to 4.

[0129] As an example, the multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least N first reference members FM are included within the measurement range of the measurement head 22 located at a first position in the machine coordinate system. Furthermore, the multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least N second reference members FM are included within the measurement range of the measurement head 22 located at a second position different from the first position in the machine coordinate system. Note that the at least N second reference members FM may be different from the at least N first reference members FM. Alternatively, some of the at least N second reference members FM may be identical to some of the at least N first reference members FM. Alternatively, all of the at least N second reference members FM may be identical to all of the at least N first reference members FM.

[0130] As another example, the multiple reference members FM may be arranged on the workpiece W and the stage 141 such that at least N third reference members FM are included in the measurement range of the measurement head 22 when the stage 141 is located at a third position in the machine coordinate system. Furthermore, the multiple reference members FM may be arranged on the workpiece W and the stage 141 such that at least N fourth reference members FM are included in the measurement range of the measurement head 22 when the stage 141 is located at a fourth position different from the third position in the machine coordinate system. 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 identical to some of the at least N third reference members FM. Alternatively, all of the at least N fourth reference members FM may be identical to all of the at least N third reference members FM.

[0131] An example of the variable N is 4. In this case, the multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least four reference members FM are included in the measurement range of the measurement head 22 located at a desired position in the machine coordinate system. The multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least four reference members FM are included in the measurement range of the measurement head 22 moving in the machine coordinate system.

[0132] One reason why the variable N is set to 4 is that the first movement error calculation operation uses the principle of multilateration, as described below. In this case, multiple lines connecting the measurement head 22 and the reference point FM are prepared, and the position of the measurement head 22 is calculated based on the lengths of these lines (i.e., the distance between the measurement head 22 and the reference member FM), and the movement error is calculated based on the position of the measurement head 22. In this embodiment, since not only the position of the measurement head 22 but also the position of the reference member FM are unknown parameters, at least four reference members FM are required to set the minimization problem described below. However, depending on the method for setting the minimization problem, the number of reference members FM may be three or less.

[0133] Here, when a reference member FM is placed on both the stage 141 and the workpiece W, there is a higher possibility that at least N reference members FM will be included within the measurement range of the measurement head 22 compared to when a reference member FM is placed only on the stage 141.

[0134] For example, FIG. 11A shows the measurement head 22 irradiating the reference member FM with the measurement light ML above the workpiece W in a situation where a reference member FM is disposed on both the stage 141 and the workpiece W. On the other hand, for example, FIG. 11B shows the measurement head 22 irradiating the reference member FM with the measurement light ML above the workpiece W in a situation where a reference member FM is disposed on the stage 141 but a reference member FM is not disposed on the workpiece W. As shown in FIG. 11B, if a reference member FM is not disposed on the workpiece W, the measurement head 22 positioned above the workpiece W may not be able to irradiate the measurement light ML onto the reference member FM disposed on the stage 141. This is because, as shown in FIG. 11B, the measurement light ML may be blocked by the workpiece W. 11A, when a reference member FM is also arranged on the workpiece W, even if the measurement head 22 located above the workpiece W cannot irradiate the measurement light ML onto the reference member FM arranged on the stage 141, the measurement head 22 can irradiate the measurement light ML onto the reference member FM arranged on the workpiece W. In other words, in the situation shown in FIG. 11A, there is a higher possibility that at least N reference members FM will be included within the measurement range of the measurement head 22 compared to the situation shown in FIG. 11B.

[0135] 11(c) shows the measurement head 22 irradiating the reference member FM with the measurement light ML above the workpiece W in a situation where the reference member FM is disposed on the workpiece W but the reference member FM is not disposed on the stage 141. In this case, as shown in FIG. 11(c), when the reference member FM is disposed on the workpiece W, even if the measurement head 22 positioned above the workpiece W cannot irradiate the reference member FM disposed on the stage 141 with the measurement light ML, the measurement head 22 can irradiate the reference member FM disposed on the workpiece W with the measurement light ML. In other words, in the situation shown in FIG. 11(c), there is a higher possibility that at least N reference members FM will be included in the measurement range of the measurement head 22 compared to the situation shown in FIG. 11(b).

[0136] 11(d) shows the measurement head 22 irradiating the reference member FM on the side of the workpiece W with the measurement light ML in a situation where the reference member FM is disposed on the workpiece W but not on the stage 141. In this case, if the reference member FM is not disposed on the stage 141, depending on the positional relationship between the measurement head 22 and the workpiece W, the measurement head 22 positioned on the side of the workpiece W may not be able to irradiate the reference member FM disposed on the workpiece W (particularly its top surface) with the measurement light ML. On the other hand, as shown in FIG. 11(e), if the reference member FM is also disposed on the stage 141, even if the measurement head 22 positioned on the side of the workpiece W cannot irradiate the reference member FM disposed on the workpiece W with the measurement light ML, the measurement head 22 can irradiate the reference member FM disposed on the stage 141 with the measurement light ML. In other words, in the situation shown in FIG. 11(e), there is a higher possibility that at least N reference members FM will be included in the measurement range of the measurement head 22 compared to the situation shown in FIG. 11(d). However, the frequency with which the measurement head 22 irradiates the reference member FM with the measurement light ML to the side of the workpiece W may be lower than the frequency with which the measurement head 22 irradiates the reference member FM with the measurement light ML above the workpiece W. Therefore, even in the situation shown in FIG. 11D , the arrangement of the reference member FM shown in FIG. 11C remains beneficial, since it can provide the effect of "increasing the likelihood that at least N reference members FM will be included within the measurement range of the measurement head 22" in the situation "where the measurement head 22 irradiates the reference member FM with the measurement light ML to the side of the workpiece W," which occurs relatively frequently. It can be said that FIG. 11E emphasizes the additional effect that can be achieved by arranging the reference members FM on both the stage 141 and the workpiece W in the situation "where the measurement head 22 irradiates the reference member FM with the measurement light ML to the side of the workpiece W," which does not occur very frequently.

[0137] 10( a) and 10(b), the reference member FM may be directly disposed on the stage 141 or the workpiece W. Alternatively, the reference member FM may be disposed 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 disposed on the stage or the workpiece W via the support member. Specifically, the support member that supports the reference member FM may be disposed directly 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 FIG. 10(b), each reference member FM is disposed on the stage 141 or the workpiece W via a rod-shaped support member. Note that a 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.

[0138] The multiple reference members FM may include at least two reference members FM that are respectively positioned at at least two different positions along the X axis of the machine coordinate system. In other words, the multiple reference members FM may include at least two reference members FM that are positioned at different positions along the X axis of the machine coordinate system. In other words, the 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 arranged 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 arranged on the stage 141. For example, at least one reference member FM that is arranged on the workpiece W and at least one reference member FM that is arranged on the stage 141 may be spaced apart from each other along the X axis of the machine coordinate system.

[0139] The multiple reference members FM may include at least two reference members FM that are respectively positioned at at least two different positions along the Y axis of the machine coordinate system. In other words, the multiple reference members FM may include at least two reference members FM that are positioned at different positions along the Y axis of the machine coordinate system. In other words, the 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 arranged 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 arranged on the stage 141. For example, at least one reference member FM that is arranged on the workpiece W and at least one reference member FM that is arranged on the stage 141 may be spaced apart from each other along the Y axis of the machine coordinate system.

[0140] The multiple reference members FM may include at least two reference members FM that are respectively positioned at at least two different positions along the Z axis of the machine coordinate system. In other words, the multiple reference members FM may include at least two reference members FM that are positioned at different positions along the Z axis of the machine coordinate system. In other words, the multiple reference members FM may include at least two reference members FM that are separated from each other along the Z axis of the machine coordinate system. Because the Z axis is vertical, the multiple reference members FM may include at least two reference members FM that are at different heights. For example, at least two reference members FM that are at different heights may be arranged on the workpiece W. For example, at least two reference members FM that are at different heights may be arranged on the stage 141. For example, the height of at least one reference member FM arranged on the workpiece W may be different from the height of at least one reference member FM arranged on the stage 141.

[0141] The height of the reference member FM may be adjusted by a support member (e.g., a jig) that supports the reference member FM. For example, at least two reference members FM may be arranged on the workpiece W, each supported by at least two rod-shaped support members having different lengths (heights). For example, at least two reference members FM may be arranged on the stage 141, each supported by at least two rod-shaped support members having different lengths (heights).

[0142] The reference member FM may be a member having known characteristics. 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 retroreflective member capable of retroreflecting the incident measurement light ML. The retroreflective member may be a corner cube or a ball lens. The reference member FM may be, as an example of a retroreflective member, an SMR (Spherically Mounted Retroreflector). The reference member FM may be referred to as a reflector or a retroreflective member. The reference member FM may be referred to as 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.

[0143] 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 presence of at least one feature point within the measurement range may refer to the presence of at least one feature point within a region of the surface of the reference member FM that corresponds to the measurement range. The feature point may be a portion of the reference member FM that satisfies the condition that the feature point is distinguishable from other portions of the reference member FM. For example, the feature point may be a portion of the reference member FM that satisfies the condition that the characteristics of the feature point are distinguishable from other characteristics of other portions 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. Using a reference member FM having at least one feature point within the measurement range of the measurement head 22 in this manner has the advantage of reducing measurement errors.

[0144] (2-2) Specific Flow of Movement Error Calculation Operation Next, a specific flow of the movement error calculation operation will be described. As described above, the movement error includes at least one of the movement error occurring in the translational movement of the machining head 11, the movement error occurring in the rotational movement of the machining head 11, and the movement error occurring in the translational movement of the stage 141 and the movement error occurring in the rotational movement of the stage 141. For convenience of explanation, the following will sequentially describe a first movement error calculation operation for calculating the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141, and a second movement error calculation operation for calculating the movement error occurring in the rotational movement of at least one of the machining head 11 and the stage 141.

[0145] (2-2-1) Specific flow of the first movement error calculation operation for calculating the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141 First, we will explain the first movement error calculation operation for calculating the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141.

[0146] When calculating a movement error that occurs in the translational movement of the machining head 11 (measurement head 22), the measurement head 22 may change the traveling direction of the measurement light ML using the galvanometer mirror 2228 each time the machining head 11 moves translationally and stops, thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In other words, each time the machining head 11 moves translationally to a plurality of different positions, the measurement head 22 may irradiate each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML whose traveling direction has been changed by the galvanometer mirror 2228. As a result, the measurement head 22 receives the return light RL from each of the at least N reference members FM each time the machining head 11 moves translationally and stops. The measurement control device 24 may calculate a movement error occurring in the translational movement of the machining head 11 based on the light reception results of the return light RL from each of the at least N reference members FM that are received by the measurement head 22 each time the machining head 11 translates to a plurality of different positions. In particular, the measurement control device 24 may calculate a movement error occurring in the translational movement of the machining head 11 in a space where the machining head 11 has translated to a plurality of different positions based on the light reception results of the return light RL from each of the at least N reference members FM that are received by the measurement head 22 each time the machining head 11 translates to a plurality of different positions.

[0147] The measurement head 22 may use the galvanometer mirror 2228 to sequentially change the direction of travel of the measurement light ML while the processing head 11 is translationally moving (when the processing head 11 is not stopped), thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In this case, too, the measurement control device 24 may calculate a movement error occurring in the translational movement of the processing head 11 in a space where the processing head 11 has translated to a plurality of different positions, based on the result of receiving the return light RL from each of the at least N reference members FM, which is received by the measurement head 22 each time the processing head 11 translates to a plurality of different positions.

[0148] When calculating a movement error that occurs in the translational movement of the stage 141, the measurement head 22 may change the traveling direction of the measurement light ML using the galvanometer mirror 2228 each time the stage 141 translates and stops, thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In other words, each time the stage 141 translates to a plurality of different positions, the measurement head 22 may irradiate each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML whose traveling direction has been changed by the galvanometer mirror 2228. As a result, the measurement head 22 receives the return light RL from each of the at least N reference members FM each time the stage 141 translates and stops. The measurement control device 24 may calculate a movement error occurring in the translational movement of the stage 141 based on the reception results of the return light RL from each of the at least N reference members FM that are received by the measurement head 22 each time the stage 141 translates to a plurality of different positions. In particular, the measurement control device 24 may calculate a movement error occurring in the translational movement of the stage 141 in a space where the stage 141 has translated to a plurality of different positions based on the reception results of the return light RL from each of the at least N reference members FM that are received by the measurement head 22 each time the stage 141 translates to a plurality of different positions.

[0149] The measurement head 22 may use the galvanometer mirror 2228 to sequentially change the direction of travel of the measurement light ML while the stage 141 is translationally moving (i.e., while the stage 141 is not stopped), thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In this case as well, the measurement control device 24 may calculate a movement error occurring in the translational movement of the stage 141 in a space where the stage 141 has translated to a plurality of different positions, based on the result of receiving the return light RL from each of the at least N reference members FM, which is received by the measurement head 22 each time the stage 141 translates to a plurality of different positions.

[0150] Note that when calculating a movement error occurring in translational movement, a workpiece W is placed on the stage 141. For example, when calculating a movement error occurring in translational movement, a workpiece W on which a reference member FM is arranged may be placed on the stage 141. For example, when calculating a movement error occurring in translational movement, a workpiece W on which a reference member FM is not arranged may be placed on the stage 141. However, when calculating a movement error occurring in translational movement, a workpiece W does not have to be placed on the stage 141. For convenience of explanation, the following describes the first movement error calculation operation performed when a workpiece W on which a reference member FM is arranged is placed on the stage 141. However, even when a workpiece W on which a reference member FM is not arranged is placed on the stage 141 or when a workpiece W is not placed on the stage 141, the machining system SYS may calculate a movement error occurring in translational movement by performing the first movement error calculation operation described below.

[0151] 12, a description will be given of the flow of the first movement error calculation operation for calculating a movement error occurring in the translational movement of at least one of the machining head 11 (measurement head 22) and the stage 141. Fig. 12 is a flowchart showing the flow of the first movement error calculation operation for calculating a movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141.

[0152] 12 , first, the measurement control device 24 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 the initial position (step S101). That is, the measurement control device 24 controls at least one of the head drive system 12 and the stage drive system 142 so that at least one of the machining head 11 and the stage 141 moves to the initial position within the machine coordinate system (step S101). More specifically, under the control of the measurement control device 24, the machining control device 16 controls at least one of the head drive system 12 and the stage drive system 142 so that at least one of the machining head 11 and the stage 141 moves to the initial position within the machine coordinate system (step S101). Note that in step S101, the measurement control device 24 may translate at least one of the machining head 11 and the stage 141.

[0153] Specifically, the measurement control device 24 may move the machining head 11 to an initial head position, which is an example of an initial position. In this case, under the control of the measurement control device 24, the machining control device 16, which controls the head drive system 12, generates a head drive control signal for controlling 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. Note that information about the initial head position used to generate the head drive control signal may be considered to be a command value regarding the movement of the machining head 11. The head drive control signal itself may also be considered to be a command value regarding the movement of the machining head 11. Thereafter, under the control of the measurement control device 24, 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.

[0154] However, at this point, the movement error of the machining head 11 has not been corrected, so the machining head 11 is not necessarily 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 match the initial head position in the machine coordinate system.

[0155] The initial head position may be the end position of the range of movement of the machining head 11 along the translational axis in the machine coordinate system. For example, the machining head 11 is movable along both the translational axis (X) and the translational axis (Z). In this case, the initial head position may be the end position on the +X side of the range of movement of the machining head 11 along the translational axis (X) in the machine coordinate system. The initial head position may be the end position on the −X side of the range of movement of the machining head 11 along the translational axis (X) in the machine coordinate system. The initial head position may be the end position on the +Z side of the range of movement of the machining head 11 along the translational axis (Z) in the machine coordinate system. The initial head position may be the end position on the −Z side of the range of movement of the machining head 11 along the translational axis (Z) in the machine coordinate system. Alternatively, the current position of the machining head 11 may be used as the initial head position. In this case, in step S101, the measurement control device 24 does not necessarily move the machining head 11. However, the initial head position is not limited to the position exemplified here.

[0156] The measurement control device 24 may move the stage 141 to an initial stage position, which is an example of an initial position. In this case, under the control of the measurement control device 24, the processing control device 16, which controls the stage drive system 142, generates a stage drive control signal for controlling 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. Note that information about the initial stage position used to generate the stage drive control signal may be considered to be a command value related to the movement of the stage 141. The stage drive control signal itself may also be considered to be a command value related to the movement of the stage 141. Thereafter, under the control of the measurement control device 24, the processing 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. As a result, the stage 141 moves to the initial stage position and then stops at the initial stage position.

[0157] However, at this point, the movement error of the stage 141 has not been corrected, so the stage 141 is not necessarily 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 match the initial stage position in the machine coordinate system.

[0158] The initial stage position may be the end position of the range of movement of the stage 141 along the translation axis in 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 the end position on the +Y side of the range of movement of the stage 141 along the translation axis (Y) in the machine coordinate system. The initial stage position may be the end position on the −Y side of the range of movement of the stage 141 along the translation axis (Y) in the machine coordinate system. Alternatively, the current position of the stage 141 may be used as the initial stage position. In this case, in step S101, the measurement control device 24 does not necessarily have to move the stage 141. However, the initial stage position is not limited to the position exemplified here.

[0159] Thereafter, the measurement control device 24 performs a global scan (step S102). Specifically, the measurement control device 24 controls the measurement head 22 to perform a global scan (step S102). As a result, the measurement head 22 performs a global scan (step S102).

[0160] As shown in FIG. 13 , which shows the measurement head 22 performing a global scan, a global scan area GSA corresponding to the measurement range of the measurement head 22 is scanned with measurement light ML. To perform a global scan, the measurement control device 24 controls the galvanometer mirror 2228 of the measurement head 22 so that the measurement light ML scans the global scan area GSA. As a result, the measurement head 22 receives return light RL from the global scan area GSA. In other words, the photodetector 2226 of the measurement head 22 receives the return light RL from the global scan area GSA.

[0161] As described above, when the measurement control device 24 calculates the distance between the measurement object and the measurement head 22, the photodetector 2226 receives the interference light between the return light RL and the reference light RB. On the other hand, when the measurement head 22 performs a global scan, the photodetector 2226 receives the return light RL but does not necessarily receive the reference light RB. In other words, the photodetector 2226 does not necessarily receive the interference light between the return light RL and the reference light RB. When the measurement head 22 performs a global scan, the measurement light source 21#1 that generates the measurement light ML#1, which is the reference light RB incident on the photodetector 2226, does not necessarily need to generate the measurement light ML#1. In other words, the measurement light source 21#1 does not necessarily need to emit the measurement light ML#1. Alternatively, a light-shielding member that blocks the measurement light ML#1 may be inserted in the optical path of the measurement light ML#1 between the measurement light source 21#1 and the photodetector 2226.

[0162] Thereafter, the measurement control device 24 calculates the direction of the local scan area LSA from the measurement head 22 based on the results of the global scan (step S103). The local scan area LSA is the region in the global scan area GSA where the reference member FM is located, as shown in Fig. 13. Therefore, in step S103, the measurement control device 24 may be considered to be calculating the direction of the reference member FM located in the global scan area GSA from the measurement head 22 based on the results of the global scan.

[0163] In particular, the local scan area LSA is smaller than the global scan area GSA. Therefore, the local scan area LSA is the area within the global scan area GSA where the reference member FM is located and corresponds to a part of the global scan area GSA.

[0164] To calculate the direction of the local scan area LSA, the measurement control device 24 acquires the detection result (i.e., the light reception result of the return light RL) by the photodetector 2226 as a result of the global scan. Here, the intensity of the return light RL when the measurement light ML is irradiated on the reference member FM is likely to be different from the intensity of the return light RL when the measurement light ML is not irradiated on the reference member FM. Conversely, the reflectance (reflectance distribution) of the reference member FM may be set so that the intensity of the return light RL when the measurement light ML is irradiated on the reference member FM is different from the intensity of the return light RL when the measurement light ML is not irradiated on the reference member FM. Typically, the intensity of the return light RL when the measurement light ML is irradiated on the reference member FM is likely to be higher than the intensity of the return light RL when the measurement light ML is not irradiated on the reference member FM. Conversely, the reflectance (reflectance distribution) of the reference member FM may be set so that the intensity of the return light RL when the measurement light ML is irradiated onto the reference member FM is higher than the intensity of the return light RL when the measurement light ML is not irradiated onto the reference member FM. In this case, for example, the measurement control device 24 can identify the period during which the measurement light ML is irradiated onto the reference member FM based on the detection result by the photodetector 2226 (i.e., the reception result of the return light RL). In other words, the measurement control device 24 can distinguish between the period during which the measurement light ML is irradiated onto the reference member FM and the period during which the measurement light ML is not irradiated onto the reference member FM. Thereafter, the measurement control device 24 may calculate, as the direction of the reference member FM from the measurement head 22, the direction in which the measurement light ML is emitted from the galvanometer mirror 2228 during the period during which the measurement light ML is irradiated onto the reference member FM, based on information regarding the driving state of the galvanometer mirror 2228 during the period during which the measurement light ML is irradiated onto the reference member FM. That is, the measurement control device 24 may calculate the direction in which the measurement light ML is emitted from the galvanometer mirror 2228 during the period in which the measurement light ML is irradiated onto the reference member FM as the direction of the local scan area LSA from the measurement head 22. An example of the information about the driving state of the galvanometer mirror 2228 is information about the rotation angle of the scanning mirror 22281 provided in the galvanometer mirror 2228.

[0165] As described above, when at least N reference members FM are included in the measurement range of the measurement head 22, the measurement control device 24 may calculate the direction of each of at least N local scan areas LSA in which the at least N reference members FM are located. In this embodiment, an example will be described in which the variable N is set to 4 when the first movement error calculation operation is performed. In this case, the multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least four reference members FM are included in the measurement range of the measurement head 22. The measurement control device 24 may calculate the direction of each of at least four local scan areas LSA in which the at least four reference members FM are located within the measurement range (i.e., within the global scan area GSA).

[0166] However, even when calculating the direction of each local scan area LSA, the measurement head 22 may receive interference light between the return light RL from the global scan area GSA (i.e., the return light RL from the reference member FM) and the reference light RB. In this case, the measurement control device 24 may calculate the distance between the measurement head 22 and the local scan area LSA where the reference member FM is located based on the reception result of the interference light between the return light RL and the reference light RB. The measurement control device 24 may then calculate the position of the local scan area LSA in the machine coordinate system based on the calculated distance to the local scan area LSA, the direction of the local scan area LSA calculated from the intensity of the return light RL, and the position of the machining head 11 in the machine coordinate system (i.e., the position of the measurement head 22 attached to the machining head 11). The position of the machining head 11 in the machine coordinate system can be obtained from a position measurement device 13 that can measure the position of the machining head 11.

[0167] The number of reference members FM included in a local scan area LSA is not limited to one. That is, at least two reference members FM may be located in one local scan area LSA. In this case, the measurement control device 24 may calculate the direction of a single local scan area LSA in which at least two reference members FM are located. In this case, the measurement control device 24 does not need to calculate the direction of each of the N local scan areas LSA in which at least N reference members FM are located. For example, when the measurement range of the measurement head 22 includes at least N reference members FM, the measurement control device 24 may calculate the direction of two or more local scan areas LSA but fewer than N.

[0168] Thereafter, the measurement control device 24 performs a local scan (step S104). Specifically, the measurement control device 24 controls the measurement head 22 to perform a local scan (step S104). As a result, the measurement head 22 performs a local scan (step S104).

[0169] As shown in FIG. 14 , which shows the measurement head 22 performing a local scan, the local scan is an operation of scanning each of at least four local scan areas LSA with the measurement light ML. To perform the local scan, the measurement control device 24 scans each of the at least four local scan areas LSA with the measurement light ML based on the respective directions of the at least four local scan areas LSA identified in step S103. Specifically, the measurement control device 24 controls the galvanometer mirror 2228 to emit the measurement light ML in the direction of one of the local scan areas LSA identified in step S103. Furthermore, the measurement control device 24 controls the galvanometer mirror 2228 to scan one of the local scan areas LSA with the measurement light ML emitted in the direction of one of the local scan areas LSA identified in step S103. As a result, the measurement head 22 scans one of the local scan areas LSA with the measurement light ML and receives the return light RL from one of the local scan areas LSA. That is, the photodetector 2226 of the measurement head 22 receives the return light RL from one local scan area LSA. The measurement control device 24 repeats this operation the number of times equal to the number of local scan areas LSA.

[0170] Thereafter, the measurement control device 24 calculates the direction of the reference member FM from the measurement head 22 based on the result of the local scan (step S105). That is, the measurement control device 24 calculates the direction of each of the at least four reference members FM from the measurement head 22 based on the result of the local scan (step S105).

[0171] To calculate the orientation of each of the at least four reference members FM, the measurement control device 24 acquires the detection results (i.e., the reception results of the return light RL) from the photodetector 2226 as a result of the local scan. As described above, the intensity of the return light RL when the measurement light ML is irradiated onto the reference member FM is likely to be different from the intensity of the return light RL when the measurement light ML is not irradiated onto the reference member FM. In this case, based on the reception results of the return light RL from one local scan area LSA, the measurement control device 24 can identify the period during which the measurement light ML scanning one local scan area LSA is irradiated onto one reference member FM located in one local scan area LSA. That is, the measurement control device 24 can distinguish between a period in which the measurement light ML scanning a local scan area LSA is irradiating a reference member FM located in the local scan area LSA and a period in which the measurement light ML scanning a local scan area LSA is not irradiating a reference member FM located in the local scan area LSA. Then, based on information about the driving state of the galvanometer mirror 2228 during the period in which the measurement light ML is irradiating a reference member FM located in the local scan area LSA, the measurement control device 24 may calculate the direction in which the measurement light ML is emitted from the galvanometer mirror 2228 during the period in which the measurement light ML is irradiating a reference member FM located in the local scan area LSA as the direction from the measurement head 22 of the reference member FM located in the local scan area LSA. The measurement control device 24 repeats this operation the number of times equal to the number of local scan areas LSA. As a result, the directions of at least four reference members FM from the measuring head 22 are calculated.

[0172] The scanning pitch of the measurement light ML in the local scan may be narrower than the scanning pitch of the measurement light ML in the global scan. For example, the measurement head 22 may scan the global scan area GSA using the measurement light ML at a first scanning pitch. On the other hand, for example, the measurement head 22 may scan each local scan area LSA using the measurement light ML at a second scanning pitch narrower than the first scanning pitch. The scanning pitch of the measurement light ML may refer to the spacing between multiple scanning points (irradiation points) irradiated with the measurement light ML. Since the measurement head 22 receives the return light RL from each scanning point (irradiation point), the scanning pitch of the measurement light ML may be considered to be equivalent to the period at which the photodetector 2226 detects the return light RL. In this case, in order to perform a global scan, the measurement head 22 may irradiate each of multiple scanning points (irradiation points) that are distributed in a relatively sparse manner within the global scan area GSA, which is wider than the local scan area LSA. As a result, the measurement head 22 can roughly search for the position where the reference member FM exists within the global scan area GSA (i.e., the position of the local scan area LSA). On the other hand, to perform a local scan, the measurement head 22 may irradiate the measurement light ML to each of multiple scanning points (irradiation points) that are distributed in a relatively dense manner within a local scan area LSA that is narrower than the global scan area GSA. As a result, the measurement head 22 can precisely search for the position where the reference member FM exists within the local scan area LSA. As a result, the measurement control device 24 can calculate the direction of the reference member FM more quickly compared to when the scanning pitch of the measurement light ML in the local scan is not narrower than the scanning pitch of the measurement light ML in the global scan.

[0173] However, the measurement control device 24 does not necessarily have to perform the local scan. That is, the measurement control device 24 does not have to perform the operations from step S103 to step S104. In this case, the measurement control device 24 may calculate the directions of at least four reference members FM from the measurement head 22 based on the results of the global scan in step S105. Specifically, the measurement control device 24 acquires the detection results of the photodetector 2226 (i.e., the results of receiving the return light RL) as the results of the global scan. As described above, the intensity of the return light RL when the measurement light ML is irradiated onto the reference member FM is likely to be different from the intensity of the return light RL when the measurement light ML is not irradiated onto the reference member FM. In this case, the measurement control device 24 can identify the period during which the measurement light ML is irradiated onto the reference member FM based on the detection results of the photodetector 2226 (i.e., the results of receiving the return light RL). Then, based on information regarding the driving state of the galvanometer mirror 2228 during the period when the measurement light ML is irradiated onto the reference member FM, the measurement control device 24 may calculate the direction in which the measurement light ML is emitted from the galvanometer mirror 2228 during the period when the measurement light ML is irradiated onto the reference member FM as the direction of the reference member FM from the measurement head 22.

[0174] When local scanning is not performed, the measurement head 22 may use the measurement light ML to scan the global scan area GSA at a relatively narrow scanning pitch used in local scanning.

[0175] In step S105, the measurement control device 24 may calculate the direction of the reference member FM from the measuring head 22 without using the results of the global scan and the local scan. For example, if the position of the reference member FM in the machine coordinate system is known, the direction of the reference member FM from the measuring head 22 may be calculated based on that position. In addition, the position of the reference member FM in the machine coordinate system does not have to be known. For example, if the machine tool 1 is equipped with a camera, the measurement control device 24 may calculate the direction of the reference member FM from the measuring head 22 by analyzing an image captured by the camera.

[0176] Furthermore, in step S105, the measurement control device 24 may calculate the position of each reference member FM in addition to or instead of calculating the orientation of each reference member FM. Once the position of each reference member FM is calculated, the orientation of each reference member FM becomes clear. Therefore, the operation of calculating the orientation of each reference member FM in step S105 may include the operation of calculating the position of each reference member FM. To calculate the position of each reference member FM, the measurement head 22 may receive interference light between the return light RL from the local scan area LSA (i.e., the return light RL from the reference member FM) and the reference light RB. In this case, the measurement control device 24 may calculate the distance between the reference member FM and the measurement head 22 based on the result of receiving the interference light between the return light RL and the reference light RB. The measurement control device 24 may then calculate the position of the reference member FM in the machine coordinate system based on the calculated distance to the reference member FM, the direction of the reference member FM calculated from the intensity of the return light RL, and the position of the machining head 11 in the machine coordinate system (i.e., the position of the measurement head 22 attached to the machining head 11).

[0177] Thereafter, the measurement control device 24 controls the measurement head 22 to irradiate the reference member FM with the measurement light ML (step S106). That is, the measurement control device 24 controls the measurement head 22 to irradiate each of the at least four reference members FM with the measurement light ML (step S106). As a result, the measurement head 22 irradiates each of the at least four reference members FM with the measurement light ML (step S106). As a result, the measurement head 22 receives the return light RL from each of the at least four reference members FM (step S106).

[0178] To irradiate each of the at least four reference members FM with the measurement light ML, the measurement control device 24 irradiates each of the at least four reference members FM with the measurement light ML based on the respective directions of the at least four reference members FM identified in step S105. Specifically, the measurement control device 24 controls the galvanometer mirror 2228 to emit the measurement light ML in the direction of one of the reference members FM identified in step S105. As a result, the measurement head 22 irradiates one of the reference members FM with the measurement light ML and receives the return light RL from the one of the reference members FM. In other words, the photodetector 2226 of the measurement head 22 receives the return light RL from the one of the reference members FM. The measurement control device 24 repeats this operation the number of times equal to the number of reference members FM included in the measurement range of the measurement head 22.

[0179] Thereafter, the measurement control device 24 determines whether or not to move either the machining head 11 or the stage 141 (step S107). In particular, in step S107, the measurement control device 24 determines whether or not to translate either the machining head 11 or the stage 141 along the translation axis. In other words, while the operations from step S102 to step S106 are being performed, neither the machining head 11 nor the stage 141 moves. While the operations from step S102 to step S106 are being performed, both the machining head 11 and the stage 141 are stationary.

[0180] For example, when 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 control device 24 may determine to move either the machining head 11 or the stage 141. For example, when 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 control device 24 may determine not to move either the machining head 11 or the stage 141.

[0181] As a result of the determination in step S107, for example, if it is determined that either the machining head 11 or the stage 141 should be moved (step S107: Yes), the measurement control device 24 moves either the machining head 11 or the stage 141 in the machine coordinate system (step S108). In particular, the measurement control device 24 translates either the machining head 11 or the stage 141 along a translation axis in the machine coordinate system (step S108). For example, the measurement control device 24 may translate the machining head 11 along at least one of the translation axis (X) and the translation axis (Z) in the machine coordinate system. For example, in addition to or instead of translating the machining head 11, the measurement control device 24 may translate the stage 141 along the translation axis (Y) in the machine coordinate system.

[0182] In step S108, the measurement control device 24 does not simultaneously translate the machining head 11 and the stage 141. For example, in step S108, when the measurement control device 24 translates the machining head 11, the measurement control device 24 does not translate the stage 141 in parallel with the translation of the machining head 11. On the other hand, in step S108, when the measurement control device 24 translates the stage 141, the measurement control device 24 does not translate the machining head 11 in parallel with the translation of the stage 141. However, in step S108, the measurement control device 24 may simultaneously translate the machining head 11 and the stage 141.

[0183] In step S108, the measurement control device 24 may move the machining head 11 so that the machining head 11 moves to a desired head position that has not yet been specified as a movement destination of the machining head 11. Because the measurement head 22 irradiates the reference member FM with the measurement light ML while the machining head 11 is stopped as described above, the measurement control device 24 may move the machining head 11 so that the machining head 11 moves to a desired head position that satisfies the condition that the measurement head 22 has not yet irradiated the reference member FM with the measurement light ML while the machining head 11 is stopped at the desired head position.

[0184] An example of the purpose of translating either the machining head 11 or the stage 141 in step S108 may be to set the relative positional relationship between the machining head 11 and the stage 141 to at least multiple different positional relationships. As a result, as described below, the measurement control device 24 can set multiple measurement points MP for calculating the movement error and can appropriately calculate the movement error resulting from the translational movement from the positions of the multiple measurement points MP. Furthermore, when either the machining head 11 or the stage 141 translates in step S108, the space in which the movement error can be calculated in the machine coordinate system is expanded compared to when either the machining head 11 or the stage 141 does not translate in step S208. This is because the measurement points MP translate in the machine coordinate system as either the machining head 11 or the stage 141 translates. Therefore, an example of the purpose of translating either the machining head 11 or the stage 141 in step S108 may be to expand the space in which the movement error can be calculated in the machine coordinate system.

[0185] When moving the machining head 11 to a desired head position in the machine coordinate system, the machining control device 16, which controls the head drive system 12 under the control of the measurement control device 24, generates a head drive control signal for controlling the head drive system 12 to move the machining head 11 to the desired head position based on the desired head position in the machine coordinate system. Note that information regarding the desired head position used to generate the head drive control signal may be considered to be a command value for moving the machining head 11. The head drive control signal itself may also be considered to be a command value for moving the machining head 11. Then, under the control of the measurement control device 24, the machining control device 16 controls the head drive system 12 based on the generated head drive control signal. As a result, the head drive system 12 moves the machining head 11 to the desired head position. As a result, the machining head 11 moves to the desired head position and then stops at the desired head position.

[0186] However, at this point, the movement error of the machining head 11 has not been corrected, so the machining head 11 is not necessarily positioned at the desired head position (i.e., stopped). In other words, the actual position of the machining head 11 in the machine coordinate system does not necessarily match the desired head position in the machine coordinate system.

[0187] In step S108, the measurement control device 24 may move the stage 141 so that the stage 141 moves to a desired stage position that has not yet been specified as a movement destination of the stage 141. Because the measurement head 22 irradiates the reference member FM with the measurement light ML while the stage 141 is stopped as described above, the measurement control device 24 may move the stage 141 so that the stage 141 moves to a desired stage position that satisfies the condition that the measurement head 22 has not yet irradiated the reference member FM with the measurement light ML while the stage 141 is stopped at the desired stage position.

[0188] When moving the stage 141 to a desired stage position in the machine coordinate system, the processing control device 16, which controls the stage drive system 142 under the control of the measurement control device 24, generates a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to the desired stage position, based on the desired stage position in the machine coordinate system. Note that information regarding the desired stage position used to generate the stage drive control signal may be considered to be a command value related to the movement of the stage 141. The stage drive control signal itself may also be considered to be a command value related to the movement of the stage 141. Thereafter, under the control of the measurement control device 24, the processing 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 desired stage position. As a result, the stage 141 moves to the desired stage position and then stops at the desired stage position.

[0189] However, at this point, because the movement error of the stage 141 has not been corrected, the stage 141 is not necessarily positioned at the desired stage position (i.e., stopped). In other words, the actual position of the stage 141 in the machine coordinate system does not necessarily match the desired stage position in the machine coordinate system.

[0190] Thereafter, the measurement control device 24 calculates the direction of the local scan area LSA from the measurement head 22 (step S109). That is, the measurement control device 24 calculates the direction of each of the at least four local scan areas LSA from the measurement head 22 (step S109). However, in step S109, the measurement control device 24 calculates the direction of the local scan area LSA without using the results of the global scan. That is, after at least one of the processing head 11 and the stage 141 moves in step S108, the measurement control device 24 does not need to perform a global scan again. As a result, the time required to perform the movement error calculation operation is shortened.

[0191] In step S109, the measurement control device 24 calculates the directions of the at least four local scan areas LSA from the measurement head 22 after at least one of the processing head 11 and the stage 141 moves in step S108, based on reference member direction information regarding the directions of the at least four reference members FM from the measurement head 22 before at least one of the processing head 11 and the stage 141 moves in step S108, and movement information regarding at least one of the movement amount and movement direction of at least one of the processing head 11 and the stage 141 in step S108. Specifically, the measurement control device 24 may calculate the direction of one local scan area LSA from the measurement head 22 after at least one of the machining head 11 and the stage 141 moves in step S108 by estimating, based on the reference member direction information and the movement information, which direction one reference member FM, which was located in one direction from the measurement head 22 before at least one of the machining head 11 and the stage 141 moved in step S108, will be located from the measurement head 22 after at least one of the machining head 11 and the stage 141 moves in step S108. The reference member direction information can be acquired as a result of the operation of step S105. On the other hand, the movement information may be generated from at least one of the head drive control signal and the stage drive control signal. Alternatively, the movement information may be generated from the measurement results of at least one of the head position measurement device 13, which measures the position of the machining head 11, and the position measurement device 143, which measures the position of the stage 141. The measurement control device 24 may repeat this operation the number of times equal to the number of local scan areas LSA. As a result, the directions from the measurement head 22 to each of the at least four local scan areas LSA are calculated.

[0192] Note that the relative positional relationship between the machining head 11 and the stage 141 changes due to the movement of at least one of the machining head 11 and the stage 141. Specifically, the relative positional relationship between the machining head 11 and the stage 141 changes from a first positional relationship to a second positional relationship due to the movement of at least one of the machining head 11 and the stage 141. In this case, the reference member direction information used in step S109 may be considered to be information regarding the directions of the at least four reference members FM from the measurement head 22 when the relative positional relationship between the machining head 11 and the stage 141 is the first positional relationship. The movement information used in step S109 may be considered to be information regarding at least one of the movement amount and movement direction of at least one of the machining head 11 and the stage 141 for changing the relative positional relationship between the machining head 11 and the stage 141 from the first positional relationship to the second positional relationship. In step S109, the measurement control device 24 may be considered to be calculating (e.g., estimating) the directions of at least four local scan areas LSA from the measurement head 22 when the relative positional relationship between the processing head 11 and the stage 141 is the second positional relationship based on the reference member direction information and movement information.

[0193] However, after at least one of the processing head 11 and the stage 141 moves in step S108, the measurement control device 24 may perform a global scan again (step S102), and calculate the direction of the local scan area LSA from the measurement head 22 based on the results of the global scan (step S103).

[0194] After the direction of the local scan area LSA is calculated in step S109 (or step S103), the measurement control device 24 performs a local scan (step S104) and calculates the direction of the reference member FM from the measurement head 22 based on the results of the local scan (step S105).

[0195] However, even after at least one of the machining head 11 and the stage 141 has moved in step S108, the measurement control device 24 does not necessarily have to perform a local scan. That is, the measurement control device 24 does not have to perform the operations of steps S109 and S104. In this case, in step S105, the measurement control device 24 may calculate, based on the reference member direction information and the movement information, the directions of the at least four reference members FM from the measurement head 22 after at least one of the machining head 11 and the stage 141 has moved in step S108. Specifically, the measurement control device 24 may calculate the direction of one reference member FM from the measurement head 22 after at least one of the machining head 11 and the stage 141 has moved in step S108 by estimating, based on the reference member direction information and the movement information, in which direction one reference member FM that was located in one direction from the measurement head 22 before at least one of the machining head 11 and the stage 141 moved in step S108 will be located from the measurement head 22 after at least one of the machining head 11 and the stage 141 has moved in step S108. The measurement control device 24 repeats this operation as many times as the number of reference members FM. As a result, the directions of at least four reference members FM from the measurement head 22 are calculated.

[0196] Note that the relative positional relationship between the machining head 11 and the stage 141 changes due to the movement of at least one of the machining head 11 and the stage 141. Specifically, the relative positional relationship between the machining head 11 and the stage 141 changes from a first positional relationship to a second positional relationship due to the movement of at least one of the machining head 11 and the stage 141. In this case, in step S105, the measurement control device 24 may be considered to have calculated (e.g., estimated) the directions of the at least four reference members FM from the measurement head 22 when the relative positional relationship between the machining head 11 and the stage 141 is the second positional relationship, based on the reference member direction information and the movement information.

[0197] Thereafter, the measurement control device 24 controls the measurement head 22 to irradiate the reference member FM with the measurement light ML (step S106). That is, the measurement control device 24 controls the measurement head 22 to irradiate each of the at least four reference members FM with the measurement light ML (step S106). In particular, in step S106, the measurement control device 24 controls the measurement head 22 to irradiate each of the at least four reference members FM with the measurement light ML, which is parallel light (step S106). As a result, the measurement head 22 irradiates each of the at least four reference members FM with the measurement light ML (step S106). As a result, the measurement head 22 receives the return light RL from each of the at least four reference members FM (step S106).

[0198] Thus, in this embodiment, each time the machining head 11 moves along the translational axis and stops, the measurement head 22 receives the return light RL from each of the at least four reference members FM. In other words, each time the machining head 11 translates to a plurality of different positions along the translational axis, the measurement head 22 receives the return light RL from each of the at least four reference members FM. In other words, each time the machining head 11 translates to a plurality of different positions along the translational axis and stops, the measurement head 22 receives the return light RL from each of the at least four reference members FM.

[0199] Similarly, in this embodiment, each time the stage 141 moves along the translational axis and stops, the measurement head 22 receives the return light RL from each of the at least four reference members FM. In other words, each time the stage 141 translates to a plurality of different positions along the translational axis, the measurement head 22 receives the return light RL from each of the at least four reference members FM. In other words, each time the stage 141 translates to a plurality of different positions along the translational axis in sequence and stops, the measurement head 22 receives the return light RL from each of the at least four reference members FM. In particular, when the stage 141 moves, the reference members FM disposed on the stage 141 or the workpiece W placed on the stage 141 also move. Therefore, it can be said that each time the stage 141 moves along the translational axis and stops, the measurement head 22 receives the return light RL from each of the at least four reference members FM that moved as the stage 141 moved.

[0200] When at least one of the machining head 11 and the stage 141 is translated in step S108, the measurement control device 24 may translate at least one of the machining head 11 and the stage 141 along the same movement direction and in the same direction to eliminate the influence of backlash components that occur in the translational movement of at least one of the machining head 11 and the stage 141. For example, the measurement control device 24 may first perform an X-scan movement operation in which the machining head 11 is repeatedly moved by a desired amount along the translation axis (X) so that the machining head 11 moves from one end to the other of the range of movement in which the machining head 11 can move along the translation axis (X) in a first direction within the machine coordinate system. Thereafter, the measurement control device 24 may perform a Y-step movement operation in which the stage 141 is moved by a predetermined amount along the translation axis (Y) in a second direction. Thereafter, the measurement control device 24 may alternately repeat the X-scan movement operation and the Y-step movement operation until the stage 141 moves from one end of the movable range of the stage 141 along the translation axis (Y) in the machine coordinate system to the other end. Then, the measurement control device 24 may perform a Z-step movement operation to move the machining head 11 in a third direction along the translation axis (Z) by a desired amount. Thereafter, the measurement control device 24 may again alternately repeat the X-scan movement operation and the Y-step movement operation until the stage 141 moves from one end of the movable range of the stage 141 along the translation axis (Y) in the machine coordinate system to the other end. Thereafter, similar operations may be repeated until the machining head 11 moves from one end of the movable range of the stage 141 along the translation axis (Z) in the machine coordinate system to the other end.

[0201] On the other hand, if the result of the determination in step S107 is, for example, that the machining head 11 and the stage 141 are not to be moved (step S107: No), the measurement control device 24 calculates the actual position of the measurement point MP at which the measurement head 22 measured the reference member FM based on the result of receiving the return light RL in step S106 (step S110). That is, the measurement control device 24 calculates the actual position of the measurement head 22 at the time of measuring the reference member FM as the actual position of the measurement point MP based on the result of receiving the return light RL in step S106 (step S110). In this embodiment, the position of the reference point FP of the measurement head 22 is used as the position of the measurement point MP. That is, in this embodiment, the position of the reference point FP of the measurement head 22 is used as the position of the measurement head 22. Therefore, in the following description, unless otherwise specified, the position of the measurement head 22 refers to the position of the reference point FP of the measurement head 22. The reference point FP is a portion of the measurement head 22 that serves as a reference for calculating the distance between the measurement head 22 and the measurement object. The pivot point PV described above is an example of the reference point FP of the measurement head 22. In this case, in step S110, the measurement control device 24 calculates the actual position of the reference point FP of the measurement head 22 based on the result of receiving the return light RL in step S106.

[0202] When the machining head 11 moves, the positional relationship between the machining head 11 and the stage 141 changes. Therefore, when the machining head 11 moves, the positional relationship between the measurement head 22 attached to the machining head 11 and the stage 141 also changes. Therefore, the positional relationship between the measurement point MP and the stage 141 changes. Similarly, when the stage 141 moves, the positional relationship between the machining head 11 and the stage 141 changes. Therefore, when the stage 141 moves, the positional relationship between the measurement head 22 attached to the machining head 11 and the stage 141 changes. Therefore, the positional relationship between the measurement point MP and the stage 141 changes. Therefore, the measurement point MP may be considered to be a point that moves relative to the stage 141 as at least one of the machining head 11 and the stage 141 moves in step S101 or step S108. The measurement point MP may be considered to be a point that moves relative to the workpiece W placed on the stage 141 as at least one of the machining head 11 and the stage 141 moves in step S101 or step S108. The measurement point MP may be considered to be a point that moves relative to the reference member FM placed on the stage 141 as at least one of the machining head 11 and the stage 141 moves in step S101 or step S108. The measurement point MP may be considered to be a point that moves relative to the reference member FM placed on the workpiece W placed on the stage 141 as at least one of the machining head 11 and the stage 141 moves in step S101 or step S108.

[0203] As described above, the measurement head 22 receives return 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 S108. Therefore, the measurement control device 24 may calculate the position of the measurement point MP that moves with the movement of at least one of the machining head 11 and the stage 141 based on the return light RL from at least four reference members FM received by the measurement head 22 each time at least one of the machining head 11 and the stage 141 moves in step S101 or step S108. Note that in the following description, for convenience of explanation, the measurement point MP whose position is calculated based on the return light RL from at least four reference members FM received by the measurement head 22 after at least one of the machining head 11 and the stage 141 moves for the jth time in step S101 or step S108 will be referred to as measurement point MP#j. That is, the measurement point MP when the measurement head 22 has performed the operation of measuring at least four reference members FM the jth time in step S106 is referred to as measurement point MP#j. Note that "j" is a variable indicating the number of times at least one of the processing head 11 and the stage 141 has moved in step S101 or step S108. "j" is a variable indicating the number of times the measurement head 22 has performed the operation of measuring at least four reference members FM in step S106.

[0204] For example, the movement of at least one of the machining head 11 and the stage 141 in step S101 is the first movement. In this case, the measurement control device 24 may calculate the position of the reference point FP of the measurement head 22 as the position of measurement point MP#1 based on the result of receiving the return light RL received by the measurement head 22 after at least one of the machining head 11 and the stage 141 has moved and stopped for the first time. Furthermore, the movement of at least one of the machining head 11 and the stage 141 in step S108, which is performed thereafter for the first time, is the second movement. In this case, the measurement control device 24 may calculate the position of the reference point FP of the measurement head 22 as the position of measurement point MP#2 based on the result of receiving the return light RL received by the measurement head 22 after at least one of the machining head 11 and the stage 141 has moved and stopped for the second time.

[0205] As will be described in detail later with reference to FIG. 17 , in step S110, the measurement control device 24 first calculates the distance between the measurement head 22 located at each measurement point MP and each of the at least four reference members FM based on the results of receiving the return 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 24 repeats this distance calculation operation the number of times (i.e., the number of times at least one of the processing head 11 and the stage 141 has moved). Thereafter, the measurement control device 24 calculates the positions of the multiple measurement points MP based on the calculated distances.

[0206] In the following description, an example will be described in which at least one of the machining head 11 and the stage 141 moves J times during the first movement error calculation operation. In this case, in step S110, the measurement control device 24 calculates the positions of each of the measurement points MP#1 to MP#J.

[0207] In this embodiment, when the first movement error calculation operation is performed, the measurement control device 24 may newly form (in other words, define) a measurement coordinate system different from the machine coordinate system within the machine coordinate system in order to calculate the positions of the measurement points MP#1 to MP#J. In step S110, the measurement control device 24 may calculate the positions of the measurement points MP#1 to MP#J in the measurement coordinate system.

[0208] The measurement coordinate system may be any coordinate system formed within the machine coordinate system, however, the measurement control device 24 may generate a measurement coordinate system that can reduce the number of unknown parameters that the measurement control device 24 must calculate in order to calculate the positions of the measurement points MP#1 to MP#J.

[0209] An example of the measurement coordinate system is shown in FIG. 15. As shown in FIG. 15, the measurement control device 24 may generate a coordinate system whose origin is the measurement point MP#1 as the measurement coordinate system. In this case, as shown in FIG. 15, the position (X ｐ１ , Y ｐ１ , Z ｐ１ As a result, the number of unknown parameters that the measurement control device 24 needs to calculate in order to calculate the positions of the measurement points MP#1 to MP#J is reduced.

[0210] The measurement control device 24 may generate, as the measurement coordinate system, a coordinate system in which an axis connecting measurement point MP#1 and measurement point MP#2 serves as the first axis (first measurement coordinate axis). In this case, the movement of at least one of the machining head 11 and the stage 141 to move the measurement head 22 from measurement point MP#1 to measurement point MP#2 may be based on a drive control signal for moving at least one of the machining head 11 and the stage 141 along one of the X-axis, Y-axis, and Z-axis (first machine coordinate axis) of the machine coordinate system. In this case, the first measurement coordinate axis of the measurement coordinate system can be used as an axis corresponding to the first machine coordinate axis of the machine coordinate system. For example, if the machining head 11 moves based on a head drive control signal for moving the machining head 11 along the X-axis of the machine coordinate system to move the measurement head 22 from measurement point MP#1 to measurement point MP#2, the measurement control device 24 may generate, as the measurement coordinate system, a coordinate system in which an axis connecting measurement point MP#1 and measurement point MP#2 serves as the X-axis. For example, when the stage 141 moves based on a stage drive control signal that moves the stage 141 along the Y-axis of the machine coordinate system in order to move the measurement head 22 from measurement point MP#1 to measurement point MP#2, the measurement control device 24 may generate a coordinate system in which the axis connecting measurement point MP#1 and measurement point MP#2 is the Y-axis as the measurement coordinate system. For example, when the machining head 11 moves based on a head drive control signal that moves the machining head 11 along the Z-axis of the machine coordinate system in order to move the measurement head 22 from measurement point MP#1 to measurement point MP#2, the measurement control device 24 may generate a coordinate system in which the axis connecting measurement point MP#1 and measurement point MP#2 is the Z-axis as the measurement coordinate system.

[0211] In the following explanation, for the sake of convenience, as shown in Fig. 15, in order to move the measurement head 22 from measurement point MP#1 to measurement point MP#2, the machining head 11 moves based on a head drive control signal that moves the machining head 11 along the X axis of the machine coordinate system, and as a result, the measurement control device 24 generates a measurement coordinate system in which the axis connecting measurement point MP#1 and measurement point MP#2 is the X axis. In this case, as shown in Fig. 15, the position (X ｐ２ , Y ｐ２, Z ｐ２ ) and the position (X ｐ２ , 0, 0) may be used. In other words, the number of unknown parameters that the measurement control device 24 needs to calculate in order to calculate the positions of the measurement points MP#1 to MP#J is reduced.

[0212] The measurement control device 24 may generate, as the measurement coordinate system, a coordinate system in which an axis that is along a plane including measurement points MP#1, MP#2, and MP#3 and that is orthogonal to the first measurement coordinate axis serves as a second axis (second measurement coordinate axis). In this case, the movement of at least one of the machining head 11 and the stage 141 to move the measurement head 22 from measurement point MP#2 to measurement point MP#3 may be based on a drive control signal that moves at least one of the machining head 11 and the stage 141 along another axis (second machine coordinate axis) that is orthogonal to the first machine coordinate axis and is one of the X-axis, Y-axis, and Z-axis of the machine coordinate system, while not moving at least one of the machining head 11 and the stage 141 along the remaining axis (third machine coordinate axis) that is orthogonal to the first machine coordinate axis and is one of the X-axis, Y-axis, and Z-axis of the machine coordinate system. In this case, the second measurement coordinate axis of the measurement coordinate system can be used as an axis corresponding to the second machine coordinate axis of the machine coordinate system. For example, in order to move the measurement head 22 from measurement point MP#2 to measurement point MP#3, the stage 141 moves based on a stage drive control signal that moves the stage 141 along the Y axis of the machine coordinate system, while the processing head 11 does not move based on a head drive control signal that moves the processing head 11 along the Z axis of the machine coordinate system. In this case, the measurement control device 24 may generate a coordinate system as the measurement coordinate system that is along a plane that includes measurement point MP#1, measurement point MP#2, and measurement point MP#3 and in which the Y axis is an axis perpendicular to the X axis of the above-mentioned measurement coordinate system. For example, in order to move the measurement head 22 from measurement point MP#2 to measurement point MP#3, if the processing head 11 moves based on a head drive control signal that moves the processing head 11 along the Z axis of the machine coordinate system, while the stage 141 does not move based on a stage drive control signal that moves the stage 141 along the Y axis of the machine coordinate system, the measurement control device 24 may generate a coordinate system as the measurement coordinate system that is along a plane that includes measurement point MP#1, measurement point MP#2, and measurement point MP#3 and in which the Z axis is an axis perpendicular to the X axis of the above-mentioned measurement coordinate system.

[0213] 15, in order to move the measurement head 22 from measurement point MP#2 to measurement point MP#3, the stage 141 moves based on a stage drive control signal that moves the stage 141 along the Y axis of the machine coordinate system, while the machining head 11 does not move based on a head drive control signal that moves the machining head 11 along the Z axis of the machine coordinate system, and as a result, the measurement control device 24 generates a measurement coordinate system that is along a plane that includes measurement points MP#1, MP#2, and MP#3 and whose Y axis is orthogonal to the X axis of the measurement coordinate system described above. In this case, as shown in FIG. 15, the position (X ｐ３ , Y ｐ３ , Z ｐ３ ) and the position (X ｐ３ , Y ｐ３ , 0) may be used. In other words, the number of unknown parameters that the measurement control device 24 needs to calculate in order to calculate the positions of the measurement points MP#1 to MP#J is reduced.

[0214] When the first and second measurement coordinate axes are determined, the remaining axis (third measurement coordinate axis) of the measurement coordinate system is also determined. Specifically, the measurement control device 24 may use an axis orthogonal to the first and second measurement coordinate axes as the third measurement coordinate axis of the measurement coordinate system.

[0215] The measurement coordinate system may be formed as a coordinate system that moves within the machine coordinate system as the stage 141 moves. For example, as shown in FIG. 16 , which shows a measurement coordinate system that moves within the machine coordinate system as the stage 141 moves, the measurement coordinate system may move along the Y axis of the machine coordinate system as the stage 141 moves along the Y axis of the machine coordinate system. On the other hand, if the stage 141 does not move, the measurement coordinate system does not need to move within the machine coordinate system. The measurement coordinate system may be referred to as a coordinate system based on the reference member FM, or as a coordinate system based on the stage 141.

[0216] After the measurement coordinate system is formed, the measurement control device 24 calculates the positions of the measurement points MP#1 to MPJ in the measurement coordinate system. In this embodiment, in the first movement error calculation operation, the measurement control device 24 may, as an example, calculate the positions of the measurement points MP#1 to MPJ using the principle of multilateration. Hereinafter, with reference to FIG. 17 , the operation of calculating the positions of the measurement points MP#1 to MPJ using the principle of multilateration will be described.

[0217] FIG. 17 shows a schematic diagram of the positional relationship between three measurement points MP (specifically, measurement points MP#1, MP#2, and MP#3) and four reference members FM (specifically, reference members FM#1, FM#2, FM#3, and FM#4). In this case, the unknown parameters to be calculated by multilateration are the position of measurement point MP#1 (X ｐ１ , Y ｐ１ , Z ｐ１ ), the position of measurement point MP#2 (X ｐ２ , Y ｐ２ , Z ｐ２ ), the position of measurement point MP#3 (X ｐ３ , Y ｐ３ , Z ｐ３ ), the position of the reference member FM#1 (X ｔ１ , Y ｔ１ , Z ｔ１ ), the position of the reference member FM#3 (X ｔ２ , Y ｔ２ , Z ｔ２ ), the position of the reference member FM#3 (X ｔ３ , Y ｔ３ , Z ｔ３ ), the position of the reference member FM#4 (X ｔ４ , Y ｔ４ , Z ｔ４ ), the distance d between the measurement point MP#1 and the reference member FM#1 １ , the distance d between the measurement point MP#1 and the reference member FM#2 ２ , the distance d between the measurement point MP#1 and the reference member FM#3 ３ , and the distance d between the measurement point MP#1 and the reference member FM#4 ４ In this case, the measurement control device 24 calculates a total of 25 unknown parameters using the principle of multilateration.

[0218] The distance between the measurement point MP#2 and the reference member FM#1 is calculated based on the distance d between the measurement point MP#1 and the reference member FM#1, which is an unknown parameter. １ This can be calculated by adding or subtracting the difference between the distance between the measurement head 22 located at measurement point MP#1 and the reference member FM#1, calculated from the above-mentioned reception result of the return light RL, and the distance between the measurement head 22 located at measurement point MP#2 and the reference member FM#1, calculated from the above-mentioned reception result of the return light RL. Therefore, the measurement control device 24 does not need to use the distance between measurement point MP#2 and the reference member FM#1 as an unknown parameter. For the same reason, the measurement control device 24 does not need to use the distances between each of measurement points MP#2 and MP#3 and each of the reference members FM#1 to FM#4 as unknown parameters.

[0219] However, if the measurement control device 24 can calculate the distance between the reference point FP of the measurement head 22 and the reference member FM (i.e., the distance between the measurement point MP and the reference member FM) as the distance between the measurement head 22 and the reference member FM based on the above-mentioned light reception result of the return light RL, the measurement control device 24 can calculate the above-mentioned distance d １ From d ４ For the sake of convenience, the distance d １ From d ４ An example will be described in which is an unknown parameter.

[0220] To calculate the unknown parameters described above, the measurement control device 24 may solve the minimization problem shown in Equation 1, for example. The minimization problem shown in Equation 1 is a minimization problem that uses the principle of multilateration. The variable i in Equation 1 is a variable for identifying the four reference members FM#1 to FM#4. "d" in Equation 1 ｉｊ " indicates the difference between the first distance between the measurement head 22 located at the measurement point MP#i and the reference member #i, calculated from the result of receiving the return light RL, and the second distance between the measurement head 22 located at the measurement point MP#j and the reference member #i, calculated from the result of receiving the return light RL. In other words, "d" in Equation 1 ｉｊ" indicates the actual change in the second distance between the measurement point MP#j and the reference member #i relative to the first distance between the measurement point MP#i and the reference member #i. ｉｊ (x)" is shown in Equation 2. ||T in Equation 2 ｉ -P ｊ || indicates the second distance between the measurement point MP#j and the reference member #i, which is calculated from the result of receiving the return light RL. ｊｉ "(x)" indicates the ideal (in other words, theoretical) amount of change in the second distance between measurement point MP#j and reference member #i relative to the first distance between measurement point MP#i and reference member #i. The calculation for solving the minimization problem shown in Equation 1 is a calculation for calculating the unknown parameters described above that satisfy the condition that the actual amount of change in the second distance between measurement point MP#j and reference member #i relative to the first distance between measurement point MP#i and reference member #i and the ideal amount of change in the second distance between measurement point MP#j and reference member #i relative to the first distance between measurement point MP#i and reference member #i are minimized.

[0221]

[0222]

[0223] In the example shown in FIG. 17, three measurement points MP#1 to MP#3 and four reference members FM#1 to FM#4 are used, so "f ｉｊ Using the function "f (x)", a simultaneous equation containing 3 x 4 = 12 equations can be generated. However, since there are 25 unknown parameters, the number of equations is insufficient by 13 (= 25 - 12). In this case, although three unknown parameters corresponding to the position of the measurement point MP increase every time a new measurement point MP is added, the "f ｊｉ(x)" to generate four new equations. Therefore, the measurement control device 24 may set the number of measurement points MP (i.e., the above-mentioned variable J) so that a simultaneous equation including a number of equations equal to or greater than the number of unknown parameters is generated. In other words, the measurement control device 24 may set the number of times that at least one of the machining head 11 and the stage 141 is moved in step S108 of FIG. 12 described above (i.e., the above-mentioned variable J) so that a simultaneous equation including a number of equations equal to or greater than the number of unknown parameters is generated.

[0224] Alternatively, when the measurement coordinate system is formed (defined) as shown in FIG. 15, the number of unknown parameters is reduced, as described above. Specifically, when the measurement coordinate system is formed (defined) as shown in FIG. 15, the X position (X ｐ１ ), the Y position of measurement point MP#1 (Y ｐ１ ), the Z position of measurement point MP#1 (Z ｐ１ ), the Y position of measurement point MP#2 (Y ｐ２ ), the Z position of measurement point MP#2 (Z ｐ２ ) and the Z position of measurement point MP#3 (Z ｐ３ ) is no longer an unknown parameter. This reduces the number of unknown parameters from 25 to 19. This reduces the number of equations required to solve the minimization problem shown in Equation 1.

[0225] To solve the above-described minimization problem, the measurement control device 24 calculates the distance between the measurement head 22 located at the measurement point MP#j and the reference member FM#i based on the result of reception of return light RL from the reference member FM#i by the measurement head 22 located at the measurement point MP#j. The measurement control device 24 performs the operation of calculating the distance between the measurement head 22 located at the measurement point MP#j and the reference member FM#i for all combination patterns of the measurement point MP#j and the reference member FM#i. The measurement control device 24 then uses the calculated distance to solve the minimization problem shown in Equation 1. As a result, as shown in FIG. 18 , the measurement control device 24 can calculate the positions of measurement points MP#1 to MP#J in the measurement coordinate system.

[0226] Although not shown, the measurement control device 24 can also calculate the position of the reference member FM in the measurement coordinate system by solving the above-mentioned minimization problem. In other words, the measurement control device 24 can also calculate the positions of at least four reference members FM in the measurement coordinate system by solving the above-mentioned minimization problem.

[0227] The positions of measurement points MP#1 to MP#J shown in Fig. 18 may be considered to be the positions of measurement points MP#1 to MP#J in a space where at least one of the machining head 11 and the stage 141 moves along the translation axis. In other words, the positions of measurement points MP#1 to MP#J shown in Fig. 18 may be considered to be the positions of measurement points MP#1 to MP#J in a space where at least one of the machining head 11 and the stage 141 moves translationally along the translation axis to a plurality of mutually different positions.

[0228] Thereafter, the measurement control device 24 converts the positions of measurement points MP#1 to MP#J in the measurement coordinate system into the positions of measurement points MP#1 to MP#J in the machine coordinate system, respectively. Specifically, because the measurement control device 24 forms a measurement coordinate system within the machine coordinate system, the measurement control device 24 can generate a coordinate transformation matrix for converting a position in either the machine coordinate system or the measurement coordinate system into a position in the other of the machine coordinate system or the measurement coordinate system. The measurement control device 24 may use this coordinate transformation matrix to convert the position of measurement point MP#j in the measurement coordinate system into the position of measurement point MP#j in the machine coordinate system. The measurement control device 24 may repeat this conversion operation for all measurement points MP#1 to MP#J to convert the positions of measurement points MP#1 to MP#J in the measurement coordinate system into the positions of measurement points MP#1 to MP#J in the machine coordinate system, respectively.

[0229] 15 , when measurement point MP#1 is used as the origin of the measurement coordinate system and the X-axis, Y-axis, and Z-axis of the measurement coordinate system correspond to the X-axis, Y-axis, and Z-axis of the machine coordinate system, respectively, the measurement control device 24 may convert the position of measurement point MP#j in the measurement coordinate system to the position of measurement point MP#j in the machine coordinate system by adding the coordinate value indicating the position of measurement point MP#1 in the machine coordinate system to the coordinate value indicating the position of measurement point MP#j in the measurement coordinate system. The position of measurement point MP#1 in the machine coordinate system (particularly, the position along each of the X-axis and Z-axis) may be calculated from the measurement result of the head position measurement device 13 that measures the position of the machining head 11 after the machining head 11 moves based on the head drive control signal for controlling the head drive system 12 to move the machining head 11 to the initial head position. Alternatively, the position of measurement point MP#1 in the machine coordinate system (particularly, the position along each of the X-axis and Z-axis) may be the initial head position used to generate a head drive control signal for controlling the head drive system 12 to move the machining head 11 to the initial head position. Furthermore, the position of measurement point MP#1 in the machine coordinate system (particularly, the position along the Y-axis) may be calculated from the measurement results of the position measurement device 143 that measures the position of the stage 141 after the stage 141 has moved based on a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to the initial stage position. Alternatively, the position of measurement point MP#1 in the machine coordinate system (particularly, the position along the Y-axis) may be the initial stage position used to generate a stage drive control signal for controlling the stage drive system 142 to move the stage 141 to the initial stage position.

[0230] As a result, as shown in FIG. 19 , the measurement control device 24 can calculate the positions of measurement points MP#1 to MP#J in the machine coordinate system. The positions of measurement points MP#1 to MP#J shown in FIG. 19 may be considered to be the positions of measurement points MP#1 to MP#J in a space where at least one of the machining head 11 and the stage 141 moves along the translation axis. In other words, the positions of measurement points MP#1 to MP#J shown in FIG. 19 may be considered to be the positions of measurement points MP#1 to MP#J in a space where at least one of the machining head 11 and the stage 141 moves translationally to a plurality of different positions along the translation axis. In particular, the positions of measurement points MP#1 to MP#J shown in FIG. 19 may be considered to be the actual positions of measurement points MP#1 to MP#J in a space where at least one of the machining head 11 and the stage 141 moves along the translation axis. In other words, the positions of measurement points MP#1 to MP#J shown in Figure 19 may be considered to be the actual positions of measurement points MP#1 to MP#J in a space in which at least one of the processing head 11 and the stage 141 moves translationally along the translation axis to multiple different positions.

[0231] In the above description, the measurement control device 24 calculates the positions of the measurement points MP#1 to MP#J in the machine coordinate system after calculating the positions of the measurement points MP#1 to MP#J in the measurement coordinate system. However, the measurement control device 24 may calculate the positions of the measurement points MP#1 to MP#J in the machine coordinate system without calculating the positions of the measurement points MP#1 to MP#J in the measurement coordinate system. For example, if the stage 141 does not move along the translation axis, the position of the reference point FP of the measurement head 22 in the machine coordinate system after at least one of the machining head 11 and the stage 141 moves for the jth time in step S101 or step S108 can be used as the position of the measurement point MP#j in the machine coordinate system.

[0232] Returning to FIG. 12, the measurement control device 24 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 position of the measurement point MP#j in the machine coordinate system calculated in step S110 (step S111).

[0233] Specifically, the movement error occurring in the translational movement of the machining head 11 corresponds to the difference between the actual position of the machining head 11 and the target position of the machining head 11. Similarly, the movement error occurring in the translational movement of the stage 141 corresponds to the difference between the actual position of the stage 141 and the target position of the stage 141. As described above, in this embodiment, the machining head 11 is capable of translational movement along each of the translational axes (X) and (Z), and the stage 141 translates along the translational axis (Y). Therefore, hereinafter, a specific description will be given of the operation of calculating the movement error occurring when the machining head 11 translates along each of the translational axes (X) and (Z) and the stage 142 translates along the translational axis (Y). However, as will be described in detail later, even when the machining head 11 translates along the translational axis (Y), the measurement control device 24 may perform an operation similar to that described below to calculate a movement error that occurs when the machining head 11 translates along the translational axis (Y). Similarly, even when the stage 141 translates along at least one of the translational axis (X) and the translational axis (Z), the measurement control device 24 may perform an operation similar to that described below to calculate a movement error that occurs when the stage 141 translates along at least one of the translational axis (X) and the translational axis (Z).

[0234] Here, the X position of measurement point MP#j shown in Fig. 19 indicates the actual X position of the measurement head 22 when the measurement head 22 is located at measurement point MP#j. The Y position of measurement point MP#j shown in Fig. 19 indicates the actual Y position of the stage 141 when the measurement head 22 is located at measurement point MP#j. The X position of measurement point MP#j shown in Fig. 19 indicates the actual Z position of the measurement head 22 when the measurement head 22 is located at measurement point MP#j.

[0235] Furthermore, because the measurement head 22 is attached to the machining head 11, the X position of the measurement point MP#j shown in FIG. 19 may be considered to essentially indicate the actual X position x_actual#j of the machining head 11 when the measurement head 22 is located at the measurement point MP#j. Specifically, the tool center point (TCP) is usually used as the position of the machining head 11. The measurement head 22 may be attached to the machining head 11 so that the reference point FP of the measurement head 22 is located at the tool center point. In this case, the X position of the measurement point MP#j shown in FIG. 19 indicates the actual X position x_actual#j of the machining head 11 when the measurement head 22 is located at the measurement point MP#j. Similarly, the Z position of the measurement point MP#j shown in FIG. 19 indicates the actual Z position z_actual#j of the machining head 11 when the measurement head 22 is located at the measurement point MP#j. On the other hand, when the reference point FP of the measurement head 22 is separated from the tool center point by a predetermined X shift amount along the X-axis direction of the machine coordinate system, the position obtained by adding the predetermined X shift amount to the X position of the measurement point MP#j shown in Fig. 19 is used as the actual X position x_actual#j of the machining head 11 in a situation where the measurement head 22 is located at the measurement point MP#j. Similarly, when the reference point FP of the measurement head 22 is separated from the tool center point by a predetermined Z shift amount along the Z-axis direction of the machine coordinate system, the position obtained by adding the predetermined Z shift amount to the Z position of the measurement point MP#j shown in Fig. 19 is used as the actual Z position z_actual#j of the machining head 11 in a situation where the measurement head 22 is located at the measurement point MP#j.

[0236] In this way, the measurement control device 24 can calculate the respective positions of the machining head 11 and the stage 141 in a situation where the measurement head 22 is located at the measurement point MP#j from the position of the measurement point MP#j calculated in step S110. In this case, the measurement control device 24 may calculate, as a movement error occurring in the translational movement of the machining head 11, the difference between the actual X position x_actual#j of the machining head 11 calculated from the measurement point MP#j and the commanded X position x_command#j where the machining head 11 should have been located in a situation where the measurement head 22 is located at the measurement point MP#j, as a movement error Δx#j. The measurement control device 24 may calculate, as a movement error Δy#j, the difference between the actual Y position y_actual#j of the stage 141 calculated from the measurement point MP#j and the commanded Y position y_command#j at which the stage 141 should originally be located when the measurement head 22 is located at the measurement point MP#j, as the movement error occurring in the translational movement of the stage 141. The measurement control device 24 may calculate, as a movement error Δz#j, the difference between the actual Z position z_actual#j of the machining head 11 calculated from the measurement point MP#j and the commanded Z position z_command#j at which the machining head 11 should originally be located when the measurement head 22 is located at the measurement point MP#j, as the movement error occurring in the translational movement of the machining head 11.

[0237] The movement error of the machining head 11 may simply be referred to as the difference between the actual position of the machining head 11 and the commanded position of the machining head 11. In other words, the movement error of the machining head 11 may simply be referred to as the difference in coordinate values ​​between the point where the machining head 11 is actually located and the point where the machining head 11 should originally be located. Similarly, the movement error of the stage 141 may simply be referred to as the difference between the actual position of the stage 141 and the commanded position of the stage 141. In other words, the movement error of the stage 141 may simply be referred to as the difference in coordinate values ​​between the point where the stage 141 is actually located and the point where the stage 141 should originally be located.

[0238] The command X position x_command#j and the command Z position z_command#j may be a target position of the machining head 11 used when generating a head drive control signal for controlling the head drive system 12. The command X position x_command#j and the command Z position z_command#j may be a measurement result of the head position measurement device 13 that measures the position of the machining head 11. The command X position x_command#j and the command Z position z_command#j may be a target position calculated from a target movement amount of the machining head 11 that can be used when generating a head drive control signal for controlling the head drive system 12. The command X position x_command#j and the command Z position z_command#j may be considered to be command values ​​related to the movement of the machining head 11.

[0239] The command Y position y_command#j may be a target position of the stage 141 used when generating a stage drive control signal for controlling the stage drive system 142. The command Y position y_command#j may be a measurement result of the position measurement device 143 that measures the position of the stage 141. The command Y position y_command#j may be a target position calculated from a target movement amount of the stage 141 that can be used when generating a stage drive control signal for controlling the stage drive system 142. The command Y position y_command#j may be considered to be a command value related to the movement of the stage 141.

[0240] As a result, the measurement control device 24 can calculate a movement error Δx#j along the translation axis (X), a movement error Δy#j along the translation axis (Y), and a movement error Δz#j along the translation axis (Z) as movement errors that occur when the machining head 11 and the stage 141 are moved so that the machining head 11 is positioned at the commanded X position x_command#j and the commanded Z position z_command#j and the stage 141 is positioned at the commanded Y position y_command#j. In other words, the measurement control device 24 can generate information related to the movement errors, including the movement error Δx#j, the movement error Δy#j, and the movement error Δz#j.

[0241] In addition, if the stage 141, rather than the machining head 11, is movable along the translation axis (X), the measurement control device 24 may calculate, as the movement error of the stage 141, the difference between the actual X position x_actual#j of the stage 141 calculated from the measurement point MP#j and the command X position x_command#j where the stage 141 should have been positioned when the measurement head 22 was located at the measurement point MP#j, as the movement error Δx#j. In this case, the command X position x_command#j may be a target position of the stage 141 used when generating a stage drive control signal for controlling the stage drive system 142. The command X position x_command#j may be a measurement result of the position measurement device 143 that measures the position of the stage 141. The command X position x_command#j may be a target position calculated from a target movement amount of the stage 141 that can be used when generating a stage drive control signal for controlling the stage drive system 142. The commanded X position x_command#j may be considered to be a command value relating to the movement of the stage 141 .

[0242] Furthermore, if the machining head 11, rather than the stage 141, is movable along the translation axis (Y), the measurement control device 24 may calculate, as the movement error of the machining head 11, the difference between the actual Y position y_actual#j of the machining head 11 calculated from the measurement point MP#j and the command Y position y_command#j where the machining head 11 should have been located when the measurement head 22 was located at the measurement point MP#j, as the movement error Δy#j. In this case, the command Y position y_command#j may be a target position of the machining head 11 used when generating a head drive control signal for controlling the head drive system 12. The command Y position y_command#j may be a measurement result of the head position measurement device 13 that measures the position of the machining head 11. The command Y position y_command#j may be a target position calculated from a target movement amount of the machining head 11 that can be used when generating a head drive control signal for controlling the head drive system 12. The command Y position y_command#j may be considered to be a command value related to the movement of the machining head 11. Furthermore, if the stage 141, rather than the machining head 11, is movable along the translational axis (Z), the measurement control device 24 may calculate, as the movement error of the stage 141, the difference between the actual Z position z_actual#j of the stage 141 calculated from the measurement point MP#j and the command Z position z_command#j where the stage 141 should have been positioned when the measurement head 22 was located at the measurement point MP#j, as the movement error Δz#j. In this case, the command Z position z_command#j may be the target position of the stage 141 used when generating a stage drive control signal for controlling the stage drive system 142. The measurement result of the position measurement device 143 that measures the position of the stage 141 may be used as the command Z position z_command#j. The command Z position z_command#j may be a target position calculated from a target movement amount of the stage 141 that can be used when generating a stage drive control signal for controlling the stage drive system 142. The command Z position z_command#j may be considered to be a command value related to the movement of the stage 141.

[0243] The measurement control device 24 may repeat this operation as many times as the number of measurement points MP. As a result, the measurement control device 24 can calculate the movement error at each position in the machine coordinate system. In other words, the measurement control device 24 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. The measurement control device 24 can calculate the movement error at each position in space where at least one of the machining head 11 and the stage 141 moves translationally to a plurality of mutually different positions along the translation axis. In other words, the measurement control device 24 can calculate the movement error (Δx#1, Δy#1, Δz#1) occurring at the first position (x_command#1, y_command#1, z_command#1) in the machine coordinate system, the movement error (Δx#2, Δy#2, Δz#2) occurring at the second position (x_command#2, y_command#2, z_command#2) in the machine coordinate system, ..., the movement error (Δx#J, Δy#J, Δz#J) occurring at the Jth position (x_command#J, y_command#J, z_command#J) in the machine coordinate system. The measurement control device 24 can calculate the movement error (Δx#1, Δy#1, Δz#1) that occurs when at least one of the machining head 11 and the stage 141 moves to be located at a first position (x_command#1, y_command#1, z_command#1) in the machine coordinate system, the movement error (Δx#2, Δy#2, Δz#2) that occurs when at least one of the machining head 11 and the stage 141 moves to be located at a second position (x_command#2, y_command#2, z_command#2) in the machine coordinate system, and... the movement error (Δx#J, Δy#J, Δz#J) that occurs when at least one of the machining head 11 and the stage 141 moves to be located at the Jth position (x_command#J, y_command#J, z_command#J) in the machine coordinate system.

[0244] In addition to or instead of the movement errors (Δx#j, Δy#j, Δz#j), the measurement control device 24 may generate a function representing a movement error occurring at an arbitrary position in the machine coordinate system as information related to the movement error. Specifically, when coordinate information indicating an arbitrary position in the machine coordinate system is input, the measurement control device 24 may calculate a function that outputs the movement error occurring at that position. In this case, the measurement control device 24 may generate the function itself. The measurement control device 24 may also generate parameters of the function (e.g., coefficients, etc.).

[0245] In addition to or instead of the movement error (Δx#j, Δy#j, Δz#j), the measurement control device 24 may generate, as information about the movement error, a function representing the actual position (i.e., x_actual#j, z_actual#j) of the machining head 11 when the machining head 11 moves based on a head drive control signal that moves the machining head 11 to a desired position in the machine coordinate system. In addition to or instead of the movement error (Δx#j, Δy#j, Δz#j), the measurement control device 24 may generate, as information about the movement error, a function representing the actual position (i.e., y_actual#j) of the stage 141 when the stage 141 moves based on a stage drive control signal that moves the stage 141 to a desired position in the machine coordinate system. In this case, the measurement control device 24 may generate the function itself. The measurement control device 24 may also generate parameters (e.g., coefficients, etc.) of the function.

[0246] After the information on the movement error is generated, the measurement control device 24 may generate error correction information for correcting the movement error based on the information on the movement error.

[0247] For example, the measurement control device 24 may generate, as error correction information, correction values ​​C#j for correcting the above-mentioned command X position x_command#j, command Y position y_command#j, and command Z position z_command#j. Specifically, when the machining head 11 moves based on a head drive control signal that moves the machining head 11 to a desired position in the machine coordinate system, the machining head 11 is actually located at a position obtained by adding a movement error Δx#j to the command X position x_command#j, rather than the command X position x_command#j. Therefore, if the position obtained by subtracting the movement error Δx#j from the command X position x_command#j is used as the new command X position x_command#j, it is assumed that the machining head 11 is located at the command X position x_command#j. For this reason, the measurement control device 24 may set the movement error Δx#j to a correction value Cx#j for correcting the commanded X position x_command#j. For the same reason, the measurement control device 24 may set the movement error Δy#j to a correction value Cy#j for correcting the commanded Y position y_command#j. The measurement control device 24 may set the movement error Δz#j to a correction value Cz#j for correcting the commanded Z position z_command#j. In other words, the measurement control device 24 may generate error correction information including multiple information sets of arbitrary positions (x_command#j, y_command#j, z_command#j) in the machine coordinate system and correction values ​​(Cx#j, Cy#j, Cz#j) at those positions.

[0248] For example, the measurement control device 24 may generate, as error correction information, a function that represents a correction value C#j at an arbitrary position in the machine coordinate system. For example, the measurement control device 24 may generate a function that outputs at least one of a correction value Cx#j, a correction value Cy#j, and a correction value Cz#j when at least one of an X position in the command x_command#j, a Y position in the command y_command#j, and a Z position in the command z_command#j is input. An example of such a function is a function that indicates at least one of the correction value Cx#j, the correction value Cy#j, and the correction value Cz#j by exponentiation. An example of a function that indicates at least one of the correction value Cx#j, the correction value Cy#j, and the correction value Cz#j by exponentiation is "Cx#j=ax×X+bx×X" ２ + ...". In this function, "X" indicates the X position x_command#j in the command, and "ax" and "bx" indicate coefficients. In this case, the measurement control device 24 may generate the function itself. Alternatively, the measurement control device 24 may generate parameters of the function (for example, coefficient ax and coefficient bx).

[0249] The measurement control device 24 may output the error correction information to the machine tool 1 (particularly the machining control device 16) as information for controlling the machine tool 1. In this case, the machining control device 16 may control the translational movement of at least one of the machining head 11 and the stage 141 based on the error correction information. Specifically, the machining control device 16 may correct the command positions of at least one of the machining head 11 and the stage 141 based on the error correction information, and generate a drive control signal for translationally moving at least one of the machining head 11 and the stage 141 using the corrected command positions. As a result, even if a movement error occurs in the translational movement of the machining head 11, the machine tool 1 can translate the machining head 11 so that the machining head 11 is positioned at the original command position before correction, just as in the case where no movement error occurs in the translational movement of the machining head 11. In other words, the machine tool 1 can translate the machining head 11 with high accuracy. Similarly, even if a translational error occurs in the translational movement of stage 141, machine tool 1 can translate stage 141 so that stage 141 is positioned at the original commanded position before correction, just as in the case where no translational error occurs in the translational movement of stage 141. In other words, machine tool 1 can translate stage 141 with high precision. As a result, machine tool 1 can machine workpiece W with high precision.

[0250] Instead of controlling the translational movement of the machining head 11 based on the error correction information, the machining control device 16 may correct the measurement result of the head position measuring device 13, which measures the position of the machining head 11, based on the error correction information. Specifically, the machining control device 16 normally controls the head drive system 12 based on the head drive control signal so that the position of the machining head 11 measured by the head position measuring device 13 becomes the commanded position. In other words, the machining control device 16 normally moves the machining head 11 until the position of the machining head 11 measured by the head position measuring device 13 becomes the commanded position. Therefore, when a movement error occurs in the machining head 11, the head position measuring device 13 outputs the commanded position of the machining head 11 that does not reflect the movement error as the measurement result of the position of the machining head 11, rather than the actual position of the machining head 11 that reflects the movement error. In this case, the machining control device 16 may correct the position of the machining head 11 measured by the head position measuring device 13 based on the error correction information so that the measurement result of the head position measuring device 13 represents the actual position of the machining head 11 reflecting the movement error. As a result, the machining control device 16 can translate the machining head 11 until the corrected position of the machining head 11 matches the command position.

[0251] Note that the head position measuring device 13 may detect the amount of movement of the machining head 11 in addition to or instead of detecting the position of the machining head 11. In this case, the machining control device 16 may correct the measurement result of the head position measuring device 13, which measures the amount of movement of the machining head 11, based on the error correction information. In other words, the machining control device 16 may correct the amount of movement of the machining head 11 measured by the head position measuring device 13 based on the error correction information.

[0252] Instead of controlling the translational movement of the stage 141 based on the error correction information, the processing control device 16 may correct the measurement result of the position measurement device 143 that measures the position of the stage 141 based on the error correction information. Specifically, the processing control device 16 normally controls the stage drive system 142 based on the stage drive control signal so that the position of the stage 141 measured by the position measurement device 143 becomes the commanded position. In other words, the processing control device 16 normally moves the stage 141 until the position of the stage 141 measured by the position measurement device 143 becomes the commanded position. Therefore, when a movement error occurs in the stage 141, the position measurement device 143 outputs the commanded position of the stage 141 that does not reflect the movement error as the measurement result of the position of the stage 141, rather than the actual position of the stage 141 that reflects the movement error. In this case, the processing control device 16 may correct the position of the stage 141 measured by the position measurement device 143 based on the error correction information so that the measurement result of the position measurement device 143 represents the actual position of the stage 141 that reflects the movement error. As a result, the processing control device 16 can translate the stage 141 until the corrected position of the stage 141 matches the command position.

[0253] Note that the stage position measuring device 143 may detect the amount of movement of the stage 141 in addition to or instead of detecting the position of the stage 141. In this case, the processing control device 16 may correct, based on the error correction information, the measurement result of the stage position measuring device 143 that measures the amount of movement of the stage 141. In other words, the processing control device 16 may correct the amount of movement of the stage 141 measured by the stage position measuring device 143 based on the error correction information.

[0254] The measurement control device 24 may generate, based on the information related to the movement error, machining path correction information for correcting a machining path indicating the machining path of the workpiece W by the machine tool 1, as information for controlling the machine tool 1. The machining path may indicate, for example, the movement path of the tool center point. The machining path may indicate, for example, the movement path of the tool center point relative to the workpiece W. The machining path may indicate, for example, the movement path of a machining position where the machine tool 1 machines the workpiece W. The machining path may indicate, for example, the movement path of a machining position where the machine tool 1 machines the workpiece W relative to the workpiece W. Such a machining path is usually generated based on the three-dimensional shape of the workpiece W before machining and the target three-dimensional shape of the workpiece W after machining. The machining path correction information may be information for correcting a machining path generated based on the three-dimensional shape of the workpiece W before machining and the target three-dimensional shape of the workpiece W after machining. In this case, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement control device 24 may generate machining path correction information for correcting the machining path so that the workpiece W is machined in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. The machining control device 16 of the machine tool 1 may correct the machining path based on the machining path correction information. Alternatively, the measurement control device 24 may correct the machining path and output the corrected machining path to the machining control device 16 as information for controlling the machine tool 1. As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the machine tool 1 can machine the workpiece W in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141.

[0255] Based on the information on the movement error, the measurement control device 24 may generate measurement path correction information for correcting a measurement path indicating 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, for example. The measurement path may indicate the movement path of the tool center point, similar to the machining path described above. The measurement path may indicate the movement path of the tool center point relative to the workpiece W, similar to the machining path described above. The measurement path may indicate, for example, the movement path of a measurement position where the measurement system 2 measures the workpiece W. The measurement path may indicate, for example, the movement path of the reference point FP of the measurement head 22. The measurement path may indicate, for example, the movement path of the pivot point PV of the measurement head 22. The measurement path may indicate, for example, the movement path of a measurement position where the measurement system 2 measures the workpiece W, relative to the workpiece W. The measurement position may mean the irradiation position of the measurement light ML on the surface of the workpiece W. Such a measurement path is usually generated based on the three-dimensional shape of the workpiece W. The measurement path correction information may be information for correcting a measurement path generated based on the three-dimensional shape of the workpiece W. In this case, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement control device 24 may generate measurement path correction information for correcting the measurement path so that the workpiece W is measured in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. The machining control device 16 of the machine tool 1 may correct the measurement path based on the measurement path correction information. Alternatively, the measurement control device 24 may correct the measurement path and output the corrected measurement path to the machining control device 16 as information for controlling the machine tool 1. As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the machine tool 1 can translate at least one of the machining head 11 and the stage 141 in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141.As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement system 2 can measure the workpiece W in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. Note that, based on the information related to the movement error, the measurement control device 24 may generate measurement path correction information for correcting a measurement path that indicates the measurement path of the workpiece W by the measurement system 2 when the measurement system 2 measures at least one of the position, orientation, and dimensions of the workpiece W, which will be described later. Furthermore, the machining control device 16 may correct the measurement path based on the generated measurement path correction information.

[0256] The measurement control device 24 may generate, based on the information regarding the movement error, 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, as information for controlling the machine tool 1. In other words, based on the information regarding the movement error, the measurement control device 24 may generate, as information for controlling the machine tool 1, drive correction information for correcting the drive control signal generated by the machining control device 16 to control at least one of the head drive system 12 and the stage drive system 142. In this case, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement control device 24 may generate drive correction information for correcting the drive control signal generated by the machining control device 16 so that the workpiece W is machined in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. The machining control device 16 of the machine tool 1 may correct the drive control signal based on the drive correction information. As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the machine tool 1 can machine the workpiece W in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141.

[0257] The measurement control device 24 may correct the drive control signal generated by the machining control device 16 based on information related to the movement error. For example, the measurement control device 24 may acquire the drive control signal generated by the machining control device 16 from the machining control device 16 and correct the acquired drive control signal. In this case, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement control device 24 may correct the drive control signal generated by the machining control device 16 so that the workpiece W is machined in the same manner as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. The measurement control device 24 may output the corrected drive control signal to the machining control device 16 as information for controlling the machine tool 1. Therefore, the operation of correcting the drive control signal may be considered equivalent to the operation of generating information for controlling the machine tool 1. The machining control device 16 of the machine tool 1 may control at least one of the head drive system 12 and the stage drive system 142 based on the drive control signal corrected by the measurement control device 24 (corrected drive signal). As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the machine tool 1 can machine the workpiece W in the same way as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. In this case, the measurement control device 24 may control at least one of the head drive system 12 and the stage drive system 142 based on the corrected drive control signal (corrected drive signal) instead of the machining control device 16.

[0258] The measurement control device 24 may generate a drive control signal based on information related to the movement error. In this case, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the measurement control device 24 may generate the drive control signal so that the workpiece W is machined in the same manner as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. The measurement control device 24 may output the generated drive control signal to the machining control device 16 as information for controlling the machine tool 1. Therefore, the operation of generating the drive control signal may be considered equivalent to the operation of generating information for controlling the machine tool 1. The machining control device 16 of the machine tool 1 may control at least one of the head drive system 12 and the stage drive system 142 based on the drive control signal generated by the measurement control device 24. As a result, even when a movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141, the machine tool 1 can machine the workpiece W in the same manner as when no movement error occurs in the translational movement of at least one of the machining head 11 and the stage 141. In this case, the measurement control device 24 may control at least one of the head drive system 12 and the stage drive system 142 based on the generated drive control signal, instead of the processing control device 16 .

[0259] (2-2-2) Specific Flow of the Second Movement Error Calculation Operation for Calculating Movement Errors Generated in the Rotational Movement of At Least One of the Machining Head 11 and the Stage 141 Next, the second movement error calculation operation for calculating movement errors generated in the rotational movement of at least one of the machining head 11 and the stage 141 will be described. Note that the following description will mainly focus on the parts of the second movement error calculation operation that are different from the first movement error calculation operation described above. Therefore, to avoid redundant explanations, the description of the parts of the second movement error calculation operation that are the same as the first movement error calculation operation described above will be omitted. In other words, in the following description, unless otherwise specified, the same operation as the first movement error calculation operation may be performed.

[0260] When calculating the movement error occurring during the rotational movement of the machining head 11, the measurement head 22 may use the galvanometer mirror 2228 to change the direction of travel of the measurement light ML each time the machining head 11 rotates and stops, thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In other words, the measurement head 22 may irradiate each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML whose direction of travel has been changed by the galvanometer mirror 2228 each time the machining head 11 rotates and stops. As a result, the measurement head 22 receives the return light RL from each of the at least N reference members FM each time the machining head 11 rotates and stops. The measurement control device 24 may calculate the movement error occurring during the rotational movement of the machining head 11 based on the reception results of the return light RL from each of the at least N reference members FM received by the measurement head 22 each time the machining head 11 rotates and stops. In particular, the measurement control device 24 may calculate the movement error that occurs in the rotational movement of the machining head 11 in space where the machining head 11 has rotated to multiple different positions, based on the reception results of the return light RL from each of at least N reference members FM that is received by the measurement head 22 each time the machining head 11 rotates to multiple different positions.

[0261] d) The measurement head 22 may use the galvanometer mirror 2228 to sequentially change the direction of travel of the measurement light ML while the processing head 11 is rotationally moving (when the processing head 11 is not stopped), thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In this case, too, the measurement control device 24 may calculate a movement error occurring in the rotational movement of the processing head 11 in space where the processing head 11 has rotationally moved to a plurality of different positions, based on the result of receiving the return light RL from each of the at least N reference members FM, which is received by the measurement head 22 each time the processing head 11 rotationally moves to a plurality of different positions.

[0262] When calculating a movement error occurring during the rotational movement of the stage 141, the measurement head 22 may use the galvanometer mirror 2228 to change the direction of travel of the measurement light ML each time the stage 141 rotates and stops, thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In other words, the measurement head 22 may irradiate each of the at least N reference members FM included in the measurement range of the measurement head 22 with the measurement light ML whose direction of travel has been changed by the galvanometer mirror 2228 each time the stage 141 rotates and stops. As a result, the measurement head 22 receives the return light RL from each of the at least N reference members FM each time the stage 141 rotates and stops. The measurement control device 24 may calculate a movement error occurring during the rotational movement of the stage 141 based on the reception results of the return light RL from each of the at least N reference members FM received by the measurement head 22 each time the stage 141 rotates and stops at each of the at least N reference members FM. In particular, the measurement control device 24 may calculate the movement error that occurs in the rotational movement of the stage 141 in space where the stage 141 has rotated to multiple different positions, based on the reception results of the return light RL from each of at least N reference members FM, which is received by the measurement head 22 each time the stage 141 rotates to multiple different positions.

[0263] Note that the measurement head 22 may use the galvanometer mirror 2228 to sequentially change the direction of travel of the measurement light ML while the stage 141 is rotationally moving (i.e., while the stage 141 is not stopped), thereby irradiating the measurement light ML onto each of the at least N reference members FM included in the measurement range of the measurement head 22. In this case as well, the measurement control device 24 may calculate a movement error that occurs in the rotational movement of the stage 141 in space where the stage 141 has rotationally moved to a plurality of different positions, based on the light reception results of the return light RL from each of the at least N reference members FM that are received by the measurement head 22 each time the stage 141 is rotationally moved to a plurality of different positions.

[0264] When calculating a movement error occurring in rotational movement, a workpiece W is placed on the stage 141. For example, when calculating a movement error occurring in rotational movement, a workpiece W on which a reference member FM is arranged may be placed on the stage 141. For example, when calculating a movement error occurring in rotational movement, a workpiece W on which a reference member FM is not arranged may be placed on the stage 141. However, when calculating a movement error occurring in rotational movement, a workpiece W does not have to be placed on the stage 141. For convenience of explanation, the following describes the first movement error calculation operation performed when a workpiece W on which a reference member FM is arranged is placed on the stage 141. However, even when a workpiece W on which a reference member FM is not arranged is placed on the stage 141 or when a workpiece W is not placed on the stage 141, the machining system SYS may calculate a movement error occurring in rotational movement by performing the first movement error calculation operation described below.

[0265] 21, a description will be given of the flow of the second movement error calculation operation for calculating a movement error occurring in the rotational movement of at least one of the processing head 11 (measurement head 22) and the stage 141. Fig. 21 is a flowchart showing the flow of the second movement error calculation operation for calculating a movement error occurring in the rotational movement of at least one of the processing head 11 and the stage 141.

[0266] As described above, in this embodiment, the stage 141 rotates while the machining head 11 does not. Therefore, the following description can be said to be mainly about the operation for calculating the movement error that occurs in the rotational movement of the stage 141. However, even when the machining head 11 rotates, the following operation can be performed to calculate the movement error that occurs in the rotational movement of the machining head 11. This is because both the rotational movement of the machining head 11 and the rotational movement of the stage 141 can be considered to be relative rotational movement of the stage 141 with respect to the machining head 11. In other words, by considering the rotational movement of the machining head 11 as relative rotational movement of the stage 141 with respect to the machining head 11, the measurement system 2 can calculate the movement error that occurs in the rotational movement of the machining head 11 by the following operation.

[0267] 21 , first, the measurement control device 24 moves at least one of the machining head 11 and the stage 141 to an initial position in the machine coordinate system and stops it at the initial position (step S201). That is, the measurement control device 24 controls at least one of the head drive system 12 and the stage drive system 142 so that at least one of the machining head 11 and the stage 141 moves to the initial position in the machine coordinate system (step S201). Note that the operation of step S201 may be the same as the operation of step S101 in FIG. 12 described above. Therefore, a detailed description of the operation of step S201 will be omitted.

[0268] However, in step S201, the measurement control device 24 corrects (i.e., cancels) the movement error occurring in 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 movement error calculation operation described above (i.e., information for correcting the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141). That is, the measurement control device 24 translates at least one of the machining head 11 and the stage 141 based on the error correction information generated in the first movement error calculation operation described above. Therefore, in this embodiment, it is preferable that the machining system SYS performs the second movement error calculation operation after performing the first movement error calculation operation described above. In this case, even if a movement error occurs in the translational movement of the machining head 11, the machining head 11 can move and stop at its initial position. That is, the actual position of the machining head 11 in the machine coordinate system coincides with the initial head position in the machine coordinate system. Similarly, even if a movement error occurs in the translational movement of the stage 141, the stage 141 can move to and stop at the initial stage position, i.e., the actual position of the stage 141 in the machine coordinate system coincides with the initial stage position in the machine coordinate system.

[0269] Alternatively, in the second movement calculation operation, the measurement control device 24 may not use the error correction information generated in the first movement error calculation operation to correct the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141. In this case, the measurement control device 24 may use, as the initial position, a position calculated from any one of the measurement points MP#1 to MP#J calculated in the first movement error calculation operation described above. As an example, the measurement control device 24 may use, as the initial position, a position calculated from the measurement point MP#m (where m is a variable indicating an integer greater than or equal to 1 and less than or equal to J) calculated in the first movement error calculation operation described above. Specifically, as described above, the measurement control device 24 can calculate, from the position of the measurement point MP#m, the X position x_actual#m at which the machining head 11 was actually located when it moved in accordance with the head drive control signal generated based on the command X position x_command#m, the Y position y_actual#m at which the stage 141 was actually located when it moved in accordance with the stage drive control signal generated based on the command Y position y_command#m, and the actual Z position z_actual#m of the machining head 11 when it moved in accordance with the head drive control signal generated based on the command Z position z_command#m. In this case, the measurement control device 24 may use the X position x_actual#m and the Z position z_actual#m as the initial head position, and the Y position y_actual#m as the initial stage position. In this case, the measurement control device 24 may move the processing head 11 to the X position x_actual#m and the Z position z_actual#m based on a head drive control signal generated based on the X position x_command#m and the Z position z_command#m in the command, and may move the stage 141 to the Y position y_actual#m based on a stage drive control signal generated based on the Y position y_command#m in the command.

[0270] In either case, in step S201 of the second movement error calculation operation, the machining head 11 and the stage 141 are positioned based on information about the movement error generated by the first movement error calculation operation. In this case, information about the actual positions of the machining head 11 and the stage 141 moved in step S201 is known to the measurement control device 24. In this respect, the second post-movement calculation operation can be said to differ from the first movement error calculation operation in which information about the actual positions of the machining head 11 and the stage 141 moved in step S101 is unknown to the measurement control device 24. Note that the measurement control device 24 does not need to use information about the movement error generated by the first movement error calculation operation when moving at least one of the machining head 11 and the stage 141 in the second movement error calculation operation.

[0271] Thereafter, the measurement control device 24 performs a global scan (step S202). Note that the operation of step S202 may be the same as the operation of step S102 in Fig. 12 described above. Therefore, a detailed description of the operation of step S202 will be omitted.

[0272] Thereafter, the measurement control device 24 calculates the directions of at least N local scan areas LSA from the measurement head 22 based on the results of the global scan (step S203). Note that the operation of step S203 may be the same as the operation of step S103 in Fig. 12 described above. Therefore, a detailed description of the operation of step S203 will be omitted.

[0273] In this embodiment, an example will be described in which the variable N is set to 3 when the second movement error calculation operation is performed. In this case, the multiple reference members FM may be arranged on the workpiece W and the stage 141 so that at least three reference members FM are included within the measurement range of the measurement head 22. The measurement control device 24 may calculate the directions of at least three local scan areas LSA in which the at least three reference members FM are respectively located within the measurement range (i.e., within the global scan area GSA).

[0274] Thereafter, the measurement control device 24 performs a local scan (step S204). Note that the operation of step S204 may be the same as the operation of step S104 in Fig. 12 described above. Therefore, a detailed description of the operation of step S204 will be omitted.

[0275] Thereafter, the measurement control device 24 calculates the directions of at least three reference members FM from the measurement head 22 based on the results of the local scan (step S205). Note that the operation of step S205 may be the same as the operation of step S105 in Fig. 12 described above. Therefore, a detailed description of the operation of step S205 will be omitted.

[0276] Thereafter, the measurement control device 24 controls the measurement head 22 to irradiate the measurement light ML onto at least three reference members FM (step S206). Note that the operation of step S206 may be the same as the operation of step S106 in Fig. 12 described above. Therefore, a detailed description of the operation of step S206 will be omitted.

[0277] Thereafter, the measurement control device 24 determines whether or not to translate at least one of the machining head 11 and the stage 141 (step S207). Note that the operation of step S207 may be the same as the operation of step S107 in Fig. 12 described above. Therefore, a detailed description of the operation of step S207 will be omitted.

[0278] As a result of the determination in step S207, for example, if it is determined that at least one of the machining head 11 and the stage 141 is to be translated (step S207: Yes), the measurement control device 24 translates at least one of the machining head 11 and the stage 141 in the machine coordinate system (step S208). Specifically, as a result of the determination in step S207, for example, if it is determined that the machining head 11 is to be translated (step S207: Yes), the measurement control device 24 translates the machining head 11 in the machine coordinate system (step S208). As a result of the determination in step S207, for example, if it is determined that the stage 141 is to be translated (step S207: Yes), the measurement control device 24 translates the stage 141 in the machine coordinate system (step S208). Note that the operation in step S208 may be the same as the operation in step S108 in FIG. 12 described above. Therefore, a detailed description of the operation in step S208 will be omitted.

[0279] However, in step S208, the measurement control device 24 corrects (i.e., cancels out) the movement error occurring in 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 movement error calculation operation described above (i.e., information for correcting the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141). That is, the measurement control device 24 translates at least one of the machining head 11 and the stage 141 based on the error correction information generated in the first movement error calculation operation described above. In this case, even if a movement error occurs in the translational movement of the machining head 11, the machining head 11 can move and stop at the desired head position. That is, the actual position of the machining head 11 in the machine coordinate system coincides with the desired head position in the machine coordinate system. Similarly, even if a movement error occurs in the translational movement of the stage 141, the stage 141 can move and stop at the desired stage position. That is, the actual position of the stage 141 in the machine coordinate system coincides with the desired stage position in the machine coordinate system.

[0280] Alternatively, in the second movement calculation operation, the measurement control device 24 may not use the error correction information to correct the movement error occurring in the translational movement of at least one of the machining head 11 and the stage 141. In this case, the measurement control device 24 may use, as the desired head position and the desired stage position, a position calculated from any one of the measurement points MP#1 to MP#J calculated in the first movement error calculation operation described above. As an example, the measurement control device 24 may use, as the desired head position and the desired stage position, a position calculated from the measurement point MP#n (n is a variable indicating an integer greater than or equal to 1 and less than or equal to N) calculated in the first movement error calculation operation described above. Specifically, as described above, the measurement control device 24 can calculate, from the position of the measurement point MP#n, the X-position x_actual#n at which the machining head 11 was actually located when it moved in accordance with the head drive control signal generated based on the commanded X-position x_command#n, the Y-position y_actual#n at which the stage 141 was actually located when it moved in accordance with the commanded Y-position y_command#n and the stage drive control signal generated based on the commanded Z-position z_command#n, and the actual Z-position z_actual#n of the machining head 11 when it moved in accordance with the commanded Z-position z_command#n. In this case, the measurement control device 24 may use the X-position x_actual#n and the Z-position z_actual#n as the desired head position, and the Y-position y_actual#n as the desired stage position. In this case, the measurement control device 24 may move the processing head 11 to the X position x_actual #n and the Z position z_actual #n based on a head drive control signal generated based on the X position x_command #n and the Z position z_command #n in the command, and may move the stage 141 to the Y position y_actual #n based on a stage drive control signal generated based on the Y position y_command #n in the command.

[0281] In either case, in step S208 of the second movement error calculation operation, the machining head 11 and the stage 141 are positioned based on information about the movement error generated by the first movement error calculation operation. In this case, information about the actual positions of the machining head 11 and the stage 141 moved in step S208 is known to the measurement control device 24. In this respect, the second post-movement calculation operation can be said to differ from the first movement error calculation operation in which information about the actual positions of the machining head 11 and the stage 141 moved in step S108 is unknown to the measurement control device 24. Note that the measurement control device 24 does not need to use information about the movement error generated by the first movement error calculation operation when translating at least one of the machining head 11 and the stage 141 in the second movement error calculation operation.

[0282] Thereafter, the measurement control device 24 calculates the directions of at least three local scan areas LSA from the measurement head 22 (step S209). Note that the operation of step S209 may be the same as the operation of step S109 in Fig. 12 described above. Therefore, a detailed description of the operation of step S209 will be omitted.

[0283] After the directions of the at least three local scan areas LSA are calculated in step S209 (or step S203), the measurement control device 24 performs a local scan (step S204) and calculates the directions of the at least three reference members FM from the measurement head 22 based on the results of the local scan (step S205). Thereafter, the measurement control device 24 controls the measurement head 22 to irradiate the measurement light ML onto the at least three reference members FM (step S206).

[0284] Thereafter, the measurement control device 24 determines whether or not to translate at least one of the machining head 11 and the stage 141 (step S207). In this embodiment, the measurement control device 24 may determine to translate at least one of the machining head 11 and the stage 141 until the relative positional relationship between the machining head 11 and the stage 141 changes between at least three different positional relationships due to the translational movement of at least one of the machining head 11 and the stage 141 in step S208. In other words, the measurement control device 24 may determine to translate at least one of the machining head 11 and the stage 141 until the measurement head 22 irradiates the measurement light ML onto at least three reference members FM under conditions in which the relative positional relationship between the machining head 11 and the stage 141 becomes each of at least three different positional relationships. Therefore, an example of the purpose of translating at least one of the machining head 11 and the stage 141 in step S208 may be considered to be to set the relative positional relationship between the machining head 11 and the stage 141 to each of at least three different positional relationships. Furthermore, when at least one of the machining head 11 and the stage 141 translates in step S208, the space in which movement errors can be calculated in the machine coordinate system is expanded compared to when at least one of the machining head 11 and the stage 141 does not translate in step S208. An example of the purpose of translating at least one of the machining head 11 and the stage 141 in step S208 may be considered to be to expand the space in which movement errors can be calculated in the machine coordinate system.

[0285] As an example, the measurement control device 24 may determine that at least one of the processing head 11 and the stage 141 will be translated until the measurement head 22 irradiates the measurement light ML onto at least three reference members FM under a condition in which the relative positional relationship between the processing head 11 and the stage 141 is a first positional relationship, the measurement head 22 irradiates the measurement light ML onto at least three reference members FM under a condition in which the relative positional relationship between the processing head 11 and the stage 141 is a second positional relationship different from the first positional relationship, and the measurement head 22 irradiates the measurement light ML onto at least three reference members FM under a condition in which the relative positional relationship between the processing head 11 and the stage 141 is a third positional relationship different from the first and second positional relationships.

[0286] On the other hand, as a result of the determination in step S207, for example, if it is determined that the machining head 11 and the stage 141 are not to be translated (step S207: No), the measurement control device 24 determines whether or not to rotate the stage 141 (step S210). In other words, the stage 141 does not rotate while the operations from step S202 to step S209 are being performed.

[0287] For example, when the number of times the stage 141 has been rotated is less than the required number of movements, the measurement control device 24 may determine to rotate the stage 141. For example, when the number of times the stage 141 has been rotated is equal to or greater than the required number of movements, the measurement control device 24 may determine not to rotate the stage 141.

[0288] As a result of the determination in step S210, for example, if it is determined that the stage 141 is to be rotationally moved (step S210: Yes), the measurement control device 24 rotationally moves the stage 141 in the machine coordinate system (step S211). For example, the measurement control device 24 may rotationally move the stage 141 around at least one of the rotation axis (X) and the rotation axis (Z) in the machine coordinate system.

[0289] As an example, when the stage 141 is to be rotationally moved around the rotation axis (X) so that the rotation angle of the stage 141 around the rotation axis (X) becomes a desired X angle, the processing control device 16, which controls the stage drive system 142 under the control of the measurement control device 24, generates a stage drive control signal for controlling the stage drive system 142 to rotationally move the stage 141 around the rotation axis (X) until the rotation angle of the stage 141 around the rotation axis (X) becomes the desired X angle, based on the desired X angle. Note that information regarding the desired X angle used to generate the stage drive control signal may be considered to be a command value regarding the movement of the stage 141. Thereafter, under the control of the measurement control device 24, the processing control device 16 controls the stage drive system 142 based on the generated stage drive control signal. As a result, the stage drive system 142 rotates the stage 141 around the rotation axis (X) so that the rotation angle of the stage 141 around the rotation axis (X) becomes the desired X angle. As a result, the stage 141 rotates around the rotation axis (X) until the rotation angle of the stage 141 around the rotation axis (X) reaches the desired X angle, and then stops.

[0290] However, at this point, the rotation angle of the stage 141 around the rotation axis (X) is not necessarily the desired X angle because the movement error occurring in the rotation movement of the stage 141 has not been corrected. In other words, the actual rotation angle of the stage 141 around the rotation axis (X) is not necessarily the same as the desired X angle.

[0291] As another example, when the stage 141 is to be rotationally moved around the rotation axis (Z) so that the rotation angle of the stage 141 around the rotation axis (Z) becomes a desired Z angle, the processing control device 16, which controls the stage drive system 142 under the control of the measurement control device 24, generates a stage drive control signal for controlling the stage drive system 142 to rotationally move the stage 141 around the rotation axis (Z) until the rotation angle of the stage 141 around the rotation axis (Z) becomes the desired Z angle, based on the desired Z angle. Note that information regarding the desired Z angle used to generate the stage drive control signal may be considered to be a command value regarding the movement of the stage 141. Thereafter, under the control of the measurement control device 24, the processing control device 16 controls the stage drive system 142 based on the generated stage drive control signal. As a result, the stage drive system 142 rotates the stage 141 around the rotation axis (Z) so that the rotation angle of the stage 141 around the rotation axis (Z) becomes the desired Z angle. As a result, the stage 141 rotates around the rotation axis (Z) until the rotation angle of the stage 141 around the rotation axis (Z) reaches the desired Z angle, and then stops.

[0292] However, at this point, the rotation ang...

Claims

1. A measurement system used in a machine tool for machining a workpiece with a tool removably attached to the spindle of the machining head while moving at least one of a stage for placing the workpiece and the machining head, an optical device that receives return light from the reference member generated by irradiating the reference member disposed on at least one of the stage and the workpiece with measurement light, and a calculation unit that calculates the position of the optical device based on the result of receiving the return light from the reference member by the optical device A measurement system comprising.

2. When the optical device irradiates the reference member with the measurement light and receives the return light, the optical device is attached to the spindle The measurement system according to claim 1.

3. The optical device has a direction changing member capable of changing the traveling direction of the measurement light The measurement system according to claim 2.

4. The calculation unit controls the direction changing member so that the measurement light scans a first region where the measurement light can be irradiated by the direction changing member changing the traveling direction of the measurement light, The optical device receives return light from the first region generated by scanning the first region with the measurement light, The calculation unit calculates the directions from the optical device of at least four reference members based on the result of receiving the return light from the first region by the optical device, The calculation unit controls the direction changing member so as to irradiate each of the at least four reference members with the measurement light based on the calculated directions The measurement system according to claim 3.

5. The calculation unit calculates the directions from the optical device of at least four second regions that are smaller than the first region and where the at least four reference members are respectively located based on the result of receiving the return light from the first region by the optical device, The calculation unit controls the direction changing member so that each of the at least four second regions is scanned with the measurement light based on the directions of the at least four second regions, The optical device receives return light from each of the at least four second regions generated by scanning each of the at least four second regions with the measurement light, Based on the light reception results of the return light from each of the at least four second regions by the optical device, the calculation unit calculates the directions of the at least four reference members from the optical device. The measurement system according to claim 4.

6. When the calculated directions of the at least four reference members from the optical device are taken as the directions of the at least four reference members from the optical device when the relative positional relationship between the stage and the machining head is the first positional relationship, Based on the directions of the at least four reference members from the optical device in the case of the first positional relationship and at least one of the movement amounts and movement directions of at least one of the stage and the machining head for changing the relative positional relationship between the stage and the machining head from the first positional relationship to the second positional relationship, the calculation unit calculates the directions of the at least four reference members from the optical device in the case of the second positional relationship. In the case of the second positional relationship, based on the calculated directions of the at least four reference members, the calculation unit controls the direction changing member to irradiate each of the at least four reference members with the measurement light. In the case of the second positional relationship, the optical device receives the return light from each of the at least four reference members generated by irradiating each of the at least four reference members with the measurement light whose traveling direction has been changed by the direction changing member. The measurement system according to claim 4 or 5.

7. Based on the directions of the at least four reference members from the optical device in the case of the first positional relationship and at least one of the movement amounts and movement directions of at least one of the stage and the machining head for changing from the first positional relationship to the second positional relationship, the calculation unit calculates the directions of at least four second regions, which are smaller than the first region and where the at least four reference members are respectively located, from the optical device in the case of the second positional relationship. In the case of the second positional relationship, based on the calculated directions of the at least four second regions from the optical device, the calculation unit controls the direction changing member to scan each of the at least four second regions with the measurement light. When the optical device is in the second positional relationship, the optical device receives return light from each of the at least four second regions generated by scanning each of the at least four second regions with the measurement light. Based on the light reception results of the return light from each of the at least four second regions by the optical device, the calculation unit calculates the directions of the at least four reference members from the optical device when in the second positional relationship. The measurement system according to claim 6.

8. The calculation unit Based on the light reception results of the return light from each of the at least four reference members by the optical device in the first positional relationship and the light reception results of the return light from each of the at least four reference members by the optical device in the second positional relationship, the position of the optical device in the first positional relationship and the position of the optical device in the second positional relationship are calculated. Based on the calculated position of the optical device in the first positional relationship and the calculated position of the optical device in the second positional relationship, the movement error in the space where the stage or the processing head has moved due to the change from the first positional relationship to the second positional relationship is calculated. The measurement system according to claim 6.

9. The movement of the stage or the processing head includes translational movement along at least one of a first translation axis, a second translation axis, and a third translation axis that are perpendicular to each other. Each time the stage or the processing head translates to a plurality of different positions, the optical device receives return light from each of the at least four reference members generated by irradiating each of the at least four reference members with the measurement light whose traveling direction has been changed by the direction changing member. Based on the light reception results of the return light from each of the at least four reference members received by the optical device each time the stage or the processing head translates to a plurality of different positions, the calculation unit calculates the position of the optical device in the space where the stage or the processing head has translated to a plurality of different positions. Based on the calculated position of the optical device in the space, the calculation unit generates information regarding the movement error occurring in the translational movement of the stage in the space and information regarding the movement error occurring in the translational movement of the processing head in the space. The measurement system according to claim 4.

10. Each time the processing head translates to a plurality of different positions along at least one of the first to third translation axes, the optical device receives the return light from each of the at least four reference members, each time the processing head translates to a plurality of different positions, the calculation unit calculates the position of the optical device in a space where the processing head has translated to a plurality of different positions along at least one of the first to third translation axes, based on the light reception results of the return light from each of the at least four reference members received by the optical device, based on the calculated position of the optical device in the space, the calculation unit calculates information regarding a movement error that occurs in the translational movement of the processing head along at least one of the first to third translation axes in the space The measurement system according to claim 9.

11. Each time the stage translates to a plurality of different positions along at least one of the first to third translation axes, the optical device receives the return light from each of the at least four reference members that has moved along with the translational movement of the stage, each time the stage translates to a plurality of different positions, the calculation unit calculates the position of the optical device with respect to at least one of the at least four reference members in a space where the stage has translated to a plurality of different positions along at least one of the first to third translation axes, based on the light reception results of the return light from each of the at least four reference members received by the optical device, based on the calculated position of the optical device in the space, the calculation unit calculates a movement error that occurs in the translational movement of the stage along at least one of the first to third translation axes in the space The measurement system according to claim 9.

12. The movement of the stage or the processing head includes rotational movement around at least one of first, second, and third rotation axes that are orthogonal to each other, in addition to the translational movement, Whenever the stage or the processing head rotates and moves to a plurality of different positions around at least one of the first to third rotation axes, for each of at least three different positional relationships of the relative positional relationship between the stage and the processing head, the measurement light whose traveling direction has been changed by the direction changing member is irradiated onto each of at least three reference members, and the return light from each of the at least three reference members generated thereby is received, Based on the light reception results of the return light from each of the at least three reference members received for each of the at least three positional relationships, the calculation unit calculates the position of each of the at least three reference members for each rotation movement, Based on the calculated positions of each of the at least three reference members for each rotation movement, the calculation unit calculates at least one of the movement error generated in the rotational movement of the processing head around at least one of the first to third rotation axes and the movement error generated in the rotational movement of the stage around at least one of the first to third rotation axes, Each of the at least three reference members is placed on the workpiece placed on the stage or arranged on the stage, At least one of the at least three reference members is the same reference member as at least one of the at least four reference members, or each of the at least three reference members is a reference member different from each of the at least four reference members, The stage or the processing head is positioned so as to have the at least three positional relationships based on information regarding the movement error generated in the translational movement. The measurement system according to claim 9.

13. The direction changing member has a reflecting member, The reflecting member can change the traveling direction of the measurement light by rotating around a rotation axis that intersects the optical path on the incident side of the measurement light incident on the reflecting member. The measurement system according to any one of claims 3 to 5.

14. The optical device further includes an irradiation optical system that irradiates the workpiece with the measurement light emitted from the direction changing member, When the reflecting member rotates around the rotation axis, the deflection angle of the measurement light emitted from the irradiation optical system is larger than the deflection angle of the measurement light emitted from the direction changing member. The measurement system according to claim 13.

15. The irradiation optical system includes a first optical system that forms a real image of the reflection member or a second optical system that forms a virtual image of the reflection member. The measurement system according to claim 14.

16. The rotation axis is a first rotation axis, The reflection member can change the traveling direction of the measurement light by rotating around a second rotation axis that intersects the optical path on the incident side of the measurement light incident on the reflection member and also intersects the first rotation axis. The measurement system according to claim 13.

17. The optical device can change the range of change in the traveling direction of the measurement light emitted from the direction changing member. The measurement system according to claim 13.

18. The optical device can change the range of change in the traveling direction of the measurement light by changing the attachment angle of the direction changing member with respect to the optical device. The measurement system according to claim 17.

19. The optical device can change the range of change in the traveling direction of the measurement light by changing the incident direction of the measurement light incident on the direction changing member. The measurement system according to claim 17.

20. The optical device includes a first reflection optical element that reflects the measurement light toward the direction changing member so that the measurement light enters the direction changing member from a first incident direction, a second reflection optical element that reflects the measurement light toward the direction changing member so that the measurement light enters the direction changing member from a second incident direction different from the first incident direction, and an optical path switching optical element that switches the optical path of the measurement light between a first optical path along which the measurement light travels toward the first reflection optical element and a second optical path along which the measurement light travels toward the second reflection optical element. and includes The measurement light incident on the direction changing member from the first incident direction is reflected by the reflection member and travels in a traveling direction within a first range of change in the traveling direction, The measurement light incident on the direction changing member from the second incident direction is reflected by the reflection member and travels in a traveling direction within a second range of change in the traveling direction that is at least partially different from the first range of change in the traveling direction. The measurement system according to claim 19.

21. The direction changing member is a first direction changing member, The reflection member is a first reflection member, The optical device includes a second reflecting member that intersects the optical path on the incident side of the measurement light incident on the reflecting member and is rotatable about a second rotation axis that intersects the first rotation axis, and includes a second direction changing member capable of changing the traveling direction of the measurement light. The measurement light emitted from the second direction changing member is incident on the first direction changing member. The measurement system according to claim 13.

22. The optical device further includes a relay optical system that is disposed on the optical path of the measurement light between the first and second direction changing members and optically conjugates the first and second direction changing members. The measurement system according to claim 21.

23. The reference member is disposed on the workpiece placed on the stage. The measurement system according to claim 3.

24. Based on the calculated position of the optical device, the calculation unit generates at least one of information regarding a movement error generated in the movement of the stage and information regarding a movement error generated in the movement of the processing head. The measurement system according to claim 23.

25. Based on the information regarding the movement error, the calculation unit generates at least one of information for correcting the movement error of the stage and information for correcting the movement error generated in the movement of the processing head. The measurement system according to claim 24.

26. Each time the stage or the processing head moves to a plurality of different positions from each other, the optical device receives return light from each of at least four reference members generated by irradiating each of the at least four reference members with the measurement light whose traveling direction has been changed by the direction changing member. Based on the light reception results of the return light from each of the at least four reference members received by the optical device each time the stage or the processing head moves to a plurality of different positions from each other, the calculation unit calculates the position of the optical device in a space where the stage or the processing head has moved to a plurality of different positions from each other. The measurement system according to claim 23.

27. Based on the calculated position of the optical device in the space, the calculation unit generates at least one of information regarding a movement error generated in the movement of the stage in the space and information regarding a movement error generated in the movement of the processing head in the space. The measurement system according to claim 26.

28. Based on the calculated position of the optical device in the space, the calculation unit generates at least one of information for correcting a movement error occurring in the movement of the stage in the space and information for correcting a movement error occurring in the movement of the machining head in the space. The measurement system according to claim 27.

29. In a situation where the optical device is located in a first space other than a second space occupied by the workpiece placed on the stage, each time the stage or the machining head moves to a plurality of different positions from each other, the measurement light whose traveling direction is changed by the direction changing member is irradiated to each of at least four reference members, and the return light from each of the at least four reference members is received. Based on the information regarding the movement error in the first space generated based on the light reception result by the optical device in the situation where the optical device is located in the first space, the calculation unit generates information regarding the movement error in the second space. The measurement system according to claim 27.

30. When the at least four reference members are defined as a second reference member group, and at least four reference members arranged on the stage when the workpiece is not placed on the stage are defined as a first reference member group. In a first situation where the workpiece is not placed on the stage, each time the stage or the machining head moves to a plurality of different positions from each other, the optical device receives the return light from each of the reference members of the first reference member group generated by irradiating the measurement light whose traveling direction is changed by the direction changing member to each of the reference members of the first reference member group. In a second situation where the workpiece is placed on the stage and the optical device is located in the first space, each time the stage or the machining head moves to a plurality of different positions from each other, the optical device receives the return light from each of the reference members of the second reference member group generated by irradiating the measurement light whose traveling direction is changed by the direction changing member to each of the reference members of the second reference member group. The calculation unit generates information regarding the movement error in the second space that occurs in a situation where the workpiece is placed on the stage, based on information regarding the movement error generated based on the light reception result by the optical device in the first situation and information regarding the movement error in the first space generated based on the light reception result by the optical device in the second situation. The measurement system according to claim 29.

31. In the first situation, the optical device is located in a third space including the space occupied by the workpiece when the workpiece is placed on the stage and the space other than the space occupied by the workpiece when the workpiece is placed on the stage. The measurement system according to claim 30.

32. The calculation unit calculates the position of the at least one reference member disposed on the workpiece placed on the stage based on the light reception result of the return light from each of at least four reference members by the optical device. The measurement system according to claim 23.

33. The calculation unit generates at least one of information regarding a movement error occurring in the movement of the stage in a space where the stage has moved to a plurality of different positions and information regarding a movement error occurring in the movement of the processing head in a space where the processing head has moved to a plurality of different positions, based on the light reception result of the return light from each of at least four reference members received by the optical device each time the stage moves to a plurality of different positions and based on the light reception result of the return light from each of at least four reference members received by the optical device each time the processing head moves to a plurality of different positions, and calculates the position of the at least one reference member based on the movement error in the generated space and the light reception result of the return light from the at least one reference member disposed on the workpiece by the optical device. The measurement system according to claim 32.

34. The calculation unit calculates the position of the workpiece based on the light reception result of the return light from each of at least four reference members by the optical device. The measurement system according to claim 23.

35. The calculation unit generates information for correcting the machining path of the workpiece in the machine tool based on the light reception results of the return light from each of at least four reference members by the optical device. The measurement system according to claim 23.

36. At least one of the reference members is disposed at the datum of the workpiece placed on the stage. The calculation unit calculates the position of the datum of the workpiece as the position of the workpiece based on the light reception results of the return light from each of at least four reference members by the optical device. The measurement system according to claim 34.

37. Each of at least two of the at least four reference members is disposed on the workpiece placed on the stage. The calculation unit calculates the position of each of at least two reference members disposed on the workpiece placed on the stage based on the light reception results of the return light from each of at least four reference members by the optical device. The measurement system according to claim 23.

38. Each time the stage moves to a plurality of different positions, the calculation unit generates at least one of information regarding the movement error that occurs in the movement of the stage in the space where the stage has moved to a plurality of different positions based on the light reception results of the return light from each of at least four reference members received by the optical device, and each time the machining head moves to a plurality of different positions, information regarding the movement error that occurs in the movement of the machining head in the space where the machining head has moved to a plurality of different positions based on the light reception results of the return light from each of at least four reference members received by the optical device. The calculation unit calculates the position of at least two reference members based on the movement error in the generated space and the light reception results of the return light from at least two reference members disposed on the workpiece by the optical device. The measurement system according to claim 37.

39. Each of at least two of the at least four reference members is disposed on the workpiece placed on the stage. The calculation unit calculates at least one of the position of the workpiece, the posture of the workpiece, and the dimensions of the workpiece based on the light reception results of the return light from each of at least four reference members by the optical device. The measurement system according to claim 23.

40. The calculation unit generates information for correcting a machining path of the workpiece on the machine tool based on at least one calculation result of a position of the workpiece, an attitude of the workpiece, and a dimension of the workpiece. The measurement system according to claim 39.

41. Each of the at least two reference members is disposed on a datum of the workpiece placed on the stage. The calculation unit calculates a position of the datum of the workpiece based on a light reception result of return light from each of the at least four reference members by the optical device. The calculation unit calculates at least one of a position of the workpiece, an attitude of the workpiece, and a dimension of the workpiece based on the calculated position of the datum. The measurement system according to claim 39 or 40.

42. The calculation unit calculates a position of the optical device based on at least one of a temperature of the workpiece and the stage detected by a temperature detector capable of detecting a temperature of at least one of the workpiece and the stage and a light reception result of return light from each of the at least four reference members by the optical device. The measurement system according to any one of claims 1 to 5, 9 to 12, and 23 to 40.

43. The reference member includes at least four first reference members. The optical device calculates a distance between the optical device and the second reference member based on a light reception result of return light from the second reference member generated by irradiating the second reference member with the measurement light at each of a first time and a second time different from the first time. The calculation unit calculates a position of the optical device based on a difference in position of the machining head when a distance between the optical device and the second reference member calculated based on the light reception result of return light from the second reference member at the first time and a distance between the optical device and the second reference member calculated based on the light reception result of return light from the second reference member at the second time are substantially the same, and a light reception result of return light from each of the at least four first reference members by the optical device. The second reference member is disposed on the workpiece placed on the stage or on the stage. The second reference member is the same reference member as at least one of the at least four first reference members, or the second reference member is a reference member different from each of the at least four first reference members. The measurement system according to claim 23.

44. Based on the light reception results of the return light from each of the at least four reference members by the optical device, the calculation unit calculates the distances between the optical device and each of the at least four reference members. Based on the calculated distances between the optical device and each of the at least four reference members, the calculation unit calculates the position of the optical device. The measurement system according to any one of claims 23 to 40.

45. Based on at least one of the temperatures of the workpiece and the stage detected by a temperature detector capable of detecting at least one of the temperatures of the workpiece and the stage, and the light reception results of the return light from each of the at least four reference members by the optical device, the calculation unit calculates the distances between the optical device and each of the at least four reference members. Based on the calculated distances between the optical device and each of the at least four reference members, the calculation unit calculates the position of the optical device. The measurement system according to claim 44.

46. The at least four reference members are at least four first reference members. Based on the light reception results of the return light from the second reference member generated by irradiating the second reference member with the measurement light at each of the second times different from the first time, the optical device calculates the distance between the optical device and the second reference member. Based on the distance between the optical device and the second reference member calculated based on the light reception result of the return light from the second reference member at the first time, the difference in the position of the processing head when the distance between the optical device and the second reference member calculated based on the light reception result of the return light from the second reference member at the second time is substantially the same, and the light reception results of the return light from each of the at least four first reference members by the optical device, the calculation unit calculates the distances between the optical device and each of the at least four first reference members. Based on the calculated distances between the optical device and each of the at least four first reference members, the calculation unit calculates the position of the optical device. The second reference member is placed on the work placed on the stage or arranged on the stage, The second reference member is the same reference member as at least one of the at least four first reference members, or the second reference member is a reference member different from each of the at least four first reference members The measurement system according to claim 44.

47. The position of the optical device is a reference point on the optical device side that serves as a reference for calculating the distance The measurement system according to claim 44.

48. Attaching the optical device of the measurement system according to any one of claims 1 to 5, 9 to 12, 23 to 40, and 43 to the main shaft, Irradiating the reference member with measurement light by the optical device, Receiving, by the optical device, the return light from the reference member generated by irradiating the reference member with the measurement light, Calculating the distance between the optical device and the reference member based on the light reception result of the return light from the reference member by the optical device A measurement method including.

49. A control method for controlling a machine tool that processes a work with a tool detachably attached to the main shaft of the processing head while moving at least one of a stage for placing the work and the processing head, Irradiating measurement light to a reference member disposed on at least one of the stage and the work, Receiving, by an optical device, the return light from the reference member generated by irradiating the reference member with the measurement light, Calculating the distance between the optical device and the reference member based on the light reception result of the return light from the reference member by the optical device, Controlling at least one of the stage and the processing head based on a command value regarding the movement of at least one of the stage and the processing head and the calculated distance A control method including.

50. When the optical device irradiates the reference member with measurement light and when receiving the return light, the optical device is attached to the main shaft The control method according to claim 49.

51. The optical device has a direction changing member capable of changing the traveling direction of the measurement light The control method according to claim 50.

52. Controlling the direction changing member so that the direction changing member scans a first region where the measurement light can be irradiated by changing the traveling direction of the measurement light with the measurement light, Calculating the directions of the at least four reference members from the optical device based on the light reception result of the return light from the first region by the optical device; Controlling the direction changing member so as to irradiate each of the at least four reference members with the measurement light based on the calculated directions; The control method according to claim 51, further comprising: **Claim 53** A computer program for causing a computer to execute the control method according to any one of claims 49 to 52. **Claim 54** A recording medium on which the computer program according to claim 53 is recorded.