Measurement system and measurement method

Abstract

To provide a measuring system that accurately measures the position of a robot in control of the robot.SOLUTION: A measuring system comprises a moving device that is movable relative to a robot including a movable part, and a measuring device 1 that is provided on the moving device and moves together with the moving device. The measuring device 1 includes: an irradiation unit that irradiates, with measuring light, a measurement target reflection element provided in the movable part of each of robots R1, R2, and irradiates, with reference measuring light, a reference reflection element arranged at a reference position in a space in which the moving device is arranged; and a measuring unit that, on the basis of reflected light of the measuring light from the measurement target reflection elements and reference reflected light of the reference measuring light from the reference reflection element, acquires position information or distance information related to the position of the measurement target reflection element provided on the movable part relative to the reference position in the space in which the robot is located.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a measurement system and a measurement method.

Background Art

[0002] Processing and assembly processes are automatically performed by robots and machine tools. In this process, in order to improve the accuracy of processing and assembly, it is necessary to measure the position of the arm of the robot to be controlled and the position of the tip of the spindle of the machine tool with high precision. For example, a device that measures a predetermined part of the position of a robot device by an external measuring device is known (Patent Document 1). In the control of a robot, it is required to measure the position of the robot with high precision.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] One aspect of the present invention includes a moving device movable with respect to a robot having a movable part, and a measuring device provided on the moving device and moving together with the moving device. The measuring device irradiates measurement light to a measurement target reflection element provided on the movable part of the robot, and irradiates reference measurement light to a reference reflection element arranged at a reference position within the space where the moving device is arranged. The measuring device further includes a measuring unit that acquires position information or distance information regarding the position of the measurement target reflection element provided on the movable part with respect to the reference position within the space where the robot is located, based on the reflected light of the measurement light from the measurement target reflection element and the reference reflected light of the reference measurement light from the reference reflection element.

[0005] One aspect of the present invention involves moving a measuring device, which is mounted on a mobile device that is movable relative to a robot having a movable part, together with the mobile device. ,before The measurement method includes measuring a reflective element to be measured, provided on the movable part of the robot, with measurement light from the measuring device; measuring a reference reflective element positioned at a reference position in the space where the moving device is located, with reference measurement light from the measuring device; and acquiring positional information or distance information regarding the position of the reflective element to be measured with respect to the reference position in the space where the robot is located, based on the reflected light of the measurement light from the reflective element to be measured and the reference reflected light of the reference measurement light from the reference reflective element. [Brief explanation of the drawing]

[0006] [Figure 1] This figure shows an example of how a mobile position measuring device according to the first embodiment moves around inside a factory. [Figure 2] This figure shows an example of the appearance of a mobile position measuring device according to the first embodiment. [Figure 3] This figure shows an example of the configuration of a position measuring device according to the first embodiment. [Figure 4] This figure shows an example of the functional configuration of a position measuring device according to the first embodiment. [Figure 5] This figure shows an example of a position measurement process according to the first embodiment. [Figure 6] This figure shows an example of the configuration of a position measuring device according to the second embodiment. [Figure 7] This figure shows an example of the functional configuration of a position measuring device according to the second embodiment. [Figure 8] This figure shows an example of a position measurement process according to the second embodiment. [Figure 9] An example of the imaging results of the second imaging unit according to the second embodiment is shown. [Figure 10] This figure shows an example of the functional configuration of a position measuring device according to the third embodiment. [Figure 11]This figure shows an example of a position measurement process according to the third embodiment. [Figure 12] This figure shows an example of how a mobile position measuring device according to the fourth embodiment measures a reference position. [Figure 13] This figure shows an example of the functional configuration of a position measuring device according to the fourth embodiment. [Figure 14] This figure shows an example of a position measurement process according to the fourth embodiment. [Figure 15] This figure shows an example of the reference position information generation process according to the fourth embodiment. [Figure 16] This figure shows an example of the operation of a mobile position measuring device according to the fifth embodiment. [Figure 17] This figure shows an example of how the reflective element according to the fifth embodiment is attached to and detached from the holder. [Figure 18] This figure shows an example of how a mobile position measuring device according to the sixth embodiment controls a control system. [Figure 19] This figure shows an example of how a mobile position measuring device according to the seventh embodiment controls multiple robots. [Figure 20] This figure shows an example of how a position measuring device according to the eighth embodiment measures position information from an optical scanner. [Figure 21] This figure shows an example of how a position measuring device according to the ninth embodiment measures position information during the turbine assembly and processing steps. [Modes for carrying out the invention]

[0007] (First Embodiment) The first embodiment will be described in detail below with reference to the drawings. Figure 1 shows an example of how the mobile position measuring device 1 according to this embodiment moves within a factory. The mobile position measuring device 1 can move freely within the factory. The mobile position measuring device 1 is a device that measures the position of measurement targets such as machine tools and robots placed within the factory with high precision, and based on these measurement results, it becomes possible to automatically calibrate the position of machine tools and robots with high precision.

[0008] The mobile position measuring device 1 irradiates the reflection element 4 arranged on the movable part of the measurement object with measurement light and receives the reflected light. The mobile position measuring device 1 measures position information based on the light reception result. The position information is information indicating the position of the reflection element 4 with respect to the reference position. The reference position is a predetermined position within the space where the reflection element 4 is arranged.

[0009] The position information is indicated by the coordinates of a coordinate system (referred to as the reference coordinate system) within the space where the reflection element 4 is arranged. The position information is, for example, indicated by the rectangular coordinates (X, Y, Z) shown in FIG. 1. The set of the coordinate X, the coordinate Y, and the coordinate Z indicates a position within the rectangular coordinates (X, Y, Z). Note that the coordinate X, the coordinate Y, and the coordinate Z may each be referred to as the distance in the X direction, the distance in the Y direction, and the distance in the Z direction. In the rectangular coordinates of FIG. 1, the angular component in the rotation direction centered on the X axis, the angular component in the rotation direction centered on the Y axis, and the angular component in the rotation direction centered on the Z axis may each be referred to as information regarding the position. Also, when the position is indicated by spherical coordinates, the angular components of the spherical coordinates may each be referred to as information regarding the position. Further, when the position is indicated by cylindrical coordinates, the angular components of the cylindrical coordinates may be referred to as information regarding the position. Note that in FIG. 1, the coordinate system around the mobile position measuring device 1 is also illustrated together.

[0010] The mobile position measuring device 1 transmits the measured position information to the control systems of a machine tool or a robot. The reference position and the coordinate system are shared in advance between the mobile position measuring device 1 and the control system. Since the control system can acquire the position of the machine tool or the robot based on the position information received from the mobile position measuring device 1, the machine tool or the robot can be calibrated with high precision.

[0011] As described above, the mobile position measuring device 1 measures the position of the reflection element 4 arranged at a predetermined part such as a movable part among the parts constituting the measurement target such as a machine tool or a robot. Therefore, the position of the measurement target is the position of a predetermined part among the parts constituting the measurement target. The predetermined part is predetermined with respect to the whole of the parts constituting the measurement target. Therefore, the control system acquires the position of a predetermined part among the parts constituting the measurement target based on the position information received from the mobile position measuring device 1, and can calibrate the measurement target with high precision based on the position of the predetermined part. Note that the predetermined part among the parts constituting the measurement target may be a part whose position in the coordinate system changes, in other words, a moving part.

[0012] The control system calculates a correction value for automatic calibration based on the position of the predetermined part. The control system controls the control target based on the calculated correction value. That is, the control system calculates a correction value for automatic calibration based on the measurement result by the mobile position measuring device 1, and performs control based on the calculation result of the correction value. Note that the calculation of the correction value for automatic calibration based on the measurement result by the mobile position measuring device 1 and the control based on the calculation result of the correction value may be performed by a host computer that controls a measurement target such as the mobile position measuring device 1, a robot, or a machine tool.

[0013] The mobile position measuring device 1 irradiates the reflection element arranged at the movable part of the measurement target with measurement light and receives the reflected light. First, the mobile position measuring device 1 calculates distance information based on the light reception result. The distance information is information indicating the distance from the mobile position measuring device 1 to the reflection element 4.

[0014] The mobile position measuring device 1 calculates direction information based on the irradiation direction of the measurement light. The direction information is information indicating the direction of the reflection element 4 with respect to the reference direction. The reference direction is, for example, the direction seen from the mobile position measuring device 1 to the reference position. The direction information is indicated by a pair of an angle in the latitude direction and an angle in the longitude direction (that is, the angular components of spherical coordinates).

[0015] The mobile position measuring device 1 calculates the relative position of the reflective element 4 with respect to the mobile position measuring device 1 based on the calculated distance information and direction information. Based on the position of the mobile position measuring device 1 with respect to the reference position and the relative position of the reflective element 4 with respect to the mobile position measuring device 1, the mobile position measuring device 1 calculates the position of the reflective element 4 with respect to the reference position (i.e., the position of the reflective element 4 in the reference coordinate system) as position information.

[0016] The position of the mobile position measuring device 1 relative to the reference position is, in other words, the position of the mobile position measuring device 1 in a coordinate system set in the space where the reflective element 4 is arranged. In this embodiment, the position of the mobile position measuring device 1 relative to the reference position may be acquired in advance before the measurement starts, after the measurement starts (during the measurement), or after the measurement is completed (after the measurement). The position of the mobile position measuring device 1 relative to the reference position is obtained, for example, from a control system. This position may also be measured by the mobile position measuring device 1 itself. The method for measuring the position of the mobile position measuring device 1 relative to the reference position (origin calibration) will be described in subsequent embodiments.

[0017] Furthermore, in this embodiment, the positional relationship between the mobile position measuring device 1 and the reference position is assumed to remain unchanged. Alternatively, in this embodiment, even if the positional relationship between the mobile position measuring device 1 and the reference position changes, the measurement results are not corrected. The case in which the positional relationship between the mobile position measuring device 1 and the reference position changes will be explained in subsequent embodiments.

[0018] The positional information may be expressed in spherical coordinates, cylindrical coordinates, or other Cartesian coordinate systems. A Cartesian coordinate system is a general term for coordinate systems in which the unit vectors are orthogonal. Position is a physical quantity that describes where an object is located in space. Distance is a physical quantity that indicates the length measured between two points in space. Distance is, for example, Euclidean distance.

[0019] Figure 2 shows an example of the external appearance of the mobile position measuring device 1 according to this embodiment. The mobile position measuring device 1 comprises a position measuring device 2 and a mobile device 3. Figures 2, 3, and 6 show the XYZ Cartesian coordinate system, a three-dimensional Cartesian coordinate system, for the sake of explanation. In this XYZ Cartesian coordinate system, the Z-axis is oriented vertically upward. In the following explanation, the direction parallel to the Z-axis is also referred to as the up and down direction. The direction of the Z-axis is also referred to as upward. The direction opposite to the direction of the Z-axis is also referred to as downward. The positive side of the Z-axis is also referred to as the upper side, and the negative side of the Z-axis is also referred to as the lower side. The direction parallel to the X-axis is also referred to as the depth direction. The positive side of the X-axis is also referred to as the front side, and the negative side of the X-axis is also referred to as the back side. The direction parallel to the Y-axis is also referred to as the left and right direction. The positive side of the Y-axis is also referred to as the right side, and the negative side of the Y-axis is also referred to as the left side.

[0020] The position measuring device 2 is placed on the mobile device 3. The mobile device 3 is movable. As a result, the position measuring device 2 is transported by the mobile device 3. The mobile device 3 is equipped with wheels or tracks and moves automatically. As a result, the mobile device 3 can move freely within the factory. One example of the mobile device 3 is an automated guided vehicle (AGV, Autonomous Mobile Robot: AMR). Note that AGVs and AMRs are also called unmanned transport robots.

[0021] Furthermore, the moving device 3 may be any transport machine other than an AGV, as long as it can move with the position measuring device 2 mounted on it. Also, the moving device 3 may be configured to move within a predetermined range or course within the factory. For example, the moving device 3 may move along rails or the like provided within the factory. Furthermore, the position measuring device 2 may be detached from the mobile device 3 and placed on the floor or other surface for use as a standalone unit.

[0022] Next, the configuration of the position measuring device 2 will be described. Figure 3 is a diagram showing an example of the configuration of the position measuring device 2 according to this embodiment. The position measuring device 2 comprises a housing 10, an optical comb interferometer 11, a four-segment position detection element (Position Sensitive Detector: PSD) 12, a coaxial camera 13, a beam steering mirror 14, a pointing mirror assembly (PMA) 15, a first half mirror 16, and a second half mirror 17.

[0023] The housing 10 is a component for installing the main body of the position measuring device 2 onto the installation target. When the position measuring device 2 is installed on the installation target, the housing 10 is positioned on the installation target. In this embodiment, the installation target is the mobile device 3. In this embodiment, the position measuring device 2 is transported by the mobile device 3 by placing the housing 10 on the mobile device 3. The installation target may be the floor of a factory, for example. The housing 10 fixes the position measuring device 2 to the installation target, for example, by its own load. The housing 10 may also include a mechanism for fixing the position measuring device 2 to the installation target.

[0024] Furthermore, the housing 10 is equipped with the various components of the position measuring device 2. The various components of the position measuring device 2 are mounted on the housing 10. The beam steering mirror 14 and PMA 15 are mounted on the outside of the housing 10. The optical comb interferometer 11, the 4-segment PSD 12, the coaxial camera 13, the first half mirror 16, and the second half mirror 17 are equipped on the inside of the housing 10. The housing 10 also has an internal space for the propagation of measurement light and reflected light.

[0025] The optical comb interferometer 11 measures the distance from itself to the object to be measured. The optical comb interferometer 11 includes an optical comb light source. The optical comb light source is a light source capable of generating pulsed light containing frequency components arranged at equal intervals on the frequency axis (hereinafter referred to as "optical frequency comb"). In this case, the optical comb light source emits pulsed light containing frequency components arranged at equal intervals on the frequency axis as measurement light. The optical comb interferometer 11 irradiates the reflective element 4, which is placed on the object to be measured, with the optical frequency comb as measurement light. The optical comb interferometer 11 receives the reflected light generated when the optical frequency comb is reflected by the reflective element 4.

[0026] In this embodiment, the optical comb interferometer 11 is equipped with a single measurement light source (i.e., an optical comb light source). However, the optical comb interferometer 11 may be equipped with multiple measurement light sources, for example, a first measurement light source and a second measurement light source. The multiple measurement light sources each emit multiple measurement lights that are phase-synchronized and coherent with each other. For example, the multiple measurement light sources may have different oscillation frequencies. Therefore, the multiple measurement lights emitted by each of the multiple measurement light sources will be multiple measurement lights with different pulse frequencies (for example, the number of pulses per unit time, which is the reciprocal of the emission period of the pulses). As an example, the first measurement light source may emit a first measurement light with a pulse frequency of 25 GHz, and the second measurement light source may emit a second measurement light with a pulse frequency of 25 GHz + α (for example, +100 kHz).

[0027] In distance measurement using the optical comb interferometer 11, the distance from the optical comb interferometer 11 to the reflecting element 4 is measured based on the position of interference fringes generated between different pulses of the optical frequency comb. The optical comb interferometer 11 can measure this distance with an accuracy on the order of submicrometers, for example.

[0028] The optical comb interferometer 11 includes an illumination unit, a light receiving unit, and a signal processing unit. The illumination unit includes an optical comb light source, a frequency control unit, etc. The illumination unit irradiates the object to be measured with pulsed light generated by the optical comb light source as measurement light. The illumination unit also branches a portion of the pulsed light generated by the optical comb light source and irradiates a reference surface inside the optical comb interferometer 11 as reference light. The light receiving unit includes a photodetector. The photodetector detects the interference light between the reflected light and the reference light irradiated onto the reference surface. When the detection result from the photodetector is input to the signal processing unit, it calculates the distance from the optical comb interferometer 11 to the reflecting element 4 based on the generation position of the pulsed light that creates the interference light between the reflected light and the reference light.

[0029] Here, we will explain in more detail the principle by which the optical comb interferometer 11 calculates the distance from the optical comb interferometer 11 to the reflecting element 4. The optical comb interferometer 11 includes two optical comb light sources: a first optical comb light source and a second optical comb light source. The optical comb interferometer 11 also includes two photodetectors: a first photodetector and a second photodetector.

[0030] The first optical comb light source generates a first measurement light, which is pulsed light with a first pulse frequency. The second optical comb light source generates a second measurement light, which is pulsed light with a second pulse frequency. The first pulse frequency and the second pulse frequency are different from each other.

[0031] When the first measurement light is emitted from the first optical comb light source, it does not irradiate the object to be measured (i.e., the reflecting element 4), but is reflected by the optical system within the first optical comb light source and then incident on the first photodetector as the first reflected light. On the other hand, the second measurement light is irradiated from the second optical comb light source to the object to be measured (i.e., the reflecting element 4), reflected by the object to be measured, and then incident on the second photodetector as the second reflected light.

[0032] A portion of the first measurement light is split and irradiated onto a reference surface in the optical comb interferometer 11 as the first reference light, and then incident on the second photodetector. Meanwhile, a portion of the second measurement light is split and irradiated onto a reference surface in the optical comb interferometer 11 as the second reference light, and then incident on the first photodetector.

[0033] Because the pulse frequencies of the first measurement light and the second measurement light are different, the pulse frequencies of the first reflected light and the pulse frequencies of the second reference light are also different. Therefore, the interference light between the first reflected light and the second reference light is interference light in which the pulsed light appears synchronized with the timing when the pulsed light constituting the first reflected light and the pulsed light constituting the second reference light are simultaneously incident on the first photodetector.

[0034] Similarly, the pulse frequencies of the first reference light and the second reflected light are different. Therefore, the interference light of the first reference light and the second reflected light is interference light in which the pulsed light appears synchronized with the timing when the pulsed light constituting the first reference light and the pulsed light constituting the second reflected light are simultaneously incident on the second photodetector.

[0035] Here, the position (on the time axis) of the pulsed light that creates the interference light detected by the second photodetector fluctuates based on the positional relationship between the optical comb interferometer 11 and the object being measured. This is because the interference light detected by the second photodetector is the interference light of the second reflected light that goes to the second photodetector via the object being measured and the first reference light that goes to the second photodetector without going through the object being measured. On the other hand, the position (on the time axis) of the pulsed light that creates the interference light detected by the first photodetector does not fluctuate based on the positional relationship between the optical comb interferometer 11 and the object being measured.

[0036] Therefore, the time difference between the pulsed light that creates the interference light detected by the second photodetector and the pulsed light that creates the interference light detected by the first photodetector indirectly indicates the positional relationship between the optical comb interferometer 11 and the object being measured (typically, the distance between the optical comb interferometer 11 and the object being measured). Thus, the optical comb interferometer 11 can calculate the distance from the optical comb interferometer 11 to the reflecting element 4 based on the time difference between the pulsed light that creates the interference light detected by the second photodetector and the pulsed light that creates the interference light detected by the first photodetector.

[0037] Here, the measurement light emitted by the optical comb interferometer 11 passes through the first half mirror 16 and the second half mirror 17, and is then reflected by the beam steering mirror 14 and emitted onto the reflecting element 4. The optical path of the measurement light emitted onto the reflecting element 4 and the reflected light reflected by the reflecting element 4 are partially common.

[0038] The first half-mirror 16 transmits the measurement light emitted from the optical comb interferometer 11. The first half-mirror 16 also transmits a portion of the reflected light, which is reflected by the reflective element 4, towards the optical comb interferometer 11, and reflects the remaining portion towards the four-segment PSD 12.

[0039] The second half-mirror 17 transmits the measurement light emitted from the optical comb interferometer 11. The second half-mirror 17 also transmits a portion of the reflected light, which is reflected by the reflective element 4, towards the optical comb interferometer 11. The remaining portion is reflected towards the four-segment PSD 12. The second half-mirror 17 also reflects the reflected light (or light from the LED) from the reflective element 4 towards the coaxial camera 13, and the coaxial camera 13 captures the reflected light (or light from the LED) from the reflective element 4.

[0040] The coaxial camera 13 captures an image of the reflective element 4, which is the object to be measured. The coaxial camera 13 captures an image of the reflective element 4 using reflected light from natural light or artificial light such as incandescent bulbs, fluorescent lamps, mercury lamps, LEDs, or strobes that is reflected by the reflective element 4.

[0041] The coaxial camera 13 is used to track the position of the reflecting element 4. By capturing an image of the reflecting element 4 with the coaxial camera 13, the position measuring device 2 roughly determines the position of the reflecting element 4 and roughly adjusts the direction of the measurement light. Here, the rough accuracy of measuring the position of the reflecting element 4 and adjusting the direction of illumination means that it is rougher than when using the 4-segment PSD 12, as will be described later. Image A1 is an example of an image of the reflective element 4 captured by the coaxial camera 13.

[0042] The term "coaxial" in "coaxial camera 13" may mean that a part of the optical system of the coaxial camera 13 and a part of the optical system of the optical comb interferometer 11 or / and a part of the optical system of the 4-segment PSD 12 are common. For example, it may mean that the optical system of the coaxial camera 13 and a part of the optical system of the optical comb interferometer 11 or a part of the optical system of the 4-segment PSD 12 share the same optical components. Furthermore, the term "coaxial" in "coaxial camera 13" includes cases where a part of the optical path of the coaxial camera 13 and a part of the optical path of the optical comb interferometer 11 or / and a part of the optical path of the 4-segment PSD 12 are in close proximity (including cases where they pass through optical paths that are not completely identical). An example of optical paths that are not completely identical is a case where a part of the optical path of the coaxial camera 13 is in close proximity to a part of the optical path of the optical comb interferometer 11 or / and a part of the optical path of the 4-segment PSD 12, but is slightly shifted. This case may be called a slightly shifted relationship or a slightly tilted relationship.

[0043] The 4-segment PSD12 measures the position of the reflecting element 4 by detecting the reflected light from the reflecting element 4. This reflected light is the light reflected by the reflecting element 4 from the measurement light irradiated by the optical comb interferometer 11. A portion of this reflected light is reflected by the first half mirror 16 and then incident on the 4-segment PSD12.

[0044] The 4-segment PSD12 includes, for example, photodiodes and resistors. The photodiodes are arranged in an array. That is, the 4-segment PSD12 includes a photodiode array. The 4-segment PSD12 has a detection surface divided into four sections. The 4-segment PSD12 measures the position of the spot light based on the amount of reflected light spot light detected at each of the four divided detection surfaces.

[0045] The 4-segment PSD12 is used to fine-tune the direction of the measurement light irradiation after the position of the reflecting element 4 has been roughly captured by the coaxial camera 13. Here, the accuracy of the position of the reflecting element 4 determined based on the image of the reflecting element 4 captured by the coaxial camera 13 is coarser than the accuracy of the position of the reflecting element 4 measured by the 4-segment PSD12. Therefore, the accuracy of adjusting the direction of the measurement light irradiation based on the position of the reflecting element 4 determined based on the image of the reflecting element 4 captured by the coaxial camera 13 is coarser than the accuracy of adjusting the direction of the measurement light irradiation based on the position of the reflecting element 4 measured by the 4-segment PSD12. The position measuring device 2 may be equipped with other position detectors instead of the 4-segment PSD12. Other position detectors include, for example, line sensors, 2D sensors (also called area sensors), and phase detection type distance measuring instruments.

[0046] The beam steering mirror 14 reflects the measurement light emitted from the optical comb interferometer 11 towards the reflective element 4. The beam steering mirror 14 also reflects the reflected light, which is the measurement light reflected from the reflective element 4, towards the optical comb interferometer 11.

[0047] The PMA15 moves (changes) the direction of the beam steering mirror 14. The PMA15, as an example, comprises a gimbal and a rotary encoder (not shown). The orientation of the beam steering mirror 14 is changed by driving the gimbal and changing the rotation angle of the gimbal. The gimbal can rotate the beam steering mirror 14 so that its orientation can be changed in both the longitude and latitude directions. The rotary encoder measures the rotation angle of the gimbal.

[0048] The first imaging unit 23 includes a coaxial camera 13. The meaning of "coaxial" in "coaxial camera 13" is as described above. In this embodiment, as an example, the optical path of the reflected light used for imaging by the coaxial camera 13 described above and the optical path of the measurement light or reflected light used for distance measurement by the optical comb interferometer 11 described above are partially common. In other words, at least a portion of the optical path of the optical system for imaging by the first imaging unit 23 is common with at least a portion of the optical path of the optical system for receiving light by the light receiving unit provided in the optical comb interferometer 11.

[0049] The imaging direction of the coaxial camera 13 is changed by changing the orientation of the beam steering mirror 14, which changes the direction of the measurement light emitted by the optical comb interferometer 11. In other words, the beam steering mirror 14 is used in common to change the direction of the measurement light emitted by the optical comb interferometer 11 and to change the imaging direction of the coaxial camera 13.

[0050] The position measuring device 2 may also be equipped with a camera on the outside of the housing 10 instead of the coaxial camera 13. In this case, the optical path of the reflected light used for imaging and the optical path of the measuring light or reflected light used by the optical comb interferometer 11 for distance measurement are not common. In this case, a drive mechanism for changing the imaging direction of the camera is provided.

[0051] The reflective element 4 is placed on the object to be measured. The reflective element 4 is placed on the movable part of the object to be measured, such as a machine tool or a robot. One example of the reflective element 4 is a retroreflector. A retroreflector is an optical element that reflects a beam in the direction of incidence, regardless of the position or direction from which the beam entered the retroreflector. In other words, a retroreflector has a retroreflective function.

[0052] In this embodiment, an example is described in which the coaxial camera 13 captures an image of the reflecting element 4 and identifies its position, but the embodiment is not limited to this. For example, the coaxial camera 13 may capture an image of a mark or the like placed on a predetermined part of the reflecting element 4 and identify the position of the reflecting element 4 by performing image analysis on the captured image.

[0053] For example, in image A1 of Figure 3, multiple marks (mark M11, mark M12, mark M13, mark M14) are captured on the outer periphery of the reflecting element 4. The coaxial camera 13 may determine the position, or the position and orientation of the reflecting element 4, by capturing images of these multiple marks (mark M11, mark M12, mark M13, mark M14). The multiple marks are, for example, members that can be fitted onto the outer periphery of the reflecting element 4. The multiple marks may also be stickers. The multiple marks may be placed on the reflecting element 4 by applying paint to the surface of the reflecting element 4.

[0054] Furthermore, the multiple marks (marks M11, M12, M13, and M14) placed on a predetermined part of the reflective element 4 shown in Figure 3 may also be light-emitting diodes (LEDs). If the multiple marks placed on a predetermined part of the reflective element 4 are LEDs, the accuracy of recognition by image analysis can be improved by blinking or lighting up. In that case, the light used by the coaxial camera 13 for imaging will be emitted light instead of reflected light from natural light reflected by the reflective element 4. Furthermore, if multiple reflective elements 4 are provided, each of the multiple reflective elements 4 may be identified by giving each reflective element 4 a different LED color or flashing cycle.

[0055] As another example of how the coaxial camera 13 tracks (locates) the position of the reflecting element 4, the coaxial camera 13 may capture an image of a feature point located at a predetermined position relative to the position of the reflecting element 4, and then locate the position of the reflecting element 4 from the position of the feature point. The feature point is, for example, a pattern on which a two-dimensional code is drawn. When the coaxial camera 13 captures an image of the feature point, it recognizes the feature point based on image recognition and locates the position of the feature point. The coaxial camera 13 then locates the position of the reflecting element 4 based on the located position. Alternatively, the coaxial camera 13 may determine the position of the reflector element 4 by imaging known feature points on the external appearance of a part of the robot arm or a part of the machine tool.

[0056] As described above, the position measuring device 2 is mounted on the moving device 3. Therefore, the illumination unit and light receiving unit of the optical comb interferometer 11, the gimbal unit of the PMA 15, and the coaxial camera 13, which are part of the position measuring device 2, are moved by the moving device 3. However, at least a part of the illumination unit of the optical comb interferometer 11, at least a part of the light receiving unit of the optical comb interferometer 11, at least a part of the gimbal unit of the PMA 15, and at least a part of the coaxial camera 13 do not have to be mounted on the moving device 3. In other words, the moving device 3 may move at least one of the illumination unit of the optical comb interferometer 11, the light receiving unit of the optical comb interferometer 11, the gimbal unit of the PMA 15, and the coaxial camera 13. Note that the illumination unit and / or light receiving unit of the optical comb interferometer 11 do not have to be moved by the moving device 3. In this case, the irradiation unit and / or the light receiving unit may be connected to the optical path of the measurement light and / or reflected light inside the housing 10 by an optical transmission member such as an optical fiber.

[0057] The irradiation unit of the optical comb interferometer 11 is mounted on the mobile device 3 and irradiates the reflective element 4 with measurement light. The light-receiving unit of the optical comb interferometer 11 is mounted on the mobile device 3 and receives the reflected light from the measurement light from the reflecting element 4. The signal processing unit of the optical comb interferometer 11 acquires positional information regarding the reflecting element 4 based on the light reception results from the light receiving unit of the optical comb interferometer 11. The signal processing unit of the optical comb interferometer 11 may also acquire distance information.

[0058] Figure 4 shows an example of the functional configuration of the position measuring device 2 according to this embodiment. The position measuring device 2 comprises a position measuring unit 20, a control unit 22, a first imaging unit 23, a reflected light detection unit 24, a communication unit 25, and a moving device 27.

[0059] The position measuring unit 20 includes a distance measuring unit 200, an illumination direction movement unit 201, an illumination direction measuring unit 202, and a position information acquisition unit 203. The distance measuring unit 200 measures the distance to the reflecting element 4 by irradiating it with measurement light and receiving the reflected light. The distance measuring unit 200 includes an irradiation unit, a light receiving unit, and a signal processing unit. The irradiation unit irradiates the reflecting element, which is located on the movable part of the object to be measured, with measurement light. The light receiving unit receives the reflected light. The signal processing unit processes the signal from the light receiving unit to obtain distance information to the reflecting element 4. The distance measuring unit 200 includes an optical comb interferometer 11. The irradiation unit includes an optical comb light source provided in the optical comb interferometer 11. The light receiving unit includes a light receiving unit provided in the optical comb interferometer 11. The signal processing unit includes a signal processing unit provided in the optical comb interferometer 11.

[0060] The irradiation direction movement unit 201 changes the irradiation direction of the measurement light. Changing the irradiation direction is also called moving the irradiation direction. The irradiation direction movement unit 201 includes the gimbal unit included in the PMA15. In this embodiment, as described above, the beam steering mirror 14 is used in common to change the irradiation direction of the measurement light emitted by the optical comb interferometer 11 and to change the imaging direction of the coaxial camera 13. The irradiation direction movement unit 201 includes an imaging adjustment unit that adjusts the imaging direction of the first imaging unit 23. The imaging adjustment unit adjusts the imaging direction of the first imaging unit 23.

[0061] The irradiation direction measuring unit 202 measures the irradiation direction of the measurement light. The irradiation direction measuring unit 202 includes a rotary encoder that is included in the PMA 15 and measures the angle of the gimbal section. The irradiation direction measuring unit 202 outputs the measurement result of the irradiation direction as direction information to the position information acquisition unit 203 of the distance measuring unit 200.

[0062] The position information acquisition unit 203 acquires the position of the reflecting element 4 in three-dimensional space (position information) from the distance to the reflecting element 4 measured by the distance measurement unit 200 (distance information) and the direction of the measured light measured by the irradiation direction measurement unit 202 (direction information). Details regarding the acquisition of position information will be described later.

[0063] The control unit 22 controls the other devices and components provided in the position measuring device 2. The control unit 22 is equipped with, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and an FPGA (field-programmable gate array), and performs various calculations and exchanges of information. The control unit 22 reads a program from ROM and executes various controls according to the read program.

[0064] The control unit 22 and the various devices and components provided in the position measuring device 2 are connected, for example, by signal lines. Alternatively, the control unit 22 and the various devices and components provided in the position measuring device 2 may communicate using short-range wireless communication with electromagnetic waves such as light or radio waves. The control unit 22 performs various calculations. The control unit 22 also includes an imaging adjustment unit.

[0065] The first imaging unit 23 captures an image of the reflective element 4. The first imaging unit 23 includes a coaxial camera 13. The reflected light detection unit 24 detects the reflected light from the reflecting element 4. The reflected light detection unit 24 includes a 4-segment PSD 12.

[0066] The communication unit 25 communicates with an external device. The external device is, for example, a control system that controls a robot on which the reflective element 4 is installed. The communication unit 25 includes a transmitting unit and a receiving unit. The transmitting unit transmits the position information of the reflective element 4, acquired by the position information acquisition unit included in the distance measuring unit 200, to the control system. The communication unit 25 includes a communication interface (I / F) for communication via a wireless network.

[0067] For communication by the communication unit 25, for example, a fifth-generation mobile communication system or a mobile communication system using light with a wavelength shorter than millimeter waves may be used. In the fifth-generation mobile communication system, the frequency bands used are the 450 MHz to 6000 MHz band and the 24250 MHz to 52600 MHz band.

[0068] Mobile device 27 is movable. Mobile device 27 includes mobile device 3. In other words, mobile device 27 includes, for example, an AGV or an AMR.

[0069] Next, with reference to Figure 5, the position measurement process by the mobile position measuring device 1 will be described. Figure 5 is a diagram showing an example of the position measurement process according to this embodiment. The position measurement process is performed by the control unit 22. The control unit 22 uses the first imaging unit 23 to capture an image of the reflecting element 4 (step S10). The control unit 22 may also use the first imaging unit 23 to capture images of at least a part of the robot being measured, and either one or both of the reflecting element 4.

[0070] Here, the imaging adjustment unit provided in the control unit 22 adjusts the imaging direction of the first imaging unit 23 so that the reflective element 4 is included in the shooting range of the first imaging unit 23. The imaging direction is, for example, the direction in which the optical axis of the imaging lens points. If the optical path for imaging is bent by the beam steering mirror 14, the optical axis of the imaging lens may include the bent optical axis. In adjusting the imaging direction of the first imaging unit 23, the imaging adjustment unit may adjust the direction in which the optical axis of the imaging lens points to coincide with the reflective element 4, or it may not coincide but should be included in the shooting range. Based on the image obtained by the first imaging unit 23, the imaging adjustment unit determines whether or not the reflective element 4 is included in the shooting range of the first imaging unit 23. The imaging adjustment unit has an image analysis function and determines the image of the reflective element 4 by analyzing the image obtained by the first imaging unit 23. The imaging adjustment unit determines the image of the reflective element 4 based on, for example, pattern matching. Furthermore, the illumination direction movement unit 201 may pre-learn images of the reflecting element 4 using AI (machine learning) and determine the image of the reflecting element 4 based on the learned results. Alternatively, immediately after detecting the reflecting element 4 by pattern matching, the imaging adjustment unit may determine the position of the image of the reflecting element 4 by identifying the characteristic information (pixel color information and / or brightness information) of the pixel region identified as the reflecting element 4 from the captured image at the time of detection or immediately before or after, and searching for similar characteristic information (pixel color information and / or brightness information) in subsequent frames.

[0071] Furthermore, regarding the imaging direction of the first imaging unit 23, the position where the mobile position measuring device 1 is installed and / or the orientation of the housing 10 may be adjusted in advance so that the reflective element 4 is included in the imaging range of the first imaging unit 23. In that case, the imaging adjustment unit may be omitted from the configuration of the control unit 22.

[0072] The control unit 22 controls the irradiation direction movement unit 201 so that the measurement light is irradiated onto the reflecting element 4 based on the imaging results from the first imaging unit 23 (step S20). The irradiation direction movement unit 201 changes the orientation of the beam steering mirror 14 using the measurement results of the irradiation direction by the rotary encoder. The irradiation direction movement unit 201 changes the orientation of the beam steering mirror 14 in the longitude and / or latitude direction via the gimbal unit. In other words, the irradiation direction movement unit 201 moves the irradiation direction according to the command of the control unit 22 so that the measurement light is irradiated onto the reflecting element 4 that is the target of measurement, which has been determined based on the imaging results from the first imaging unit 23.

[0073] The latitudinal direction is the direction indicated by the angle between the first predetermined axis (the Z-axis in the example shown in Figure 3) and the radial vector in a spherical coordinate system. The longitude direction is the direction indicated by the angle between the projection of the radial vector onto a second predetermined axis (the X-axis in the example shown in Figure 3) that is contained in a plane perpendicular to the first predetermined axis.

[0074] Furthermore, the control unit 22 controls the irradiation direction movement unit 201 based on the imaging results from the first imaging unit 23 so that the measurement light follows the movement of the reflective element 4 to be measured. Because the irradiation direction movement unit 201 is driven so that the measurement light follows the reflective element 4, even if the reflective element 4 moves, the measurement light continues to illuminate the reflective element 4, and the first imaging unit 23 can continue to image the reflective element 4.

[0075] Furthermore, when changing the measurement target, the position of the changed measurement target can be determined by imaging the reflective element 4 installed on the changed measurement target. For example, in Figure 1, when changing the measurement target from robot R1 to robot R2, the first imaging unit 23 changes the imaging target from the reflective element 4 installed on robot R1 to the reflective element 4 installed on robot R2 to determine the position of robot R2.

[0076] The irradiation direction movement unit 201 determines the image of the reflecting element 4 by performing image analysis on the imaging results from the first imaging unit 23. In the process of driving the irradiation unit to follow the reflecting element 4, the irradiation direction movement unit 201 repeatedly performs image analysis to determine the image of the reflecting element 4 at each time point.

[0077] As described above, the first imaging unit 23 receives light from the space in which the reflective element 4 is located. In other words, the first imaging unit 23 is included in the second detection unit that receives light from the space in which the reflective element 4 is located. The irradiation direction movement unit 201 determines the position of the reflective element 4 to be measured based on the detection result by the second detection unit and moves the irradiation direction of the measurement light.

[0078] In this way, the measurement light from the optical comb interferometer 11 included in the distance measuring unit 200 is directed toward the reflecting element 4 (step S30). When the measurement light is directed toward the reflecting element 4, the reflected light is reflected by total internal reflection.

[0079] Note that the reflective element 4 does not have to be an element that performs total internal reflection. For example, a corner cube reflector may be used as the reflective element 4. The corner cube reflector may be a reflective element of a corner cube having a reflection-enhancing coating. A ball reflector or a cat's eye may also be used as the reflective element 4.

[0080] In the process of capturing an image of the reflective element 4 as described above (step S10), the moving device 3 may be moving. The process of controlling the irradiation direction moving unit 201 so that the measurement light is irradiated onto the reflective element 4 based on the imaging result by the first imaging unit 23 (step S20) is executed after the moving device 3 has stopped. Therefore, the process of irradiating the reflective element 4 with measurement light (step S30) is executed after the moving device 3 has stopped. In other words, the irradiation unit provided in the distance measuring unit 200 irradiates the reflective element 4 with measurement light after the moving device 3 has stopped. However, the irradiation unit provided in the distance measuring unit 200 may irradiate the reflective element 4 with measurement light while the moving device 3 is moving (while the moving device 3 is moving).

[0081] The reflected light from the reflective element 4 passes through the same path as the measurement light but in the reverse direction and is received by the light receiving unit of the distance measuring unit 200, which includes the optical comb interferometer 11 (step S40). In addition, a portion of the reflected light is detected by the 4-segment PSD 12. Based on the detection result from the 4-segment PSD 12, the control unit 22 controls the irradiation direction movement unit 201 again so that the measurement light continues to irradiate the reflective element 4. Here, the control unit 22 fine-tunes the irradiation direction of the measurement light using the irradiation direction movement unit 201 based on the detection result from the 4-segment PSD 12.

[0082] Here, the 4-segment PSD12 receives light from the space in which the reflecting element 4 is located. The 4-segment PSD12 is included in the first detection unit that receives light from the space in which the reflecting element 4 is located. Therefore, the irradiation direction movement unit 201 determines the position of the reflecting element 4 to be measured based on the detection result by the first detection unit and drives the irradiation unit provided in the distance measuring unit 200 so that the measurement light is irradiated onto the reflecting element 4.

[0083] In the mobile position measuring device 1, even if the measurement light is lost during the measurement process, the irradiation direction movement unit 201 can drive the irradiation unit so that the measurement light is irradiated onto the reflecting element 4 with an accuracy of the order of submicrometers by the optical comb interferometer 11. For example, the measurement light may be lost if an obstacle remains between the distance measuring unit 200 and the reflecting element 4.

[0084] The position information acquisition unit 203 acquires position information of the reflecting element 4 from the detection results (distance information) from the distance measurement unit 200, which includes the optical comb interferometer 11, and the direction information measured by the irradiation direction measurement unit 202 (step S50). The acquired position information is output to the calculation unit 26 via the control unit 22. This position information is expressed in three-dimensional spherical coordinates with respect to the position measurement device 2. At this time, the position information may be converted to orthogonal coordinates with respect to the position measurement device 2.

[0085] The control unit 22 transmits the position information acquired by the position information acquisition unit to the control system (step S60). This control system is a control system that controls the robot on which the reflective element 4 is installed. The control unit 22 causes the communication unit 25 to transmit the position information via wireless communication. With this, the control unit 22 terminates the position measurement process.

[0086] When the control system receives position information from the mobile position measuring device 1, it controls the robot based on that position information. Based on that position information, the control system calibrates the position of the robot's movable parts.

[0087] In this embodiment, an example of how the mobile position measuring device 1 measures the position information of the reflective element 4 has been described, but it is not limited to this. The mobile position measuring device 1 may transmit one or more of the following as measurement results to the control system: distance information and / or direction information.

[0088] (Second embodiment) A second embodiment of the present invention will be described in detail below with reference to the drawings. In the first embodiment described above, the case in which the mobile position measuring device 1 uses the imaging result obtained by the first imaging unit 23 (coaxial camera 13) to change the direction of irradiation of the measurement light. In this embodiment, the case in which the reflective element 4 is imaged in advance by a second imaging unit having a wider imaging range than the imaging range of the first imaging unit 23 before the first imaging unit 23 images the reflective element 4 is described. In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1a, and the position measuring device is referred to as position measuring device 2a. Note that components identical to those in the first embodiment described above are denoted by the same reference numerals, and descriptions of identical components and operations may be omitted.

[0089] Figure 6 shows an example of the configuration of the position measuring device 2a according to this embodiment. The position measuring device 2a comprises a housing 10, an optical comb interferometer 11, a four-segment PSD 12, a coaxial camera 13, a beam steering mirror 14, a PMA 15, a first half mirror 16, a second half mirror 17, and a 360-degree camera 18.

[0090] The 360-degree camera 18 captures images of its surroundings within a 360-degree range. The 360-degree camera 18 captures images of its surroundings within a 360-degree range by periodically rotating an imaging unit having a predetermined imaging range in the horizontal direction. In the following description, the imaging range is indicated by the horizontal field of view and / or the vertical field of view. The horizontal field of view is the field of view in the horizontal direction, and the vertical field of view is the field of view in the vertical direction. The imaging range of the 360-degree camera 18 is a horizontal field of view of 360 degrees and a vertical field of view of, for example, -45 degrees to 225 degrees.

[0091] The imaging range of the 360-degree camera 18 includes the robot on which the reflecting element 4 is installed. There are no objects (obstacles) between the 360-degree camera 18 and the robot that would prevent the robot from being included in the imaging range of the 360-degree camera 18.

[0092] Furthermore, the accuracy of the position of the reflecting element 4 determined based on the image of the reflecting element 4 captured by the 360-degree camera 18 is coarser than the accuracy of the position of the reflecting element 4 determined based on the image of the reflecting element 4 captured by the coaxial camera 13.

[0093] The position measuring device 2a may be equipped with a camera having a predetermined field of view instead of the 360-degree camera 18. This camera may be, for example, a wide-angle camera with a horizontal field of view of 120 to 150 degrees. The field of view of this camera may also be larger or smaller than the horizontal field of view of 120 to 150 degrees.

[0094] Figure 7 shows an example of the functional configuration of the position measuring device 2a according to this embodiment. The position measuring device 2a comprises a position measuring unit 20, a control unit 22, a first imaging unit 23, a reflected light detection unit 24, a communication unit 25, a moving device 27, and a second imaging unit 28.

[0095] The second imaging unit 28 captures an image of the reflecting element 4. The imaging range of the second imaging unit 28 is wider than that of the first imaging unit 23. The second imaging unit 28 includes a 360-degree camera 18. However, the second imaging unit 28 may be equipped with a camera having a predetermined field of view instead of the 360-degree camera 18. This camera may be, for example, a wide-angle camera with a horizontal field of view of 120 to 150 degrees. The field of view of this camera may also be a horizontal field of view larger or smaller than 120 to 150 degrees.

[0096] Next, with reference to Figure 8, the position measurement process by the mobile position measuring device 1a will be described. Figure 8 is a diagram showing an example of the position measurement process according to this embodiment. The position measurement process is performed by the control unit 22.

[0097] The imaging adjustment unit provided in the control unit 22 uses the second imaging unit 28 to capture an image of the robot to be measured (step S110). The imaging adjustment unit only needs to capture an image of at least a portion of the robot using the second imaging unit 28.

[0098] The imaging adjustment unit in the control unit 22 determines the position of the robot to be measured based on the imaging results of the second imaging unit 28 (step S120). Here, the imaging adjustment unit in the control unit 22 determines the image of the robot within the field of view of the imaging results of the second imaging unit 28 based on image analysis. The imaging adjustment unit determines the image of the robot based on image analysis such as pattern matching and / or machine learning, thereby determining the position of the robot.

[0099] Figure 9 shows an example of the imaging results of the second imaging unit 28. The imaging range D1 represents a 360-degree range around the position measuring device 2 imaged by the second imaging unit 28. The imaging range D2 represents the imaging range of the first imaging unit 23. The imaging range of the first imaging unit 23 is, for example, roughly rectangular. In the example shown in Figure 9, the images of robots R91, R92, R93, and R94 are included in the imaging range D1. In the example shown in Figure 9, the reflective element 4 installed on robot R91 is included in the imaging range D2.

[0100] Here, the imaging range of the second imaging unit 28 is wider than that of the first imaging unit 23 in both the horizontal and vertical directions. Therefore, the imaging adjustment unit determines the position of the reflecting element 4 in both the horizontal and vertical directions based on the imaging results of the second imaging unit 28.

[0101] Note that the imaging range D1 shown in Figure 9 is the imaging range captured by the 360-degree camera 18 when the second imaging unit 28 is equipped with the 360-degree camera 18. If the second imaging unit 28 is equipped with a camera with a predetermined field of view instead of the 360-degree camera 18, the imaging range D1 will change according to that field of view. For example, if the second imaging unit 28 is equipped with a wide-angle camera with a horizontal field of view of 120 to 150 degrees, the imaging range D1 will represent the range from 120 to 150 degrees around the position measuring device 2.

[0102] Furthermore, if the second imaging unit 28 includes, for example, a 360-degree spherical camera with a horizontal field of view of 360 degrees and a vertical field of view of 180 degrees, the imaging range D1 will be an imaging range with a horizontal field of view of 360 degrees and a vertical field of view of 180 degrees, similar to a 360-degree spherical image. Also, if the second imaging unit 28 includes, for example, a hemispherical camera with a horizontal field of view of 360 degrees and a vertical field of view smaller than 180 degrees, the imaging range D1 will be an imaging range with a horizontal field of view of 360 degrees and a vertical field of view smaller than 180 degrees, similar to a hemispherical image.

[0103] Returning to Figure 8, we will continue the explanation of the position measurement process. The imaging adjustment unit provided in the control unit 22 adjusts the imaging direction of the first imaging unit 23 (step S130). Here, the imaging adjustment unit provided in the control unit 22 determines the position of the robot to be measured based on the imaging result from the second imaging unit 28, and adjusts the imaging direction of the first imaging unit 23 so that it faces the position of the robot.

[0104] Here, the imaging adjustment unit adjusts the imaging direction of the first imaging unit 23 to follow the robot being measured, based on the imaging results from the second imaging unit 28. The imaging adjustment unit makes the imaging direction of the first imaging unit 23 follow the robot by image recognition of a predetermined object included in the imaging results from the second imaging unit 28. The predetermined object is one or more of the following, for example, the characteristics of the entire robot, the characteristics of the tip of the robot arm, the characteristics of a part of the robot other than the tip, the characteristics of a mark attached to the robot, an end effector attached to the tip of the robot, a reflective element, etc. Because the imaging direction of the first imaging unit 23 is adjusted to follow the robot, the first imaging unit 23 can continue to image the robot even if the robot moves.

[0105] In step S120, the measurement target whose position is determined is not limited to the current measurement target that follows the imaging direction of the first imaging unit 23. The control unit 22 may determine the position of a robot to be newly measured based on the imaging results of the second imaging unit 28. For example, in the example shown in Figure 9 above, the imaging adjustment unit provided in the control unit 22 determines the position of robot R91 as the measurement target. However, if the measurement target is changed from robot R91 to robot R92, robot R93, robot R94, etc., the imaging adjustment unit provided in the control unit 22 may determine the position of the robot to be measured based on the imaging results of the second imaging unit. In that case, the imaging adjustment unit provided in the control unit 22 may determine the position of the measurement target after the measurement target has been changed based on the first imaging unit 23. In other words, after the measurement target has been changed, the imaging direction may be adjusted to face the position of the measurement target (to follow the measurement target) based on the imaging results of the first imaging unit. In the imaging adjustment unit provided in the control unit 22, the imaging direction of the first imaging unit 23 is adjusted to the changed measurement target. Therefore, even if the measurement target is changed, the first imaging unit 23 can image the changed measurement target.

[0106] The second imaging unit 28 receives light from the space in which the object to be measured, which is equipped with the reflective element 4, is located. The second imaging unit 28 is included in the third detection unit which receives light from the space in which the object to be measured, which is equipped with the reflective element 4, is located. The imaging adjustment unit moves the detection direction of the second detection unit which receives light from the space in which the reflective element 4 is located, based on the detection result of the third detection unit. The imaging adjustment unit is a detection direction movement unit which moves the detection direction of the second detection unit based on the detection result of the third detection unit. The second detection unit includes the first imaging unit 23. The third detection unit includes a second imaging unit 28, which has a wider imaging range than the first imaging unit 23. Although the imaging range of the second imaging unit 28 is wider than that of the first imaging unit 23, the adjustment accuracy based on the imaging results from the second imaging unit 28 is less precise than the adjustment accuracy based on the imaging results from the first imaging unit 23.

[0107] Note that the processes from step S140 to step S190 are the same as the processes from step S10 to step S60 in Figure 5, so their explanation will be omitted. With this, the control unit 22 terminates the position measurement process.

[0108] The position at which the mobile position measuring device 1a will stop may be determined based on the imaging results of the second imaging unit 28. In this case, the first imaging unit 23 may not be provided. The mobile position measuring device 1a moves within the factory to the measurement position, which is the position for measuring the position of the object to be measured. The control unit 22 pre-images the object to be measured using the second imaging unit 28 before starting the measurement and determines the measurement position based on the imaging results of the second imaging unit 28. When the mobile position measuring device 1a moves within the factory to the determined measurement position, it stops at that measurement position. In this case, the control unit 22 may determine the measurement position when the mobile position measuring device 1a is stopped, or when the mobile position measuring device 1a is moving, before starting the measurement.

[0109] For example, if the mobile position measuring device 1a determines, based on the imaging results of the second imaging unit 28, that the position of the object to be measured is far from the position of the mobile position measuring device 1a, it first moves closer to the object to be measured. At that time, the mobile position measuring device 1a moves while changing its own orientation so that the orientation of the mobile position measuring device 1a itself is such that it is easy to measure the object to be measured. An orientation that is easy to measure the object to be measured is, for example, an orientation in which the reflective element 4 is visible from the front. The mobile position measuring device 1a determines the orientation in which the reflective element 4 is visible from the front by, for example, determining the image of the front of the reflective element 4 based on image recognition. The mobile position measuring device 1a may also determine the imaging direction of the second imaging unit 28 that maximizes the area of ​​the image of the reflective element 4 in the image captured by the second imaging unit 28 as the orientation in which the reflective element 4 is visible from the front.

[0110] (Third embodiment) A third embodiment of the present invention will be described in detail below with reference to the drawings. The position measurement results obtained by a mobile position measuring device may be affected by the vibration of the mobile position measuring device itself. In this embodiment, we will describe the case in which the mobile position measuring device measures position only when it is not vibrating itself, or when it is in an environment with vibrations that are negligible. Vibrations that are negligible for the mobile position measuring device itself are vibrations that do not affect the accuracy required for position measurement of the object being measured. In addition, the mobile position measuring device may be equipped with a vibration damping mechanism and / or vibration isolation mechanism to suppress vibrations in the position measuring part. In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1b, and the position measuring device is referred to as position measuring device 2b. Note that components identical to those in the embodiments described above are denoted by the same reference numerals, and descriptions of identical components and operations may be omitted.

[0111] Figure 10 shows an example of the functional configuration of the position measuring device 2b according to this embodiment. The position measuring device 2b comprises a position measuring unit 20, a control unit 22, a first imaging unit 23, a reflected light detection unit 24, a communication unit 25, a moving device 27, and a vibration detection unit 29. The position measuring device 2b may also include a second imaging unit 28, similar to the position measuring device 2a according to the second embodiment described above.

[0112] The vibration detection unit 29 detects vibrations of at least a portion of the position measuring device 2b. The vibration detection unit 29 includes one or more of the following: a velocity sensor, an acceleration sensor, an angular velocity sensor, an angular acceleration sensor, or a gyro sensor.

[0113] The vibration detection unit 29 detects vibrations in at least one of the following directions: roll, pitch, and yaw. Roll, pitch, and yaw, respectively, refer to, for example, rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis. The vibration detection unit 29 may also detect high-frequency vibrations and low-frequency vibrations separately by analyzing the vibrations over time.

[0114] The vibration detection unit 29 may also detect vibrations of the position measuring device 2b based on the image captured by the first imaging unit 23. When the position measuring device 2b is vibrating, the first imaging unit 23, which is provided in the housing 10, will vibrate. In that case, the image captured by the first imaging unit 23 will show the reflective element 4 or the scenery vibrating. Furthermore, if the position measuring device 2b is equipped with a second imaging unit 28, the vibration detection unit 29 may also detect vibrations of the position measuring device 2b based on the image captured by the second imaging unit 28.

[0115] Next, with reference to Figure 11, the position measurement process by the mobile position measuring device 1b will be described. Figure 11 is a diagram showing an example of the position measurement process according to this embodiment. The position measurement process is performed by the control unit 22. Note that steps S110, S120, and steps S150 through S180 are the same as steps S10, S20, and steps S30 through S60 in Figure 5, so their explanation will be omitted.

[0116] The control unit 22 determines whether or not vibration has been detected by the vibration detection unit 29 (step S130). If the vibration detection unit 29 detects vibration, it outputs a detection result indicating the amount of vibration to the control unit 22. The control unit 22 determines that vibration has been detected when it receives the vibration detection result from the vibration detection unit 29.

[0117] The control unit 22 may determine the presence or absence of vibration based on the vibration frequency, even if the vibration amount is the same. For example, the control unit 22 may determine that no vibration is detected in the case of high-frequency (long-period) vibrations, and determine that vibration is detected in the case of low-frequency (short-period) vibrations. The threshold for determining whether it is low-frequency or high-frequency may be determined based on the time it takes for the position measuring device 2b to measure the position of the object to be measured.

[0118] If the control unit 22 determines that vibration has been detected by the vibration detection unit 29 (step S130; YES), it determines whether the amount of vibration is less than a predetermined amount (also called vibration stopping sensitivity) (step S140). Here, the control unit 22 makes the determination by comparing the amount of vibration indicated by the detection result obtained from the vibration detection unit 29 with the predetermined amount.

[0119] The vibration damping sensitivity may be set as a design value during the manufacturing of the position measuring device 2b, or it may be set by the user of the position measuring device 2b. When the vibration damping sensitivity is set by the user, the user can easily set the vibration damping sensitivity by selecting a value that indicates the degree of vibration damping sensitivity. For example, the user can select one of three values, such as "high," "medium," or "low," as the value that indicates the degree of vibration damping sensitivity. In this case, the control unit 22 sets a predetermined set value as the vibration damping sensitivity according to the selected value. When the vibration damping sensitivity is set by the user, the user may set the vibration damping sensitivity by continuously changing it, or the user may input a value for the vibration damping sensitivity.

[0120] If the control unit 22 determines that the vibration amount is less than a predetermined amount (step S140; YES), it executes the processing from step S150 onward. In other words, when the vibration amount detected by the vibration detection unit 29 is less than a predetermined amount, the control unit 22 irradiates the reflecting element 4 with measurement light. The control unit 22 terminates the position measurement process if it determines that the vibration amount is greater than a predetermined amount (step S140; NO). In other words, if the vibration amount of the position measuring device 2 is greater than a predetermined amount, the control unit 22 terminates the position measurement process without irradiating the measuring light.

[0121] On the other hand, if the vibration detection unit 29 does not detect vibration (step S130; NO), the control unit 22 executes the processing from step S150 onward. Therefore, the control unit 22 irradiates the reflective element 4 with measurement light when the vibration detection unit 29 does not detect vibration. In other words, the irradiation unit provided in the distance measuring unit 200 irradiates the reflective element 4 with measurement light based on the detection result by the vibration detection unit 29. With this, the control unit 22 terminates the position measurement process.

[0122] In this embodiment, the control unit 22 has described a case in which it terminates the position measurement process without irradiating with measurement light when the vibration amount is greater than a predetermined amount, but it is not limited to this. When vibration is detected by the vibration detection unit 29, the control unit 22 may terminate the position measurement process without irradiating with measurement light, regardless of the vibration amount.

[0123] Furthermore, if vibration is detected by the vibration detection unit 29, the control unit 22 may control the distance measurement unit 200 to irradiate it with measurement light, and then prevent the calculation unit 26 from performing signal processing to calculate the distance. Furthermore, if the vibration detection unit 29 detects vibration and the amount of vibration is greater than a predetermined amount, the control unit 22 may control the distance measuring unit 200 to irradiate with measurement light and then prevent the calculation unit 26 from performing signal processing to calculate position information. In other words, in that case, the position measuring unit 20 acquires the position information of the reflecting element 4 based on the light reception result received by the light receiving unit provided in the optical comb interferometer 11 when the amount of vibration detected by the vibration detection unit 29 is less than a predetermined amount.

[0124] Furthermore, when vibration is detected by the vibration detection unit 29, the control unit 22 may, regardless of the amount of vibration, irradiate the distance measuring unit 200 with measuring light, then have the calculation unit 26 perform signal processing to calculate position information, and then determine whether or not to have the position measuring unit 20 acquire the position information calculated by the calculation unit 26.

[0125] In that case, the control unit 22, for example, causes the calculation unit 26 to generate reliability information based on the vibration amount indicated by the vibration detection unit 29. The reliability information indicates a lower reliability the larger the vibration amount indicated by the detection result, and a higher reliability the smaller the vibration amount. If the reliability information indicates a reliability higher than a predetermined value, the control unit 22 causes the position measurement unit 20 to acquire the position information calculated by the calculation unit 26. On the other hand, if the reliability information indicates a reliability lower than a predetermined value, the control unit 22 does not cause the position measurement unit 20 to acquire the position information calculated by the calculation unit 26.

[0126] (Fourth embodiment) A fourth embodiment of the present invention will be described in detail below with reference to the drawings. When measuring the position information of an object using the mobile position measuring device 1, fluctuations in the relative relationship between the position of the mobile position measuring device 1 and the position of the object may affect the measurement results as an error. Such fluctuations can be caused, for example, by vibrations of the floor on which the object is placed. Furthermore, if the mobile position measuring device 1 and the robot being measured are installed inside a large workpiece, such fluctuations can be caused by the reaction force from the robot's movement being transmitted to the mobile position measuring device 1.

[0127] In this embodiment, we will explain a case in which a mobile position measuring device corrects for the influence of fluctuations in the relative relationship between the mobile position measuring device and the position of the object being measured on the measurement results of position information based on the displacement of the mobile position measuring device relative to its reference position. Furthermore, in this embodiment, the calibration of the origin will also be described.

[0128] In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1c, and the position measuring device is referred to as position measuring device 2c. Note that components identical to those in the embodiments described above are denoted by the same reference numerals, and descriptions of identical components and operations may be omitted.

[0129] Figure 12 shows an example of how the mobile position measuring device 1c according to this embodiment measures a reference position. In this embodiment, the object to be measured is, for example, a machine tool. The reflective element 4c is placed in the movable part of the machine tool. In this embodiment, the machine tool has a machining head, and the machining head has an end effector such as an end mill. The movable part of the machine tool is, for example, a mechanism for changing the angle and position of the end mill to a desired angle and position. The reference reflective element 5 consists, for example, of three elements: a first reference reflective element 5-1, a second reference reflective element 5-2, and a third reference reflective element 5-3.

[0130] The reference position is a predetermined position (e.g., the origin) in a three-dimensional coordinate system based on multiple reference reflective elements 5. The position of the origin of the three-dimensional coordinate system is, for example, the position of any of the multiple reference reflective elements 5. In the following explanation, the first reference reflector 5-1, the second reference reflector 5-2, and the third reference reflector 5-3 may be collectively referred to as multiple reference reflectors 5.

[0131] Each of the multiple reference reflective elements 5 is a retroreflector. In other words, each of the multiple reference reflective elements 5 has a retroreflective function similar to that of the reflective element 4c.

[0132] The mobile position measuring device 1c includes a reference measuring light irradiation unit 19. The reference measuring light irradiation unit 19 is provided as part of the optical comb interferometer 11. The reference measuring light irradiation unit 19 includes a first reference irradiation unit, a second reference irradiation unit, and a third reference irradiation unit. In this embodiment, the position measuring device 2c is equipped with an optical system inside the housing 10 for branching the measurement light emitted from the optical comb interferometer 11. The position measuring device 2c can branch the measurement light into up to eight beams using this optical system. In this embodiment, the first reference measurement light, the second reference measurement light, and the third reference measurement light emitted by the reference measurement light irradiation unit 19 are beams obtained by branching the measurement light emitted from the optical comb interferometer 11.

[0133] Furthermore, the first light-receiving unit that receives the first reference reflected light, the second light-receiving unit that receives the second reference reflected light, and the third light-receiving unit that receives the third reference reflected light are provided separately from the light-receiving unit provided in the optical comb interferometer 11 that receives the reflected light reflected from the reflecting element 4c.

[0134] In this embodiment, an example is described in which the measurement light emitted from one optical comb interferometer 11 is branched, and a portion of the branched measurement light is used as the first reference measurement light, the second reference measurement light, and the third reference measurement light, but the embodiment is not limited to this. The position measuring device 2c may also include an optical comb interferometer inside the housing 10 that branches a single measurement light and emits it as the first reference measurement light, the second reference measurement light, and the third reference measurement light, separate from the optical comb interferometer 11 that emits the measurement light.

[0135] Each of the multiple reference reflective elements 5 is positioned at a different predetermined location on the machine tool. The multiple reference reflective elements 5 are positioned so that measurement light can be irradiated from the mobile position measuring device 1c, such as behind the machine tool. Furthermore, the multiple reference reflective elements 5 are positioned so that the reference measurement light irradiated onto each of them does not overlap. In the example shown in Figure 12, each of the multiple reference reflective elements 5 is positioned on the surface plate of the machine tool. The reference reflective element 5 may be placed above the robot or machine tool, or on the ceiling of the factory where the robot or machine tool is located.

[0136] In this embodiment, it is assumed that the reference reflective element 5 is placed at a predetermined position (i.e., a fixed position) within the machine tool. However, the reference reflective element 5 may be placed at a specific position on a movable part (i.e., a moving part) of the machine tool, and the reference position may be measured when the movable part is stopped. Alternatively, the operator may place the reference reflective element 5 at any position.

[0137] In the mobile position measuring device 1c, the position measuring device 2c is mounted on the mobile device 3. Therefore, the optical comb interferometer 11 provided in the position measuring device 2c, and the reference measurement light irradiation unit 19 provided in the optical comb interferometer 11, are located on the mobile device 3. The irradiation unit provided in the optical comb interferometer 11 is located on the mobile device 3 and includes a first irradiation unit that irradiates a first measurement light onto a first reflective element provided on the object to be measured. The reference measurement light irradiation unit 19 is provided on the mobile device 3 and is included in the reference irradiation unit that irradiates a reference reflective element with reference measurement light with respect to a reference position in the space in which the mobile device 3 is located. The signal processing unit provided in the optical comb interferometer 11 is included in a measurement unit that acquires positional information or distance information regarding the first reflecting element with respect to a reference position, based on the reference reflected light obtained from the first reflected light of the first measurement light from the first reflecting element and the reference measurement light from the reference reflecting element.

[0138] Figure 13 shows an example of the functional configuration of the position measuring device 2c according to this embodiment. The position measuring device 2c comprises a position measuring unit 20, a reference position measuring unit 21, a control unit 22, a first imaging unit 23, a reflected light detection unit 24, a communication unit 25, a calculation unit 26, and a moving device 27.

[0139] The reference position measuring unit 21 consists of, for example, three parts: reference position measuring unit 21-1, reference position measuring unit 21-2, and reference position measuring unit 21-3. The number of reference position measuring units 21 may be other than three. In the following explanation, the reference position measuring units 21-1, 21-2, and 21-3 are sometimes collectively referred to as the reference position measuring unit 21. Since the reference position measuring units 21-1, 21-2, and 21-3 have similar functions, the functional configuration of the reference position measuring unit 21 will be explained using the reference position measuring unit 21-1 as a representative example, and the explanations of the reference position measuring units 21-2 and 21-3 will be omitted.

[0140] The reference position measuring unit 21-1 includes a reference distance measuring unit 210-1, a reference irradiation direction movement unit 211-1, a reference irradiation direction measuring unit 212-1, and a reference position information acquisition unit 213-1.

[0141] The reference distance measuring unit 210-1 irradiates the first reference reflecting element 5-1 with reference measurement light, receives the reference reflected light, and measures the distance to the first reference reflecting element 5-1. The reference distance measuring unit 210-1 includes a first reference irradiation unit, a first reference light receiving unit, and a first reference signal processing unit.

[0142] The first reference irradiation unit irradiates the first reference reflecting element 5-1 with the first reference measurement light. The first reference irradiation unit includes an optical system for branching the measurement light emitted from the optical comb interferometer 11. The first reference light receiving unit receives the first reference reflected light from the first reference reflective element 5-1. This unit includes a light receiving unit located inside the housing 10 of the mobile position measuring device 1c.

[0143] The first reference signal processing unit processes the signal from the first reference light receiving unit and acquires first reference distance information. The first reference distance information is information indicating the distance from the mobile position measuring device 1c to the first reference reflecting element 5-1.

[0144] The reference irradiation direction movement unit 211-1 changes the irradiation direction of the reference measurement light. Changing the irradiation direction is also called moving the irradiation direction. The reference irradiation direction movement unit 211-1 includes the gimbal unit included in the PMA15. The reference irradiation direction measuring unit 212-1 measures the irradiation direction of the reference measurement light. The reference position information acquisition unit 213-1 acquires the position of the first reference reflecting element 5-1 in three-dimensional space (first reference position information) from the distance to the first reference reflecting element 5-1 measured by the reference distance measurement unit 210 (distance information) and the irradiation direction of the reference measurement light measured by the reference irradiation direction measurement unit 212-1 (direction information). Details regarding the acquisition of reference position information will be described later.

[0145] The reference position measuring unit 21-2 irradiates the second reference reflective element 5-2 with reference measurement light and receives the reference reflected light to measure the position of the second reference reflective element 5-2. The reference position measuring unit 21-3 irradiates the third reference reflective element 5-3 with reference measurement light and receives the reference reflected light to measure the position of the third reference reflective element 5-3. The functional configuration of the reference position measuring units 21-2 and 21-3 is the same as that of the reference position measuring unit 21-1, so a detailed explanation is omitted.

[0146] Note that any of the reference distance measuring units 210-1, 210-2, or 210-3 may simply be referred to as the reference distance measuring unit 210. Also, reference distance measuring units 210-1, 210-2, and 210-3 may be collectively referred to as multiple reference distance measuring units 210. Furthermore, any one of the reference irradiation direction moving parts 211-1, 211-2, or 211-3 may simply be referred to as the reference irradiation direction moving part 211. Also, the reference irradiation direction moving parts 211-1, 211-2, and 211-3 may be collectively referred to as multiple reference irradiation direction moving parts 211. Furthermore, any one of the reference irradiation direction measuring units 212-1, 212-2, or 212-3 may simply be referred to as the reference irradiation direction measuring unit 212. Also, the reference irradiation direction measuring units 212-1, 212-2, and 212-3 may be collectively referred to as multiple reference irradiation direction measuring units 212. Furthermore, any one of the reference position information acquisition units 213-1, 213-2, or 213-3 may simply be referred to as the reference position information acquisition unit 213. Also, reference position information acquisition units 213-1, 213-2, and 213-3 may be collectively referred to as multiple reference position information acquisition units 213.

[0147] The calculation unit 26 includes a reference coordinate setting unit 260 and a first correction unit 261. The reference coordinate setting unit 260 sets the reference (origin) and reference coordinate system based on the first reference position information, the second reference position information, and the third reference position information.

[0148] The first correction unit 261 acquires position information of the reflective element 4c relative to a reference generated by the reference coordinate setting unit 260. The position information of the reflective element 4 relative to the reference includes acquiring the position information of the reflective element 4 in the set reference coordinate system. The first correction unit 261 further corrects the variation in the position information of the reflective element 4 relative to the reference.

[0149] Here, the first correction unit 261 converts the position of the reflective element 4 indicated by the position information based on the position of the mobile position measuring device 1c relative to the reference position indicated by the reference position information and the position of the reflective element 4 indicated by the position information acquired by the position measuring unit 20. Through this conversion, the first correction unit 261 converts the position of the reflective element 4 relative to the mobile position measuring device 1c to the position of the reflective element 4 relative to the reference (origin). The first correction unit 261 generates information indicating the position of the reflective element 4 within the reference coordinate system as corrected position information. The reference position information acquisition unit 213 acquires the position information corrected by the first correction unit 261 as position information of the reflective element 4c relative to the reference (origin).

[0150] Next, with reference to Figure 14, the position measurement process by the mobile position measuring device 1c will be described. Figure 14 is a diagram showing an example of the position measurement process according to this embodiment. The position measurement process is performed by the control unit 22.

[0151] The position measuring unit 20 acquires the position information of the reflective element 4c (step S210). Here, the process of acquiring the position information of the reflective element 4c in step S210 is the same as the position measuring process in Figure 5 described above, so the explanation is omitted.

[0152] The reference position measuring unit 21-1 acquires reference position information of the first reference reflective element 5-1 (step S220). Referring now to Figure 15, the details of the process by which the reference position measuring unit 21-1 generates reference position information for the first reference reflective element 5-1 (referred to as the reference position information generation process) will be explained. Figure 15 is a diagram showing an example of the reference position information generation process according to this embodiment. The processes from step S310 to step S350 shown in Figure 15 are executed as the process of step S220 shown in Figure 14. Note that the processes from step S310 to step S350 shown in Figure 15 may be performed at the start of measurement.

[0153] The control unit 22 uses the first imaging unit 23 to capture images of multiple reference reflective elements 5 (step S310).

[0154] The control unit 22 controls each of the multiple reference irradiation direction movement units 211 so that each of the three reference measurement beams illuminates each of the multiple reference reflecting elements 5 (step S320). In the control of step S320, the control unit 22 uses the image acquisition result of the multiple reference reflecting elements 5 by the first imaging unit 23.

[0155] The control unit 22 controls the reference irradiation direction movement unit 211 so that multiple reference measurement beams are irradiated onto each of the multiple reference reflecting elements 5 (step S330). The control unit 22 may irradiate each of the multiple reference irradiation units with reference measurement beams simultaneously, or may irradiate them sequentially.

[0156] The control unit 22 determines that the reflected light from the reference reflective element 5 passes through the same path as the reference measurement light in the reverse direction and is received by the reference light receiving unit provided in the reference distance measuring unit 210 (step S340).

[0157] The reference position information acquisition unit 213 acquires reference position information of the reference reflecting element 5 from the measurement results (reference distance information) from the reference distance measurement unit 210 and the reference irradiation direction information acquired by the reference irradiation direction measurement unit 212 (step S350). In this embodiment, the reference position generation process described here is performed in each of the reference position measurement units 21-1, 21-2, and 21-3, and the first reference position information, second reference position information, and third reference position information are acquired. The acquired first, second, and third reference position information is output to the calculation unit 26 via the control unit 22. The reference position information is expressed in three-dimensional spherical coordinates with respect to the position measuring device 2.

[0158] As described above, the reference position measuring unit 21 acquires position information of the reference reflecting element 5 in three-dimensional space from the distance to the reference reflecting element 5 measured by the reference distance measuring unit 210 and the irradiation direction of the reference measuring light measured by the reference irradiation direction measuring unit 212.

[0159] Returning to Figure 14, we will continue the explanation of the position measurement process. The reference coordinate setting unit 260 of the calculation unit 26 sets a reference (origin) and a reference coordinate system based on the first, second, and third reference position information acquired by the reference position measurement unit 21 and obtained via the control unit 22 (step S30). In this embodiment, at least three pieces of reference position information, from the first to the third, are acquired, and based on these three pieces of reference position information, the reference coordinate setting unit 260 sets a desired orthogonal coordinate system (reference coordinate system).

[0160] The reference coordinate system can be arbitrarily set in the space in which the object to be measured (reflector 4) moves, depending on the installation positions of the first reference reflector 5-1, the second reference reflector 5-2, and the third reference reflector 5-3. As the reference coordinate system, for example, as shown in Figure 12, a Cartesian coordinate system can be set in the space in which the movable part C2, which is the object to be measured, moves, so as to include two axes parallel to the surface plate on which the object to be measured is placed. Furthermore, the reference coordinate setting unit 260 sets a reference origin within the reference coordinate system. The origin may be any of the three first reference reflector 5-1, the second reference reflector 5-2, and the third reference reflector 5-3 (reference position).

[0161] Alternatively, the movable part C2 (and by extension, the reflective element 4), which is the object to be measured, may be positioned at a predetermined location within the reference coordinate system, for example, at the origin of the movable part C2 as defined by the machine tool, and the position information of the reflective element 4 at that time may be made to coincide with the origin in the reference coordinate system. This makes it possible to make the position information acquired by the position measuring unit 20 and the position information acquired by the reference position measuring unit 21 the same for the same position in space, and to eliminate (correct) the discrepancy between the position information acquired by the position measuring unit 20 and the position information acquired by the reference position measuring unit 21. In either case, the reference coordinate system and the reference (origin) are set based on the reference position information obtained from the reference reflective element.

[0162] The first correction unit 261 of the calculation unit 26 converts the position information of the reflecting element 4 into position information in a reference coordinate system (step S240). The first correction unit 261 converts the position information of the reflecting element 4 measured by the position measurement unit 20 from three-dimensional spherical coordinates based on the position measurement device 2 to orthogonal coordinates in a reference coordinate system set by the reference coordinate setting unit 260. As a result, the position information of the object to be measured (i.e., the position information of the reflecting element 4) can be obtained in orthogonal coordinates in the reference coordinate system in the space in which the object to be measured is moving.

[0163] The first correction unit 261 corrects the position information of the reflective element 4c using the reference position information of the reference reflective element 5 (step S250). The correction may include resetting the reference (origin) and reference coordinate system set in step S230. For example, after the start of acquiring position information, the same operation as in step S230 may be performed at regular time intervals or irregularly to acquire the deviation of the reference coordinate system and correct that deviation. This makes it possible to calibrate the change in the origin over time (origin calibration). Alternatively, the reference position information of the reference reflective element 5 may be continuously acquired, and fluctuations in the reference (origin) and reference coordinate system may be continuously corrected. In this case, even short-term fluctuations (vibrations) can be corrected.

[0164] In this way, by installing the reference reflective element 5 on a measurement reference object that serves as the reference for measuring the position of the object to be measured, and by setting the reference coordinate system and origin based on the reference position information of the reference reflective element 5 acquired by the position measuring device 2, fluctuations in the relative positional relationship between the position measuring device 2 and the object to be measured (reflective element 4) can be canceled (corrected). In this sense, the conversion of the position information of the reflective element 4 to position information in the reference coordinate system, which is performed by the first correction unit 261, can also be said to be a correction of the position information of the reflective element 4.

[0165] As described above, the position information of the reflective element 4c is acquired by the position information acquisition unit. Based on the reference position information acquired by the reference position measurement unit 21, the first correction unit 261 calculates the amount of displacement of the current position of the mobile position measuring device 1c relative to the reference position from the position of the mobile position measuring device 1c relative to the reference position at the time of origin calibration. The first correction unit 261 corrects the position information of the reflective element 4c by the calculated amount of displacement.

[0166] As described above, the position information of the reflective element 4c is measured based on the light reception result from the light receiving unit provided in the distance measuring unit 200. Therefore, the position information of the reflective element 4c corrected based on the reference position information is the position information generated based on the light reception result from the light receiving unit provided in the distance measuring unit 200 and the reference position information. On the other hand, the reference position information is measured based on the light reception result from the first reference light receiving unit, the light reception result from the second reference light receiving unit, and the light reception result from the third reference light receiving unit. Therefore, in the mobile position measuring device 1, position information of the reflective element 4c relative to the reference position is generated based on the light reception result from the light receiving unit provided in the distance measuring unit 200, the light reception result from the first reference light receiving unit, the light reception result from the second reference light receiving unit, and the light reception result from the third reference light receiving unit.

[0167] The relative positional relationship between the mobile position measuring device 1c and the reference position may change due to floor vibrations, vibrations caused by robot movement, etc. Even in such cases, the mobile position measuring device 1c can correct the positional information of the reflecting element 4c based on the amount of displacement in the relative positional relationship of the mobile position measuring device 1c with respect to the reference position.

[0168] The control unit 22 transmits the corrected position information to the control system (step S260). With this, the control unit 22 terminates the position measurement process.

[0169] The control system receives corrected position information transmitted from the mobile position measuring device 1c. The position of the object measured by the mobile position measuring device 1c, as indicated by this position information, is the position of the object controlled by the control system. If the position of the object controlled, as indicated by the received position information, deviates from the assumed position, the control system performs calibration to cancel out the difference between the position indicated by the received position information and the assumed position. The assumed position is the position that the control system has predetermined for controlling the object, such as a robot or machine tool. Alternatively, the control system may calculate a correction amount for the control of the controlled object based on the received position information, and then correct subsequent controls based on the calculated correction amount. For example, in controls performed after receiving position information, the control system may correct the drive amount using a correction amount calculated based on that position information.

[0170] In the process of capturing an image of the reference reflective element 5 as described above (step S310), the moving device 3 may be in motion. The process of directing the reference measurement light from the reference measurement light irradiation unit 19 toward the reference reflective element 5 based on the imaging result from the first imaging unit 23 (step S320) is executed after the moving device 3 has stopped. Therefore, the process of directing the reference measurement light toward the reference reflective element 5 (step S330) is executed after the moving device 3 has stopped. In other words, the reference measurement light irradiation unit 19 irradiates the reference measurement light onto the reference reflective element 5 after the moving device 3 has stopped. In addition, the position measurement unit 20 generates information regarding the reference position after the moving device 3 has stopped.

[0171] Furthermore, the position measuring device 2c may also include a vibration detection unit 29, similar to the position measuring device 2b according to the third embodiment. Similar to the position measuring device 2b according to the third embodiment, the vibration detection unit 29 detects vibrations of at least a portion of the position measuring device 2c. The position measuring unit 20 generates information regarding the reference position based on the detection result by the vibration detection unit 29. The reference measurement light irradiation unit 19 irradiates the reference reflective element 5 with reference measurement light based on the detection result by the vibration detection unit 29. For example, the reference measurement light irradiation unit 19 irradiates the reference reflective element 5 with reference measurement light when the amount of vibration detected by the vibration detection unit 29 is smaller than a predetermined amount. In that case, the signal processing unit provided in the optical comb interferometer 11 acquires information regarding the position of the reflective element 4c based on the first reflected light of the first measurement light from the reflective element 4c when the amount of vibration detected by the vibration detection unit 29 is smaller than a predetermined amount, and the reference reflected light of the reference measurement light from the reference reflective element 5. In other words, if the position measuring device 2c is equipped with a vibration detection unit 29, it generates information regarding the reference position when the amount of vibration detected by the vibration detection unit is smaller than a predetermined amount. The imaging result of the first imaging unit 23 may be corrected based on the detection result of the vibration detection unit 29.

[0172] As described above, the mobile position measuring device 1c includes a reference position measuring unit 21 that acquires information (reference position information) regarding the reference position within the space in which the robot is deployed. The reference position measuring unit 21 includes a first reference irradiation unit, a second reference irradiation unit, a third reference irradiation unit, a first reference light receiving unit, a second reference light receiving unit, and a third reference light receiving unit. The first reference irradiation unit irradiates the first reference reflective element 5-1 with the first reference measurement light with respect to the reference position. The second reference irradiation unit irradiates the second reference reflective element 5-2 with the second reference measurement light with respect to the reference position. The third reference irradiation unit irradiates the third reference reflective element 5-3 with third reference measurement light with respect to the reference position. In the mobile position measuring device 1, position information with respect to the reference position of the first reflecting element (reflecting element 4c) is generated based on the light reception result from the first light receiving unit (light receiving unit provided in the distance measuring unit 200), the light reception result from the first reference light receiving unit, the light reception result from the second reference light receiving unit, and the light reception result from the third reference light receiving unit.

[0173] In this embodiment, an example has been described in which the mobile position measuring device 1c, in order to generate reference position information (i.e., measure the reference position), is equipped with three irradiation units (first reference irradiation unit, second reference irradiation unit, third reference irradiation unit), three light receiving units (first reference light receiving unit, second reference light receiving unit, third reference light receiving unit), and three reference reflecting elements (first reference reflecting element 5-1, second reference reflecting element 5-2, third reference reflecting element 5-3), but it is not limited to this. Examples of other configurations for generating reference position information are described below.

[0174] In this embodiment, the reference measurement light irradiation unit 19 can irradiate three reference measurement lights simultaneously. Alternatively, the reference measurement light irradiation unit 19 may irradiate the three reference measurement lights sequentially instead of simultaneously.

[0175] Alternatively, instead of irradiating with three reference measurement beams, one reference measurement beam may be used to sequentially irradiate each of the three reference reflecting elements. In that case, the reference position measuring unit 21 includes a reference irradiation unit and a reference light receiving unit. The reference irradiation unit irradiates the first reference reflecting element, the second reference reflecting element, and the third reference reflecting element with reference position light. The reference light receiving unit receives the first reference reflected light from the first reference reflecting element, the second reference reflected light from the second reference reflecting element, and the third reference reflected light from the third reference reflecting element. Based on the light reception result from the first light receiving unit (a light receiving unit provided in the distance measuring unit 200) and the light reception result from the reference light receiving unit, position information of the first reflecting element (reflecting element 4c) relative to the reference position is generated.

[0176] The position measuring device 2c may include three reference irradiation units and one reference light receiving unit. In that case, the reference position measuring unit 21 includes a first reference irradiation unit, a second reference irradiation unit, a third reference irradiation unit, and a reference light receiving unit. The first reference irradiation unit irradiates the first reference reflective element 5-1 with the first reference measurement light with respect to the reference position. The second reference irradiation unit irradiates the second reference reflective element 5-2 with the second reference measurement light with respect to the reference position. The third reference irradiation unit irradiates the third reference reflective element 5-3 with third reference measurement light with respect to the reference position. The reference light receiving unit receives the first reference reflected light from the first reference reflecting element 5-1, the second reference reflected light from the second reference reflecting element 5-2, and the third reference reflected light from the third reference reflecting element 5-3. Based on the light reception result from the first light receiving unit (a light receiving unit provided in the distance measuring unit 200) and the light reception result from the reference light receiving unit, position information of the first reflecting element (reflecting element 4c) relative to the reference position is generated.

[0177] Furthermore, although this embodiment describes an example where the number of reference reflective elements 5 is three, it is not limited to this. The number of reference reflective elements 5 may be four or more. For the mobile position measuring device 1c to measure the displacement of the mobile position measuring device 1c with respect to its reference position, one reference reflective element 5 is sufficient. However, there may be two reference reflective elements 5.

[0178] For example, if the number of reference reflective elements 5 is 1, the reference position measuring unit 21 includes a reference irradiation unit and a reference light receiving unit. The reference irradiation unit irradiates a reference reflective element, which is positioned at a reference location, with reference measurement light. The reference light receiving unit receives the reference reflected light from the reference reflective element. Based on the light reception result from the first light receiving unit (a light receiving unit provided in the distance measuring unit 200) and the light reception result from the reference light receiving unit, position information of the first reflecting element (reflecting element 4c) relative to the reference position is generated.

[0179] In this embodiment, an example has been described in which the mobile position measuring device 1c is illuminated with a reference measuring light for measuring a reference position, in addition to the measuring light for measuring the position of the reflecting element 4c, but it is not limited to this example. The measuring light for measuring the position of the reflecting element 4c may also be used as the reference measuring light. In that case, the irradiation direction movement unit 201 adjusts the irradiation direction so that the measurement light is directed toward the reference reflecting element with respect to the reference position. The light-receiving unit provided in the distance measuring unit 200 receives the reference reflected light from the reference reflecting element. The position measuring unit 20 generates position information of the reflective element 4c relative to the reference position based on the light reception result from the light receiving unit provided in the distance measuring unit 200.

[0180] Furthermore, when the measurement light used to measure the position of the reflective element 4c is used as the reference measurement light, the irradiation unit provided in the optical comb interferometer 11 is moved by the moving device 3, and the measurement light is irradiated onto the reference reflective element 5 with respect to the reference position in the space where the moving device 3 is located, and the measurement light is irradiated onto the reflective element 4c provided on the object to be measured. The signal processing unit provided in the optical comb interferometer 11 acquires position information or distance information regarding the reflective element 4c with respect to the reference position based on the first reflected light of the measurement light from the reflective element 4c and the reference reflected light of the measurement light from the reference reflective element 5.

[0181] Furthermore, if the number of reference reflective elements 5 is N, and the number of reference measurement beams emitted from the reference irradiation unit is X, and the number of measurement beams emitted from the irradiation unit of the optical comb interferometer 11 that are used as reference measurement beams is Y, then as long as the condition that the sum of X and Y is equal to N is met, it is possible to perform measurements similar to those of the mobile position measuring device 1c according to this embodiment by various combinations.

[0182] In this embodiment, an example of how reference position information can be used to correct position information indicating the position of the reflective element 4 has been described, but the embodiment is not limited to this. For example, reference position information may be used to determine the movement path of the mobile position measuring device 1c. Also, if the mobile position measuring device 1c moves using the well-known SLAM (Simultaneous Localization and Mapping), reference position information may be used to confirm whether the mobile position measuring device 1c is moving along the path indicated by the SLAM.

[0183] (Fifth embodiment) A fifth embodiment of the present invention will be described in detail below with reference to the drawings. In this embodiment, we will describe the case in which the mobile position measuring device 1d holds a reflective element for installation on the robot that is the object to be measured. In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1d, and the mobile device is referred to as mobile device 3d. Note that components identical to those in the embodiments described above are denoted by the same reference numerals, and descriptions of identical components and operations may be omitted.

[0184] Figure 16 shows an example of the operation of the mobile position measuring device 1d according to this embodiment. The mobile position measuring device 1d comprises a position measuring device 2 and a mobile device 3d. Robot T1 is an arm-type robot and is an example of a measurement target.

[0185] The moving device 3d includes a holding portion 30. The holding portion 30 detachably holds the reflective element 4d. The holding portion 30 is provided on the moving device 3d. The holding portion 30 has a groove (not shown) for detachably holding the reflective element 4d. The groove has a shape corresponding to the shape of the holder T10 that holds the reflective element 4d. Figure 16 shows the state in which reflective element 4d-2 and reflective element 4d-3 are held in the holding portion 30 as the reflective element 4d.

[0186] A holder T10 is provided at the tip of the arm of robot T1. The holder T10 holds the reflective element 4d. The reflective element 4d is detachable from the holder T10. Figure 16 shows an example of a reflective element 4d, specifically reflective element 4d-1, held in the holder T10. The holder T10 is an example of a holding part for holding a reflective element provided on a robot.

[0187] Figure 17 shows an example of how the reflective element 4d according to this embodiment is attached to and detached from the holder T10. In Figure 17(A), the reflective element 4d is held in the groove of the holding part 30. Here, as an example, the reflective element 4d is held in the holding part 30 with the reflective element facing downwards. In Figure 17(B), the reflective element 4d is held in the holder T10. The robot T1 brings the tip of the arm on which the holder T10 is attached close to the holding part 30 of the moving device 3d, thereby holding the reflective element 4d in the holder T10.

[0188] The holder T10 is, for example, a prism with a regular hexagonal base. The reflective element 4d can be installed, for example, at three locations on the side of the prism. The base of the prism may be a polygonal surface other than a hexagon, or a circular, elliptical, or other surface shape. In this embodiment, the bottom portion of the holder T10 is used as the base, but it may be a sphere or other three-dimensional shape. During measurement, it is sufficient that at least one reflective element 4d is installed on the holder T10. In the measurement, the mobile position measuring device 1d only needs to measure the position of any of the three reflective elements 4d installed on the three sides of the holder T10.

[0189] For the reflective elements 4d to be positioned in a location where the mobile position measuring device 1d can irradiate with measurement light, it is preferable to have a large number of reflective elements 4d installed on the holder T10. As described above, the holder T10 is a prism with a regular hexagonal base, so as shown in Figure 17, the irradiation unit of the optical comb interferometer 11 can irradiate with measurement light from any direction within the 360-degree angle around the holder T10.

[0190] Furthermore, the multiple reflective elements 4d may include multiple types of reflective elements. These multiple types may include, for example, the material, size, and structure of the reflective elements. An example of multiple structures might be a structure combining planar mirrors and a spherical structure. Furthermore, each of the multiple reflective elements 4d may be assigned an identifier. This identifier allows the mobile position measuring device 1d to identify which of the multiple reflective elements 4d is installed in the holder T10 provided on the robot T1, or which is held in the holding part 30 of the mobile position measuring device 1d.

[0191] Since the reflective element 4d is not needed except for position measurement, it does not need to be permanently installed on the robot T1. If the reflective element 4d is permanently installed on the robot T1, its surface may become dirty. Dirt on the surface of the reflective element 4d can be a source of error in position measurement using measurement light.

[0192] In the mobile position measuring device 1d, the reflective element 4d is held in the holding unit 30 of the mobile position measuring device 1d when not measuring, and the reflective element 4d is installed on the robot T1 only when measuring. This reduces the risk, for example, of the surface of the reflective element 4d becoming dirty. The holding unit 30 may also be equipped with a function to clean the reflective element 4d while it is being held.

[0193] (Sixth embodiment) A sixth embodiment of the present invention will be described in detail below with reference to the drawings. In this embodiment, we will describe a case in which a mobile position measuring device controls the control system of a robot or machine tool that is being measured, based on the measurement results. In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1e, and the position measuring device is referred to as position measuring device 2e.

[0194] Figure 18 shows an example of how the mobile position measuring device 1e according to this embodiment controls the machine tool T2. The machine tool T2 controls the spindle T20 that is installed within it. The spindle T20 is installed inside the machine tool T2. The spindle T20 is the shaft in the machine tool T2 used to rotate an object that is attached to its shaft end. Examples of objects that are rotated include cutting tools and grinding wheels. The machine tool T2 is provided with a window that allows the inside of the machine tool T2 to be monitored from the outside. The spindle T20 is located inside the machine tool T2. The reflective element is located on the spindle T20. In other words, the reflective element is located inside the machine tool T2. The reflective element is located, for example, on top of the spindle T20.

[0195] The mobile position measuring device 1e transmits measuring light through the window of the machine tool T2 and irradiates a reflective element installed on the spindle T20. The mobile position measuring device 1e receives the reflected light from the reflective element that has been transmitted through the window of the machine tool T2. The window of the machine tool T2 preferably has a shape and material (refractive index, transmittance) that allows sufficient transmission of measuring light and reflected light, and the refraction of measuring light and reflected light to be below a predetermined level.

[0196] The mobile position measuring device 1e communicates with the machine tool T2 via optical wireless communication. The mobile position measuring device 1e transmits the measured position information to the machine tool T2 via optical wireless communication. In the mobile position measuring device 1e, the communication unit 25 includes a communication module for performing optical wireless communication.

[0197] The mobile position measuring device 1e may correct the measured position information based on the optical characteristics (refractive index, transmittance, etc.) of the window of the machine tool T2. Furthermore, the mobile position measuring device 1e may calculate the position information based on the optical characteristics of the window of the machine tool T2 during the calculation process. The mobile position measuring device 1e acquires information indicating the optical characteristics of the window of the machine tool T2 in advance through communication with the machine tool T2.

[0198] The machine tool T2 uses the position information of the spindle T20, measured by the mobile position measuring device 1e, for calibration of the spindle T20 for machining. When the machine tool T2 receives position information from the mobile position measuring device 1e, it immediately performs calibration based on that position information. The machine tool T2 is equipped with a position measuring instrument for measuring the position of the spindle T20. During calibration, the machine tool T2 outputs the position of the spindle T20 indicated by the position information received from the mobile position measuring device 1e to the position measuring instrument.

[0199] Furthermore, if the control unit 22 of the mobile position measuring device 1e and the control unit of the machine tool T2 are compatible, the mobile position measuring device 1e may control the machine tool T2 based on the measurement results. In that case, the mobile position measuring device 1e controls the spindle T20 on behalf of the machine tool T2. The mobile position measuring device 1e functions as a position measuring device installed outside the machine tool T2. As a position measuring device installed outside the machine tool T2, the mobile position measuring device 1e immediately performs calibration of the position of the spindle T20 during machining.

[0200] Furthermore, when the mobile position measuring device 1e controls the machine tool T2, even if the machine tool T2 does not have a function to perform calibration based on high-precision position information from the mobile position measuring device 1e, the spindle T20 can be calibrated with high precision based on that position information. Furthermore, the mobile position measuring device 1e may also control the position of the processing head of the laser processing device with high precision. Furthermore, the mobile position measuring device 1e may measure position information and / or control the machining head while the window of the machine tool T2 is open.

[0201] (Seventh Embodiment) A seventh embodiment of the present invention will be described in detail below with reference to the drawings. This embodiment describes a case in which a mobile position measuring device controls a host computer that controls factory facilities. In this embodiment, the mobile position measuring device is referred to as mobile position measuring device 1f, and the position measuring device is referred to as position measuring device 2f. Mobile position measuring device 1f includes, for example, the configuration of mobile position measuring device 1c and the configuration of mobile position measuring device 1d described above.

[0202] Figure 19 shows an example of how a mobile position measuring device 1f according to this embodiment controls multiple robots T3. The mobile position measuring device 1f and the multiple robots T3 are installed in a factory facility. The mobile position measuring device 1f can move freely within the factory facility. In the example shown in Figure 19, seven robots, robots T3-1 to T3-7, are shown as the multiple robots T3. The factory facility is controlled by a host computer H1. The host computer H1 is an example of a control system for the multiple robots T3.

[0203] The mobile position measuring device 1f measures positional information for each of the multiple robots T3. The mobile position measuring device 1f performs measurements by sequentially changing the robot T3 being measured. The mobile position measuring device 1f moves the factory facility to a position where the measurement light can be shone onto the reflective element installed on the robot T3 currently being measured, stops, and then performs the measurement.

[0204] The mobile position measuring device 1f measures multiple robots T3 based on a predetermined order, for example. The predetermined order is, for example, the order in which the multiple robots T3 are positioned within the factory facility. The predetermined order may also be an order specified in advance by the host computer H1. The mobile position measuring device 1f may measure multiple robots T3 without following a predetermined order. For example, the mobile position measuring device 1f may use the second imaging unit 28 to image a 360-degree range around the mobile position measuring device 1f, and based on the imaging results, the imaged robots T3 may be used as the measurement targets.

[0205] The mobile position measuring device 1f, after measuring position information, sequentially transmits the position information to the host computer H1. The mobile position measuring device 1f may also transmit the position information for each of the multiple robots T3 to the host computer H1 all at once.

[0206] Furthermore, the mobile position measuring device 1f transmits adjustment information for robot T3 based on the position information to the host computer H1. This adjustment information includes control signals for controlling robot T3. The control signals include, for example, signals for controlling the position of the object that robot T3 operates or the object that robot T3 processes. The control signals may also include signals for controlling the object that robot T3 operates and signals for controlling the position of the object that robot T3 processes. The control signals may also include signals for controlling the position and movement of multiple robots T3. These signals allow multiple robots T3 to be controlled to avoid contact with each other.

[0207] As described above, in this embodiment, the mobile position measuring device 1f generates adjustment information for the first measurement target based on the position information of the first measurement target. The mobile position measuring device 1f may also generate adjustment information for a second measurement target different from the first measurement target based on the position information of the first measurement target. The second measurement target is, for example, a measurement target located within a predetermined range from the position where the first measurement target is located. For example, the mobile position measuring device 1f controls robot T3-2 or robot T3-7, which are located within a predetermined range from robot T3-1, based on the position information of robot T3-1.

[0208] The mobile position measuring device 1f transmits adjustment information to the host computer H1 via wireless communication. This wireless communication may be optical wireless communication. By using optical wireless communication, the mobile position measuring device 1f can communicate with the host computer H1 without interference from other wireless communications.

[0209] When the host computer H1 receives adjustment information from the mobile position measuring device 1f, it controls multiple robots T3 based on the received adjustment information. Control based on adjustment information includes, as an example, control to instruct the robot T3 on the target position of the workpiece to be machined. If the position of the workpiece indicated by the workpiece position information deviates from the expected position, the workpiece position information may be corrected by the amount of the deviation based on the adjustment information. Alternatively, based on the adjustment information, the position indicated by the workpiece position information may be used as the initial position, and the position of the workpiece may be calculated (converted) as a relative position from that initial position.

[0210] Therefore, the mobile position measuring device 1f can control multiple robots T3 via the host computer H1 by transmitting adjustment information to the host computer H1. In other words, the mobile position measuring device 1f functions as a mobile controller that transmits commands from a higher level to multiple robots T3 placed within the factory.

[0211] The mobile position measuring device 1f transmits one or more of the following to the host computer H1: position information and / or adjustment information. Alternatively, the mobile position measuring device 1f may transmit position information to the host computer H1, and the host computer H1 may generate adjustment information based on the position information received from the mobile position measuring device 1f. Furthermore, the mobile position measuring device 1f may directly control multiple robots T3 based on adjustment information without going through the host computer H1.

[0212] Furthermore, the position measuring unit 20 provided in the position measuring device 2f acquires information about the coordinate system within the space where the robot T3 is positioned from the host computer H1. Alternatively, the position measuring unit 20 may acquire the coordinate system information by reading it from a storage medium in the mobile position measuring device 1f. Based on the coordinate system information, the position measuring unit 20 generates coordinate position information for the robot T3 in that coordinate system. This coordinate system is the reference coordinate system within the factory where the robot T3 is positioned. Therefore, the mobile position measuring device 1f can control multiple robots T3 based on a highly accurate coordinate system.

[0213] In this embodiment, an example has been described in which a single mobile position measuring device 1f that can be freely moved around the factory facility is provided, but the embodiment is not limited to this. The mobile position measuring device 1f may be used in a position measuring system that includes multiple mobile position measuring devices 1f.

[0214] Furthermore, a factory facility may be equipped with multiple (N) mobile position measuring devices 1f. N mobile position measuring devices 1f may control M robots. In this case, each of the multiple mobile position measuring devices 1f measures the position to one or more reflective elements provided on each of the multiple robots. Here, the number N may be greater than the number M, less than the number M, or equal to the number M. The number N or the number M may also be 1. Multiple stationary position measuring devices 2 may be provided along with multiple mobile position measuring devices 1f.

[0215] In this embodiment, an example was described in which the control system is a host computer H1 that manages and controls the entire factory facility, but the invention is not limited to this example. The control system may include a local server that manages and controls a portion of the factory facilities, a server that manages and controls some of the multiple robots deployed in the factory facilities, or a CPU (Central Processing Unit) that manages and controls a single robot.

[0216] The position measuring device 2f may also include a second imaging unit 28, similar to the position measuring device 2a in the second embodiment described above. In that case, the position where the mobile position measuring device 1f stops may be determined based on the imaging results of the second imaging unit 28. The mobile position measuring device 1f moves within the factory to the measurement position, which is the position for measuring the position of the object to be measured. The control unit 22 pre-images the object to be measured using the second imaging unit 28 before starting the measurement and determines the measurement position based on the imaging results of the second imaging unit 28. When the mobile position measuring device 1f moves within the factory to the determined measurement position, it stops at that measurement position. In this case, the control unit 22 may determine the measurement position when the mobile position measuring device 1f is stopped, or when the mobile position measuring device 1f is moving, before starting the measurement.

[0217] For example, if the mobile position measuring device 1f determines, based on the imaging results of the second imaging unit 28, that the position of the object to be measured is far from the position of the mobile position measuring device 1f, it first moves closer to the object to be measured. At that time, the mobile position measuring device 1f moves while changing its own orientation so that the orientation of the mobile position measuring device 1f itself is such that it is easy to measure the object to be measured. An orientation that is easy to measure the object to be measured is, for example, an orientation in which the reflective element 4 is visible from the front. The mobile position measuring device 1f determines the orientation in which the reflective element 4 is visible from the front by, for example, determining the image of the front of the reflective element 4 based on image recognition. The mobile position measuring device 1f may also determine the imaging direction of the second imaging unit 28 that maximizes the area of ​​the image of the reflective element 4 in the image captured by the second imaging unit 28 as the orientation in which the reflective element 4 is visible from the front.

[0218] (Eighth embodiment) Hereinafter, an eighth embodiment of the present invention will be described in detail with reference to the drawings. In the embodiments described above, the mobile position measuring device was described in the case of measuring position information for a robot or machine tool that processes a workpiece. In this embodiment, the mobile position measuring device 1 will be described in the case of measuring position information in the process of assembling parts together.

[0219] Figure 20 shows an example of how the mobile position measuring device 1 according to this embodiment measures the position information of the optical scanner T4. The optical scanner T4 is a coordinate measuring machine (CMM) that measures the shape of an object in three dimensions using irradiated light. In Figure 20, the optical scanner T4 measures the shape of the assembly part T5. The optical scanner T4 has an arm-like shape, and illumination light is irradiated onto the assembly part T5 from the tip of the arm.

[0220] A reflective element 4 is installed at the tip of the arm of the optical scanner T4. The mobile position measuring device 1 measures the position information of the reflective element 4 installed on the optical scanner T4. The mobile position measuring device 1 transmits the measured position information to the control system of the optical scanner T4. The control system of the optical scanner T4 corrects the measurement result of the shape of the optical scanner T4 based on the position information measured by the mobile position measuring device 1.

[0221] Note that the CMM to be measured by the mobile position measuring device 1 is not limited to the optical scanner T4. The mobile position measuring device 1 may also be used to assist in the measurement of a stationary CMM. In that case, the mobile position measuring device 1 may be installed in part of the stationary CMM. For example, the mobile position measuring device 1 may be installed on the ceiling of a stationary CMM. The mobile position measuring device 1 installed on the ceiling measures the position information of the reflective element 4 installed in the measurement section of the stationary CMM.

[0222] (Ninth embodiment) A ninth embodiment of the present invention will be described in detail below with reference to the drawings. This embodiment describes a case in which the mobile position measuring device 1 is used to measure positional information in a process in which the assembly process and the processing process of a large machine are carried out in parallel. In this embodiment, we will describe the case in which the mobile position measuring device 1 provided in the mobile position measuring device 1 according to the first embodiment described above is used.

[0223] Figure 21 shows an example of how the mobile position measuring device 1 according to this embodiment measures position information during the assembly and processing of the turbine T7. The optical scanner T6-1 is a CMM that measures the shape of the turbine T7 in three dimensions. The optical processing machine T6-2 processes parts of the turbine T7, such as blades, by processing with light irradiation. The cutting machine T6-3 processes parts of the turbine T7, such as blades, by cutting. Reflective elements 4-1, 4-2, and 4-3 are installed in the optical scanner T6-1, the optical processing machine T6-2, and the cutting machine T6-3, respectively.

[0224] The mobile position measuring device 1 measures position information for each of the reflective elements 4-1, 4-2, and 4-3. The mobile position measuring device 1 transmits the measured position information to the control system that controls the optical scanner T6-1, the optical processing machine T6-2, and the cutting machine T6-3. Based on the position information measured by the mobile position measuring device 1, it becomes possible to measure the assembly accuracy with high precision in a process in which the assembly and processing processes of parts for large machinery such as turbine T7 are carried out in parallel.

[0225] Furthermore, while the above-described embodiment described an example of the mobile position measuring device 1 being used in the machine assembly process, it is not limited to this. The mobile position measuring device 1 may also be used to measure position information in the process of disassembling, cleaning, and reassembling an assembled machine (overhaul).

[0226] As described above, the position measuring device according to the embodiment (in the above embodiment, the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, 1f) comprises a movable mobile device 3, a position measuring unit 20 including an illumination unit that irradiates measuring light onto reflective elements 4, 4c arranged on the movable part of the robot, a light receiving unit that receives reflected light from the reflective elements 4, 4c, a position information acquisition unit that acquires position information of the reflective elements 4, 4c, a moving unit (in the embodiment, an illumination direction moving unit 201) that changes the direction of irradiation of the measuring light, an imaging unit (in the embodiment, a first imaging unit 23), and a transmission unit that transmits the position information acquired by the position measuring unit 20, or robot adjustment information based on said position information, to the robot control system. The moving device 3 moves at least one of the following: the irradiation unit, the light receiving unit, the moving unit (in this embodiment, the irradiation direction moving unit 201), and the imaging unit (in this embodiment, the first imaging unit 23). The position measuring device (in the above embodiment, the mobile position measuring device 1, 1a, 1b, 1c, 1d, 1e, 1f) uses the imaging unit (in the embodiment, the first imaging unit 23) to image at least a part of the robot, one or both of the reflective elements 4, 4c, and controls the moving unit (in the embodiment, the irradiation direction moving unit 201) so that the measurement light is irradiated onto the reflective elements 4, 4c, based on the imaging results from the imaging unit (in the embodiment, the first imaging unit 23).

[0227] With this configuration, the position measuring device according to the embodiment (in the above embodiment, the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, 1f) can use the imaging unit (in the embodiment, the first imaging unit 23) to image at least a part of the robot, one or both of the reflective elements 4, 4c, and based on the imaging results, the moving unit (in the embodiment, the irradiation direction moving unit 201) can be controlled so that the measurement light is irradiated onto the reflective elements 4, 4c, thereby enabling high-precision measurement of the robot's position during robot control.

[0228] Furthermore, the measuring device according to the embodiment (in the above embodiment, the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, 1f) comprises a movable mobile device 3, an illumination unit provided on the mobile device 3 for irradiating the reflective elements 4, 4c with measurement light, a light receiving unit provided on the mobile device 3 for receiving the reflected measurement light from the reflective elements 4, 4c, and a measuring unit (in the embodiment, the signal processing unit of the optical comb interferometer 11) that acquires position information or distance information regarding the reflective elements 4, 4c based on the light receiving result by the light receiving unit.

[0229] With this configuration, the measuring device according to the embodiment (in the above embodiment, the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, 1f) can acquire positional information or distance information regarding the reflecting elements 4, 4c based on the light reception result by the light receiving unit, thereby enabling high-precision measurement of the position of the object to be measured or the distance from the measuring device (in the above embodiment, the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, 1f).

[0230] Furthermore, the measuring device according to the embodiment (mobile position measuring device 1c in the above embodiment) comprises a movable mobile device 3, a first irradiation unit provided on the mobile device 3 that irradiates a first measuring light onto a first reflective element (reflecting element 4c in the embodiment) provided on the object to be measured, a reference irradiation unit (reference measuring light irradiation unit 19 in the embodiment) provided on the mobile device 3 that irradiates a reference measuring light onto a reference reflective element 5 relating to a reference position in the space in which the mobile device 3 is located, and a measuring unit (signal processing unit of the optical comb interferometer 11 in the embodiment) that acquires position information or distance information relating to the first reflective element (reflecting element 4c in the embodiment) with respect to a reference position based on the first reflected light of the first measuring light from the first reflective element (reflecting element 4c in the embodiment) and the reference reflected light of the reference measuring light from the reference reflective element 5.

[0231] With this configuration, even if a reference position has not been acquired in advance, the measuring device according to the embodiment (in the above embodiment, the mobile position measuring device 1c) can acquire position information or distance information regarding the first reflecting element (in the embodiment, the reflecting element 4c) relative to the reference position based on the first reflected light of the first measurement light from the first reflecting element (in the embodiment, the reflecting element 4c) and the reference reflected light of the reference measurement light from the reference reflecting element 5. Therefore, even if a reference position has not been acquired in advance, the position of the object to be measured or the distance from the measuring device (in the above embodiment, the mobile position measuring device 1c) can be measured with high accuracy.

[0232] Furthermore, the measuring device according to the embodiment (mobile position measuring device 1c in the above embodiment) comprises a movable mobile device 3, an irradiation unit provided on the mobile device 3 that irradiates a reference reflective element 5 with respect to a reference position in the space in which the mobile device 3 is located with measurement light, and irradiates a first reflective element (reflecting element 4c in the embodiment) provided on the object to be measured with measurement light, and a measuring unit (signal processing unit of the optical comb interferometer 11 in the embodiment) that acquires position information or distance information regarding the first reflective element (reflecting element 4c in the embodiment) with respect to a reference position based on the first reflected light of the measurement light from the first reflective element (reflecting element 4c in the embodiment) and the reference reflected light of the measurement light from the reference reflective element 5.

[0233] With this configuration, the measuring device according to the embodiment (mobile position measuring device 1c in the above embodiment) can use the measuring light used to acquire position information or distance information related to the first reflecting element (reflecting element 4c in the embodiment) to measure the reference position. Therefore, without providing a separate reference irradiation unit for irradiating the reference measuring light, the position of the object to be measured or the distance from the measuring device (mobile position measuring device 1c in the above embodiment) can be measured with high accuracy even if the reference position has not been acquired in advance, using a simple configuration.

[0234] In addition, while an example has been described in which each of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f in the above embodiment is equipped with an optical comb interferometer 11, the invention is not limited to this example. Each of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f may measure the position of the object to be measured based on a distance measuring method other than the optical comb method. The distance measuring methods used by each of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f may be, for example, coaxial or non-coaxial. Coaxial methods include, for example, methods that measure the TOF (Time of Flight) of an optical pulse, methods that measure the arrival time of modulated laser light, and methods that utilize the coherence of laser light. Non-coaxial methods include, for example, triangulation, stereo camera methods, and moiré methods.

[0235] The types of communication performed by the communication unit 25 provided in each of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f in the above-described embodiments are not limited to those described in each embodiment. The communication unit 25 may perform various types of wireless communication using radio waves, optical wireless communication, and wired communication. Various types of wireless communication include short-range wireless communication.

[0236] Furthermore, some parts of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f in the above-described embodiments, such as the control unit 22 and the calculation unit 26, may be implemented using a computer. In that case, the program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. Here, "computer system" refers to the computer system built into the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f, and includes hardware such as an OS and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. In addition, "computer-readable recording medium" may also include those that dynamically hold programs for a short period of time, such as communication lines when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in such a case. Furthermore, the above program may be intended to implement some of the functions described above, and may also be able to implement the above functions in combination with programs already recorded in the computer system. Furthermore, some or all of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f in the above-described embodiments may be implemented as integrated circuits such as LSIs (Large Scale Integration). Each functional block of the mobile position measuring devices 1, 1a, 1b, 1c, 1d, 1e, and 1f may be individually implemented as a processor, or some or all of them may be integrated into a single processor. In addition, the method of implementing integrated circuits is not limited to LSIs; dedicated circuits or general-purpose processors may also be used. Furthermore, if advances in semiconductor technology lead to the emergence of integrated circuit implementation technologies that can replace LSIs, integrated circuits using such technologies may be used.

[0237] As described above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist of the present invention.

[0238] In addition, those skilled in the art will understand that the above-described plurality of embodiments or modifications thereof are specific examples of the following aspects. (Appendix 1) The measuring device includes a movable moving device, an irradiation unit provided on the moving device for irradiating a measurement light to a reflection element, a light receiving unit provided on the moving device for receiving the reflected light of the measurement light from the reflection element, and a measurement unit for acquiring position information or distance information regarding the reflection element based on the light receiving result by the light receiving unit.

[0239] (Appendix 2) The above-described measuring device further includes a first detection unit for receiving light from the space where the reflection element is arranged, and a moving unit for discriminating the position of the reflection element to be measured based on the detection result by the first detection unit and driving the irradiation unit so that the measurement light is irradiated to the reflection element.

[0240] (Appendix 3) The above-described measuring device further includes a second detection unit for receiving light from the space where the reflection element is arranged, and the moving unit discriminates the position of the reflection element to be measured based on the detection result by the second detection unit and moves the irradiation direction of the measurement light.

[0241] (Appendix 4) The above-described measuring device further includes a third detection unit for receiving light from the space where the measurement object provided with the reflection element is arranged, and a detection direction moving unit for moving the detection direction by the second detection unit based on the detection result by the third detection unit.

[0242] (Appendix 5) The above-described measuring device includes, in the first detection unit, at least a photodiode array; in the second detection unit, a first imaging unit; and in the third detection unit, a second imaging unit having a wider imaging range than the first imaging unit.

[0243] (Note 6) In the above-described measuring device, the reflective element is located inside a robot or machine tool.

[0244] (Note 7) In the above measuring device, the measuring light is an optical comb.

[0245] (Note 8) The position measurement method comprises a movable moving device, a position measurement unit including an illumination unit that irradiates a reflective element positioned on a movable part of a robot with measurement light, a light receiving unit that receives reflected light, a position information acquisition unit that acquires position information of the reflective element, a moving unit that changes the direction of irradiation of the measurement light, an imaging unit, and a transmission unit that transmits the position information acquired by the position information acquisition unit, or adjustment information of the robot based on said position information, to the control system of the robot, wherein the moving device is a position measurement method using a position measurement device comprising at least the illumination unit, the light receiving unit, the moving unit, and the imaging unit, comprising: imaging at least a part of the robot, one or both of the reflective element using the imaging unit; controlling the moving unit so that the measurement light is irradiated onto the reflective element based on the imaging result obtained by imaging; irradiating the reflective element with measurement light using the illumination unit; receiving reflected light using the light receiving unit; and acquiring position information of the reflective element using the position information acquisition unit.

[0246] (Note 9) The measurement method is a measurement method using a measurement device comprising: a movable mobile device; an illumination unit provided on the mobile device for irradiating a reflective element with measurement light; a light receiving unit provided on the mobile device for receiving reflected light from the reflective element; and a measurement unit for acquiring positional information or distance information relating to the reflective element based on the light receiving result by the light receiving unit, wherein the method comprises irradiating the reflective element with measurement light using the illumination unit; receiving reflected light from the reflective element with the light receiving unit; and acquiring positional information or distance information relating to the reflective element based on the light receiving result by the light receiving unit.

[0247] (Note 10) The measurement method uses a measurement device comprising: a movable mobile device; a first irradiation unit provided on the mobile device for irradiating a first measurement light onto a first reflective element provided on an object to be measured; a reference irradiation unit provided on the mobile device for irradiating a reference measurement light onto a reference reflective element relating to a reference position in the space in which the mobile device is located; and a measurement unit for acquiring positional information or distance information relating to the first reflective element with respect to the reference position based on the first reflected light of the first measurement light from the first reflective element and the reference reflected light of the reference measurement light from the reference reflective element, wherein the measurement method comprises irradiating the first reflective element with the first measurement light using the first irradiation unit; irradiating the reference reflective element with the reference measurement light using the reference irradiation unit; and acquiring positional information or distance information relating to the first reflective element with respect to the reference position based on the first reflected light of the first measurement light from the first reflective element and the reference reflected light of the reference measurement light from the reference reflective element using the measurement unit.

[0248] (Note 11) The measurement method uses a measuring apparatus comprising: a movable mobile device; an illumination unit provided on the mobile device which irradiates a measurement light onto a reference reflective element relating to a reference position in the space in which the mobile device is located, and irradiates a measurement light onto a first reflective element provided on the object to be measured; and a measurement unit which acquires positional information or distance information relating to the first reflective element with respect to the reference position based on the first reflected light of the measurement light from the first reflective element and the reference reflected light of the measurement light from the reference reflective element, wherein the measurement method comprises irradiating the reference reflective element with measurement light using the illumination unit and irradiating the first reflective element with measurement light, and acquiring positional information or distance information relating to the first reflective element with respect to the reference position based on the first reflected light of the measurement light from the first reflective element and the reference reflected light of the measurement light from the reference reflective element using the measurement unit. [Explanation of Symbols]

[0249] 1, 1a, 1b, 1c, 1d, 1e, 1f... Mobile position measuring device, 11... Optical comb interferometer, 25... Communication unit, 23... First imaging unit, 20... Position measuring unit, 201... Irradiation direction moving unit, 4, 4c... Reflecting element

Claims

1. A mobile device that can move for a robot equipped with movable parts, A measuring device is provided on the aforementioned mobile device and moves together with the aforementioned mobile device. Equipped with, The measuring device is, An irradiation unit that irradiates a reflective element to be measured, which is provided on the movable part of the robot, with measurement light, and also irradiates a reference reflective element, which is positioned at a reference location in the space in which the moving device is arranged, A measuring unit acquires positional information or distance information regarding the position of the reflective element to be measured, which is provided on the movable part, relative to the reference position in the space in which the robot is located, based on the reflected light of the measurement light from the reflective element to be measured and the reference reflected light of the reference measurement light from the reference reflective element. A measurement system equipped with the following features.

2. Based on the result of receiving the reflected light, which is the measurement light, from the irradiation unit via the reflective element under measurement, and the result of receiving the reference reflected light, which is the reference measurement light, from the irradiation unit via the reference reflective element, position information of the reflective element under measurement with respect to the reference position is generated. The measurement system according to claim 1.

3. The aforementioned reference reflector comprises a first reference reflector, a second reference reflector, and a third reference reflector. Position information of the reflective element under measurement relative to the reference position is generated based on a first result obtained by receiving the reference reflected light, which is the reference measurement light from the irradiation unit via the first reference reflective element; a second result obtained by receiving the reference reflected light, which is the reference measurement light from the irradiation unit via the second reference reflective element; a third result obtained by receiving the reference reflected light, which is the reference measurement light from the irradiation unit via the third reference reflective element; and a fourth result obtained by receiving the reflected light, which is the measurement light, from the irradiation unit via the reflective element under measurement. The measurement system according to claim 1.

4. The measuring device includes a distance measuring unit that emits the measurement light and receives the reflected light from the reflective element to be measured to measure the distance to the reflective element, and an irradiation direction moving unit that changes the irradiation direction of the measurement light from the distance measuring unit. The measurement system according to any one of claims 1 to 3.

5. The irradiation direction movement unit includes a beam steering mirror that reflects the measurement light, The beam steering mirror is rotatable in the longitude and latitudinal directions. The measurement system according to claim 4.

6. A detection unit that receives light from the space in which the reflective element to be measured is arranged, Based on the detection result by the detection unit, the control unit determines the position of the reflective element to be measured and controls the irradiation direction movement unit so that the measurement light is irradiated onto the reflective element to be measured. Equipped with The measurement system according to claim 4 or claim 5.

7. The detection unit includes a detection surface, The position of the light from the space where the reflective element to be measured is arranged on the detection surface is measured. The measurement system according to claim 6.

8. The detection unit includes a camera for imaging the reflective element to be measured. The measurement system according to claim 6 or claim 7.

9. The irradiation direction movement unit adjusts the irradiation direction so that the reference measurement light is directed toward the reference reflecting element with respect to the reference position. The measurement unit receives reference reflected light from the reference reflective element and generates positional information of the reflective element to be measured relative to the reference position based on the light reception result by the detection unit. The measurement system according to any one of claims 6 to 8.

10. The irradiation unit irradiates the reflective element to be measured with the measurement light after the moving device has stopped. The measurement system according to any one of claims 1 to 9.

11. The measuring unit acquires information about the coordinate system within the space where the robot is positioned, and generates coordinate position information of the robot in the coordinate system based on the information about the coordinate system. The measurement system according to any one of claims 1 to 10.

12. The aforementioned coordinate system is the reference coordinate system within the factory where the robot is located. The measurement system according to claim 11.

13. The measuring unit generates information regarding the reference position after the moving device has stopped. The measurement system according to any one of claims 1 to 12.

14. The aforementioned mobile device includes an automated guided vehicle. The measurement system according to any one of claims 1 to 13.

15. The device comprises multiple of the aforementioned measuring devices. The measurement system according to any one of claims 1 to 14.

16. Each of the plurality of measuring devices measures the position of one or more of the reflective elements to be measured, which are provided on each of the plurality of robots, relative to the reference position. The measurement system according to claim 15.

17. The measuring device is detachable from the mobile device. The measurement system according to any one of claims 1 to 16.

18. Moving a measuring device, which is mounted on a mobile device that can move relative to a robot equipped with movable parts, together with the said mobile device, The reflective element to be measured, provided on the movable part of the robot, is measured using the measurement light from the measuring device. The process involves measuring a reference reflective element positioned at a reference location within the space where the moving device is located, using reference measurement light from the measuring device, Based on the reflected light of the measurement light from the reflective element under measurement and the reference reflected light of the reference measurement light from the reference reflective element, positional information or distance information regarding the position of the reflective element under measurement provided on the movable part is acquired with respect to the reference position in the space in which the robot is located. Measurement methods including

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