Measurement device, robot system, management method, target member, and measurement method

Abstract

A measurement device according to the present invention is a measurement device that measures a position of a movable robot, and a position in a rotational direction. The measurement device includes a radiating unit that is capable of radiating measurement light to each of at least three reflecting elements attached to a robot, a photoreceptor that is capable of receiving reflected light reflected by each of the three reflecting elements, and a position acquiring unit that acquires, on the basis of a result of light received by the photoreceptor, positional information relating to a first axis of the robot, positional information relating to a second axis that intersects the first axis, positional information relating to a third axis that intersects the first axis and the second axis, information relating to a position in a rotational direction about the first axis, information relating to a position in a rotational direction about the second axis, and information relating to a position in a rotational direction about the third axis.

Description

MEASURING APPARATUS, ROBOT SYSTEM, MANAGEMENT METHOD, TARGET MEMBER, AND MEASURING METHOD

[0001] The present invention relates to a measuring device, a robot system, a management method, a target member, and a measuring method.

[0002] Robots and machine tools are used to automatically perform machining and assembly processes. In these processes, in order to improve the accuracy of machining and assembly, it is necessary to measure with high precision the position and orientation of the arm of the robot to be controlled. For example, a device is known that measures the position of a predetermined part of a robot device using an external measuring device (Patent Document 1). In controlling a robot, it is required to measure the position and orientation of the robot with high precision.

[0003] International Publication No. 2007 / 002319

[0004] One aspect of the present invention is a measuring device that measures the position and rotational position of a movable robot, and includes an irradiation unit that can irradiate measurement light onto each of at least three reflective elements attached to the robot, a light receiving unit that can receive reflected light reflected by each of the three reflective elements, and a position acquisition unit that acquires, based on the light receiving results by the light receiving unit, position information regarding a first axis of the robot, position information regarding a second axis that intersects with the first axis, position information regarding a third axis that intersects with the first axis and the second axis, information regarding the position in the rotational direction around the first axis, information regarding the position in the rotational direction around the second axis, and information regarding the position in the rotational direction around the third axis.

[0005] One aspect of the present invention is a robot system including the above-described measuring device.

[0006] One aspect of the present invention is a management method for managing a robot using the above-described measurement device.

[0007] One aspect of the present invention is a target member that can be attached to a movable measurement object, and that includes a first reflecting element, a second reflecting element, and a third reflecting element onto which measurement light is irradiated to obtain position information about a first axis, position information about a second axis that intersects the first axis, and position information about a third axis that intersects the first axis and the second axis, as well as information about the position in a rotational direction around the first axis, information about the position in a rotational direction around the second axis, and information about the position in a rotational direction around the third axis, wherein the lengths of a first side connecting a first position where the first reflecting element is located and a second position where the second reflecting element is located, a second side connecting the second position and a third position where the third reflecting element is located, and a third side connecting the third position and the first position are all different.

[0008] One aspect of the present invention is a measuring device that measures the position of a measuring object, and includes an irradiation unit that can sequentially irradiate measuring light onto each of at least three reflecting elements attached to the measuring object, a light receiving unit that can sequentially receive the reflected light of the measuring light reflected by each of the three reflecting elements, and an information acquisition unit that acquires information regarding the position of the measuring object based on the light receiving results by the light receiving unit.

[0009] One aspect of the present invention is a measuring device that measures the position of a measuring object, and includes an irradiation unit that can scan measuring light along a trajectory that can pass through at least three reflecting elements attached to the measuring object, a light receiving unit that can receive reflected light of the measuring light reflected by each of the three reflecting elements, and an information acquisition unit that acquires information regarding the position of the measuring object based on the light receiving results by the light receiving unit.

[0010] One aspect of the present invention is a target member that can be attached to a measurement object and that includes a first reflective element, a second reflective element, and a third reflective element for measuring the position of the measurement object, wherein the lengths of a first side connecting a first position where the first reflective element is located and a second position where the second reflective element is located, a second side connecting the second position and a third position where the third reflective element is located, and a third side connecting the third position and the first position are all different.

[0011] One aspect of the present invention is a measurement method for measuring the position and rotational position of a movable robot, the measurement method including: irradiating measurement light onto each of at least three reflective elements attached to the robot; receiving reflected light reflected by each of the three reflective elements; and, based on the light reception results, acquiring position information regarding a first axis of the robot, position information regarding a second axis intersecting the first axis, and position information regarding a third axis intersecting the first axis and the second axis, as well as information regarding the rotational position around the first axis, information regarding the rotational position around the second axis, and information regarding the rotational position around the third axis.

[0012] One aspect of the present invention is a measurement method for measuring the position of a measurement object, the measurement method including: sequentially irradiating measurement light onto at least three reflective elements attached to the measurement object; sequentially receiving the reflected light of the measurement light reflected by each of the three reflective elements; and acquiring information about the position of the measurement object based on the light receiving results.

[0013] One aspect of the present invention is a measurement method for measuring the position of a measurement object, comprising: scanning measurement light along a trajectory that can pass through at least three reflective elements attached to the measurement object; receiving reflected light of the measurement light reflected by each of the three reflective elements; and acquiring information about the position of the measurement object based on the light receiving results.

[0014] 1 is a diagram showing an example of how the measurement device according to the first embodiment measures the position and orientation of a measurement target. FIG. 1 is a diagram showing an example of an arrangement of three reflecting elements and markers according to the first embodiment. FIG. 2 is a diagram showing an example of the configuration of the measurement device according to the first embodiment. FIG. 3 is a diagram showing an example of the cross-sectional configuration of a reflecting element according to the first embodiment. FIG. 4 is a diagram showing an example of the appearance of a reflecting element according to the first embodiment. FIG. 5 is a diagram showing an example of how the reflecting element according to the first embodiment reflects measurement light. FIG. 6 is a diagram showing an example of the functional configuration of the measurement device according to the first embodiment. FIG. 7 is a diagram showing an example of how scanning is performed by measurement light according to the first embodiment. FIG. 8 is a diagram showing an example of a position in a rotation direction around a coordinate axis when position information according to the first embodiment is represented by Cartesian coordinates. FIG. 9 is a diagram showing an example of a measurement process according to the first embodiment. FIG. 10 is a diagram showing an example of a rough search process according to the first embodiment. FIG. 11 is a diagram showing an example of a fine search process according to the first embodiment. FIG. 12 is a diagram showing an example of a trajectory of measurement light in area scanning according to the first embodiment. FIG. 13 is a diagram showing an example of how the reflecting element according to the first embodiment is irradiated with measurement light while being scanned along a spiral trajectory. FIG. 14 is a diagram showing an example of how an image of a reflective element moves within the field of view of a 4-segment PSD during scanning according to the first embodiment. FIG. 1 is a diagram showing an example of the horizontal position of a reflective element within the field of view of a four-segment PSD relative to the irradiation direction of the measurement light in the azimuth direction according to the first embodiment. FIG. 2 is a diagram showing an example of the vertical position of a reflective element within the field of view of a four-segment PSD relative to the irradiation direction of the measurement light in the elevation direction according to the first embodiment. FIG. 3 is a diagram showing an example of the position of a reflective element within the field of view of a four-segment PSD obtained as a result of scanning according to the first embodiment. FIG. 4 is a diagram showing an example of area scanning according to the first embodiment. FIG. 5 is a diagram showing an example of the horizontal position of three reflective elements within the field of view of a four-segment PSD relative to the irradiation direction of the measurement light in the azimuth direction according to the first embodiment. FIG. 6 is a diagram showing an example of the vertical position of three reflective elements within the field of view of a four-segment PSD relative to the irradiation direction of the measurement light in the elevation direction according to the first embodiment. FIG. 7 is a diagram showing an example of area scanning when the trajectory of the measurement light according to the first embodiment is a wavy line. FIG. 8 is a diagram showing an example of a position and orientation acquisition process according to the first embodiment. FIG. 9 is a diagram showing an example of a method for calculating a circular trajectory according to the first embodiment.FIG. 1 is a diagram showing an example of an overview of an orientation acquisition process according to the first embodiment. FIG. 2 is a diagram showing an example of a process of superimposing four points, the coordinates of which are known in a known coordinate system according to the first embodiment, on the positions of four reflecting elements. FIG. 3 is a diagram showing an example of a graph showing the magnitude of an error vector according to the first embodiment. FIG. 4 is a diagram showing an example of the configuration of a target member according to the first embodiment. FIG. 5 is a diagram showing an example of a cross-sectional view in a state in which a reflecting element according to the first embodiment is held by a holder. FIG. 6 is a diagram showing an example of the height of three reflecting elements on an installation surface according to the first embodiment. FIG. 7 shows an example of how the position and orientation of a measurement object according to the second embodiment are measured by measurement light when the measurement object moves. FIG. 8 is a diagram showing an example of a position and orientation acquisition process according to the second embodiment.

[0015] First Embodiment Hereinafter, the first embodiment will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of how a measuring device 1 according to this embodiment measures the position and orientation of a measurement target. The measuring device 1 measures the position and rotational position of a movable measurement target. The rotational position is also referred to as the orientation or direction. In this embodiment, the measurement target whose position and orientation is measured by the measuring device 1 is, for example, a robot T1. The robot T1 has a movable part, i.e., a movable part. The position and orientation of the movable part of the robot T1 can change. In other words, the robot T1 is a movable robot. The robot T1 is, for example, a robot that performs processing and assembly processes at a manufacturing site such as a factory.

[0016] Note that the measurement object may have either a fixed position or a fixed orientation. Furthermore, the measurement object may have a fixed position and an fixed orientation. In other words, the measurement object does not have to be movable. Note that the measurement object may be a movable machine tool, etc. The measurement object may also be a machining head of a machining center, a tool that is replaceably attached to the machining head, or a component in which a measuring member (fixture) is fixed to the machining head separately from the tool that is replaceably attached to the machining head. Furthermore, the measurement object may be a component that constitutes a large product such as an aircraft during assembly, or the measurement head of a coordinate measuring machine, etc.

[0017] A target member 4 is attached to the movable part of the robot T1. The target member 4 includes at least three reflective elements. In this embodiment, the target member 4 includes three reflective elements: a reflective element 41, a reflective element 42, and a reflective element 43. In this embodiment, the target member 4 also includes a marker 44.

[0018] 2 shows an example of the arrangement of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) and the marker 44. The marker 44 is arranged so that the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are arranged in the vicinity of the marker 44. "In the vicinity of the marker 44" means a range within a predetermined distance from the marker 44. The marker 44 may be, for example, a light-emitting body such as a light-emitting diode (LED), or may be a non-light-emitting body.

[0019] Next, a description will be given of the configuration of the measurement device 1. Fig. 3 is a diagram showing an example of the configuration of the measurement device 1 according to this embodiment. The measurement device 1 includes a housing 10, an optical comb interferometer 11, a four-segment PSD 12, a beam steering mirror 13, a pointing mirror assembly (PMA) 14, and a half mirror 15.

[0020] The housing 10 is a component for installing the measuring device 1 on an installation target. In this embodiment, the installation target is a factory floor or a self-propelled transport device such as an AGV (Automatic Guide Vehicle) or an AMR (Autonomous Mobile Robot). The housing 10 fixes the measuring device 1 to the installation target by, for example, its own weight. The housing 10 may also include a mechanism for fixing the measuring device 1 to the installation target.

[0021] The housing 10 also contains the various components of the measurement device 1. The various components of the measurement device 1 are attached to the housing 10. A beam steering mirror 13 and a PMA 14 are attached to the outside of the housing 10. The housing 10 also contains an optical comb interferometer 11, a four-segment PSD 12, and a PMA 14. The housing 10 also has a space inside for the propagation of measurement light and reflected light.

[0022] The optical comb interferometer 11 measures the distance from itself to a measurement object. 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 evenly spaced on the frequency axis (hereinafter referred to as an "optical frequency comb"). In this case, the optical comb light source emits pulsed light containing frequency components evenly spaced on the frequency axis as measurement light. Here, the reflecting elements 41, 42, and 43 have similar configurations, so in the following description, the reflecting elements 41, 42, and 43 may be represented by the reflecting element 41. The optical comb interferometer 11 irradiates the reflecting element 41, which is arranged on the measurement object, with an optical frequency comb as measurement light. The optical comb interferometer 11 receives reflected light generated when the optical frequency comb is reflected by the reflecting element 41.

[0023] In this embodiment, the optical comb interferometer 11 includes a single measurement light source (i.e., an optical comb light source). The optical comb interferometer 11 may include multiple measurement light sources, such as a first measurement light source and a second measurement light source. The multiple measurement light sources each emit multiple measurement light beams 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 light beams emitted by the multiple measurement light sources each have different pulse frequencies (e.g., the number of pulsed light beams per unit time, which is the reciprocal of the emission period of the pulsed light beam). For example, the first measurement light source may emit a first measurement light beam with a pulse frequency of 25 GHz, and the second measurement light source may emit a second measurement light beam with a pulse frequency of 25 GHz+α (e.g., +100 kHz).

[0024] In distance measurement using the optical comb interferometer 11, the distance from the optical comb interferometer 11 to the reflecting element 41 is measured based on the position where interference fringes between different pulses of the optical frequency comb occur. The optical comb interferometer 11 can measure the distance with accuracy on the order of submicrometers, for example.

[0025] The optical comb interferometer 11 includes an irradiation unit, a light receiving unit, and a signal processing unit. The irradiation unit includes an optical comb light source, a frequency control unit, etc. The irradiation unit irradiates the measurement object with pulsed light generated by the optical comb light source as measurement light. The irradiation unit also branches a portion of the pulsed light generated by the optical comb light source and irradiates it as reference light on a reference surface within the optical comb interferometer 11. The light receiving unit includes a photodetector. The photodetector detects interference light between the reflected light and the reference light irradiated on the reference surface. When the detection result from the photodetector is input, the signal processing unit calculates the distance from the optical comb interferometer 11 to the reflecting element 41 based on the generation position of the pulsed light that creates interference light between the reflected light and the reference light.

[0026] Here, the principle by which the optical comb interferometer 11 calculates the distance from the optical comb interferometer 11 to the reflecting element 41 will be described in more detail. The optical comb interferometer 11 includes two optical comb light sources, a first optical comb light source and a second optical comb light source, and two optical detectors, a first optical detector and a second optical detector.

[0027] The first optical frequency comb light source generates a first measurement light, which is pulsed light having a first pulse frequency, as the measurement light. The second optical frequency comb light source generates a second measurement light, which is pulsed light having a second pulse frequency, as the measurement light. The first pulse frequency and the second pulse frequency are different from each other.

[0028] The first measurement light emitted from the first optical frequency comb source is not irradiated onto the measurement target (i.e., the reflecting element 41) but is reflected by the optical system in the first optical frequency comb source and then enters the first optical detector as the first reflected light. On the other hand, the second measurement light is irradiated onto the measurement target (i.e., the reflecting element 41) from the second optical frequency comb source, is reflected by the measurement target, and then enters the second optical detector as the second reflected light.

[0029] A part of the first measurement light is split and irradiated as a first reference light onto a reference surface in the optical comb interferometer 11, and then incident on the second photodetector. On the other hand, a part of the second measurement light is split and irradiated as a second reference light onto a reference surface in the optical comb interferometer 11, and then incident on the first photodetector.

[0030] Since the pulse frequency of the first measurement light is different from the pulse frequency of the second measurement light, the pulse frequency of the first reflected light is different from the pulse frequency of the second reference light, and therefore, the interference light between the first reflected light and the second reference light is an interference light in which pulse light appears in synchronization with the timing when the pulse light constituting the first reflected light and the pulse light constituting the second reference light are simultaneously incident on the first photodetector.

[0031] Similarly, the pulse frequency of the first reference light is different from the pulse frequency of the second reflected light, and therefore the interference light between the first reference light and the second reflected light is interference light in which pulsed light appears in synchronization with the timing at which the pulsed light constituting the first reference light and the pulsed light constituting the second reflected light are simultaneously incident on the second photodetector.

[0032] Here, the position (position on the time axis) of the pulsed light that creates the interference light detected by the second photodetector varies based on the positional relationship between the optical comb interferometer 11 and the measurement object. This is because the interference light detected by the second photodetector is interference light between the second reflected light that travels toward the second photodetector via the measurement object and the first reference light that travels toward the second photodetector without passing through the measurement object. On the other hand, the position (position on the time axis) of the pulsed light that creates the interference light detected by the first photodetector does not vary based on the positional relationship between the optical comb interferometer 11 and the measurement object.

[0033] 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 measurement object (typically, the distance between the optical comb interferometer 11 and the measurement object). Therefore, the optical comb interferometer 11 can calculate the distance from the optical comb interferometer 11 to the reflecting element 41 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.

[0034] Here, the measurement light emitted by the optical comb interferometer 11 passes through the half mirror 15, is reflected by the beam steering mirror 13, and is then irradiated onto the reflecting element 41. Here, the optical path of the measurement light irradiated onto the reflecting element 41 and the reflected light reflected by the reflecting element 41 share a part of the same path within the housing 10.

[0035] The half mirror 15 transmits the measurement light emitted from the optical comb interferometer 11. The half mirror 15 also transmits a portion of the measurement light reflected by the reflecting element 41 toward the optical comb interferometer 11 and reflects the remaining portion toward the four-segment PSD 12.

[0036] The four-segment PSD 12 measures the position of the reflecting element 41 by detecting the reflected light from the reflecting element 41. The reflected light is measurement light emitted by the optical comb interferometer 11 and reflected by the reflecting element 41. A portion of the reflected light is reflected by the half mirror 15 and enters the four-segment PSD 12.

[0037] The four-segment PSD 12 includes, for example, photodiodes and resistors. The photodiodes are arranged in an array. That is, the four-segment PSD 12 includes a photodiode array. The detection surface of the four-segment PSD 12 is divided into four. The four-segment PSD 12 measures the position of the spot light based on the light intensity of the spot light of reflected light detected on each of the four divided detection surfaces.

[0038] The four-segment PSD 12 is used to estimate the position of each of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) by scanning with the measurement light L1 after the position of the marker 44 is roughly captured by the stereo camera 3. The measuring device 1 does not necessarily have to include the stereo camera 3. If the measuring device 1 does not have the stereo camera 3, the four-segment PSD 12 may estimate the position of each of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) by scanning with the measurement light L1 without using the results of roughly capturing the position of the marker 44 by the stereo camera 3. The measuring device 1 may also include another position detector instead of the four-segment PSD 12. Examples of other position detectors include a line sensor, a two-dimensional sensor (also called an area sensor), and a phase detection distance measuring device.

[0039] The beam steering mirror 13 reflects the measurement light emitted from the optical comb interferometer 11 toward the reflecting element 41. The beam steering mirror 13 also reflects the measurement light reflected from the reflecting element 41 toward the optical comb interferometer 11. The beam steering mirror 13 is an example of a movable mirror.

[0040] The PMA 14 moves (changes) the direction of the beam steering mirror 13. The PMA 14 includes, for example, a gimbal unit and a rotary encoder (not shown). The orientation of the beam steering mirror 13 is changed by driving the gimbal unit and changing the rotation angle of the gimbal unit. The gimbal unit can rotate the beam steering mirror 13 so that the direction of the beam steering mirror 13 can be changed in both the longitude and latitude directions. The rotary encoder measures the rotation angle of the gimbal unit.

[0041] 4 to 6, the configurations of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) will be described using reflective element 41 as a representative. FIG. 4 is a diagram showing an example of the cross-sectional configuration of reflective element 41 according to this embodiment. FIG. 5 is a diagram showing an example of the appearance of reflective element 41 according to this embodiment. Reflective element 41 includes a lens 410, a mirror surface 411, a storage member 412, and a marker installation surface 413.

[0042] The lens 410 is a substantially spherical lens. In this embodiment, the diameter of the lens 410 is, for example, 35 mm. The lens 410 has a predetermined refractive index with respect to the wavelength of the measurement light L1. The lens 410 has a mirror surface 411 on its spherical surface. The mirror surface 411 is formed by mirror vapor deposition so as to cover a portion of the spherical lens 410. The mirror surface 411 has a reflectance equal to or greater than a predetermined value with respect to the wavelength of the measurement light L1.

[0043] The storage member 412 stores the lens 410. The lens 410 is stored in the storage member 412 and adhesively fixed to the storage member 412 so that a portion of the lens 410 is exposed. The "part" roughly corresponds to a portion of the spherical lens 410 where the mirror surface 411 is not formed. In order to sufficiently widen the range over which the reflective element 41 can reflect incident light, it is preferable that at least a hemisphere of the lens 410 is exposed. Note that the storage member 412 may be referred to as a holding portion because it fixes the lens 410.

[0044] The storage member 412 includes a marker installation surface 413. An LED or a reflective sticker may be installed on the marker installation surface 413.

[0045] 6 is a diagram showing an example of how the reflecting element 41 according to this embodiment reflects measurement light. In FIG. 6, measurement light L11 and measurement light L12 are shown as examples of the measurement light L1 that the measurement device 1 irradiates onto the reflecting element 41. After entering the lens 410, the measurement light L11 and measurement light L12 are each reflected by the mirror surface 411 in the direction of incidence. The reflecting element 41 is an optical element that reflects the beam in the incident direction regardless of the position or direction from which the beam is incident relative to the reflecting element 41. In other words, the reflecting element 41 has a retroreflective function.

[0046] 7 is a diagram showing an example of the functional configuration of the measuring device 1 according to this embodiment. The measuring device 1 includes a position measurement unit 20, a control unit 21, a first imaging unit 22, a communication unit 23, and a storage unit 24.

[0047] The position measurement unit 20 includes a distance measurement unit 200, an irradiation direction driving unit 204, an irradiation direction measurement unit 205, and a position acquisition unit 206. The distance measurement unit 200 irradiates the reflecting element 41 with measurement light, receives the reflected light, and measures the distance to the reflecting element. The distance measurement unit 200 includes an irradiation unit 201, a light receiving unit 202, and a signal processing unit 203. The irradiation unit 201 irradiates the measurement light to each of at least three reflecting elements attached to the movable part of the measurement target. In other words, the irradiation unit 201 can irradiate the measurement light L1 to each of at least three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) attached to the robot T1. The light receiving unit 202 receives the reflected light. Here, the light receiving unit 202 can receive the reflected light reflected by each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0048] The signal processing unit 203 processes the signal from the light receiving unit 202 to obtain distance information to the reflecting element 41. The distance measurement unit 200 includes the optical comb interferometer 11. The irradiating unit 201 includes an optical comb light source provided in the optical comb interferometer 11. The irradiating unit 201 is capable of irradiating the optical comb as measurement light L1. The irradiating unit 201 irradiates the measurement light L1 to each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) via the reflecting surface of the beam steering mirror 13. The light receiving unit 202 includes a light receiving unit provided in the optical comb interferometer 11. The light receiving unit 202 receives reflected light from each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) via the reflecting surface of the beam steering mirror 13. The signal processing unit 203 includes a signal processing unit provided in the optical comb interferometer 11.

[0049] The irradiation direction driving unit 204 changes the irradiation direction of the measurement light. Changing the irradiation direction is also referred to as moving the irradiation direction. The irradiation direction driving unit 204 includes a gimbal unit included in the PMA 15.

[0050] The irradiation direction measurement unit 205 measures the irradiation direction of the measurement light. The irradiation direction measurement unit 205 includes a rotary encoder that is included in the PMA 15 and measures the angle of the gimbal unit. The irradiation direction measurement unit 205 outputs the measurement result of the irradiation direction as direction information to the position acquisition unit 206 of the distance measurement unit 200.

[0051] The position acquisition unit 206 acquires the position (position information) in three-dimensional space for each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) from the distance (distance information) to the reflecting element 41 measured by the distance measurement unit 200 and the irradiation direction (direction information) of the measurement light measured by the irradiation direction measurement unit 205. Furthermore, the position acquisition unit 206 calculates direction information for each of the three reflecting elements based on the position information for each of the three reflecting elements.

[0052] The position information includes position information regarding a first axis of the measurement object (in this embodiment, robot T1), position information regarding a second axis intersecting the first axis, and position information regarding a third axis intersecting the first and second axes. The first axis is, for example, the x-axis in a Cartesian coordinate system set in the space in which the measurement object is placed. The second axis is, for example, the y-axis in the Cartesian coordinate system. The third axis is, for example, the z-axis in the Cartesian coordinate system. The position information regarding the first axis is, for example, the x-axis coordinate. The position information regarding the second axis is, for example, the y-axis coordinate. The position information regarding the third axis is, for example, the z-axis coordinate.

[0053] The direction information includes information about the rotational position of the measurement object around a first axis (e.g., the x-axis), information about the rotational position of the measurement object around a second axis (e.g., the y-axis), and information about the rotational position of the measurement object around a third axis (e.g., the z-axis). In other words, the direction information is information that indicates the rotational position around a specific axis. In other words, the direction information is information that indicates the attitude or orientation of the measurement object.

[0054] The position acquisition unit 206 acquires position information regarding the first axis (x-axis) of the robot T1, position information regarding the second axis (y-axis) intersecting the first axis (x-axis), position information regarding the third axis (z-axis) intersecting the first axis (x-axis) and the second axis (y-axis), as well as information regarding the position in the rotation direction around the first axis (x-axis), information regarding the position in the rotation direction around the second axis (y-axis), and information regarding the position in the rotation direction around the third axis (z-axis) based on the light reception results from the light receiving unit 202. Details of the acquisition of position information and direction information will be described later.

[0055] The control unit 21 controls the other devices and components provided in the measuring device 1. The control unit 21 includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (Field-Programmable Gate Array), etc., and performs various calculations and information transmission and reception. The control unit 21 loads programs from the ROM and executes various controls in accordance with the loaded programs.

[0056] The control unit 21 and each device and component included in the measuring device 1 are connected by, for example, a signal line. The control unit 21 and each device and component included in the measuring device 1 may communicate with each other by short-range wireless communication using electromagnetic waves such as light or radio waves. The control unit 21 also performs various calculations.

[0057] The first imaging unit 22 captures images of at least some of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43). The first imaging unit 22 includes a four-segment PSD 12.

[0058] The communication unit 23 communicates with an external device. The external device is, for example, a control system that controls the robot T1 on which the reflecting element 41 is installed, and the second imaging unit 30. The communication unit 23 includes a transmission unit and a reception unit. The transmission unit transmits position information and direction information of the reflecting element 41 acquired by the position acquisition unit 206 included in the position measurement unit 20 to the control system. The communication unit 23 includes a communication interface (I / F) for communicating via a wireless network.

[0059] 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 for communication by the communication unit 23. In the fifth generation mobile communication system, frequency bands of 450 MHz to 6000 MHz and 24250 MHz to 52600 MHz are used.

[0060] The second imaging unit 30 captures an image of the marker 44. The second imaging unit 30 captures an image of the marker 44 using natural light or artificial light such as an incandescent light, fluorescent light, mercury lamp, LED, or strobe light reflected by the reflecting element 41. As described above, the marker 44 is disposed at a predetermined position relative to the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43). The second imaging unit 30 includes a stereo camera 3. Note that, in this embodiment, an example in which the second imaging unit 30 is provided separately from the measuring device 1 will be described, but this is not limiting. The second imaging unit 30 may be provided integrally with the measuring device 1.

[0061] The storage unit 24 stores various types of information. For example, reflective element arrangement information is stored in advance in the storage unit 24. The reflective element arrangement information is information that indicates the arrangement of each of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43). The arrangement is determined according to the positions at which the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are arranged on the target member 4.

[0062] The measuring device 1 irradiates the measurement light L1 onto each of three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) attached to the robot T1. The measuring device 1 receives the reflected light of the measurement light L1 reflected by each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). The measuring device 1 measures the position and rotational position of the robot T1 based on the reception results of the reflected light.

[0063] The stereo camera 3 estimates the position of the marker 44 by capturing an image of the marker 44. The stereo camera 3 estimates the position of the marker 44 with rough accuracy based on the parallax between the pair of cameras. The rough accuracy is, for example, an accuracy of about 100 mm.

[0064] The measurement device 1 uses measurement light L1 to scan a predetermined range based on the position of the marker 44 estimated by the stereo camera 3. Fig. 8 shows an example of scanning with measurement light L1. The estimated range R1 is a predetermined range based on the position of the marker 44 estimated by the stereo camera 3. The estimated range R1 includes the position of the marker 44 estimated by the stereo camera 3. The estimated range R1 is, for example, a rectangular range with one side approximately 100 mm long.

[0065] The measurement device 1 sets a predetermined range including the estimated range R1 as the scanning range R2. The scanning range R2 is a range scanned with the measurement light L1. The measurement device 1 performs scanning along the trajectory TR1. The trajectory TR1 is, for example, a wavy or spiral trajectory. As described above, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are disposed near the marker 44, and therefore the positions of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are included in the scanning range R2.

[0066] The measurement device 1 estimates the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) irradiated with the measurement light L1 using a position sensitive detector (PSD). The PSD detects the reflected light of the measurement light L1 reflected by each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0067] The measuring device 1 scans the measurement light L1 along a predetermined trajectory that can pass through three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). The trajectory is calculated based on the estimation results of the positions of the three reflecting elements by the PSD. The measuring device 1 measures the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) based on the light reception results of the reflected light of the scanning measurement light L1 reflected by each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). The measuring device 1 measures the position and rotational position of the robot T1 to which the target member 4 is attached based on the measurement results of the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0068] In this embodiment, the position of the robot T1 is the position of the target member 4 attached to the movable part of the robot T1. The position information indicating the position is information indicating the position of the target member 4 relative to a reference position. The reference position is a predetermined position in space where the target member 4 is placed.

[0069] Position information indicating the position of the target member 4 is represented by coordinates of a coordinate system (called a reference coordinate system) in the space in which the target member 4 is placed. The position information is represented, for example, by rectangular coordinates (X, Y, Z). A set of coordinates X, Y, and Z indicates a position in the rectangular coordinates (X, Y, Z). Note that coordinates X, Y, and Z may also be referred to as the distance in the X direction, the distance in the Y direction, and the distance in the Z direction, respectively.

[0070] The rotational position of the robot T1 is the rotational position of the movable part to which the target member 4 is attached. Information regarding the rotational position (referred to as "directional information") indicating the rotational position is represented by the rotational position around each of the three coordinate axes of the reference coordinate system. The rotational position around each coordinate axis is represented by an angle indicating the rotation. When the above position information is represented using rectangular coordinates, the directional information is represented by the rotational position around the coordinate axis of the rectangular coordinates. In other words, the directional information is represented by the position around the X-axis, the position around the Y-axis, and the position around the Z-axis. FIG. 9 shows an example of the rotational position around the coordinate axes when the position information is represented using rectangular coordinates. In FIG. 9, the position around the X-axis is represented by the rotation angle θX, the position around the Y-axis is represented by the rotation angle θY, and the position around the Z-axis is represented by the rotation angle θZ. The rotational position around an axis may also be referred to as a direction, an attitude, or the like.

[0071] The measuring device 1 transmits the measured position information and direction information to a control system (not shown) of the robot T1. The reference position and coordinate system are shared in advance between the measuring device 1 and the control system. The control system can obtain the position of the robot T1 based on the position information received from the measuring device 1, and can therefore calibrate the robot T1 with high accuracy.

[0072] In this embodiment, an example will be described in which a target member 4 including three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is attached to the robot T1, that is, three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the robot T1, but this is not limiting. It is sufficient that at least three or more reflective elements are attached to the robot T1. For example, four or more reflective elements may be attached to the robot T1.

[0073] Next, the measurement process, which is a process for acquiring position information and direction information by the measuring device 1, will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of the measurement process according to this embodiment. The measurement process is executed by the control unit 21. Note that in this embodiment, the robot T1 does not move while the measuring device 1 is performing the measurement process. In other words, the position and posture of the robot T1 do not change while the measuring device 1 is performing the measurement process.

[0074] The control unit 21 executes a rough search (step S10). Details of the rough search process will now be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of the rough search process according to this embodiment.

[0075] The control unit 21 uses the second imaging unit 30 to capture an image of the marker 44 (step S110). The control unit 21 controls the second imaging unit 30 via the communication unit 23. The second imaging unit 30 is controlled by the control unit 21 to capture an image of the marker 44 using the stereo camera 3.

[0076] The stereo camera 3 captures an image of the field of view in the direction in which the stereo camera 3 is pointed, using each of the pair of cameras. Here, it is assumed that the stereo camera 3 is previously pointed in the direction in which the target member 4 is arranged.

[0077] The stereo camera 3 generates a high-contrast image by image processing from the images captured by each of the pair of cameras. The high-contrast image is an image with higher contrast than the image before the image processing. As an example, the stereo camera 3 determines an area corresponding to the image of the marker 44 from the entire area of ​​the high-contrast image based on artificial intelligence (AI) (also called segmentation). Various types of machine learning may be used as the AI. The stereo camera 3 determines an area corresponding to the image of the marker 44 for each of the images captured by each of the pair of cameras.

[0078] The stereo camera 3 determines the position of the marker 44 in the image based on the determined region. The stereo camera 3 determines the position of the marker 44 in the image as two-dimensional coordinates in the image. The stereo camera 3 determines the position of the marker 44 in the image for each of the images captured by each of the pair of cameras. The stereo camera 3 estimates the position of the marker 44 based on the position of the marker 44 in the image for each of the images captured by each of the pair of cameras and the parallax between the pair of cameras (step S120). The position of the marker 44 is the position in space where the target member 4 is placed, as described above.

[0079] The stereo camera 3 transmits marker position information, which is position information indicating the estimated position of the marker 44, to the control unit 21 via the communication unit 23 of the measurement device 1 (step S130). The control unit 21 acquires the marker position information from the stereo camera 3 via the communication unit 23. Based on the acquired marker position information, the control unit 21 controls the irradiation direction driving unit 204 to direct the irradiation direction of the measurement light toward the position of the marker 44 (step S140). Here, the control unit 21 controls the irradiation direction driving unit 204 based on the marker position information, thereby directing the irradiation direction of the measurement light toward the position of the marker 44.

[0080] In step S120, if multiple markers 44 are arranged in the field of view in the direction in which the stereo camera 3 is pointed, the stereo camera 3 may estimate the position of each of the multiple markers 44. In this case, the stereo camera 3 may transmit marker position information for each of the markers 44 whose position has been estimated to the measurement device 1.

[0081] In step S120, an example in which AI is used to determine the image of the marker 44 has been described, but this is not limiting. Template matching may also be used to determine the image of the marker 44.

[0082] Although an example has been described in which the position of the marker 44 is estimated by the stereo camera 3 and transmitted as marker position information to the measurement device 1, this is not limiting. At least one of the process of determining an area corresponding to the image of the marker 44 and the process of estimating the position of the marker 44 based on the parallax of the pair of cameras may be executed by the control unit 21. Furthermore, when the measurement device 1 is equipped with the stereo camera 3, the process of determining an area corresponding to the image of the marker 44 and the process of estimating the position of the marker 44 based on the parallax of the pair of cameras are executed by the control unit 21.

[0083] Returning to Fig. 10, the description of the position measurement process will be continued. The control unit 21 executes fine search processing (step S20). The fine search is a search that provides higher accuracy in position measurement compared to the rough search described above. The fine search may also be a search with a narrower search range compared to the rough search. Details of the fine search processing will now be described with reference to Fig. 12. Fig. 12 is a diagram showing an example of the fine search processing according to this embodiment.

[0084] The control unit 21 performs an area scan (step S210). Here, as shown in FIG. 8 , the control unit 21 scans a predetermined range based on the position of the marker 44 estimated by the stereo camera 3 with the measurement light L1. The control unit 21 performs the area scan by controlling the irradiation direction driving unit 204 and the first imaging unit 22. The control unit 21 estimates the position of the center of the reflective element based on the result of the area scan (step S220).

[0085] Details of area scanning will now be described with reference to FIGS. 13 to 22. FIG. 13 is a diagram showing an example of the trajectory of the measurement light L1 in area scanning according to this embodiment. In FIG. 13, the trajectory of the measurement light L1 is a spiral trajectory. In FIG. 13, the predetermined range for area scanning is indicated by azimuth and elevation. Azimuth indicates the horizontal position (azimuth angle). Elevation indicates the vertical direction (elevation angle). The estimation range R11 indicates a predetermined range based on the position of the marker 44 estimated by the stereo camera 3. The estimation range R11 is a rectangular range with sides of 300 mm in the field of view of the four-segment PSD 12 when the distance between the measurement device 1 and the target member 4 is 10 m.

[0086] The control unit 21 scans a predetermined range including the estimated range R11 with the measurement light L1. The control unit 21 scans the predetermined range with the measurement light L1 along a spiral trajectory. The scanning may be performed from the center of the spiral toward the outside, or from the outside toward the center of the spiral. Point P11 indicates the current irradiation position of the measurement light L1.

[0087] 13, as an example, one reflective element A11 is located within the estimation range R11. For the sake of explanation, consider a case where only one of three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is attached to the target member 4. The reflective element A11 is that one reflective element.

[0088] The four-segment PSD 12 detects the measurement light L1 reflected by the reflecting element A11. Fig. 14 shows an example of the measurement light L1 being irradiated onto the reflecting element A11 while being scanned along a spiral trajectory. As shown in Fig. 14, the measurement light L1 is irradiated intermittently every 0.1 ms, for example. In other words, the measurement light L1 is irradiated at 10 kHz.

[0089] In the area scan, the measurement light L1 is irradiated so that the four-segment PSD 12 detects the reflected light from the reflecting element, and the optical comb interferometer 11 does not measure the distance.

[0090] The four-segment PSD 12 detects the reflected light of the measurement light L1, and the optical path of the measurement light L1 coincides with the optical path of the reflected light. Therefore, the direction of irradiation of the measurement light L1 coincides with the direction of the field of view of the four-segment PSD 12. In other words, the direction of the field of view of the four-segment PSD 12 changes as the direction of irradiation of the measurement light L1 changes due to area scanning.

[0091] 15 is a diagram showing an example of how the image of the reflective element moves within the field of view of the four-segment PSD 12 during scanning according to this embodiment. Images A121 and A122 each show how the image of the reflective element A11 detected by the four-segment PSD 12 moves within the field of view of the four-segment PSD 12 when scanning is performed along a spiral trajectory.

[0092] In order to estimate the position of the reflecting element A11, it is necessary to determine the direction of the field of view of the four-segment PSD 12 when the image of the reflecting element A11 is detected at the center PC1 of the field of view of the four-segment PSD 12. As described above, the direction of the field of view of the four-segment PSD 12 is the irradiation direction of the measurement light L1. The irradiation direction of the measurement light L1 is measured by the irradiation direction measurement unit 205 as the rotation angle of the gimbal unit.

[0093] Figures 16, 17, and 18 show the relationship between the irradiation direction of the measurement light L1 and the position of the reflective element A11 within the field of view of the four-segment PSD 12 obtained as a result of scanning. Figure 16 shows the horizontal position of the reflective element A11 within the field of view of the four-segment PSD 12 relative to the irradiation direction in the azimuth direction of the measurement light L1. Figure 17 shows the vertical position of the reflective element A11 within the field of view of the four-segment PSD 12 relative to the irradiation direction in the elevation direction of the measurement light L1. Figure 18 shows the position of the reflective element A11 within the field of view of the four-segment PSD 12 obtained as a result of scanning.

[0094] From the plots of the position of reflective element A11 within the field of view of the four-segment PSD 12 shown in Figures 16 and 17, the direction of the field of view of the four-segment PSD 12 when the image of reflective element A11 is detected at the center PC1 of the field of view of the four-segment PSD 12 can be determined.

[0095] The control unit 21 approximates the plot of the position of the reflective element A11 within the field of view of the four-segment PSD 12 shown in Figure 16 using a straight line based on the least squares method. The line F1 indicates the line obtained by this approximation. The control unit 21 determines the azimuth direction indicated by the intersection of the line F1 and the axis AX1 as the irradiation direction of the measurement light L1 in the azimuth direction when the image of the reflective element A11 is detected at the center PC1 of the field of view of the four-segment PSD 12. The axis AX1 is the horizontal axis of the coordinate plane shown in Figure 16 and indicates the horizontal position of the center PC1 of the field of view of the four-segment PSD 12.

[0096] Similarly, the control unit 21 approximates the plot of the position of the reflective element A11 within the field of view of the four-segment PSD 12 shown in Figure 17 by a straight line based on the least squares method. Line F2 represents the line obtained by this approximation. The control unit 21 determines the elevation direction indicated by the intersection of line F2 and axis AY1 as the elevation direction irradiation direction of the measurement light L1 when the image of the reflective element A11 is detected at the center PC1 of the field of view of the four-segment PSD 12. The axis AY1 is the horizontal axis of the coordinate plane shown in Figure 17 and represents the vertical position of the center PC1 of the field of view of the four-segment PSD 12.

[0097] As described above, the control unit 21 determines the irradiation direction in the azimuth direction and the irradiation direction in the elevation direction of the measurement light L1 when the image of the reflective element A11 is detected at the center PC1 of the field of view of the four-segment PSD 12. The control unit 21 determines the determined irradiation direction of the measurement light L1 as the center position of the reflective element A11.

[0098] Next, a case where the position of the center of each of a plurality of reflecting elements is estimated will be described with reference to Figs. 19, 20, and 21. Fig. 19 is a diagram showing an example of area scanning according to this embodiment. An estimation range R12 indicates a predetermined range based on the position of the marker 44 estimated by the stereo camera 3. Comparing Fig. 19 with Fig. 13, Fig. 19 is similar to Fig. 13 except that three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) are located within the estimation range R12.

[0099] 20 and 21 show the relationship between the irradiation direction of the measurement light L1 and the positions of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) within the field of view of the four-segment PSD 12, obtained as a result of scanning. Fig. 20 shows the horizontal positions of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) within the field of view of the four-segment PSD 12 relative to the irradiation direction of the measurement light L1 in the azimuth direction. Fig. 21 shows the vertical positions of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) within the field of view of the four-segment PSD 12 relative to the irradiation direction of the measurement light L1 in the elevation direction.

[0100] 20 and 21 , when multiple reflective elements are located within estimation range R12, the multiple reflective elements are detected without distinguishing between them by four-segment PSD 12. Control unit 21 classifies the detection results as to which of the multiple reflective elements they represent, based on the time at which each reflective element was detected.

[0101] When scanning is performed along a predetermined trajectory such as a spiral trajectory, the time from when a certain reflective element is detected until the next time that reflective element is detected is predetermined. Based on this time, the control unit 21 classifies the detection results as the detection result of one reflective element. In the examples shown in Figures 20 and 21, the control unit 21 classifies the detection result as the detection result of one of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) based on the time from when a certain reflective element is detected until the next time that reflective element is detected when scanning is performed along a spiral trajectory.

[0102] For each of the classified detection results shown in Fig. 20, the control unit 21 approximates the plots indicated by the detection results with a straight line based on the least squares method. In Fig. 20, the straight line F11 indicates the straight line obtained by approximating the plots classified as the detection results of the reflective element 41. The straight line F12 indicates the straight line obtained by approximating the plots classified as the detection results of the reflective element 42. The straight line F13 indicates the straight line obtained by approximating the plots classified as the detection results of the reflective element A23.

[0103] The control unit 21 determines the azimuth direction indicated by the intersection of the line F11 and the axis AX2 as the irradiation direction of the measuring light L1 in the azimuth direction when the image of the reflecting element 41 is detected at the center PC1 of the field of view of the four-segment PSD 12. The control unit 21 determines the azimuth direction indicated by the intersection of the line F12 and the axis AX2 as the irradiation direction of the measuring light L1 in the azimuth direction when the image of the reflecting element 42 is detected at the center PC1 of the field of view of the four-segment PSD 12. The control unit 21 determines the azimuth direction indicated by the intersection of the line F13 and the axis AX2 as the irradiation direction of the measuring light L1 in the azimuth direction when the image of the reflecting element A23 is detected at the center PC1 of the field of view of the four-segment PSD 12. The axis AX2 is the horizontal axis of the coordinate plane shown in FIG. 20 and indicates the horizontal position of the center PC1 of the field of view of the four-segment PSD 12.

[0104] Similarly, for each of the classified detection results shown in Fig. 21, the control unit 21 approximates the plots indicated by the detection results with a straight line based on the least squares method. In Fig. 21, the line F21 indicates the line obtained by approximating the plots classified as the detection results of the reflective element 41. The line F22 indicates the line obtained by approximating the plots classified as the detection results of the reflective element 42. The line F23 indicates the line obtained by approximating the plots classified as the detection results of the reflective element A23.

[0105] The control unit 21 determines the elevation direction indicated by the intersection of the line F21 and the axis AY2 as the elevation direction irradiation direction of the measuring light L1 when the image of the reflecting element 41 is detected at the center PC1 of the field of view of the four-segment PSD 12. The control unit 21 determines the elevation direction indicated by the intersection of the line F22 and the axis AY2 as the elevation direction irradiation direction of the measuring light L1 when the image of the reflecting element 42 is detected at the center PC1 of the field of view of the four-segment PSD 12. The control unit 21 determines the elevation direction indicated by the intersection of the line F23 and the axis AY2 as the elevation direction irradiation direction of the measuring light L1 when the image of the reflecting element A23 is detected at the center PC1 of the field of view of the four-segment PSD 12. The axis AY2 is the horizontal axis of the coordinate plane shown in FIG. 21 and indicates the vertical position of the center PC1 of the field of view of the four-segment PSD 12.

[0106] In this embodiment, an example has been described in which the control unit 21 approximates the detection results of the four-segment PSD 12 with a straight line based on the least squares method, but the present invention is not limited to this. The control unit 21 may use other fitting methods when approximating the detection results of the four-segment PSD 12 with a straight line.

[0107] In this embodiment, an example in which the trajectory of the measurement light L1 in the area scan is a spiral trajectory has been described, but this is not limited thereto. The trajectory of the measurement light L1 in the area scan may be a wavy line. Fig. 22 shows an example of area scan in which the trajectory of the measurement light L1 is a wavy line. Comparing Fig. 22 with Fig. 19, Fig. 22 is the same as Fig. 19 except that the trajectory of the measurement light L1 is a wavy line.

[0108] Returning to Fig. 10, the description of the measurement process will continue. The control unit 21 acquires the position and orientation (step S30). Here, details of the position and orientation acquisition process, which is the process of acquiring the position and orientation, will be described with reference to Fig. 23. Fig. 23 is a diagram showing an example of the position and orientation acquisition process according to this embodiment.

[0109] The control unit 21 calculates a circular trajectory TC1 based on the positions of the centers of the reflecting elements (step S310). The positions of the centers of the reflecting elements are the positions of the centers of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) estimated in the fine search process (step S20). The circular trajectory TC1 is an example of a predetermined trajectory that can pass through the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0110] The process of calculating the circular orbit TC1 may be performed by a control device separate from the measurement device 1. The control device calculates the trajectory (for example, the circular orbit TC1) of the measurement light L1 passing through three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) based on the measurement result acquired by the position acquisition unit 206, which is the measurement result of the measurement light L1 scanned along a spiral trajectory within a predetermined range. The control unit 21 is an example of a control device that controls the measurement device 1. That is, in this embodiment, the measurement device 1 includes the control device as the control unit 21.

[0111] Here, two methods for calculating the circular orbit TC1 will be described with reference to Fig. 24. Fig. 24 is a diagram showing an example of a method for calculating the circular orbit TC1 according to this embodiment. The first method for calculating the circular orbit TC1 is to extend the equation of a circle on a two-dimensional plane to the equation of a circle in three-dimensional space.

[0112] 24, positions P1, P2, and P3 indicate the positions of the centers of reflecting element 41, reflecting element 42, and reflecting element 43, respectively. A circular orbit TC1 indicates a circle that passes through positions P1, P2, and P3.

[0113] The equation of a circle in three-dimensional space is given by Equation (1). In the explanation of Fig. 24, three-dimensional vectors are indicated by adding an arrow symbol to a letter, such as "X→".

[0114]

[0115] Here, the three-dimensional vector X→ indicates the position of a point on the circular orbit TC1 at any time. The three-dimensional vector A→ indicates the position of the center CP1 of the circle indicated by the circular orbit TC1. r indicates the radius of the circle indicated by the circular orbit TC1. The three-dimensional vector u→ indicates a unit vector whose direction is from the center CP1 to the position P1. The three-dimensional vector v→ indicates a unit vector that is orthogonal to the three-dimensional vector u→ in the two-dimensional plane π that includes the positions P1, P2, and P3. Note that there are two types of unit vectors that are orthogonal to the three-dimensional vector u→ in the two-dimensional plane π, and the three-dimensional vector v→ may be either of these two unit vectors. t indicates a parameter corresponding to time.

[0116] In the example shown in FIG. 24 , the three-dimensional vector A→ is calculated by solving simultaneous equations with the components of the three-dimensional vector A→ as variables, based on the following three conditions. The first condition is that the center CP1 is located on the two-dimensional plane π. The second condition is that a vector having a start point at position P1 and an end point at position P3 is orthogonal to a vector j→ having a start point at the midpoint between positions P1 and P3 and an end point at the center CP1. The third condition is that a vector having a start point at position P1 and an end point at position P2 is orthogonal to a vector k→ having a start point at the midpoint between positions P1 and P2 and an end point at the center CP1.

[0117] The second method for calculating the circular orbit TC1 is a method using quaternions (also called quaternions). In the method using quaternions, the coordinates of the point to be rotated are made to correspond to a quaternion p, and the coordinates of the point after rotation are made to correspond to a quaternion p'. The relationship between the quaternion p and the quaternion p' is expressed by Equation (2).

[0118]

[0119] Here, quaternion q indicates the rotation axis and the rotation amount. Quaternion q-1 indicates the quaternion that is the conjugate of quaternion q. The three-dimensional vector s→ indicating the coordinates of a point on the trajectory at time t is expressed as in equation (3).

[0120]

[0121] Here, the three-dimensional vector A→ is a three-dimensional vector indicating the coordinates of the center of the circular orbit TC1, and the three-dimensional vector p′→ is a three-dimensional vector corresponding to the quaternion p′.

[0122] The method using quaternions can reduce the computational load for calculating rotation in three-dimensional space compared to the method using three-dimensional vectors, and therefore the method using quaternions is suitable for the process of calculating the circular orbit TC1 based on the position of the center of the reflective element.

[0123] 23 , the description of the position and orientation acquisition process will be continued. The control unit 21 acquires the positions of the three reflecting elements (the reflecting elements 41, 42, and 43) by irradiating the measurement light L1 along the calculated circular trajectory TC1 (step S320). The control unit 21 controls the irradiation unit 201 and the irradiation direction driving unit 204 to acquire the positions of the three reflecting elements (the reflecting elements 41, 42, and 43).

[0124] The control unit 21 acquires the position of the robot T1 (step S330) based on the positions of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43).

[0125] Here, the position of the robot T1 is the reference position of the target member 4 attached to the movable part of the robot T1. The reference position of the target member 4 is, for example, a predetermined position of a predetermined part of the target member 4. The predetermined part of the target member 4 is, for example, a part of the target member 4 that is close to the movable part of the robot T1. The predetermined part of the target member 4 is, for example, an installation member 45 described below. The predetermined position of the predetermined part of the target member 4 is, for example, the center position of the surface of the installation member 45 that contacts the movable part of the robot T1, or the center position of an installation surface 46 described below.

[0126] When the position of the movable part of the robot T1 moves, the reference position of the target member 4 attached to the movable part also moves. The position information of the robot T1 is information that indicates the reference position of the target member 4 attached to the movable part of the robot T1.

[0127] There is a predetermined positional relationship between the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) and the reference position of the target member 4. The control unit 21 calculates the reference position of the target member 4 based on the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). In other words, the control unit 21 acquires position information of the robot T1 based on position information of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0128] Here, the irradiation unit 201 can scan the measurement light L1 along a predetermined orbit (circular orbit TC1) that can pass through three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). Furthermore, the irradiation unit 201 sequentially irradiates each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) with the measurement light L1 while scanning along the circular orbit TC1 at a predetermined speed or faster. In other words, the irradiation unit 201 can sequentially irradiate each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) with the measurement light L1 while scanning along the predetermined orbit at a predetermined speed or faster.

[0129] In order to obtain the position information and rotational position information of the robot T1, which is the measurement target, it is necessary to obtain the position information of at least three reflective elements attached to the robot T1. In order to obtain the position information and rotational position information of the robot T1 at a certain time, it is required that the time difference between obtaining the position information of each of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is as small as possible (i.e., the position information of each of the three reflective elements is obtained as close to the same time as possible).

[0130] In the measurement apparatus 1 according to this embodiment, the irradiation unit 201 includes one optical comb interferometer 11. In the measurement apparatus 1 according to this embodiment, the irradiation unit 201 sequentially irradiates the measurement light L1 onto each of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) while scanning along a predetermined trajectory at a predetermined speed or faster. Therefore, even in the measurement apparatus 1 according to this embodiment, even if it includes only one optical comb interferometer 11, it is possible to reduce the time difference between when the position information of each of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) is acquired.

[0131] As described above, the circular orbit TC1 is a trajectory calculated based on the detection results (fine search results) of the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) by the four-segment PSD 12. The position detection results by the four-segment PSD 12 are the imaging results by the first imaging unit 22. In other words, the circular orbit TC1 is a trajectory calculated based on the imaging results of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) by the first imaging unit 22. Also, as described above, the measurement light L1 is irradiated along the circular orbit TC1. Therefore, the measurement light L1 is irradiated based on the imaging results of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) by the first imaging unit 22.

[0132] In this embodiment, as described above, in order to perform a fine search using the four-segment PSD 12, a rough search is performed in advance to capture images of the marker 44 using the stereo camera 3. That is, the fine search using the first imaging unit 22 is performed based on the results of capturing images of the marker 44 using the second imaging unit 30. Therefore, the measurement light L1 is irradiated based on the results of capturing images using the second imaging unit 30.

[0133] In this embodiment, an example has been described in which a circular orbit TC1 is calculated as the predetermined orbit for the irradiation unit 201 to scan the measurement light L1 along a predetermined orbit that can pass through three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). The circular orbit TC1 is an example of an orbit in which the change in acceleration of the change in the irradiation direction of the measurement light L1 is small. That is, in this embodiment, the position acquisition unit 206 calculates an orbit in which the change in acceleration of the change in the irradiation direction of the measurement light L1 is small as the predetermined orbit so that the irradiation unit 201 scans along the predetermined orbit. Another example of an orbit in which the change in acceleration of the change in the irradiation direction of the measurement light L1 is small is an elliptical orbit. In this case, the position acquisition unit 206 calculates an elliptical orbit as the predetermined orbit in step S310. Another example of an orbit in which the change in acceleration of the change in the irradiation direction of the measurement light L1 is small is a Lissajous orbit. In this case, the position acquisition unit 206 calculates a Lissajous trajectory as the predetermined trajectory in step S310.

[0134] A predetermined trajectory that can pass through three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) that reduces the change in acceleration due to the change in the irradiation direction of the measurement light L1 reduces the load on the gimbal portion of the PMA 14 included in the irradiation direction driving unit 204 compared to a trajectory that does not reduce the change in acceleration.

[0135] In addition, a polygonal trajectory may be calculated as the predetermined trajectory that can pass through the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). In order to reduce the change in acceleration due to the change in the irradiation direction of the measurement light L1, it is preferable to calculate a polygon having the same number of vertices as the number of reflecting elements as the predetermined trajectory. Furthermore, a trajectory other than a circular trajectory, an elliptical trajectory, or a polygonal trajectory (such as a curved trajectory) may be calculated as the predetermined trajectory for scanning the measurement light L1. Even in this case, it is preferable to calculate a trajectory that reduces the change in acceleration due to the change in the irradiation direction of the measurement light L1.

[0136] The control unit 21 acquires the posture of the robot T1 based on the acquired positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) (step S340).

[0137] Here, the posture of the robot T1 refers to the rotational position (posture, orientation) of the target member 4 attached to the movable part of the robot T1. The rotational position of the target member 4 is, for example, the rotational position of a portion of the target member 4 that is close to the movable part of the robot T1. The rotational position of the target member 4 is, for example, the rotational position of an installation member 45 (described later) or the rotational position of an installation surface 46 (described later).

[0138] When the rotational position of the movable part of the robot T1 changes, the rotational position of the target member 4 attached to the movable part also changes. The direction information of the robot T1 is information that indicates the direction information of the target member 4 attached to the movable part of the robot T1.

[0139] There is a predetermined relationship between the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) and the position in the rotational direction of the target member 4. The control unit 21 calculates the position in the rotational direction of the target member 4 based on the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). In other words, the control unit 21 obtains direction information of the robot T1 (the posture or orientation of the robot T1) based on the position information of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43).

[0140] 25 to 27, the posture acquisition process, which is a process for acquiring the posture of the robot T1, will be described. In this embodiment, a case where three reflecting elements are attached to the robot T1 is described, but in the description of the posture acquisition process, an example where four reflecting elements are attached to the robot T1 will be described. The posture acquisition process when three reflecting elements are attached to the robot T1 is similar to the posture acquisition process when four reflecting elements are attached to the robot T1.

[0141] 25 is a diagram showing an example of an outline of the posture acquisition process according to this embodiment. As an example, the posture acquisition process involves fitting a known coordinate system to multiple reflecting elements. Fitting a known coordinate system to multiple reflecting elements means superimposing multiple points whose coordinates in the known coordinate system are known on the centers of the multiple reflecting elements by rotating and / or translating each of the points. In the posture acquisition process, the posture (direction) of the robot T1 to which the multiple reflecting elements are attached is estimated based on the known coordinate system fitted to the multiple reflecting elements.

[0142] Here, it is assumed that the relationship between the positions of the centers of the multiple reflective elements is known. The fact that the relationship between the positions of the centers of the multiple reflective elements is known corresponds to the fact that the relationship between the positions of the centers of the multiple reflective elements is known when the multiple reflective elements are attached to the target member. As described above, the relationship between the positions of the centers of the multiple reflective elements when the multiple reflective elements are attached to the target member is stored in advance in the storage unit 24 as reflective element arrangement information. Note that the number of points whose coordinates in the known coordinate system are known is equal to the number of the multiple reflective elements.

[0143] In FIG. 25 , points xp, yp, zp, and op respectively indicate the positions of the centers of the four reflecting elements. In the example shown in FIG. 25 , a known coordinate system C0 is shown as the known coordinate system. As an example, the known coordinate system C0 is a Cartesian coordinate system with point o1 as its origin. Point x1 is a point on the x-axis of the known coordinate system C0, and the x-coordinate of point x1 is coordinate K1. Point y1 is a point on the y-axis of the known coordinate system C0, and the y-coordinate of point y1 is coordinate K2. Point z1 is a point on the z-axis of the known coordinate system C0, and the z-coordinate of point z1 is coordinate K3. In the known coordinate system C0, coordinate K1 is equal to the length of the side connecting point xp and point op, coordinate K2 is equal to the length of the side connecting point yp and point op, and coordinate K3 is equal to the length of the side connecting point zp and point op. As the known coordinate system C0, for example, the above-mentioned reference coordinate system (the coordinate system in the space in which the target member 4 is placed) may be selected.

[0144] In the orientation acquisition process, points x1, y1, z1, and o1 are rotated and / or translated to overlap points xp, yp, zp, and op, respectively. During the rotation and / or translation process, the relative positions of points x1, y1, z1, and o1 do not change. In other words, the rotation and / or translation is common to multiple points whose coordinates in a known coordinate system are known.

[0145] 25, as an example, the length of the side connecting point xp and point op, the length of the side connecting point yp and point op, and the length of the side connecting point zp and point op are all different. Therefore, coordinates K1, K2, and K3 are all different. Therefore, in the example shown in FIG. 25, when points x1, y1, z1, and o1 are respectively superimposed on points xp, yp, zp, and op by rotation and / or translation operations, the superimposition (fitting) method is unique.

[0146] In order to fit a known coordinate system to a plurality of reflecting elements, it is necessary to calculate a coordinate transformation indicating rotation and / or translation. In this embodiment, as an example, a matrix indicating rotation among matrices indicating coordinate transformation is calculated based on principal component analysis.

[0147] Consider three-dimensional vectors Ai (i = 1, 2, ..., N: N is the number of points whose coordinates in the known coordinate system are known, and is 4 if four reflecting elements are attached to robot T1), each indicating the position of a plurality of reflecting elements (i = 1, 2, ..., N: N is the number of reflecting elements, and is 4 if four reflecting elements are attached to robot T1). Note that if three reflecting elements are attached to robot T1, N is 3. A matrix R indicating rotation can be calculated by performing singular value decomposition on matrix H shown in equation (4).

[0148]

[0149] Here, matrix A is a matrix in which three-dimensional vectors Ai are arranged as columns. Matrix A indicates a set of points indicated by three-dimensional vectors Ai. Matrix B is a matrix in which three-dimensional vectors Bi are arranged as columns. Matrix B indicates a set of points indicated by three-dimensional vectors Bi. Matrix centroidA is a matrix in which three-dimensional vectors indicating the positions of the centers of gravity of multiple points whose coordinates in a known coordinate system are known are arranged as columns, as shown in equation (5).

[0150]

[0151] As shown in equation (6), the matrix centroidB is a matrix in which three-dimensional vectors indicating the positions of the centers of gravity of the positions of a plurality of reflecting elements are arranged as columns.

[0152]

[0153] As shown in equation (4), in matrix H, the matrix obtained by subtracting matrix centroidA from matrix A is multiplied by the transpose of the matrix obtained by subtracting matrix centroidB from matrix B. Therefore, by considering matrix H, the problem of overlapping a set of points indicated by matrix A with a set of points indicated by matrix B can be reduced to the problem of overlapping by rotation, after subtracting in advance the components that will be overlapped by translation. To calculate the rotation, singular value decomposition is performed on matrix H, as shown in equation (7).

[0154]

[0155] Here, the singular value decomposition for a matrix E is defined by equations (8) and (9).

[0156]

[0157]

[0158] In equations (8) and (9), matrix U is a left singular vector matrix, matrix V is a right singular vector matrix, and matrix S is a matrix having singular values ​​on the diagonal components.

[0159] Using matrix V obtained by performing singular value decomposition on matrix H as in equation (7) and matrix U, matrix R indicating the rotation when a set of points indicated by matrix A and a set of points indicated by matrix B are superimposed is calculated as in equation (10).

[0160]

[0161] Next, a matrix t indicating a translation is calculated. Matrices A and B are expressed as shown in equation (11) using a matrix R indicating a rotation and a matrix t indicating a translation.

[0162]

[0163] Using the above-described matrix centroidA and matrix centroidB, equation (12) is obtained from equation (11).

[0164]

[0165] From equation (12), the matrix t indicating the translation is calculated as shown in equation (13) using the matrix R indicating the rotation, the matrix centroidA, and the matrix centroidB.

[0166]

[0167] 26 shows an example of a process for superimposing four points, x1, y1, z1, and o1, whose coordinates in the known coordinate system C0 are known, on the positions of four reflecting elements. Points xp, yp, zp, and op indicate the positions of the four reflecting elements, respectively. Rotation and / or translation is performed on points x1, y1, z1, and o1 so that points x1, y1, z1, and o1 are superimposed on points xp, yp, zp, and op, respectively. By superimposing points x1, y1, z1, and o1 on points xp, yp, zp, and op, respectively, the known coordinate system C0 and the target coordinate system C1 are associated with each other.

[0168] Simply measuring the position of each of the multiple reflecting elements does not allow each of the multiple reflecting elements to be identified. After fitting the known coordinate system C0 to the multiple reflecting elements, each of the multiple reflecting elements is associated with each of the multiple points whose coordinates in the known coordinate system C0 are known. Therefore, after fitting the known coordinate system C0 to the multiple reflecting elements, each of the multiple reflecting elements can be identified.

[0169] Furthermore, after the known coordinate system C0 has been fitted to the multiple reflecting elements, various calculations can be performed based on the known coordinate system C0. The various calculations include, for example, calculation of the position of the tool center point of the robot T1, various POST processes, etc. For example, the calculation of the position of the tool center point of the robot T1 is performed by the position acquisition unit 206. That is, the position acquisition unit 206 acquires information related to the tool center point of the robot T1.

[0170] In the above-described processing, the length of the side connecting points xp and op, the length of the side connecting points yp and op, and the length of the side connecting points zp and op are assumed to be different from one another, and a case has been described in which a method of superimposing a known coordinate system on a plurality of reflective elements is unique, but this is not limiting. The length of the side connecting points xp and op, the length of the side connecting points yp and op, and the length of the side connecting points zp and op may be equal to one another.

[0171] If the lengths of the sides connecting points xp and op, the lengths of the sides connecting points yp and op, and the lengths of the sides connecting points zp and op are equal, the method of superimposing the known coordinate system onto the multiple reflective elements will not be unique.Since the method of superimposing the known coordinate system onto the multiple reflective elements will not be unique, some of the multiple reflective elements will be indistinguishable, and therefore it may not be possible to uniquely determine the orientation of the target member on which the multiple reflective elements are arranged.

[0172] For example, if four reflective elements are placed at positions corresponding to the vertices of a regular tetrahedron, multiple points whose coordinates in a known coordinate system are known will have coordinates that correspond to the vertices of the regular tetrahedron. When a regular tetrahedron whose vertices are multiple points whose coordinates in a known coordinate system are known is superimposed on a regular tetrahedron whose vertices are the centers of four reflective elements, the method of superimposition is not unique, and therefore the orientation of the target member on which the four reflective elements are placed cannot be uniquely determined. Note that even if the orientation of the target member cannot be uniquely determined, it can be determined that the orientation of the target member is one of multiple orientations.

[0173] 26 shows errors in measuring the position of the target member 4 by the measuring device 1. These errors are errors with respect to the coordinates of four points x1, y1, z1, and o1 whose coordinates in the known coordinate system C0 are known, that is, the coordinates of points xp, yp, zp, and op measured by the measuring device 1.

[0174] 26 shows error vectors, the magnitude of which indicates the error, for each of points xp, yp, zp, and op. Error vector dx→ indicates the error of the position of point x1 relative to the position of point xp. Error vector dy→ indicates the error of the position of point y1 relative to the position of point yp. Error vector dz→ indicates the error of the position of point z1 relative to the position of point zp. Error vector do→ indicates the error of the position of point o1 relative to the position of point op.

[0175] Figure 27 shows a graph indicating the magnitude of the error vector. According to Figure 27, the magnitude of the error vector is approximately 0.6 µm. If the accuracy of the measurement of the position of the target member 4 by the measuring device 1 is approximately 1 µm, the accuracy of the measurement of the position and orientation of the target member 4 will be approximately 0.6 µm. If the accuracy of the measurement of the position of the target member 4 by the measuring device 1 is approximately 1 nm, the accuracy of the measurement of the position and orientation of the target member 4 is expected to be approximately sub-nanometer.

[0176] Returning to Fig. 23, the description of the position and orientation acquisition process will be continued. The control unit 21 outputs the estimated position and orientation (step S350). The control unit 21 outputs position information indicating the estimated position and direction information indicating the estimated orientation of the robot T1. The control unit 21 outputs this by, for example, transmitting it to the control system of the robot T1. With this, the control unit 21 ends the position and orientation acquisition process.

[0177] In the present embodiment, an example has been described in which the position and posture of the robot T1 do not change while the measurement device 1 performs the measurement process, but this is not limited to this. The position and posture of the robot T1 may change while the measurement device 1 performs the measurement process. If the position and posture of the robot T1 change during the measurement process, the positions and postures of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) may change between the times when the measurement light L1 is sequentially irradiated onto the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43).

[0178] When the position and posture of the robot T1 change during the measurement process, the measurement device 1 may estimate the positions of the three reflecting elements (the reflecting elements 41, 42, and 43) based on, for example, the difference between the times when the measurement light L1 is irradiated onto each of the three reflecting elements (the reflecting elements 41, 42, and 43). The measurement device 1 may estimate the positions of the three reflecting elements (the reflecting elements 41, 42, and 43) at a certain time based on, for example, the difference between the time when the measurement light L1 is irradiated onto the reflecting element 41 and the time when the measurement light L1 is irradiated onto the reflecting element 42, and the difference between the time when the measurement light L1 is irradiated onto the reflecting element 42 and the time when the measurement light L1 is irradiated onto the reflecting element 43. The measurement device 1 may acquire the position and posture of the robot T1 based on the results of estimating the positions of the three reflecting elements (the reflecting elements 41, 42, and 43) at a certain time.

[0179] The measurement device 1 may use a measured value for the position of one of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) and an estimated value for the positions of the remaining two. For example, if the time when the position of the reflecting element 42 is measured (i.e., the time when the measurement light L1 is irradiated onto the reflecting element 42) is used as the reference time, the measurement device 1 uses the measured value for the position of the reflecting element 42. The measurement device 1 calculates estimated values ​​for the positions of the reflecting element 41 and the reflecting element 43 at the reference time. Note that the time when the position of the reflecting element 41 or the time when the position of the reflecting element 43 is measured may be used as the reference time.

[0180] Even if the position and posture of the robot T1 change during the measurement process, the measurement device 1 may ignore the time difference between the times when the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) are measured, and may use the measurement results of the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) as position information as is. The time difference between the times when the positions of the three reflecting elements are measured can be ignored when the time difference is extremely short and the change in the position and posture of the robot T1 during the measurement process is approximately the same as the measurement accuracy of the measurement device 1.

[0181] Furthermore, the robot T1 may be temporarily stopped during the measurement process. In this case, for example, a measurement start signal indicating the start of measurement may be transmitted from the control system of the robot T1 to the measuring device 1. When the measurement start signal is transmitted from the control system of the robot T1 to the measuring device 1, the control system temporarily stops the robot T1 and then transmits the measurement start signal to the measuring device 1. Furthermore, a stop signal indicating an instruction to temporarily stop the robot T1 may be transmitted from the measuring device 1 to the control system of the robot T1. When the stop signal is transmitted from the measuring device 1 to the control system of the robot T1, the control system temporarily stops the robot T1 based on the stop signal. The control system transmits a signal indicating that the robot T1 has stopped to the measuring device 1. In either case, when the measurement start signal or the stop signal is transmitted, the measuring device 1 starts the measurement process after confirming that the robot T1 has stopped.

[0182] As described above, in the position and orientation acquisition process, the position acquisition unit 206 acquires position information and direction information based on information about the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43). In this embodiment, the information about the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) is, as an example, information indicating the positions of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) detected by the four-segment PSD 12. As an example, the position information is represented by coordinates of a reference coordinate system in a space in which the target member 4 is placed, and indicates a position within a Cartesian coordinate system (X, Y, Z). In this case, the position information includes position information regarding a first axis (X-axis), position information regarding a second axis (Y-axis), and position information regarding a third axis (Z-axis). The direction information includes information regarding a position in a rotational direction around the first axis (X-axis), information regarding a position in a rotational direction around the second axis (Y-axis), and information regarding a position in a rotational direction around the third axis (Z-axis).

[0183] As described above, in the position and orientation acquisition process, the control unit 21 controls the irradiation unit 201 to repeatedly irradiate each of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) with the measurement light L1. In the measurement device 1, even if the measurement light L1 is lost during the measurement process, the irradiation direction driving unit 204 can drive the irradiation unit 201 so that the optical comb interferometer 11 irradiates the measurement light onto the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) with accuracy on the order of submicrometers. For example, the measurement light L1 is lost when an obstacle remains between the measurement device 1 and the target member 4.

[0184] Next, the configuration of the target member 4 will be described with reference to FIGS. 28 to 30. FIG. 28 is a diagram showing an example of the configuration of the target member 4 according to this embodiment. A holding portion 47, a holding portion 48, and a holding portion 49 are provided on an installation surface 46 of an installation member 45. The holding portion 47 is a member that holds the reflective element 41. The reflective element 41 is held by the holding portion 47 and placed on the installation surface 46. The holding portion 48 is a member that holds the reflective element 42. The reflective element 42 is held by the holding portion 48 and placed on the installation surface 46. The holding portion 49 is a member that holds the reflective element 43. The reflective element 43 is held by the holding portion 49 and placed on the installation surface 46. Note that the installation surface 46 may be flat.

[0185] Marker 44 is placed on installation surface 46. Marker 44 is placed at a position on installation surface 46 closer to the center of installation surface 46 than the positions at which the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are placed. In other words, marker 44 is placed on installation surface 46 so as to be surrounded by the three reflective elements (reflective element 41, reflective element 42, and reflective element 43). Note that marker 44 may be placed on any of holding portion 47, holding portion 48, or holding portion 49.

[0186] 29 shows a cross-sectional view of reflecting element 41 held by holding portion 47. The shape of reflecting element 41 is, for example, a sphere. Center SC1 indicates the center of reflecting element 41, which is spherical. The shapes of reflecting elements 42 and 43 are each spherical, the same as the shape of reflecting element 41. Reflecting elements 41, 42, and 43 are all equal in size. The state in which reflecting element 42 is held by holding portion 48 and the state in which reflecting element 43 is held by holding portion 49 are each similar to the state in which reflecting element 41 is held by holding portion 47.

[0187] Here, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are examples of a first reflective element, a second reflective element, and a third reflective element, respectively. The position of the center SC1 of reflective element 41 when reflective element 41 is held by holder 47 is referred to as a first position, which is the position where reflective element 41 is arranged on target member 4. Similarly, the position of the center of reflective element 42 when reflective element 42 is held by holder 48 is referred to as a second position, which is the position where reflective element 42 is arranged on target member 4. The position of the center SC1 of reflective element 43 when reflective element 43 is held by holder 49 is referred to as a third position, which is the position where reflective element 43 is arranged on target member 4.

[0188] In this embodiment, the lengths of the first side connecting the first position where the reflective element 41 is disposed and the second position where the reflective element 42 is disposed, the second side connecting the second position and the third position where the reflective element 43 is disposed, and the third side connecting the third position and the first position are all different. Note that the first to third positions may be the center positions of the reflective element 41, the reflective element 42, and the reflective element 43, respectively.

[0189] Furthermore, the first to third positions may be other than the center positions of the reflecting elements 41, 42, and 43, respectively. For example, the first to third positions may be positions where a perpendicular line drawn from the center positions of the reflecting elements 41, 42, and 43 to the installation surface intersects with the installation surface, respectively. As another example, the first to third positions may be predetermined positions offset from the centers of the reflecting elements 41, 42, and 43, respectively, as long as they are positions included inside the reflecting elements 41, 42, and 43, respectively. As another example, the first to third positions may be outer positions of the reflecting elements 41, 42, and 43, respectively, as long as they are predetermined positions (i.e., predetermined relative positions) with respect to the reflecting elements 41, 42, and 43, respectively.

[0190] As described above, the measurement device 1 acquires the positions of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) by irradiating the measurement light L1 along the circular orbit TC1. Simply acquiring the positions of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) may not be able to distinguish the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) from one another. For example, if the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) are positioned at equal distances from the position of the marker 44 on the installation surface 46, simply acquiring the positions of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) may not be able to distinguish the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) from one another.

[0191] In this embodiment, since the lengths of the first side, the second side, and the third side are different, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) can be distinguished from one another by fitting a known coordinate system to the three reflective elements.

[0192] 28 , the first position, the second position, and the third position are located on concentric circles on the installation surface 46. The centers of the concentric circles are predetermined positions on the installation surface 46 that are different from the position of the marker 44. On the installation surface 46, the distance between the center of the reflective element 41 and the marker 44, the distance between the center of the reflective element 42 and the marker 44, and the distance between the center of the reflective element 43 and the marker 44 are different from one another. The three reflective elements (reflective element 41, reflective element 42, and reflective element 43) may be distinguished from one another based on their distances from the marker 44.

[0193] The lengths of the first, second, and third sides of the target member 4 may be changeable. For example, a sliding plate-like member may be provided on the installation surface 46 for each of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43), and the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the plate-like member. The lengths of the first, second, and third sides may be changeable by sliding the plate-like member. Alternatively, a plurality of attachment positions may be provided on the installation surface 46 for each reflective element, and the lengths of the first, second, and third sides may be changeable by changing the attachment positions for each reflective element.

[0194] Referring again to Figure 29, the following description will be given. A groove 470 is provided in the holding portion 47. The groove 470 is a groove for filling with adhesive. The groove 470 is a ring-shaped groove. The reflective element 41 is adhered and held to the holding portion 47 by the adhesive filled in the groove 470. Here, a cohesive force is generated as the adhesive hardens. A vector CF1 represents the cohesive force.

[0195] The installation member 45 is a member for attaching the target member 4 to the robot T1. As an example, the installation member 45 is fixed to the robot T1 by screws through screw holes (not shown). Therefore, the target member 4 can be attached to the object to be measured. The installation member 45 may be attached to the robot T1 using adhesive tape, adhesive, a magnet, or the like.

[0196] Next, the heights of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) on the installation surface 46 will be described with reference to Fig. 30. Fig. 30 is a diagram showing an example of the heights of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) on the installation surface 46 according to this embodiment. The axis BX1 is an axis perpendicular to the installation surface 46 and passes through the position of the marker 44. The axis BX1 indicates the orientation of the installation surface 46.

[0197] The three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are positioned at a height that does not hide the marker 44 when the orientation of the installation surface 46 is such that the smallest angle between the axis BX1 and the irradiation direction of the measurement light L1 is equal to or smaller than a predetermined angle. In other words, the irradiation direction of the measurement light L1 is the direction in which the target member 4 is viewed from the measurement device 1. The predetermined angle is, for example, 60 degrees. Therefore, when attached to the target member 4, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are positioned at a height that does not hide the marker 44 when viewed from a predetermined orientation.

[0198] In the present embodiment, an example has been described in which the target member 4 to which three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached is attached to the robot T1, but this is not limiting. The three reflective elements (reflective element 41, reflective element 42, and reflective element 43) may be attached to the robot T1. When the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the robot T1, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to a portion of the robot T1 such that the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are within the field of view of the measurement device 1 when the robot T1 is viewed from the measurement device 1.

[0199] When three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the target member 4, the arrangement of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is known depending on the structure of the target member 4. When three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the robot T1, the arrangement of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is not necessarily known. Therefore, the arrangement of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) is acquired by scanning after the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached to the robot T1. In this scan, the first imaging unit 22 captures an image of at least a portion of the robot T1 to which the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) are attached. The arrangement of the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) obtained by scanning is stored in the storage unit 24 as reflective element arrangement information.

[0200] As described above, the first imaging unit 22 captures an image of at least a portion of the three reflective elements (the reflective elements 41, 42, and 43). Therefore, the first imaging unit 22 captures an image of at least one of at least a portion of the three reflective elements (the reflective elements 41, 42, and 43) and at least a portion of the robot.

[0201] As described above, the measuring device 1 according to this embodiment is a measuring device that measures the position and rotational position of the mobile robot T1, and includes an irradiating unit 201, a light receiving unit 202, and a position acquiring unit 206. The irradiating unit 201 can irradiate measurement light L1 onto at least three reflecting elements (in this embodiment, reflecting elements 41, 42, and 43) attached to the robot T1. The light receiving unit 202 can receive light reflected by each of the three reflecting elements (in this embodiment, reflecting elements 41, 42, and 43). Based on the light reception results by the light receiving unit 202, the position acquisition unit 206 acquires position information regarding the first axis (in this embodiment, the x-axis) of the robot T1, position information regarding the second axis (in this embodiment, the y-axis) that intersects with the first axis (in this embodiment, the x-axis), position information regarding the third axis (in this embodiment, the z-axis) that intersects with the first axis (in this embodiment, the x-axis) and the second axis (in this embodiment, the y-axis), information regarding the position in the rotational direction around the first axis (in this embodiment, the x-axis), information regarding the position in the rotational direction around the second axis (in this embodiment, the y-axis) (position information), and information regarding the position in the rotational direction around the third axis (in this embodiment, the z-axis) (directional information).

[0202] With this configuration, the measuring device 1 of this embodiment can obtain position information and information regarding the position in the rotational direction based on the reception results of the reflected light from the measurement light L1 irradiated onto each of at least three reflecting elements attached to the robot T1 and reflected by each of the three reflecting elements, thereby enabling the position and posture of the robot T1 to be measured with high accuracy when controlling the robot T1.

[0203] Second Embodiment A second embodiment of the present invention will be described in detail below with reference to the drawings. In the first embodiment, the position and posture of the robot T1 do not change while the measuring device 1 performs the measurement process. In this embodiment, a case will be described in which the measuring device 1 repeatedly performs the measurement process while the robot T1 is moving.

[0204] 31 shows an example of how the position and orientation of a moving measurement target are measured using the measurement light L1 according to this embodiment. The robot T1 is stationary until time t0, at which point it starts moving. Accordingly, the three reflective elements (reflective element 41, reflective element 42, and reflective element 43) provided on the target member 4 attached to the robot T1 are stationary until time t0, at which point they start moving.

[0205] 31A is a circular orbit calculated for the position and orientation acquisition process based on the central positions (i.e., the first position, the second position, and the third position) of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) when the target member 4 is stationary. In other words, the trajectory TR0 is a circular orbit calculated before time t0.

[0206] The measurement device 1 sequentially irradiates the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) with the measurement light L1 along the trajectory TR0, and calculates the change in the position of each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) over time. The measurement device 1 sequentially calculates a direction vector for each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) based on the position of the reflecting element detected by, for example, the four-segment PSD 12. The direction vector indicates the change in the position of the reflecting element over time.

[0207] Fig. 31(B) shows how the measurement light L1 irradiated to the reflecting element is reflected and detected by the four-segment PSD 12. Fig. 31(B) shows an enlarged view of the range RB1 in Fig. 31(A), and shows, as an example, how the measurement light L1 irradiated to the reflecting element 43 is reflected and detected by the four-segment PSD 12.

[0208] The measuring device 1 calculates a circular orbit that can pass through the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) at time t1 based on the change over time (directional vector) in the positions of each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) detected at time t0. Here, time t1 is a predetermined time after time t0. The measuring device 1 similarly calculates a circular orbit that can pass through the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) at each subsequent time (time t1, time t2, and time t3 in FIG. 31 ).

[0209] Next, with reference to Fig. 32 , a position and orientation acquisition process when the measurement target moves will be described. Fig. 32 is a diagram showing an example of the position and orientation acquisition process according to this embodiment. The position and orientation acquisition process shown in Fig. 32 is executed as step S30 in the measurement process shown in Fig. 10. The position and orientation acquisition process shown in Fig. 32 is executed, for example, every time the position onto which the measurement light L1 is irradiated rotates a predetermined number of times along a circular orbit. The predetermined number is, for example, once. Note that the predetermined number may be two or more times.

[0210] The processes of steps S410, S420, S430, S440, and S450 are similar to the processes of steps S310, S320, S330, S340, and S350 in FIG. 23, and therefore will not be described again.

[0211] Step S460: The position acquisition unit 206 determines whether a termination condition is satisfied. The termination condition is, for example, that the measurement device 1 acquires a signal (command) to terminate the measurement process. The signal is supplied to the measurement device 1 from an external device based on an operation by the user of the measurement device 1, for example. The measurement device 1 may be provided with an operation acceptance unit, and the signal may be supplied to the measurement device 1 based on an operation by the user accepted by the operation acceptance unit. The termination condition may also be that a predetermined time has elapsed since the measurement device 1 started the measurement process.

[0212] If the position acquisition unit 206 determines that the termination condition is satisfied (step S460; YES), the control unit 21 terminates the position and orientation acquisition process. On the other hand, if the position acquisition unit 206 determines that the termination condition is not satisfied (step S460; NO), the control unit 21 executes the process of step S470.

[0213] Step S470: The position acquisition unit 206 estimates a change in the position of the center of the reflective element based on the imaging result of the reflective element. The imaging result of the reflective element is the result of the reflected light reflected from the reflective element irradiated with the measurement light L1 being detected by the four-segment PSD 12. The position acquisition unit 206 calculates a direction vector indicating a change in the position of the center of the reflective element based on the position of the center of the reflective element indicated by the newly acquired imaging result of the reflective element and the position of the center of the reflective element indicated by the previously acquired imaging result of the reflective element. The position acquisition unit 206 estimates a change in the position of the center of the reflective element based on the calculated direction vector.

[0214] Thereafter, the position acquisition unit 206 executes the process of step S410 again. In the process of step S410 executed again, the position acquisition unit 206 calculates the circular orbit TC1 based on the position of the center of the reflecting element based on the change in the position of the center of the reflecting element estimated in step S470.

[0215] As described above, in the position and orientation acquisition process according to this embodiment, the circular orbit TC1 is calculated at predetermined times based on changes in the center positions of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43). Because the circular orbit TC1 is calculated at predetermined times based on changes in the center positions of the three reflecting elements, the irradiation unit 201 sequentially irradiates each of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) with the measurement light L1 while scanning along the predetermined orbit to follow the movement of the three reflecting elements. While the robot T1 is moving, irradiation of each of the three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43) with the measurement light L1 is repeatedly performed. This allows the position and orientation of the robot T1 to be continuously acquired even while the robot T1 is moving.

[0216] In each of the above-mentioned embodiments, an example has been described in which measurement light L1 is irradiated based on the results of three reflective elements (reflective element 41, reflective element 42, and reflective element 43) being imaged by the first imaging unit 22 (i.e., the results of the rough search), but the method of rough search is not limited to this.

[0217] Furthermore, instead of performing a rough search, the measuring device 1 may acquire information indicating the position and posture of the robot T1 from the control system of the robot T1, and acquire the positions of each of the three reflecting elements (reflecting element 41, reflecting element 42, and reflecting element 43) with coarse accuracy based on the mounting position information and reflecting element arrangement information. Note that the information indicating the position and posture of the robot T1 acquired from the control system indicates the position and posture of the robot T1 with coarse accuracy.

[0218] In either case, the measuring device 1 performs fine search processing based on the acquired positions of the three reflecting elements (the reflecting elements 41, 42, and 43). That is, the measuring light L1 is irradiated based on the imaging results obtained by the imaging units (the first imaging unit 22 and the second imaging unit 30).

[0219] In the above-described embodiments, except for the description of the posture acquisition process, an example has been described in which the position and posture of the robot T1 are measured based on the positions of three reflecting elements (the reflecting element 41, the reflecting element 42, and the reflecting element 43). However, this is not limiting. Four or more reflecting elements may be attached to the target member 4, and the measurement device 1 may measure the position and posture of the robot T1 based on the results of measuring the positions of the four or more reflecting elements. Here, measuring the positions of three reflecting elements is sufficient to measure the position and posture of the robot T1. When the positions of four or more reflecting elements are measured, for example, the measurement result of the position of one of the four reflecting elements may be used to verify the measurement results of the position and posture of the robot T1 measured based on the positions of three of the four reflecting elements. In this case, for example, the position and posture of the robot T1 are measured for verification based on two of the three reflecting elements used for measurement and one reflecting element used for verification. The measurement results for the measurement are verified by determining whether the position and posture of the robot T1 measured for verification match the position and posture of the robot T1 measured for measurement with a specified accuracy.

[0220] Alternatively, the position and orientation of the robot T1 may be measured based on an average value of the position measurement results of four or more reflecting elements. For example, the six reflecting elements may be divided into two groups, and the position and orientation measurement results of the robot T1 measured based on the positions of three reflecting elements in each group may be averaged to obtain the measurement result.

[0221] Furthermore, in the measurement apparatus 1 according to each of the above-described embodiments, an example has been described in which the irradiating unit 201 includes one optical comb interferometer 11 and sequentially irradiates each of the multiple reflecting elements with the measurement light L1, but this is not limited thereto. As described above, the irradiating unit 201 may include multiple optical comb interferometers. When the irradiating unit 201 includes multiple optical comb interferometers, some of the multiple optical comb interferometers may be used to sequentially irradiate each of the multiple reflecting elements with the measurement light as in each of the above-described embodiments, and the remaining optical comb interferometers of the multiple optical comb interferometers may each be used to irradiate one reflecting element associated with the remaining optical comb interferometer with the measurement light.

[0222] In particular, the irradiation unit 201 may include the same number of optical comb interferometers 11 as the plurality of reflecting elements. When the irradiation unit 201 includes the same number of optical comb interferometers as the plurality of reflecting elements, the irradiation unit 201 irradiates each of the plurality of reflecting elements with measurement light emitted from each of the optical comb interferometers, the number of which is the same as the plurality of reflecting elements.

[0223] In the above-described embodiments, the measuring device 1 has been described as acquiring position information and information relating to the position in the rotational direction (directional information), but the present invention is not limited to this. The measuring device 1 may acquire only the position information of the position information and directional information. When the measuring device 1 acquires only the position information of the position information and directional information, the directional information may be calculated by a calculation device separate from the measuring device 1 based on the position information acquired by the measuring device 1.

[0224] The measuring device 1, the robot T1, and the control system for the robot T1 in each of the above-described embodiments are preferably included in a robot system and used at production sites such as factories. The measuring device 1 in each of the above-described embodiments is also preferably used in a management method for managing the robot T1 using the measuring device 1.

[0225] Note that a portion of the measuring device 1 in the above-described embodiment, such as the position acquisition unit 206 and the control unit 21, may be implemented by a computer. In this case, a program for implementing this control function may be recorded on a computer-readable recording medium, and the program may be loaded and executed by a computer system. Note that the term "computer system" as used herein refers to a computer system built into the measuring device 1, including hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into the computer system. Furthermore, the term "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or media that store programs for a fixed period of time, such as volatile memory within the computer system that serves as the server or client in such cases. Furthermore, the program may be designed to implement a portion of the above-described functions, or may be capable of implementing the above-described functions in combination with programs already stored in the computer system. Furthermore, part or all of the measuring device 1 in the above-described embodiment may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each functional block of the measuring device 1 may be individually implemented as a processor, or part or all of the functional blocks may be integrated into a processor. Furthermore, the integrated circuit implementation method is not limited to LSI, and may be implemented using a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit implementation technology that can replace LSI emerges due to advances in semiconductor technology, an integrated circuit based on that technology may be used.

[0226] One embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes and the like are possible within the scope that does not deviate from the gist of the present invention.

[0227] 1...measuring device, 201...irradiation unit, 202...light receiving unit, 206...position acquisition unit, T1...robot, 41, 42, 43...reflection elements, L1...measurement light

Claims

1. 1. A measurement device for measuring the position and rotational position of a mobile robot, comprising: an irradiation unit capable of irradiating measurement light onto each of at least three reflecting elements attached to the robot; a light receiving unit capable of receiving light reflected by each of the three reflecting elements; a position acquisition unit that acquires, based on a result of light reception by the light receiving unit, position information regarding a first axis of the robot, position information regarding a second axis intersecting with the first axis, position information regarding a third axis intersecting with the first axis and the second axis, information regarding a position in a rotational direction around the first axis, information regarding a position in a rotational direction around the second axis, and information regarding a position in a rotational direction around the third axis; Equipped Measuring equipment.

2. The irradiation unit is capable of scanning the measurement light along a curved trajectory that can pass through the at least three reflecting elements that are not arranged on a single straight line.

2. The measuring device of claim 1.

3. An imaging unit that images at least one of at least a portion of the three reflecting elements and at least a portion of the robot, The measurement light is irradiated based on the image pickup result by the image pickup unit. The measuring device according to claim 1 or 2.

4. An imaging unit that images a marker that is disposed at a predetermined position relative to the three reflecting elements, The measurement light is irradiated based on the image pickup result by the image pickup unit. The measuring device according to claim 1 or 2.

5. The irradiation unit is capable of scanning the measurement light along a predetermined trajectory that can pass through the three reflecting elements. The measuring device according to any one of claims 1 to 4.

6. In order to perform scanning along the predetermined trajectory, a trajectory in which the change in acceleration of the change in the irradiation direction of the measurement light is small is calculated as the predetermined trajectory.

6. The measuring device according to claim 5.

7. Calculating an elliptical orbit as the predetermined orbit The measuring device according to claim 5 or 6.

8. A control device for controlling the measuring device is further provided. The control device calculates a trajectory of the measurement light passing through the three reflecting elements based on a measurement result acquired by the position acquisition unit, the measurement result being obtained by scanning a predetermined range along a spiral trajectory of the measurement light. The measuring device according to any one of claims 1 to 7.

9. The irradiation unit is capable of irradiating an optical comb as the measurement light. A measuring device according to any one of claims 1 to 8.

10. The irradiation unit is capable of sequentially irradiating the measurement light onto each of the three reflecting elements while scanning along a predetermined trajectory at a predetermined speed or faster. The measuring device according to any one of claims 1 to 9.

11. The irradiation unit sequentially irradiates the measurement light onto each of the three reflecting elements while scanning along a predetermined trajectory so as to follow the movements of the three reflecting elements. A measuring device according to any one of claims 1 to 10.

12. The measurement light is repeatedly irradiated onto each of the three reflecting elements. A measuring device according to any one of claims 1 to 11.

13. During the movement of the robot, the measurement light is repeatedly irradiated onto each of the three reflecting elements.

13. The measuring device of claim 12.

14. The irradiation unit irradiates the measurement light onto each of the three reflection elements via a reflection surface of a movable mirror, The light receiving unit receives reflected light from each of the three reflecting elements via the reflecting surface. A measuring device according to any one of claims 1 to 13.

15. Based on information about the positions of the three reflective elements, position information about the first axis, position information about the second axis, and position information about the third axis, as well as information about a position in a rotational direction around the first axis, information about a position in a rotational direction around the second axis, and information about a position in a rotational direction around the third axis are obtained.

15. The measuring device according to any one of claims 1 to 14.

16. The three reflective elements are a first reflective element, a second reflective element, and a third reflective element, and the lengths of a first side connecting a first position where the first reflective element is disposed and a second position where the second reflective element is disposed, a second side connecting the second position and a third position where the third reflective element is disposed, and a third side connecting the third position and the first position are different from each other, and the first position, the second position, and the third position are located on concentric circles.

15. The measuring device according to any one of claims 1 to 14.

17. The position acquisition unit acquires information regarding a tool center point of the robot.

17. A measuring device according to any one of claims 1 to 16.

18. A robot system comprising the measuring device according to any one of claims 1 to 17.

19. A method for managing a robot, using the measurement device according to any one of claims 1 to 17.

20. A target member that can be attached to a movable measurement object, the target member including a first reflecting element, a second reflecting element, and a third reflecting element, to which a measurement light is irradiated in order to obtain position information of the movable measurement object with respect to a first axis, with respect to a second axis intersecting the first axis, and with respect to a third axis intersecting the first axis and the second axis, and with respect to a rotational position around the first axis, with respect to a rotational position around the second axis, and with respect to a rotational position around the third axis, the target member comprising: A first side connecting a first position where the first reflecting element is disposed and a second position where the second reflecting element is disposed, a second side connecting the second position and a third position where the third reflecting element is disposed, and a third side connecting the third position and the first position have different lengths. Target material.

21. A target member comprising a first reflecting element, a second reflecting element, and a third reflecting element for measuring a position of the measurement object, the target member being attachable to the measurement object, A first side connecting a first position where the first reflecting element is disposed and a second position where the second reflecting element is disposed, a second side connecting the second position and a third position where the third reflecting element is disposed, and a third side connecting the third position and the first position have different lengths. Target material.

22. The length of the first side, the length of the second side, and the length of the third side are each variable.

22. A target member according to claim 20 or claim 21.

23. Further comprising markers arranged at predetermined positions relative to the first reflective element, the second reflective element, and the third reflective element. A target member according to any one of claims 20 to 22.

24. The first reflective element, the second reflective element, and the third reflective element are arranged at a height such that the marker is not hidden when viewed from a predetermined direction.

24. The target member of claim 23.

25. The first reflecting element, the second reflecting element, and the third reflecting element are arranged at a height such that the marker is not hidden when viewed from the direction in which the measurement light is irradiated.

24. The target member of claim 23.

26. The marker is arranged on an installation surface on which the first reflective element, the second reflective element, and the third reflective element are arranged so as to be surrounded by the first reflective element, the second reflective element, and the third reflective element.

24. The target member of claim 23.

27. ​​A distance from the marker to the first reflective element, a distance from the marker to the second reflective element, and a distance from the marker to the third reflective element are different from each other.

24. The target member of claim 23.

28. A measuring device for measuring a position of a measurement object, comprising: an irradiation unit capable of sequentially irradiating measurement light onto at least three reflecting elements attached to the measurement object; a light receiving unit capable of sequentially receiving reflected light of the measurement light reflected by each of the three reflecting elements; an information acquisition unit that acquires information regarding a position of the measurement target based on a light receiving result by the light receiving unit; A measuring device comprising:

29. A measuring device for measuring a position of a measurement object, comprising: an irradiation unit capable of scanning a measurement light along a trajectory that can pass through at least three reflecting elements attached to the measurement object; a light receiving unit capable of receiving reflected light of the measurement light reflected by each of the three reflecting elements; and an information acquiring unit that acquires information regarding the position of the measurement object based on a light receiving result by the light receiving unit; A measuring device comprising:

30. The irradiation unit is capable of scanning the measurement light along a curved trajectory that can pass through the at least three reflecting elements that are not arranged on a single straight line.

30. The measuring device according to claim 28 or 29.

31. 1. A method for measuring the position and rotational position of a mobile robot, comprising: Irradiating a measurement light beam onto at least three reflective elements attached to the robot; receiving light reflected by each of the three reflecting elements; acquiring, based on a result of receiving light, position information regarding a first axis of the robot, position information regarding a second axis intersecting with the first axis, position information regarding a third axis intersecting with the first axis and the second axis, information regarding a position in a rotational direction around the first axis, information regarding a position in a rotational direction around the second axis, and information regarding a position in a rotational direction around the third axis; Includes Measurement method.

32. A method for measuring a position of a measurement object, comprising the steps of: Sequentially irradiating at least three reflecting elements attached to the measurement object with measurement light; Sequentially receiving reflected light of the measurement light reflected by each of the three reflecting elements; acquiring information regarding a position of the measurement target based on a result of the light receiving; Includes Measurement method.

33. A method for measuring a position of a measurement object, comprising the steps of: Scanning the measurement light along a trajectory that can pass through at least three reflecting elements attached to the measurement object; receiving reflected light of the measurement light reflected by each of the three reflecting elements; acquiring information regarding a position of the measurement target based on a result of the light receiving; Equipped Measurement method.

34. The measurement light is scanned along a curved trajectory that can pass through the at least three reflecting elements that are not arranged on a single straight line. The measurement method according to any one of claims 31 to 33.