Position measurement system and position measurement method

Abstract

To accurately measure the position of a control point of a robot by a simple device.SOLUTION: A position measurement system includes a robot having a plurality of axes, a target attached to the robot, a sensor for measuring the two-dimensional cross-sectional shape of the target in a predetermined operation of the robot, and a processor for computing three-dimensional information on the target based on the two-dimensional cross-sectional shape measured by the sensor. The processor includes a detection unit and an arithmetic unit. The detection unit detects a feature value of the target based on the two-dimensional cross-sectional shape measured by the sensor. The arithmetic unit computes three-dimensional information on the robot on the basis of the feature value detected by the detecting unit and information on the shape of the target.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a position measurement system and a position measurement method. [Background technology]

[0002] Patent Document 1 discloses a method for calibrating a work robot in which, after the work robot is installed in a production facility, the deviation (offset) of the encoder installed on each axis of the work robot is calculated and a teaching program is automatically calibrated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-38662 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure has been devised in consideration of the above-mentioned conventional situation, and has an object to accurately measure the position of a control point of a robot using a simple device. [Means for solving the problem]

[0005] The present disclosure provides a position measurement system comprising a robot having multiple axes, a target attached to the robot, a sensor that measures a two-dimensional cross-sectional shape of the target during a predetermined movement of the robot, and a processor that calculates three-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor.

[0006] The present disclosure also provides a position measurement system comprising a robot having multiple axes, a target attached to the robot, a sensor that measures a two-dimensional cross-sectional shape of the target during a predetermined movement of the robot, and a processor that outputs at least two-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor.

[0007] The present disclosure also provides a position measurement system comprising a robot having a drive shaft, a target attached to the robot, and a processor that detects feature values ​​of the target based on a two-dimensional cross-sectional shape of the target during a predetermined movement of the robot received from a sensor, and calculates three-dimensional information of the robot based on the detected feature values ​​and information related to the shape of the target.

[0008] The present disclosure also provides a position measurement method for a position measurement system including a robot having a drive shaft, a target attached to the robot, and a sensor that measures a two-dimensional cross-sectional shape of the target during a predetermined operation of the robot, the position measurement method having the steps of detecting feature values ​​of the target based on the two-dimensional cross-sectional shape measured by the sensor, and calculating a three-dimensional trajectory of the robot based on the detected feature values ​​and information related to the shape of the target.

[0009] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0010] According to the present disclosure, the position of a control point of a robot can be measured with high accuracy using a simple device. [Brief description of the drawings]

[0011] [Figure 1]System configuration diagram of the position measurement system [Diagram 2] Diagram showing the method for measuring the two-dimensional cross-sectional depth of a target [Diagram 3] A diagram showing various feature values ​​of targets [Figure 4] Diagram showing cross-sectional circle of detected target [Diagram 5] Diagram showing the method for measuring the two-dimensional cross-sectional depth of a target [Figure 6] Cross section of the target viewed from the first direction [Figure 7] Cross section of the target viewed from a second direction [Figure 8] Diagram showing a target rotated by a given angle [Figure 9] Diagram showing various parameters DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Background to the present embodiment) When controlling a robot, in order to position the tip of the robot at a desired position, it is necessary to know the values ​​of various parameters that define the relationship between the angular displacement of each robot axis and the position and posture of the robot's hand. However, when machining or assembling a robot, it is inevitable that errors will occur in the various parameters, and it is difficult to directly measure the parameters of an assembled robot. For this reason, in order to control the robot with high precision, it is necessary to perform calibration by measuring the relationship between the input displacement and output displacement of the robot after assembly, and estimating and correcting the optimal values ​​of the parameters based on the measurement results. There are various calibration methods, and for example, a method that uses information on the actual control point position of the robot and the target control point position is known.

[0013] In order to position the actual control point of the robot with high accuracy, it is necessary to accurately obtain parameters required to calculate the three-dimensional trajectory of the robot. Conventional three-dimensional trajectory measurement methods include methods using laser marker tracking, stereo vision, or the Direct Linear Transformation method (hereinafter referred to as the "DLT method"). However, in the case of a method using a laser as disclosed in Patent Document 1, there is a problem that the device is large-scale or cannot respond to changes in the posture of the control point. In addition, in the case of the DLT method, there is a problem that the device is large-scale because the robot is surrounded by multiple cameras. In addition, in the case of stereo vision, there are problems such as the need for highly accurate calibration of multiple cameras, the difficulty of highly accurately adjusting the optical system that depends on the accuracy of the calibration, and the influence of visible light disturbance.

[0014] Hereinafter, with reference to the drawings as appropriate, an embodiment specifically disclosing a position measurement system and a position measurement method according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters and duplicated description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0015] First, the system configuration of the localization system 1 will be described with reference to Fig. 1. Fig. 1 is a system configuration diagram of the localization system 1.

[0016] The position measurement system 1 includes a control device 10 , a robot 20 , a sensor 30 , a disturbance detection device 31 and a transport device 32 .

[0017] The control device 10 is a device that controls the movement of the robot and calculates the position of a control point of the robot. The control device 10 has a communication I / F 11, a memory 12, and a processor 13.

[0018] The communication I / F 11 is an interface circuit that performs wireless or wired communication between the control device 10 and the sensor 30, between the control device 10 and the robot 20, and between the control device 10 and the disturbance detection device 31. Here, I / F stands for interface. The communication method by the communication I / F 11 is, for example, a Wide Area Network, a Local Area Network, Long Term Evolution, mobile communication such as 4G or 5G, power line communication, short-distance wireless communication (for example, Bluetooth (registered trademark) communication), or communication for mobile phones.

[0019] The memory 12 is configured using, for example, a Random Access Memory (hereinafter referred to as "RAM") and a Read Only Memory (hereinafter referred to as "ROM"), and temporarily stores programs necessary for the operation of the control device 10 and data generated during the operation. The RAM is, for example, a work memory used during the operation of the control device 10. The ROM, for example, stores and holds in advance programs for controlling the control device 10.

[0020] The processor 13 is, for example, a central processing unit, a digital signal processor, a graphic processing unit, or a field programmable gate array. The processor 13 functions as a controller that manages the overall operation of the control device 10. The processor 13 performs control processing for managing the operation of each part of the control device 10, data input / output processing between each part of the control device 10, data calculation processing, and data storage processing. The processor 13 operates according to a program stored in the memory 12. The processor 13 uses the memory 12 during operation, and temporarily stores data generated or acquired by the processor 13 in the memory 12. The processor 13 has a detection unit 14 and a calculation unit 15. The processor 13 can output at least two-dimensional information of the control points from the three-dimensional trajectories of the targets 21, 50 calculated by the calculation unit 15 to an external device (not shown) as a calculation result.

[0021] The detection unit 14 detects the feature value based on the two-dimensional cross-sectional shapes of the targets 21, 50 output from the sensor 30. The feature value will be described in detail in the first and second embodiments.

[0022] The calculation unit 15 calculates the three-dimensional trajectories of the targets 21 and 50 using the feature values ​​output from the detection unit 14 and information on the shapes of the targets 21 and 50. The detailed processing performed by the calculation unit 15 will be described in detail in the first and second embodiments.

[0023] The robot 20 is a robot having a drive axis. The robot 20 is, for example, a welding robot, a vertical articulated robot having an arm, a SCARA robot, a CNC machine tool (such as a five-axis processing machine), or a mounting machine. In particular, the present invention is effective for the robot 20 having four or more drive axes and capable of adopting different postures at any point. Targets 21 and 50 are attached to the robot 20.

[0024] The target 21, 50 is a jig made of metal or the like that is attached to the robot 20. The target 21, 50 needs to have a shape that allows a specific point on the target 21, 50 to be obtained from information on the two-dimensional cross-sectional shape detected by the sensor 30 and known information on the shape of the target 21. For example, the target 21, 50 is a jig such as a sphere, a cone, or a triangular plane of a finite thickness. Note that the target 21, 50 is not limited to a sphere, a cone, or a triangular plane, and may have any shape as long as a specific point on the target 21, 50 can be obtained from the two-dimensional cross-sectional shape and known information on the shape of the target 21, 50.

[0025] The sensor 30 is a device that measures the cross-sectional shape of the targets 21, 50. The sensor 30 is, for example, a semiconductor laser of visible light. The sensor 30 is a small sensor with a size of about 20 [cm] and a measurement range of about 30 [cm]. Note that 20 [cm] is one example of the size of the sensor 30 and is not limited. Also, 30 [cm] is one example of the measurement range of the sensor 30 and is not limited. The sensor 30 may be fixed at a predetermined position, or may be attached to a transport device 32 or the like and controlled to be movable. The transport device 32 is, for example, a device that moves on a rail by a motor or the like. Note that the transport device 32 may be omitted. Also, the sensor 30 may be manually movable.

[0026] The disturbance detection device 31 is a device that detects a disturbance in the environment in which the robot 20 is placed. The disturbance detection device 31 is, for example, a temperature sensor that detects the temperature in the environment or an acceleration sensor that measures the acceleration of the robot 20. When the disturbance detection device 31 is an acceleration sensor, the processor 13 determines whether or not the vibration of the robot 20 is within an allowable range using the acceleration of the robot 20 as an index.

[0027] <Embodiment 1> In the first embodiment, a method for measuring the three-dimensional trajectory of the control point of the robot 20 when the shape of the target 21 is a sphere (a sphere with almost minimal sphericity) will be described. In the first embodiment, the center of the sphere of the target 21 is fixed so as to coincide with the control point of the robot 20. The position measurement system 1 measures the trajectory of the control point of the robot 20 by measuring the trajectory of the center of the sphere of the target 21. In the first embodiment, the center position of the sphere of the target 21 is set as the point to be measured (hereinafter referred to as the "measurement point").

[0028] A method for measuring the two-dimensional cross-sectional depth of the target 21 will be described with reference to Fig. 2. Fig. 2 is a diagram showing a method for measuring the two-dimensional cross-sectional depth of the target 21.

[0029] The sensor 30 irradiates the target 21 with the emitted laser light 23 and detects the reflected light from the target 21 to measure the depth of the target 21 (i.e., the length from the irradiation surface of the target 21 with the laser light 23 in the depth direction of the target 21 (i.e., the optical axis direction)). The depth of the target 21 is calculated using a known technique.

[0030] The measurement range 22 is a range of the laser light 23 radially irradiated in a two-dimensional plane. The sensor 30 is fixed at a predetermined position, and measures the depth of the target 21 by moving the target 21 to the measurement range 22. The position of the sensor 30 relative to the target 21 may be controlled by the transport device 32. Here, the processor 13 determines whether or not the target 21 is present within the measurement range 22 of the sensor 30 based on the measurement result sent from the sensor 30. If the processor 13 determines that the target 21 is present within the measurement range 22, the processor 13 causes the robot 20 to perform a predetermined operation and measure the two-dimensional cross-sectional shape of the target 21. Here, the predetermined operation is, for example, an operation of moving in the X-axis direction within the measurement range 22 at a predetermined speed and acceleration. Note that the predetermined operation is not limited to the above example, and can be arbitrarily set by the user. If the processor 13 determines that the target 21 is not present within the measurement range 22, the processor 13 operates the robot 20 so that the target 21 is present within the measurement range 22, and controls the position of the target 21. If the processor 13 determines that the target 21 does not exist within the measurement range 22 , the processor 13 may control the position of the sensor 30 by operating the transport device 32 so that the target 21 exists within the measurement range 22 .

[0031] Next, a method for measuring the three-dimensional position of the target 21 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing various characteristic values ​​of the target 21. Fig. 4 is a diagram showing the cross-sectional circle of the detected target 21.

[0032] As shown in FIG. 3, the target 21 has a spherical tip. Hereinafter, the target 21 refers to the spherical tip portion. Point C1 is the center of the target 21. The AA section is a section measured by the sensor 30. In the two-dimensional plane of the AA section shown in FIG. 3, the direction from point C2, which is the center of the AA section, toward the connection part 24 that connects the target 21 and the robot 20 is the X-axis. In the two-dimensional plane of the AA section, the axis perpendicular to the X-axis is the Y-axis. The axis perpendicular to the X-axis and the Y-axis is the Z-axis. The XYZ coordinates are coordinates set for the measurement system by the sensor 30 (see FIG. 2). Note that these expressions related to directions are used for convenience of explanation and are not intended to limit the posture of the structure during actual use.

[0033] The XYZ coordinates of point C1, which is the center of target 21, are (X S, Y S ,Z S ) The radius of the sphere of the target 21 is Rs. The XY coordinates of the point C2, which is the center of the AA cross section, are (X C ,Y C ) The radius of the AA cross section of the target 21 is Rc. Hereinafter, the AA cross section will be referred to as a cross-sectional circle.

[0034] 4 shows the depth of the portion of the target 21 irradiated with the laser light 23 detected by the sensor 30. In the graph 41, the vertical axis shows the depth of the target 21 in the Y direction, and the horizontal axis shows the distance from a reference point in the X-axis direction. The reference point is a zero point that is arbitrarily set for the sensor 30.

[0035] The detection unit 14 approximately determines the cross-sectional circle 42 from the depth information (i.e., the graph 41) of the target 21 detected by the sensor 30. The detection unit 14 obtains the XY coordinates (X C ,Y C ) and the radius Rc of the cross-sectional circle are calculated as feature values. The detection unit 14 outputs the feature values ​​to the calculation unit 15.

[0036] The calculation unit 15 receives the characteristic value from the detection unit 14, which is the XY coordinates (X C ,Y C ) and the radius Rc of the cross-sectional circle, and the known information about the shape of the target 21, the coordinates of the point C1, which is the center of the sphere of the target 21 (X S, Y S ,Z S The known information regarding the shape of the target 21 is the radius Rs of the sphere of the target 21. The calculation unit 15 calculates the coordinates (X S, Y S ,Z S ) is required.

[0037]

number

[0038]

number

[0039]

number

[0040] In this way, the position measurement system 1 calculates the coordinates (X S, Y S ,Z S) can be obtained. The position measurement system 1 uses a small sensor 30 to obtain the measurement points of the target 21 attached to the robot 20, and can obtain the control point positions (or control point trajectories) of the robot 20 with high accuracy without requiring any large-scale equipment. The position measurement system 1 also outputs at least two-dimensional information of the control point positions of the robot 20. The position measurement system 1 can calculate the measurement points by moving the target 21 into the measurement range 22 of the sensor 30, and can therefore obtain the control point positions (or control point trajectories) of the robot 20 with high accuracy regardless of the attitude angle of the control point of the robot 20 (that is, even if the attitude angle of the control point of the robot 20 changes significantly).

[0041] The position measuring system 1 determines the coordinates (X S, Y S ,Z S ) as the actual control point position (or control point trajectory) of the robot 20, that is, as the actual measurement value. The position measurement system 1 performs calibration based on information on the actual measurement value and the target value, which is the target control point position (or control point trajectory). As the calibration, for example, the mechanical parameters of the robot 20 are adjusted. The mechanical parameters of the robot 20 are, for example, parameters used in a relational expression that determines the correlation between the displacement (input) of each drive shaft of the robot 20 used when controlling the robot 20 and the tip position (output) of the robot 20. Representative examples of parameters are the length of the link, the origin position of each drive shaft, backlash caused by the rotation direction of the shaft, elastic deformation of the link or the amount of elastic deformation of the reducer, etc. The position measurement system 1 calculates the obtained coordinates (X S, Y S ,Z S ) (that is, the control point position of the robot 20), the calibration is performed by adjusting the above-mentioned parameters. Note that the parameters to be adjusted are not limited to the above-mentioned examples.

[0042] In the first embodiment, a method for calculating three-dimensional position information of X, Y, and Z has been shown, but any two or more of them may be used, and attitude information may also be used in addition. To obtain the attitude information, for example, two or more sensors 30 for measuring the two-dimensional cross-sectional shape may be installed to measure two or more points of the target 21, or the sensor 30 may be transported by a transport device and the two-dimensional cross-sectional shape may be obtained by two pivot operations.

[0043] <Embodiment 2> In the second embodiment, a method for measuring the three-dimensional trajectory of the control point of the robot 20 when the shape of the target 50 is a cone will be described. In the second embodiment, the apex of the cone shape of the target 50 is fixed so as to coincide with the control point of the robot 20. The position measurement system 1 measures the trajectory of the control point of the robot 20 by measuring the apex of the cone shape of the target 50. In the second embodiment, the apex of the cone of the target 50 is set as the measurement point.

[0044] First, a method for measuring the two-dimensional cross-sectional depth of the target 50 will be described with reference to Fig. 5. Fig. 5 is a diagram showing a method for measuring the two-dimensional cross-sectional depth of the target 50.

[0045] As in the first embodiment, the sensor 30 irradiates the target 50 with the emitted laser light 23 and measures the depth of the target 50 by detecting the reflected light from the target 50. The control device 10 moves the target 50 into the measurement range 22 so that the cross section of the target 50 formed by the laser light 23 from the sensor 30 passes through the rotation axis of the cone.

[0046] Next, a method for calculating measurement points of the target 50 will be described with reference to Figs. 6, 7, 8 and 9. Fig. 6 is a diagram showing a cross section of the target 50 viewed from a first direction. Fig. 7 is a diagram showing a cross section of the target 50 viewed from a second direction. Fig. 8 is a diagram showing the target 50 rotated by a predetermined angle. Fig. 9 is a diagram showing various parameters.

[0047] An xyz coordinate is set for the sensor 30. The direction in which the laser light is emitted from the sensor 30 is the x-axis. The axes perpendicular to the x-axis are the y-axis and z-axis, respectively. The y-axis and z-axis are perpendicular to each other. Note that the expressions relating to these directions are used for convenience of explanation and are not intended to limit the posture of the structure during actual use.

[0048] 6, a cross section Rk is a surface when the target 50 is cut along the surface irradiated with the laser light 23. The apex angle of the cone of the target 50 is set to 2A.

[0049] Fig. 7 is a diagram of the target 50 shown in Fig. 6 when viewed from the positive direction of the z-axis. The cross section Rk has an elliptical shape. The xyz coordinates of point M at the center of the cross section Rk are (xe, ye, ze). The xyz coordinates of point O, which is the apex of the cone of the target 50, are (xs, ys, zs). In the second embodiment, the measurement point is point O (xs, ys, zs), and the known information regarding the target 50 is the apex angle 2A of the cone.

[0050] The length of the semi-major axis 4 of the cross section Rk is a, and the length of the semi-minor axis 5 is b. The angle between the x-axis and the semi-major axis of the cross section Rk is angle φ (0°<φ<180°). The coordinates (xe, ye, ze) of point M, the length of the semi-major axis 4 is a, the length of the semi-minor axis 5 is b, and the angle φ are information obtained from the cross-sectional shape output from the sensor 30, and are feature values ​​extracted by the detection unit 14. A method for deriving the xyz coordinates (xs, ys, zs) of point O will be described below.

[0051] FIG. 8 is a diagram showing the target 50 shown in FIG. 7 rotated by an angle φ around an axis passing through point M and parallel to the z-axis. When the target 50 rotates by an angle φ around an axis passing through point M and parallel to the z-axis, the long axis direction of the cross section Rk is parallel to the x-axis, and the short axis direction of the cross section Rk is parallel to the y-axis. The coordinates of point O', which is the apex of the cone when the target 50 has rotated by the angle φ, are (x's, y's, z's). Point O and

number

[0052]

number

[0053]

number

[0054]

number

[0055] Where:

number

[0056] The angle θ between the plane having the axis of the cone as its normal line and the cross section Rk is set to be 0°<θ<90°-A (see step FIG. 9). FIG. 9 is a cross-sectional view of a plane that passes through point M, the center of the cross section Rk, and is parallel to the xz plane. In FIG. 9, focusing on triangle ABC, from the sine theorem,

number

number

number

[0057] Moreover, the eccentricity e of the cross-sectional ellipse (that is, the cross-section Rk) when the target 50 is cut at the angle θ is expressed by the formula (10) using the apex angle of the cone and the angle θ.

[0058]

number

[0059] Furthermore, from the definition of the eccentricity of an ellipse, the eccentricity e is expressed by equation (11).

[0060]

number

[0061] From equations (10) and (11),

number

[0062] Also,

number

number

number

[0063] Where:

number

number

number

number

[0064] From equation (13), point O' is given by equation (14).

[0065]

number

[0066] From equations (4), (5), (6), and (14),

number

[0067] Where:

number

number

number

number

[0068] As a result, the calculation unit 15 can determine the xyz coordinates (xs, ys, zs) of the measurement point O from the information on the feature values ​​output from the detection unit 14 and the known information on the target 50 using equation (16).

[0069] In the second embodiment, a method for calculating three-dimensional position information of X, Y, and Z has been shown, but any two or more of them may be used, and attitude information may also be used in addition. To obtain the attitude information, for example, two or more sensors 30 for measuring the two-dimensional cross-sectional shape may be installed to measure two or more points of the target 21, or the sensor 30 may be transported by a transport device to obtain the two-dimensional cross-sectional shape by two pivot operations.

[0070] As described above, the position measurement system 1 can obtain the xyz coordinates (xs, ys, zs) of the point O, which is the measurement point of the target 50 that is equal to the control point position of the robot 20, from the feature values ​​of the cone-shaped target 50 detected by the sensor 30. As a result, in the second embodiment as in the first embodiment, the position measurement system 1 can obtain the control point position (or the control point trajectory) of the robot 20 with high accuracy without requiring a large-scale device by obtaining the measurement point of the target 50 attached to the robot 20 using the small sensor 30. In addition, since the position measurement system 1 can calculate the measurement point by moving the target 50 into the measurement range 22 of the sensor 30, it can obtain the control point position (or the control point trajectory) of the robot 20 with high accuracy regardless of the attitude angle of the control point of the robot 20 (that is, even if the attitude angle of the control point of the robot 20 changes significantly).

[0071] In the second embodiment, the target 50 is described using a cone-shaped object, but the shape is not limited to a cone, and may be a triangular plane having a finite thickness. In this case, the triangular plane is arranged with respect to the sensor 30 in the same manner as in the case of the cone shape shown in FIG. 5, with one point on the triangular plane defined as the apex. In the triangular plane, the measurement point is the XYZ coordinates of the apex on the sensor side that is farthest from the robot's hand and measures the two-dimensional cross-sectional shape, and the known information is the angle formed by two sides including the apex of the triangular plane. The method of calculating the measurement point when the target is a triangular plane is different only in the part where the cross section Rk is rectangular, and is otherwise the same as in the case of the cone shape. In other words, the detection unit 14 detects the long side, short side, and center coordinate of the rectangle of the cross section of the target of the triangular plane as the feature value. The calculation unit 15 calculates the measurement point based on the detected feature value and the angle formed by two sides including the set apex of the target.

[0072] In the first and second embodiments, the processor 13 may cause the robot 20 to execute a predetermined operation multiple times. The processor 13 causes the sensor 30 to measure the two-dimensional cross-sectional shape of the target 21, 50 in the predetermined operation executed multiple times. The operation of causing the sensor 30 to measure the two-dimensional cross-sectional shape of the target 21, 50 in the predetermined operation executed multiple times is referred to as an error determination operation. The processor 13 calculates an error in the two-dimensional cross-sectional shape of the target 21, 50 in the predetermined operation executed multiple times. The error is calculated, for example, by the coincidence rate of the graph 41 shown in FIG. 4, which indicates the depth of the portion irradiated with the laser light 23. Note that the error calculation method is not limited to the above-mentioned example, and other known techniques may be used. When the error exceeds a first predetermined value, the processor 13 executes the error determination operation again. As a result, the position measurement system 1 can suppress the error in the feature value of the target 21, 50 calculated using the measurement value of the sensor 30, and can calculate the measurement point with high accuracy.

[0073] In the first and second embodiments, when the disturbance received from the disturbance detection device 31 exceeds a predetermined threshold, the processor 13 makes the robot 20 execute the predetermined operation again since it is considered that an error occurs in the measurement value of the sensor 30 due to the influence of the disturbance. For example, when the disturbance detection device 31 is an acceleration sensor that measures the acceleration of the robot 20, the processor 13 may make the robot 20 execute the predetermined operation again if the acceleration measured when the sensor 30 measures the two-dimensional cross-sectional shape meets a predetermined criterion. Also, when the disturbance detection device 31 is a temperature sensor that measures the temperature in the environment in which the robot 20 is placed, the processor 13 may make the robot 20 execute the predetermined operation again if the temperature measured when the sensor 30 measures the two-dimensional cross-sectional shape meets a predetermined criterion. In this way, when it is determined that the influence of the disturbance is large, the position measurement system 1 makes the robot 20 execute the predetermined operation again and measures again with the sensor 30, so that the influence of the disturbance can be suppressed and the measurement point can be calculated with high accuracy.

[0074] The position measurement system 1 may further include a wide-area sensor (not shown) that is separate from the sensor 30 and capable of measuring a wider area than the sensor 30. The wide-area sensor measures the positional relationship between the robot 20 and the sensor 30. The wide-area sensor is communicatively connected to the processor 13. The processor 13 may cause the wide-area sensor to measure the positional relationship between the robot 20 and the sensor 30, and adjust the positions of the robot 20 and the sensor 30 based on the measurement results obtained from the wide-area sensor. The wide-area sensor is a device that can measure the position of a target. The wide-area sensor is, for example, a laser range finder, a depth camera, or an RGB-D camera.

[0075] In addition, in the first and second embodiments, the control device 10 may calculate two-dimensional information of the targets 21, 50, and calculate three-dimensional information based on the two-dimensional information. For example, the control device 10 calculates two-dimensional information of the targets 21, 50 in two planes, for example, the XY plane and the YZ plane, by moving the targets 21, 50 twice at the same place by pivoting. Note that the two planes are not limited to the XY plane and the YZ plane, and are merely examples. The control device 10 calculates three-dimensional information based on the calculated two-dimensional information of the targets 21, 50 in the two planes.

[0076] (Summary of this embodiment) The above description of the present embodiment discloses the following techniques.

[0077] <Technology 1> The position measurement system of this embodiment comprises a robot having multiple axes, a target attached to the robot, a sensor that measures the two-dimensional cross-sectional shape of the target during a predetermined movement of the robot, and a processor that calculates three-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor.

[0078] As a result, the position measurement system according to this embodiment can calculate and obtain three-dimensional information about the robot based on the two-dimensional cross-sectional shape measured using a small sensor. As a result, the position measurement system can obtain the control point position of the robot in a simple measurement environment without using a large-scale device. Furthermore, since the position measurement system can measure the two-dimensional cross-sectional shape of the target by the sensor simply by moving the target into the irradiation range of the laser light emitted from the sensor, it can obtain the control point position of the robot without being limited by the postures that the control point position of the robot can take. In other words, the position measurement system can flexibly respond to posture changes of the control point position of the robot.

[0079] <Technology 2> The position measurement system described in Technology 1 includes a robot having multiple axes, a target attached to the robot, a sensor that measures a two-dimensional cross-sectional shape of the target during a predetermined movement of the robot, and a processor that outputs at least two-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor.

[0080] As a result, the position measurement system according to this embodiment can output two-dimensional information on the control point position of the robot based on the two-dimensional cross-sectional shape measured by the sensor.

[0081] <Technology 3> In the position measurement system described in Technology 1 or Technology 2, the processor includes a detection unit and a calculation unit, and the detection unit detects feature values ​​of a target based on the two-dimensional cross-sectional shape measured by the sensor, and the calculation unit calculates three-dimensional information of the robot based on the feature values ​​detected by the detection unit and information on the shape of the target.

[0082] As a result, the localization system according to the present embodiment can obtain three-dimensional information of the robot based on the feature values ​​detected by the detection unit. The localization system can obtain three-dimensional information of the robot with high accuracy through simple processing.

[0083] <Technology 4> In the position measurement system described in any one of Techniques 1 to 3, the target is spherical, and the detection unit detects, as feature values, a radius of a cross-sectional circle of the target and a circle center coordinate of the cross-sectional circle of the target in a coordinate system of the sensor, and the calculation unit calculates three-dimensional information of the robot based on the feature value and the spherical radius of the target.

[0084] As a result, in the position measurement system according to this embodiment, by using a spherical target, it is possible to calculate the coordinates of the measurement point from information on the known radius of the sphere and obtain three-dimensional information about the robot.

[0085] <Technology 5> In the position measurement system described in any one of Techniques 1 to 4, the target is conical, and the detection unit detects, as feature values, the major axis and minor axis of a cross-sectional ellipse and the center coordinates of the ellipse of the target in the coordinate system of the sensor, and the calculation unit calculates three-dimensional information of the robot based on the feature value and the cone apex angle of the target.

[0086] As a result, the position measurement system according to this embodiment uses a cone-shaped target, and can calculate the coordinates of the measurement point from information on the known apex angle of the cone, thereby determining three-dimensional information about the robot.

[0087] <Technology 6> In the position measurement system according to any one of Techniques 1 to 5, the three-dimensional information includes at least one of a three-dimensional trajectory of the robot and a three-dimensional position of the robot.

[0088] As a result, the position measurement system according to this embodiment can obtain the three-dimensional trajectory and three-dimensional position of the robot.

[0089] <Technology 7> In the position measurement system according to any one of Techniques 1 to 6, the sensor is transported by a transport device separate from the robot.

[0090] As a result, the position measurement system according to this embodiment can control the position of the sensor so that the sensor is positioned appropriately relative to the target.

[0091] <Technology 8> In a position measurement system described in any one of Technology 1 to Technology 7, a processor determines whether a target is present within a measurement range of a sensor, and if it determines that the target is not present within the measurement range, operates a robot so that the target is present within the measurement range.

[0092] As a result, the position measurement system according to this embodiment can control the target so that it is located at a position where it can be measured by the sensor 30. As a result, the position measurement system can easily bring the positional relationship between the sensor and the target into an appropriate state.

[0093] <Technology 9> In a position measurement system described in any one of Techniques 1 to 8, the processor is capable of executing an error determination operation in which the robot executes a predetermined operation multiple times and the sensor measures two-dimensional cross-sectional shapes of the target in the predetermined operation executed multiple times, and if an error in the multiple two-dimensional cross-sectional shapes measured by the sensor exceeds a first predetermined value, the error determination operation is executed again.

[0094] As a result, the position measurement system according to the present embodiment calculates measurement points under conditions in which the sensor measurement values ​​do not contain large errors, and therefore can calculate the position of the robot's control point with high accuracy.

[0095] <Technology 10> In the position measurement system according to any one of Techniques 1 to 9, a disturbance detection device is further provided for detecting a disturbance, such as a temperature change in the environment in which the robot is placed or a vibration of the robot, and when the disturbance detected by the disturbance detection device exceeds a threshold value, the processor causes the robot to perform a predetermined operation again.

[0096] As a result, when it is determined that the influence of the disturbance is large, the position measurement system according to the present embodiment causes the robot to perform the predetermined operation again and causes the sensor to measure the two-dimensional cross-sectional shape of the target again, thereby enabling the position measurement system to calculate the position of the control point of the robot with high accuracy under conditions where the influence of the disturbance is small.

[0097] <Technology 11> In the position measurement system described in any one of Techniques 1 to 10, the disturbance detection device measures the acceleration of the robot, and the processor causes the robot to perform a predetermined operation again if the acceleration measured by the disturbance detection device exceeds a second predetermined value when the sensor measures the two-dimensional cross-sectional shape.

[0098] As a result, when it is determined that the acceleration of the robot exceeds a predetermined value and the target is vibrating, the position measurement system according to the present embodiment can cause the robot to execute the predetermined operation again, thereby enabling the position measurement system to calculate the position of the control point of the robot with high accuracy under the condition that the vibration of the target is small.

[0099] <Technology 12> The position measurement system according to any one of Techniques 1 to 11 further includes a wide-area sensor that is provided separately from the sensor and is capable of measuring a wider area than the sensor.

[0100] As a result, the position measurement system according to this embodiment can measure the positional relationship between the sensor and the robot using the wide-area sensor. The position measurement system can control the sensor and the robot to have an appropriate positional relationship based on the information on the positional relationship between the sensor and the robot measured by the wide-area sensor.

[0101] <Technology 13> In the position measurement system according to any one of the first to twelfth techniques, the wide-area sensor is a laser range finder.

[0102] This enables the position measurement system according to this embodiment to measure the relative positional relationship between the sensor and the target.

[0103] <Technology 14> In the position measurement system according to any one of the first to thirteenth techniques, the wide-area sensor is a device capable of measuring the position of a target using an RGB camera.

[0104] As a result, the position measurement system according to this embodiment can control the position of the robot or the sensor by using the position of the target measured by the wide-area sensor.

[0105] <Technology 15> In the position measurement system according to any one of the techniques 1 to 14, the wide-area sensor is a depth camera or an RGB-D.

[0106] As a result, the position measurement system according to this embodiment can use the wide-area sensor to measure the distance from the wide-area sensor to the target or the sensor, the distance between the target and the sensor, and the three-dimensional positions of the target and the sensor.

[0107] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. In addition, the components in the above-mentioned embodiments may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0108] The technology disclosed herein is useful as a position measurement system and a position measurement method that accurately measures the position of a control point of a robot using a simple device. [Explanation of symbols]

[0109] 1 Positioning system 10 Control device 11 Communication I / F 12. Memory 13 Processors 14 Detection section 15 Arithmetic section 20. Robot 21,50 Target 22 Measurement range 23 Laser light 24 Connection 30 Sensors 31 Disturbance detection device 32 Transport equipment 41 Graph 42 Section circle C1,C2 points

Claims

1. A robot having multiple axes; a target attached to the robot; a sensor for measuring a two-dimensional cross-sectional shape of the target during a predetermined operation of the robot; A processor that calculates three-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor. Position measuring system.

2. A robot having multiple axes; a target attached to the robot; a sensor for measuring a two-dimensional cross-sectional shape of the target during a predetermined operation of the robot; and a processor that outputs at least two-dimensional information of the target based on the two-dimensional cross-sectional shape measured by the sensor. Position measuring system.

3. The processor includes a detection unit and a calculation unit. The detection unit detects a feature value of the target based on the two-dimensional cross-sectional shape measured by the sensor, The calculation unit calculates three-dimensional information of the robot based on the feature value detected by the detection unit and information on the shape of the target. A position measurement system according to claim 1 or 2.

4. the target is spherical; the detection unit detects, as the feature value, a radius of a cross-sectional circle of the target and a circle center coordinate of the cross-sectional circle of the target in a coordinate system of the sensor; The calculation unit calculates the three-dimensional information of the robot based on the feature value and a sphere radius of the target.

4. The position measurement system of claim 3.

5. the target is conical; the detection unit detects, as the feature value, a major axis and a minor axis of an ellipse in cross section and a center coordinate of the ellipse of the target in a coordinate system of the sensor; The calculation unit calculates the three-dimensional information of the robot based on the feature value and a cone apex angle of the target.

4. The position measurement system of claim 3.

6. The three-dimensional information includes at least one of a three-dimensional trajectory of the robot and a three-dimensional position of the robot.

2. The position measurement system of claim 1.

7. The sensor is transported by a transport device separate from the robot.

2. The position measurement system of claim 1.

8. The processor determines whether the target is present within a measurement range of the sensor; When it is determined that the target is not present within the measurement range, the robot is operated so that the target is present within the measurement range.

8. The position measurement system of claim 7.

9. The processor, an error determination operation is performed in which the robot executes the predetermined operation a plurality of times, and the sensor measures the two-dimensional cross-sectional shape of the target during the predetermined operation that has been executed a plurality of times; When an error in the two-dimensional cross-sectional shapes measured by the sensor exceeds a first predetermined value, the error determination operation is executed again.

2. The position measurement system of claim 1.

10. A disturbance detection device is further provided for detecting a disturbance such as a temperature change in an environment in which the robot is placed or a vibration of the robot, The processor causes the robot to perform the predetermined operation again when the disturbance detected by the disturbance detection device exceeds a threshold value.

2. The position measurement system of claim 1.

11. The disturbance detection device measures the acceleration of the robot, the processor causes the robot to perform the predetermined operation again when the acceleration measured by the disturbance detection device exceeds a second predetermined value in a case where the sensor measures the two-dimensional cross-sectional shape; The position measurement system of claim 10.

12. Further comprising a wide-area sensor provided separately from the sensor and capable of measuring a wider area than the sensor.

2. The position measurement system of claim 1.

13. The wide-area sensor is a laser range finder.

13. The position measurement system of claim 12.

14. The wide-area sensor is an RGB camera and is a device capable of measuring the position of the target.

13. The position measurement system of claim 12.

15. The wide-area sensor is a depth camera or RGB-D; 13. The position measurement system of claim 12.

16. A robot having multiple axes; a target attached to the robot; A processor that calculates three-dimensional information of the target based on a two-dimensional cross-sectional shape of the target during a predetermined operation of the robot received from a sensor. Position measuring system.

17. The processor includes a detection unit and a calculation unit. The detection unit detects a feature value of the target based on the two-dimensional cross-sectional shape received from the sensor, The calculation unit calculates three-dimensional information of the robot based on the feature value detected by the detection unit and information on the shape of the target.

17. The position measurement system of claim 16.

18. the target is spherical; the detection unit detects, as the feature value, a radius of a cross-sectional circle of the target and a circle center coordinate of the cross-sectional circle of the target in a coordinate system of the sensor; The calculation unit calculates the three-dimensional information of the robot based on the feature value and a sphere radius of the target.

20. The position measurement system of claim 17.

19. the target is conical; the detection unit detects, as the feature value, a major axis and a minor axis of an ellipse in cross section and a center coordinate of the ellipse of the target in a coordinate system of the sensor; The calculation unit calculates the three-dimensional information of the robot based on the feature value and a cone apex angle of the target.

20. The position measurement system of claim 17.

20. The three-dimensional information includes at least one of a three-dimensional trajectory of the robot and a three-dimensional position of the robot. A position measurement system according to any one of claims 16 to 19.

21. A trajectory measurement method for a position measurement system including a robot having multiple axes, a target attached to the robot, and a sensor for measuring a two-dimensional cross-sectional shape of the target during a predetermined motion of the robot, the method comprising the steps of: calculating a three-dimensional trajectory of the target based on the two-dimensional cross-sectional shape measured by the sensor; Position measurement method.

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