Position measuring system and position measuring method

Abstract

Provided is a position measurement system for measuring the position of a control point of a robot with high precision by a simple device. A position measurement system includes: a robot having a plurality of axes; an object attached to the robot; a sensor that measures a two-dimensional cross-sectional shape of an object in a predetermined operation of the robot; and a processor that computes three-dimensional information of the object on the basis of the two-dimensional cross-sectional shape measured by the sensor. The processor includes a detection unit that detects a feature value of the object on the basis of the two-dimensional cross-sectional shape measured by the sensor, and a calculation unit that calculates three-dimensional information of the robot on the basis of the feature value detected by the detection unit and information relating to the shape of the object.

Description

Technical Field

[0001] The present disclosure relates to a position determination system and a position determination method. Background Art

[0002] Patent Document 1 discloses a method for calibrating a working robot. After the working robot is installed in a production facility, the deviation amount (offset amount) of the encoder installed on each axis of the working robot is calculated, and the teaching program is automatically corrected.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-038662 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure has been made in view of the above-mentioned conventional situation, and an object of the present disclosure is to measure the position of a control point of a robot with high accuracy using a simple device.

[0008] Technical solutions to solve problems

[0009] The present disclosure provides a position measurement system, comprising: a robot having multiple axes; an object mounted on the robot; a sensor for measuring a two-dimensional cross-sectional shape of the object in a given action of the robot; and a processor for calculating three-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

[0010] In addition, the present disclosure provides a position measurement system, comprising: a robot having multiple axes; an object mounted on the robot; a sensor for measuring the two-dimensional cross-sectional shape of the object in a given action of the robot; and a processor for outputting at least two-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

[0011] In addition, the present disclosure provides a position measurement system, comprising: a robot having a drive axis; an object mounted on the robot; and a processor, which detects feature values ​​of the object based on the two-dimensional cross-sectional shape of the object in a given action 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 object.

[0012] In addition, the present disclosure provides a position measurement method, which is a position measurement method of a position measurement system, wherein the position measurement system comprises: a robot having a drive axis; an object mounted on the robot; and a sensor for measuring the two-dimensional cross-sectional shape of the object in a given action of the robot, the position measurement method comprising: a step of detecting a feature value of the object based on the two-dimensional cross-sectional shape measured by the sensor; and a step of calculating a three-dimensional trajectory of the robot based on the detected feature value and information related to the shape of the object.

[0013] In addition, these general or specific aspects may be implemented by a system, an apparatus, a method, an integrated circuit, a computer program or a recording medium, or may be implemented by any combination of systems, apparatuses, methods, integrated circuits, computer programs and recording media.

[0014] Effects of the Invention

[0015] According to the present disclosure, the position of the control point of the robot can be measured with high accuracy by a simple device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a system structure diagram of the position measurement system.

[0017] Figure 2 It is a diagram showing a method for measuring the depth of a two-dimensional cross section of an object.

[0018] Figure 3 It is a diagram showing various feature values ​​of an object.

[0019] Figure 4 It is a diagram showing a cross-sectional circle of a detected object.

[0020] Figure 5 It is a diagram showing a method for measuring the depth of a two-dimensional cross section of an object.

[0021] Figure 6 This is a diagram of a cross section of an object as viewed from a first direction.

[0022] Figure 7 This is a diagram of a cross section of the object as viewed from the second direction.

[0023] Figure 8 This is a diagram showing an object rotated by a given angle.

[0024] Fig. 9 is a graph showing various parameters.

[0025] Description of Reference Numerals

[0026] 1: Position measurement system

[0027] 10: Control device

[0028] 11: Communication I / F

[0029] 12: Memory

[0030] 13: Processor

[0031] 14: Inspection Department

[0032] 15: Operation unit

[0033] 20: Robot

[0034] 21, 50: Object

[0035] 22: Measurement range

[0036] 23: Laser

[0037] 24: Connection

[0038] 30: Sensor

[0039] 31: Interference detection device

[0040] 32: Transport device

[0041] 41: Curve

[0042] 42: Section circle

[0043] C1, C2: points. DETAILED DESCRIPTION

[0044] (Process of realizing this embodiment)

[0045] When controlling a robot, in order to position the front end of the robot to the 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 fingertips. However, errors in various parameters are inevitable during the processing or assembly of the robot, and it is difficult to directly measure the parameters of the assembled robot. Therefore, in order to control the robot with high precision, it is necessary to measure the relationship between the input displacement and the output displacement of the robot after assembly, and perform calibration to estimate and correct the optimal value of the parameter based on the measurement result. There are various calibration methods, for example, there is a known method that uses information on the actual control point position of the robot and the control point position of the target.

[0046] In order to locate the actual control points of the robot with high precision, it is necessary to accurately find the parameters required for calculating the three-dimensional trajectory of the robot. As previous three-dimensional trajectory measurement methods, there are methods using laser marker tracking, stereoscopic observation or direct linear transformation (Direct Linear Transformation) method (hereinafter referred to as "DLT method") and the like. However, in the case of the method using laser as disclosed in Patent Document 1, there are problems such as the device being bulky or being unable to cope with the posture changes of the control points. In addition, in the case of the DLT method, since the robot is surrounded by multiple cameras, there is a problem that the device becomes bulky. In addition, in the case of stereoscopic observation, there are problems such as difficulty in adjusting with high precision the optical system that requires high-precision calibration of multiple cameras and depends on the accuracy of calibration or being affected by visible light interference.

[0047] Hereinafter, with appropriate reference to the accompanying drawings, the embodiments of the position measurement system and the position measurement method specifically disclosed in the present disclosure are described in detail. However, detailed descriptions beyond necessity are sometimes omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures are sometimes omitted. This is to avoid the following description from becoming unnecessarily lengthy and to make it easy for those skilled in the art to understand. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims through them.

[0048] First, refer to Figure 1 , the system structure of the position measurement system 1 is described. Figure 1 1 is a system configuration diagram of the position measurement system 1 .

[0049] The position measurement system 1 includes a control device 10 , a robot 20 , a sensor 30 , an interference detection device 31 , and a conveying device 32 .

[0050] The control device 10 is a device that controls the movement of the robot and calculates the position of the control point of the robot. The control device 10 includes a communication I / F 11 , a memory 12 , and a processor 13 .

[0051] The communication I / F 11 is an interface circuit for 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 interference detection device 31. Here, I / F represents an interface. The communication method using the communication I / F 11 is, for example, a wide area network (Wide Area Network), a local area network (Local Area Network), long term evolution (Long Term Evolution), 4G, 5G and other mobile communications, power line communication, short-range wireless communication (such as Bluetooth (registered trademark) communication), or communication for a portable phone.

[0052] The memory 12 is composed of, for example, a random access memory (RAM) and a read only memory (ROM), and temporarily stores programs required for the operation of the control device 10 and data generated during the operation. The RAM is, for example, a working memory used in the operation of the control device 10. The ROM stores and stores, for example, a program for controlling the control device 10 in advance.

[0053] The processor 13 is, for example, a central processing unit (CPU), a digital signal processor (DSP), a graphic processing unit (GPU), or a field programmable gate array (FPGA). The processor 13 functions as a controller that controls the overall operation of the control device 10. The processor 13 performs control processing for overall control of the operation of each part of the device 10, data input and output processing between the various parts of the control device 10, data calculation processing, and data storage processing. The processor 13 operates according to the program stored in the memory 12. The processor 13 uses the memory 12 when operating, and temporarily stores the 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 point as a calculation result to an external device (not shown) based on the three-dimensional trajectory of the object 21, 50 calculated by the calculation unit 15.

[0054] The detection unit 14 detects the characteristic value based on the two-dimensional cross-sectional shape of the object 21 or 50 output from the sensor 30. The characteristic value is described in detail in each of the first embodiment and the second embodiment.

[0055] The calculation unit 15 calculates the three-dimensional trajectory of the object 21 or 50 using the feature value output from the detection unit 14 and the information on the shape of the object 21 or 50. The detailed processing performed by the calculation unit 15 is described in detail in the first and second embodiments.

[0056] The robot 20 is a robot having a drive axis. The robot 20 is, for example, a welding robot, a vertical multi-joint robot having an arm, a selective compliance assembly robot arm (SCARA) robot, a CNC machine tool (five-axis machining center, etc.), or an assembly machine. In particular, the present invention is effective for a robot 20 having four or more drive axes and capable of achieving different postures at any position. The robot 20 is equipped with objects 21 and 50.

[0057] The object 21, 50 is a fixture made of metal or the like and mounted on the robot 20. The object 21, 50 needs to be a fixture that can determine the shape of a specific point of the object 21, 50 based on the information of the two-dimensional cross-sectional shape detected by the sensor 30 and the known information about the shape of the object 21. For example, the object 21, 50 is a fixture such as a sphere, a cone, or a triangular plane with a limited thickness. In addition, the object 21, 50 is not limited to a sphere, a cone, or a triangular plane, and can be any shape as long as the shape of a specific point of the object 21, 50 can be determined based on the two-dimensional cross-sectional shape and the known information about the shape of the object 21, 50.

[0058] The sensor 30 is a device for measuring the cross-sectional shape of the object 21, 50. The sensor 30 may be, for example, a semiconductor laser for visible light. The sensor 30 is a small sensor of about 20 [cm] and a measuring range of about 30 [cm]. In addition, 20 [cm] is an example of the size of the sensor 30 and is not limited thereto. In addition, 30 [cm] is an example of the measuring range of the sensor 30 and is not limited thereto. The sensor 30 may be fixedly set at a given position or may be mounted on a conveying device 32 and controlled so as to be movable. The conveying device 32 may be, for example, a device that moves on a track by a motor or the like. In addition, the conveying device 32 may also be omitted. In addition, the sensor 30 may also be manually movable.

[0059] The interference detection device 31 is a device that detects interference in the environment where the robot 20 is placed. The interference 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 interference detection device 31 is an acceleration sensor, the processor 13 uses the acceleration of the robot 20 as an indicator to determine whether the vibration of the robot 20 is within the allowable range.

[0060] <Implementation Method 1>

[0061] 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 object 21 is a sphere (a sphere with almost extremely small sphericity) is described. In the first embodiment, the center of the sphere of the object 21 is fixed 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 object 21. In the first embodiment, the center position of the sphere of the object 21 is set as a point of the measurement object (hereinafter referred to as a "measurement point").

[0062] Reference Figure 2 , a method for measuring the two-dimensional cross-sectional depth of the object 21 is described. Figure 2 1 is a diagram showing a method for measuring the depth of a two-dimensional cross section of the object 21 .

[0063] The sensor 30 irradiates the laser beam 23 to the object 21, and measures the depth of the object 21 (that is, the length of the object 21 in the depth direction (that is, the optical axis direction) from the irradiation surface of the object 21 irradiated by the laser beam 23) by detecting the reflected light from the object 21. The depth of the object 21 is calculated using a known technique.

[0064] The measurement range 22 is the range of the laser 23 radiated radially in a two-dimensional plane. The sensor 30 is fixed at a given position, and the depth of the object 21 is measured by moving the object 21 in the measurement range 22. In addition, the position of the sensor 30 relative to the object 21 may be controlled by the conveying device 32. Here, the processor 13 determines whether the object 21 exists in the measurement range 22 of the sensor 30 based on the measurement result sent from the sensor 30. When the processor 13 determines that the object 21 exists in the measurement range 22, the robot 20 performs a given action to measure the two-dimensional cross-sectional shape of the object 21. Here, the so-called given action is, for example, an action of moving in the X-axis direction in the measurement range 22 at a predetermined speed and acceleration. In addition, the given action is not limited to the above example, and can be arbitrarily set by the user. When the processor 13 determines that the object 21 does not exist in the measurement range 22, the robot 20 moves to control the position of the object 21 so that the object 21 exists in the measurement range 22. Alternatively, when the processor 13 determines that the object 21 does not exist within the measurement range 22 , the processor 13 may operate the conveying device 32 to control the position of the sensor 30 so that the object 21 exists within the measurement range 22 .

[0065] Next, refer to Figure 3 as well as Figure 4 , a method for measuring the three-dimensional position of the object 21 is described. Figure 3 2 is a diagram showing various feature values ​​of the object 21 . Figure 4 It is a diagram showing a cross-sectional circle of the detected object 21 .

[0066] like Figure 3 As shown in FIG. 1 , the tip of the object 21 is spherical. Hereinafter, the object 21 is assumed to be the spherical portion of the tip. Point C1 is the center of the object 21. The AA section is the section measured by the sensor 30. Figure 3 In the two-dimensional plane of the AA section shown in FIG. 1 , the direction from the point C2 which is the center of the AA section toward the connection portion 24 connecting the object 21 and the robot 20 is set as the X axis. In the two-dimensional plane of the AA section, the axis orthogonal to the X axis is set as the Y axis. The axis orthogonal to the X axis and the Y axis is set as the Z axis. The XYZ coordinates are coordinates set for the measurement system based on the sensor 30 (refer to Figure 2 ). In addition, the expressions related to these directions are used for convenience of explanation and are not intended to limit the posture of the structure during actual use.

[0067] The XYZ coordinates of the point C1, which is the center of the object 21, are represented by (X S , Y S , Z S ). Let the length of the radius of the sphere of the object 21 be Rs. Let the XY coordinates of the point C2, which is the center of the AA cross section, be (X C , Y C ). The length of the radius of the AA section of the object 21 is denoted as Rc. Hereinafter, the AA section is referred to as a cross-sectional circle.

[0068] Figure 4 The curve 41 shown represents the depth of the portion of the object 21 irradiated with the laser beam 23 detected by the sensor 30. The vertical axis of the curve 41 represents the depth of the object 21 in the Y direction, and the horizontal axis represents the distance from the reference point in the X direction. The reference point is a zero point arbitrarily set for the sensor 30.

[0069] The detection unit 14 approximates the cross-sectional circle 42 based on the information on the depth of the object 21 detected by the sensor 30 (that is, the curve 41). The detection unit 14 calculates the XY coordinates (XY coordinates) of the point C2 which is the center of the cross-sectional circle 42 based on the cross-sectional circle 42. C , Y C ) and the radius Rc of the cross-sectional circle are used as feature values. The detection unit 14 outputs the feature values ​​to the calculation unit 15.

[0070] The calculation unit 15 calculates the XY coordinate (XY coordinate) of the point C2 at the center of the cross-sectional circle 42 based on the characteristic value received from the detection unit 14. C , Y C) and the radius Rc of the cross-sectional circle, and known information about the shape of the object 21, the coordinates (X S , Y S , Z S ). The known information about the shape of the object 21 is the radius Rs of the sphere of the object 21. The calculation unit 15 calculates the coordinates (X S , Y S , Z S ).

[0071]

Mathematical formula 1

[0072] X S =X C (1)

[0073]

Mathematical formula 2

[0074] Y S =Y C (2)

[0075]

Mathematical formula 3

[0076]

[0077] In this way, the position measuring system 1 can obtain the coordinates (X / X) of the center point C1 of the object 21 which is equal to the control point position of the robot 20 based on the characteristic value of the cross-sectional circle of the spherical object 21 detected by the sensor 30. S , Y S , Z S ). The position measurement system 1 uses a small sensor 30 to obtain the measurement point of the object 21 installed on the robot 20, thereby being able to obtain the control point position (or control point trajectory) of the robot 20 with high accuracy without the need for a large device. In addition, the position measurement system 1 outputs at least two-dimensional information of the control point position of the robot 20. In addition, the position measurement system 1 can calculate the measurement point by moving the object 21 within the measurement range 22 of the sensor 30, so regardless of the posture angle of the control point of the robot 20 (that is, even if the posture angle of the control point of the robot 20 changes significantly), the control point position (or control point trajectory) of the robot 20 can be obtained with high accuracy.

[0078] The position measurement system 1 calculates the coordinates (X S , Y S , Z S) as the actual control point position (or control point trajectory) of the robot 20, that is, the measured value. The position measurement system 1 is calibrated based on the information of the measured value and the target value of the control point position (or control point trajectory) as the target. As a calibration, for example, the mechanism parameters of the robot 20 are adjusted. The so-called mechanism parameters of the robot 20 are, for example, the parameters used in the relationship that determines the correlation between the displacement (input) of each drive shaft of the robot 20 and the front end position (output) of the robot 20 used when controlling the robot 20. Representative examples of parameters include the length of the connecting rod, the origin position of each driving shaft, the tooth backlash caused by the rotation direction of the shaft, the elastic deformation of the connecting rod or the elastic deformation of the reducer, etc. The position measurement system 1 is based on the obtained coordinates (X S , Y S , Z S ) (that is, the control point position of the robot 20) to adjust the above parameters, thereby performing calibration. In addition, the adjusted parameters are not limited to the above examples.

[0079] In addition, in the first embodiment, a method of calculating the three-dimensional position information of X, Y, and Z is shown, but any two or more of them may be used, and posture information may be used in addition. In acquiring the posture information, for example, two or more sensors 30 for measuring the two-dimensional cross-sectional shape may be provided to measure two or more parts of the object 21, and further, the two-dimensional cross-sectional shape may be acquired by conveying the sensor 30 by a conveying device through two pivoting operations.

[0080] <Implementation Method 2>

[0081] 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 object 50 is a cone is described. In the second embodiment, the apex of the cone shape of the object 50 is fixed 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 object 50. In the second embodiment, the apex of the cone of the object 50 is set as the measurement point.

[0082] First, refer to Figure 5 , a method for measuring the two-dimensional cross-sectional depth of the object 50 is described. Figure 5 1 is a diagram showing a method for measuring the depth of a two-dimensional cross section of an object 50 .

[0083] As in the first embodiment, the laser light 23 emitted from the sensor 30 is irradiated onto the object 50, and the depth of the object 50 is measured by detecting the reflected light from the object 50. The control device 10 moves the object 50 within the measurement range 22 so that the cross section of the object 50 obtained based on the laser light 23 from the sensor 30 passes through the rotation axis of the cone.

[0084] Next, refer to Figure 6 , 7 , 8, and 9 illustrate a method for calculating measurement points of the object 50. Figure 6 This is a diagram of a cross section of the object 50 as viewed from the first direction. Figure 7 This is a diagram of a cross section of the object 50 as viewed from the second direction. Figure 8 FIG. 5 is a diagram showing an object 50 rotated by a given angle. Fig. 9 is a graph showing various parameters.

[0085] The xyz coordinates are set for the sensor 30. The direction in which the laser is emitted from the sensor 30 is set as the x-axis. The axes orthogonal to the x-axis are set as the y-axis and the z-axis, respectively. In addition, the y-axis and the z-axis are orthogonal. In addition, the expressions involving these directions are used for convenience of explanation and are not intended to limit the posture of the structure when it is actually used.

[0086] like Figure 6 As shown, a surface of the object 50 cut in the irradiation surface of the laser beam 23 is a cross section Rk. The apex angle of the cone of the object 50 is 2A.

[0087] Figure 7 Observed from the positive direction of the z axis Figure 6 The cross section Rk is an elliptical shape. The xyz coordinates of the point M at the center of the cross section Rk are (xe, ye, ze). The xyz coordinates of the point O which is the vertex of the cone of the object 50 are (x S ,y S , z S In the second embodiment, the measurement point is point O (x S ,y S , z S ), the known information about the object 50 is the apex angle 2A of the cone.

[0088] The length of the major radius 4 of the cross section Rk is represented by a, and the length of the minor radius 5 is represented by b. In addition, the angle formed by the x-axis and the major axis of the cross section Rk is represented by an angle The coordinates of point M (xe, ye, ze), the length a of the major radius 4, the length b of the minor radius 5, and the angle is information obtained from the cross-sectional shape output from the sensor 30 and is a feature value extracted by the detection unit 14.S ,y S , z S ) export method.

[0089] Figure 8 yes Figure 7 The object 50 is shown rotated by an angle about an axis passing through point M and parallel to the z-axis. If the object 50 is rotated by an angle about an axis passing through point M and parallel to the z-axis The major axis of the cross section Rk is parallel to the x-axis, and the minor axis of the cross section Rk is parallel to the y-axis. The coordinates of the point O' which is the vertex of the cone at that time are (x's, y's, z's). The relationship between the point O and the mathematical formula 4 is as shown in formulas (4), (5), and (6).

[0090]

Mathematical formula 4

[0091]

[0092]

Mathematical formula 5

[0093]

[0094]

Mathematical formula 6

[0095]

[0096]

Mathematical formula 7

[0097]

[0098] Here,

[0099]

Mathematical formula 8

[0100]

[0101] The angle between the plane whose normal line is the axis of the cone and the cross section Rk is θ (0°<θ<90°-A) (refer to Fig. 9 ). Fig. 9 It is a cross-sectional view of a plane passing through point M which is the center of the cross section Rk and parallel to the xz plane. Fig. 9 In the figure, we focus on triangle ABC. According to the law of sines, it becomes

[0102]

Mathematical formula 9

[0103] |CA|=2a, so it becomes

[0104]

Mathematical formula 10

[0105]

[0106]

Mathematical formula 11

[0107]

[0108] Furthermore, the eccentricity e of the cross-sectional ellipse (that is, the cross section Rk) when the object 50 is cut at the angle θ is expressed by the formula (10) using the apex angle of the cone and the angle θ.

[0109]

Mathematical formula 12

[0110]

[0111] Furthermore, according to the definition of the eccentricity of an ellipse, the eccentricity e is expressed by formula (11).

[0112]

Mathematical formula 13

[0113]

[0114] According to formula (10) and formula (11), it becomes mathematical formula 14.

[0115]

Mathematical formula 14

[0116]

[0117] Furthermore, equation 15 becomes equation 16 and equation 17.

[0118]

Mathematical formula 15

[0119]

[0120]

Mathematical formula 16

[0121]

[0122]

Mathematical formula 17

[0123]

[0124] Here, it is mathematical formula 18,

[0125]

Mathematical formula 18

[0126]

[0127] According to formula (8) and formula (9), we get formula 19:

[0128]

Mathematical formula 19

[0129]

[0130] Therefore, the mathematical formula becomes 20.

[0131]

Mathematical formula 20

[0132]

[0133] This yields mathematical formula 21.

[0134]

Mathematical formula 21

[0135]

[0136] According to formula (13), point O' becomes formula (14).

[0137]

Mathematical formula 22

[0138]

[0139] According to formulas (4), (5), (6), and (14), we get formula 23.

[0140]

Mathematical formula 23

[0141]

[0142] Here, it can be transformed into mathematical formula 24,

[0143]

Mathematical formula 24

[0144]

[0145] Therefore, the mathematical formula becomes 25.

[0146]

Mathematical formula 25

[0147]

[0148] Deleting the angle θ from equation (12), equation 26, and equation (15) yields equation 27.

[0149]

Mathematical formula 26

[0150]

[0151]

Mathematical formula 27

[0152]

[0153] Based on the above, the operation unit 15 can calculate the xyz coordinates (x y z ) of the point O as the measurement point by using the formula (16) based on the information of the feature value output from the detection unit 14 and the known information of the object 50. S ,y S, z S ).

[0154] In the second embodiment, a method of calculating the three-dimensional position information of X, Y, and Z is shown, but any two or more of them may be used, and the posture information may be used in addition. In acquiring the posture information, for example, two or more sensors 30 for measuring the two-dimensional cross-sectional shape may be provided to measure two or more parts of the object 21, and the two-dimensional cross-sectional shape may be acquired by conveying the sensor 30 by a conveying device through two pivoting operations.

[0155] Based on the above, the position measurement system 1 can obtain the xyz coordinates (x,y,z) of the point O as the measurement point of the object 50 which is equal to the control point position of the robot 20 based on the feature value of the conical object 50 detected by the sensor 30. S ,y S , z S ). Thus, in Embodiment 2, similarly to Embodiment 1, the position measurement system 1 uses a small sensor 30 to obtain the measurement point of the object 50 mounted on the robot 20, thereby being able to obtain the control point position (or control point trajectory) of the robot 20 with high accuracy without requiring a large device. In addition, the position measurement system 1 can calculate the measurement point by moving the object 50 within the measurement range 22 of the sensor 30, so that the control point position (or control point trajectory) of the robot 20 can be obtained with high accuracy regardless of the posture angle of the control point of the robot 20 (that is, even if the posture angle of the control point of the robot 20 changes significantly).

[0156] In the second embodiment, the object 50 is described using a conical object, but the object is not limited to a conical shape and may be a triangular plane with a limited thickness. In this case, a certain point of the triangular plane is determined as a vertex, and Figure 5 The case of the cone shape shown is similarly configured with respect to the sensor 30. In the triangular plane, the measurement point is the XYZ coordinate of the vertex on the sensor side that is farthest from the fingertip of the robot and measures the two-dimensional cross-sectional shape, and the known information is the angle formed by the two sides containing the vertex of the triangular plane. Regarding the calculation method of the measurement point when the object is a triangular plane, only the part where the cross section Rk becomes a rectangle is different, and the rest is the same as the case of the cone shape. That is, the detection unit 14 detects the long side, short side and center coordinates of the rectangle of the cross section of the object of the triangular plane as feature values. The calculation unit 15 calculates the measurement point based on the detected feature values ​​and the angle formed by the two sides containing the vertex determined by the object.

[0157] In Embodiment 1 and Embodiment 2, the processor 13 may cause the robot 20 to perform a given action multiple times. The processor 13 causes the sensor 30 to measure the two-dimensional cross-sectional shape of the object 21, 50 in the given action that is performed multiple times. Causing the sensor 30 to measure the two-dimensional cross-sectional shape of the object 21, 50 in the given action that is performed multiple times is called an error determination action. The processor 13 calculates the error of the two-dimensional cross-sectional shape of the object 21, 50 in the given action that is performed multiple times. In the error calculation method, for example, by Figure 4 The calculation is performed by the consistency rate of the curve 41 showing the depth of the portion irradiated with the laser 23 shown in FIG. 1 . In addition, the method for calculating the error is not limited to the above example, and other well-known techniques can be used. When the error exceeds the predetermined first given value, the processor 13 performs the error determination operation again. Thus, the position measurement system 1 can suppress the error of the characteristic value of the object 21, 50 calculated using the measurement value of the sensor 30, thereby calculating the measurement point with high accuracy.

[0158] In addition, in the first and second embodiments, when the interference received from the interference detection device 31 exceeds a given threshold, the processor 13 determines that an error has occurred in the measurement value of the sensor 30 due to the influence of the interference, and thus causes the robot 20 to perform a given action again. For example, when the interference detection device 31 is an acceleration sensor that measures the acceleration of the robot 20, the processor 13 may cause the robot 20 to perform a given action again when the acceleration measured by the sensor 30 when measuring the two-dimensional cross-sectional shape satisfies a given reference. In addition, when the interference detection device 31 is a temperature sensor that measures the temperature of the environment in which the robot 20 is placed, the processor 13 may cause the robot 20 to perform a given action again when the temperature when the sensor 30 measures the two-dimensional cross-sectional shape satisfies a given reference. In this way, when it is determined that the influence of the interference is large, the position measurement system 1 causes the robot 20 to perform a given action again to measure again by the sensor 30, so that the influence of the interference can be suppressed and the measurement point can be calculated with high accuracy.

[0159] In addition, the position measurement system 1 may also include a wide area sensor (not shown) that can measure a wider area than the sensor 30, and the wide area sensor is separate from the sensor 30. The wide area sensor measures the positional relationship between the robot 20 and the sensor 30. The wide area sensor and the processor 13 are connected so as to be communicable. The processor 13 may also 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 an object. The wide area sensor is, for example, a laser rangefinder, a depth camera, or an RGB-D camera.

[0160] In addition, in Embodiment 1 and Embodiment 2, the control device 10 may also calculate the two-dimensional information of the object 21, 50, and calculate the three-dimensional information based on the two-dimensional information. For example, the control device 10 causes the object 21, 50 to move twice in the same place through a pivoting action, thereby calculating the two-dimensional information of the object 21, 50 in two planes, such as the XY plane and the YZ plane. In addition, regarding the two planes, the XY plane and the YZ plane are examples and are not limited. The control device 10 calculates the three-dimensional information based on the calculated two-dimensional information of the object 21, 50 in the two planes.

[0161] (Summary of this embodiment)

[0162] According to the above description of the present embodiment, the following technology is disclosed.

[0163] <Technology 1>

[0164] The position measurement system involved in this embodiment comprises: a robot having multiple axes; an object mounted on the robot; a sensor for measuring the two-dimensional cross-sectional shape of the object in a given action of the robot; and a processor for calculating three-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

[0165] Thus, the position measurement system involved in this embodiment can calculate and obtain the three-dimensional information of the robot based on the two-dimensional cross-sectional shape measured using a small sensor. Thus, the position measurement system can obtain the control point position of the robot through a simple measurement environment without using a large device. In addition, the position measurement system can measure the two-dimensional cross-sectional shape of the object by the sensor only by moving the object within the irradiation range of the laser emitted from the sensor, so that the control point position of the robot can be obtained without being restricted by the posture that the control point position of the robot may take. In other words, the position measurement system can flexibly respond to the posture changes of the control point position of the robot.

[0166] <Technology 2>

[0167] The position measurement system described in technology 1 comprises: a robot having multiple axes; an object mounted on the robot; a sensor for measuring the two-dimensional cross-sectional shape of the object in a given action of the robot; and a processor for outputting at least two-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

[0168] Thus, the position measurement system according to the present embodiment can output two-dimensional information on the control point positions of the robot based on the two-dimensional cross-sectional shape measured by the sensor.

[0169] <Technology 3>

[0170] In the position measurement system described in Technology 1 or Technology 2, the processor includes a detection unit and a calculation unit. The detection unit detects characteristic values ​​of an object based on a two-dimensional cross-sectional shape measured by a sensor, and the calculation unit calculates three-dimensional information of the robot based on the characteristic values ​​detected by the detection unit and information related to the shape of the object.

[0171] Thus, the position measurement system according to the present embodiment can obtain the three-dimensional information of the robot based on the feature value detected by the detection unit. The position measurement system can obtain the three-dimensional information of the robot with high accuracy through simple processing.

[0172] <Technique 4>

[0173] In the position measurement system described in any one of Technology 1 to Technology 3, the object is spherical, the detection unit detects the radius of the cross-sectional circle of the object and the center coordinates of the cross-sectional circle of the object in the coordinate system of the sensor as feature values, and the calculation unit calculates the three-dimensional information of the robot based on the feature value and the spherical radius of the object.

[0174] Thus, in the position measurement system according to the present embodiment, by using a spherical object, the coordinates of the measurement points can be calculated based on the known information on the radius of the sphere, thereby obtaining the three-dimensional information of the robot.

[0175] <Technique 5>

[0176] In the position measurement system described in any one of Technology 1 to Technology 4, the object is cone-shaped, the detection unit detects the major diameter and minor diameter of the cross-sectional ellipse and the ellipse center coordinates of the object in the coordinate system of the sensor as feature values, and the calculation unit calculates the three-dimensional information of the robot based on the feature values ​​and the cone apex angle of the object.

[0177] Thus, the position measurement system according to the present embodiment uses a cone-shaped object, and can calculate the coordinates of the measurement points based on known information on the apex angle of the cone, thereby obtaining three-dimensional information of the robot.

[0178] <Technique 6>

[0179] In the position measurement system described in 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.

[0180] Thus, the position measurement system according to the present embodiment can obtain the three-dimensional trajectory and three-dimensional position of the robot.

[0181] <Technique 7>

[0182] In the position measuring system described in any one of Techniques 1 to 6, the sensor is transported by a transport device that is separate from the robot.

[0183] Thus, the position measurement system according to the present embodiment can control the position of the sensor so that the sensor is at an appropriate position relative to the object.

[0184] <Technology 8>

[0185] In the position measurement system described in any one of techniques 1 to 7, the processor determines whether an object exists within the measurement range of the sensor, and if it is determined that the object does not exist within the measurement range, the processor moves the robot so that the object exists within the measurement range.

[0186] Thus, the position measurement system according to the present embodiment can perform control so that the object comes to a position measurable by the sensor 30. Thus, the position measurement system can easily set the positional relationship between the sensor and the object to an appropriate state.

[0187] <Technique 9>

[0188] In the position measurement system recorded in any one of Technology 1 to Technology 8, the processor is capable of causing the robot to perform a given action multiple times, and performing an error judgment action in which the sensor measures the two-dimensional cross-sectional shape of the object in the given action performed multiple times, and when the error of the multiple two-dimensional cross-sectional shapes measured by the sensor exceeds a first given value, the error judgment action is performed again.

[0189] Thus, the position measurement system according to the present embodiment calculates the measurement point under the condition that the measurement value of the sensor does not include a large error, and thus can calculate the position of the control point of the robot with high accuracy.

[0190] <Technique 10>

[0191] In the position measurement system recorded in any one of Technology 1 to Technology 9, there is also an interference detection device for detecting interference, wherein the interference is temperature changes in the environment in which the robot is placed or vibrations of the robot. When the interference detected by the interference detection device exceeds a threshold, the processor causes the robot to perform a given action again.

[0192] Therefore, when the position measurement system of this embodiment determines that the influence of the interference is large, the robot performs the given action again and the sensor measures the two-dimensional cross-sectional shape of the object again. As a result, the position measurement system can calculate the position of the robot's control point with high accuracy under the condition that the influence of the interference is small.

[0193] <Technology 11>

[0194] In the position measurement system described in any one of Technology 1 to Technology 10, the interference detection device measures the acceleration of the robot, and when the sensor measures a two-dimensional cross-sectional shape, the processor causes the robot to perform a given action again when the acceleration measured by the interference detection device exceeds a second given value.

[0195] Thus, the position measurement system of this embodiment can make the robot perform a given action again when it is determined that the acceleration of the robot exceeds a given value and the object is vibrating. Thus, the position measurement system can calculate the position of the control point of the robot with high accuracy under the condition that the vibration of the object is small.

[0196] <Technology 12>

[0197] The position measurement system according to any one of the techniques 1 to 11 further includes a wide area sensor which is provided separately from the sensor and can measure a wider area than the sensor.

[0198] Thus, the position measurement system according to the present 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.

[0199] <Technology 13>

[0200] In the position measurement system described in any one of Techniques 1 to 12, the wide area sensor is a laser rangefinder.

[0201] Thus, the position measurement system according to the present embodiment can measure the relative positional relationship between the sensor and the object.

[0202] <Technology 14>

[0203] In the position measurement system described in any one of Techniques 1 to 13, the wide area sensor is a device capable of measuring the position of an object using an RGB camera.

[0204] Thus, the position measurement system according to the present embodiment can control the position of the robot or the sensor using the position of the object measured by the wide area sensor.

[0205] <Technology 15>

[0206] In the position measurement system described in any one of Techniques 1 to 14, the wide area sensor is a depth camera or RGB-D.

[0207] Thus, the position measurement system according to the present embodiment can measure the distance between an object or the sensor and the wide area sensor, the distance between an object and the sensor, and the three-dimensional position of the object and the sensor using the wide area sensor.

[0208] The above embodiments are described with reference to the accompanying drawings, but the present disclosure is not limited to the above examples. It is understood that, if a person skilled in the art can obviously think of various changes, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, they also belong to the technical scope of the present disclosure. In addition, the various components in the above embodiments can also be combined arbitrarily without departing from the scope of the main purpose of the invention.

[0209] Industrial Applicability

[0210] The technology disclosed in the present invention is useful as a position measurement system and a position measurement method for measuring the position of a control point of a robot with high accuracy using a simple device.

Claims

1. A position measurement system comprising: Robots, with multiple axes; An object, mounted on the robot; a sensor for measuring a two-dimensional cross-sectional shape of the object in a given motion of the robot; and The processor calculates three-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

2. The position determination system according to claim 1, wherein: The processor includes a detection unit and a calculation unit. The detection unit detects a characteristic value of the object 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 about the shape of the object.

3. The position determination system according to claim 2, wherein: The object is spherical, The detection unit detects, as the feature value, a radius of a cross-sectional circle of the object and a circle center coordinate of the cross-sectional circle of the object in a coordinate system of the sensor, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the spherical radius of the object.

4. The position determination system according to claim 2, wherein: The object is conical. The detection unit detects the major diameter and the minor diameter of the cross-sectional ellipse and the ellipse center coordinates of the object in the coordinate system of the sensor as the feature values, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the cone apex angle of the object.

5. The position determination system according to claim 1, wherein: The three-dimensional information includes at least one of a three-dimensional trajectory of the robot and a three-dimensional position of the robot.

6. The position determination system according to claim 1, wherein: The sensor is transported by a transport device that is separate from the robot.

7. The position determination system according to claim 6, wherein: The processor determines whether the object exists within the measurement range of the sensor. When it is determined that the object does not exist within the measurement range, the robot is operated so that the object exists within the measurement range.

8. The position determination system according to claim 1, wherein: The processor is capable of causing the robot to perform the given action multiple times, and performing an error determination operation of causing the sensor to measure the two-dimensional cross-sectional shape of the object in the given action performed multiple times. The processor executes the error determination operation again when an error among the plurality of two-dimensional cross-sectional shapes measured by the sensor exceeds a first predetermined value.

9. The position determination system according to claim 1, wherein: The position measurement system further includes a disturbance detection device for detecting disturbance, wherein the disturbance is a temperature change in an environment in which the robot is placed or a vibration of the robot. When the interference detected by the interference detection device exceeds a threshold, the processor causes the robot to perform the given action again.

10. The position determination system according to claim 9, wherein: The interference detection device measures the acceleration of the robot, When the sensor measures the two-dimensional cross-sectional shape, and when the acceleration measured by the interference detection device exceeds a second predetermined value, the processor causes the robot to perform the predetermined action again.

11. The position determination system according to claim 1, wherein: The position measurement system further includes a wide area sensor provided separately from the sensor, and the wide area sensor can measure a wider area than the sensor.

12. The position determination system according to claim 11, wherein: The wide area sensor is a laser rangefinder.

13. The position determination system according to claim 11, wherein: The wide area sensor is a device capable of measuring the position of the object using an RGB camera.

14. The position determination system according to claim 11, wherein: The wide area sensor is a depth camera or RGB-D.

15. A position determination system comprising: Robots, with multiple axes; An object mounted on the robot; a sensor for measuring a two-dimensional cross-sectional shape of the object in a given motion of the robot; and The processor outputs at least two-dimensional information of the object based on the two-dimensional cross-sectional shape measured by the sensor.

16. The position determination system according to claim 15, wherein: The processor includes a detection unit and a calculation unit. The detection unit detects a characteristic value of the object 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 about the shape of the object.

17. The position determination system according to claim 16, wherein: The object is spherical, The detection unit detects, as the feature value, a radius of a cross-sectional circle of the object and a circle center coordinate of the cross-sectional circle of the object in a coordinate system of the sensor, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the spherical radius of the object.

18. The position determination system according to claim 16, wherein: The object is conical. The detection unit detects the major diameter and the minor diameter of the cross-sectional ellipse and the ellipse center coordinates of the object in the coordinate system of the sensor as the feature values, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the cone apex angle of the object.

19. A position determination system comprising: Robots, with multiple axes; an object mounted on the robot; and The processor calculates three-dimensional information of the object based on the two-dimensional cross-sectional shape of the object in a given motion of the robot received from a sensor.

20. The position determination system according to claim 19, wherein: The processor includes a detection unit and a calculation unit. The detection unit detects a feature value of the object 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 about the shape of the object.

21. The position determination system according to claim 20, wherein: The object is spherical, The detection unit detects, as the feature value, a radius of a cross-sectional circle of the object and a circle center coordinate of the cross-sectional circle of the object in a coordinate system of the sensor, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the spherical radius of the object.

22. The position determination system according to claim 20, wherein: The object is conical. The detection unit detects the major diameter and the minor diameter of the cross-sectional ellipse and the ellipse center coordinates of the object in the coordinate system of the sensor as the feature values, The calculation unit calculates the three-dimensional information of the robot based on the feature value and the cone apex angle of the object.

23. A position determination system according to any one of claims 19 to 22, wherein: The three-dimensional information includes at least one of a three-dimensional trajectory of the robot and a three-dimensional position of the robot.

24. A position measurement method, which is a position measurement method of a position measurement system, wherein the position measurement system comprises: a robot having a plurality of axes; an object mounted on the robot; and a sensor for measuring a two-dimensional cross-sectional shape of the object in a given movement of the robot, wherein: The position measurement method includes a step of calculating a three-dimensional trajectory of the object based on the two-dimensional cross-sectional shape measured by the sensor.

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