Device and method for measuring linear track guide precision of robot vision system

Abstract

The invention discloses a device and a method for measuring linear trajectory guide precision of a robot visual system, and relates to the technical field of robot guidance. Coordinates of point positions at two ends of a V-shaped calibration part are measured based on a laser tracker, a robot tool center point is calibrated to the center of a target ball, and the robot tool center point is adjusted to coincide with the two end points of the V-shaped calibration part; a robot is operated to teach and record point positions at two ends of the V-shaped calibration part, and the robot adopts a linear track motion instruction; the laser tracker adopts a dynamic measurement mode to measure coordinate values of a plurality of point positions moving along a bus at the top end of the V-shaped calibration piece, namely theoretical values of the spatial linear trajectory guide precision of the visual system; a robot vision system guides a robot tool center point to move along a bus track at the top end of a V-shaped calibration piece, a laser tracker dynamically measures an actual motion track of a robot guided by the vision system, and the robot tool center point is determined according to a theoretical track point position and an actual track point position guided by the vision system. Therefore, the guiding precision of the space linear track of the robot visual system can be accurately measured.

Description

Technical Field

[0001] The present invention relates to the field of robot guidance technology, and in particular to a device and method for measuring the linear trajectory guidance accuracy of a robot vision system. Background Art

[0002] Robots are essential basic production equipment in the fields of aviation, aerospace, national defense, and mechanical manufacturing. With the development towards Industry 4.0, the integration and application of robot systems are moving towards intelligence. The intelligence of robot systems is often reflected in the integration of high-precision vision systems at the end of the robot. After the robot is integrated with the vision system, the vision system usually establishes a corresponding posture matrix relationship with the robot base coordinate system and the tool coordinate system. The calibration of the robot vision system and the tool coordinate system (commonly known as "hand-eye" calibration) is an important step for the robot to rely on the vision system to guide the end tool to complete the task. The accuracy of the "hand-eye" calibration determines whether the vision system can accurately complete the spatial linear trajectory guidance of the robot;

[0003] In the robot vision system welding trajectory guidance, vision system gluing trajectory guidance, vision system spraying trajectory guidance, etc., the accuracy of the vision system trajectory guidance is the key factor affecting the quality of the final product.

[0004] Currently, there are no relevant testing standards and methods for the spatial linear trajectory guidance accuracy of robot vision systems. Summary of the invention

[0005] The present invention aims to solve the deficiencies of the prior art and to provide a device and method for measuring the linear trajectory guidance accuracy of a robot vision system, so as to obtain the guidance accuracy of the spatial linear trajectory of the robot vision system by accurately measuring.

[0006] The present invention is achieved through the following technical solutions:

[0007] A device for measuring the linear trajectory guidance accuracy of a robot vision system, comprising:

[0008] A liftable workbench, on which a V-shaped calibration piece is transversely fixed, the V-shaped calibration piece is linearly arranged; a V-shaped target seat is slidably connected to the V-shaped calibration piece, the V-shaped target seat can slide along the length direction of the V-shaped calibration piece; the V-shaped target seat is used to fix a target ball.

[0009] Further solutions:

[0010] The present invention also provides a method for measuring the linear trajectory guidance accuracy of a robot vision system, comprising the following steps:

[0011] S1: Raise the workbench to a fixed position A, and establish a coordinate system {W} on the workbench by a laser tracker;

[0012] S2: Measure the target ball center coordinates D1 and D2 when the V-shaped target seat is at the front and rear ends of the V-shaped calibration piece, and locate the two center coordinates on the top generatrix of the V-shaped calibration piece along the coordinate axis direction of the coordinate system {W} to obtain the current center coordinates D3 and D4;

[0013] S3: adsorb the target ball onto the target seat at the end of the robot, and calibrate the tool center point of the robot to the center of the target ball;

[0014] S4: lower the workbench to the fixed position B. In the dynamic measurement mode of the laser tracker, adjust the center point of the robot end tool to coincide with D3 and teach and record the current position of the robot as P1. Adjust the center point of the robot end tool to coincide with D4 and teach and record the current position of the robot as P2.

[0015] S5: Control the robot to move from point P1 to point P2 at a fixed speed through a program, and the laser tracker dynamically measures the movement trajectory of the robot in real time at a fixed sampling frequency to obtain a number of sampling points of the straight line trajectory of the robot from point P1 to point P2, and the collected sampling points are used as theoretical values ​​of the linear trajectory guidance of the robot vision system;

[0016] S6: Control the workbench to rise to the fixed position A, identify and scan the top busbar of the V-shaped calibration piece, generate a visual system point cloud based on the top busbar of the V-shaped calibration piece, and control the workbench to descend to the fixed position B; then the visual system guides the center point of the robot tool to move along the track of the top busbar of the V-shaped calibration piece at a fixed speed, and the laser tracker dynamically measures the actual motion track of the robot after the visual system guides it at a fixed sampling frequency, and obtains the actual value of the robot visual system after the linear track is guided;

[0017] S7: According to the theoretical value before the linear trajectory guidance of the robot vision system and the actual value after the linear trajectory guidance of the robot vision system, the trajectory accuracy after the spatial linear trajectory guidance of the robot vision system is obtained.

[0018] In this solution, the speed values ​​of the robot running in step S5 and step S6 are consistent, and the sampling frequency values ​​of the laser tracking dynamic measurement in step S5 and step S6 are consistent.

[0019] Furthermore, the step S1 further includes the following specific steps:

[0020] Install a laser tracker, move the target ball on the workbench, measure three non-collinear positions Q1, Q2, Q3 on the workbench, and construct a vector Cross product Get the normal vector of the worktable surface, use point Q1 as the origin of the coordinate system, and the vector The X-axis is the normal vector, the Z-axis is the normal vector, and the right-hand rule is used to establish the measurement coordinate system {W} based on the laser tracker.

[0021] Furthermore, the step S3 also includes the following specific steps:

[0022] S31: Move the robot to a suitable position, adsorb the target ball to the target seat at the end of the robot, teach and record the robot posture P0; the robot moves around the flange coordinate system X F , Y F , Z F The laser tracker collects the spatial coordinate points of the target ball at each posture of the robot and converts the X coordinates of the flange coordinate system into F , Y F , Z F All spatial points of the axis rotation measurement are fitted to obtain a spatial sphere, and the circles and their planes rotating around Rx, Ry, and Rz are fitted, and the normal vectors of the circles and their planes rotating around Rx, Ry, and Rz are constructed. Find the angle between any two normal vectors;

[0023] S32: The robot returns to P0 position. The two normal vectors closest to 90° between the three vectors are used as reference axes, and the coordinate system {F} is established using the right-hand rule with the center of the sphere as the origin; at this time, the coordinate system {F} based on laser tracking coincides with the robot flange coordinate system;

[0024] S33: Measure the coordinate value of the target ball at the end of the robot in the laser tracking coordinate system {F}. This value is the offset value of the center of the target ball relative to the origin of the robot flange coordinate system. Import the coordinate value of the target ball into the robot controller. At this time, the tool center point of the robot is the center of the target ball.

[0025] Furthermore, in step S31, when solving the angle between any two normal vectors, if θ XY ,θ YZ ,θ XZ If any one of the angles is within the range of 90°±0.03°, stop step S31; if all three angles are not within the range of 90°±0.03°, repeat step S31.

[0026] Furthermore, the angle between normal vectors is calculated as:

[0027]

[0028] Furthermore, in step S5, the specific steps of dynamically measuring the motion trajectory of the robot in real time by a laser tracker to obtain a number of sampling points of the straight line trajectory of the robot from point P1 to point P2 are:

[0029] The laser tracker is set to a fixed sampling frequency of Q Hz in the dynamic measurement mode, and the robot tool center point is moved to point P1. The robot's straight line trajectory program from point P1 to point P2 is automatically run at a speed of S m / s. The laser tracker dynamically measures the robot's motion trajectory in real time at a sampling frequency of Q Hz, and collects several sampling points C of the robot's straight line trajectory from point P1 to point P2. i (Xc i , Yc i , Zc i ), where i = 1, 2, 3, 4…m, C i (Xc i , Yc i , Zc i ) is the theoretical value of the robot vision system trajectory guidance.

[0030] Furthermore, in step S6, the specific steps of guiding the center point of the robot tool to move along the top generatrix trajectory of the V-shaped calibration piece and dynamically measuring the actual motion trajectory of the robot after being guided by the visual system in real time by a laser tracker are as follows:

[0031] The trajectory running speed S m / s is set in the robot control program. The robot vision system guides the robot tool center point to move from the front end of the V-shaped calibration piece to the end of the V-shaped calibration piece at a speed of S m / s. The laser tracker dynamically measures the motion trajectory of the robot after vision guidance at a sampling frequency of Q Hz and collects several sampling points K of the motion trajectory after the robot vision system guides. i (X i , Y i , Z i ), where i = 1, 2, 3, 4…m, K i (X i , Y i , Z i ) is the actual value after the linear trajectory guidance of the robot vision system.

[0032] Furthermore, after collecting several sampling points K of the spatial motion trajectory guided by the robot vision system for the first time i (X i , Y i , Z i ), further comprising the following steps:

[0033] Repeat step S6 for n times (n≥10) in total. Through n times of recognition and scanning by the robot vision system, the vision system guides the target ball at the end of the robot to run along the track of the top generatrix of the V-shaped calibration piece at a fixed speed S m / s. The laser tracker also performs n times of dynamic real-time measurement of the target ball (TCP) on the robot at a fixed sampling frequency Q Hz, and the coordinates of the n measurement points K can be obtained. ij (X ij , Y ij , Z ij ), where j = 1, 2, 3, 4…n.

[0034] Furthermore, the trajectory accuracy AT P The calculation formula is:

[0035] Where: i = 1, 2, 3, 4 ... m;

[0036]

[0037] The calculation method of trajectory repeatability after n-time linear trajectory guidance by the robot vision system is as follows:

[0038]

[0039] Where: i = 1, 2, 3, 4 ... m;

[0040]

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] The invention provides a device and method for measuring the linear trajectory guidance accuracy of a robot vision system. The device measures the coordinates of the two end points of a V-shaped straight line calibration piece based on a laser tracker, calibrates the center point of a robot tool to the center of a target ball, monitors and adjusts the center point of the robot tool (the center of the target ball) to coincide with the two end points of the V-shaped straight line calibration piece based on the dynamic measurement function of the laser tracker, operates the robot to teach and record the two end points (P1, P2) of the V-shaped calibration piece, and the robot adopts a straight line trajectory motion instruction, and runs the straight line trajectory instruction at a fixed speed S m / s in an automatic mode; the laser tracker adopts a dynamic measurement mode with a fixed sampling frequency Q Hz to measure the straight line motion trajectory of the robot, and the coordinate values ​​of several points of the straight line trajectory used for fitting are the theoretical values ​​of the spatial linear trajectory guidance accuracy of the vision system; the robot vision system identifies the top busbar of the V-shaped straight line calibration piece, and generates a point cloud based on the top busbar of the V-shaped straight line calibration piece; the robot vision system guides the center point of the robot tool (the center of the target ball) to move along the top busbar trajectory of the V-shaped straight line calibration piece at a fixed speed S m / s, and the laser tracker measures the straight line motion trajectory of the robot at a fixed sampling frequency Q Hz. Hz dynamically measures the actual motion trajectory of the robot after being guided by the visual system. In the laser tracking measurement system, both the theoretical trajectory points based on the V-shaped linear calibration parts and the actual trajectory points after the visual system guidance are available, so the guidance accuracy of the spatial linear trajectory of the robot vision system can be accurately measured.

[0043] In summary, for the same feature of the V-shaped linear calibration part, the laser tracker is used to measure its feature and the visual system is used to scan and identify its feature. Before and after the guidance of the robot vision system, the robot adopts a unified running speed S m / s, and the laser tracker adopts a unified dynamic sampling frequency Q Hz. Based on the above constraints, the theoretical value of the robot vision system before guidance and the measured value after guidance are obtained under the same experimental conditions, so that the guidance accuracy of the linear trajectory of the robot vision system can be accurately, conveniently and quickly measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0045] Figure 1 A schematic diagram of a robot end provided by the present invention rotating around the flange coordinate axis to fit the space ball;

[0046] Figure 2 A schematic diagram of the structure of a V-shaped calibration piece and a V-shaped target base provided by the present invention;

[0047] Figure 3 A schematic diagram of the structure of the workbench provided by the present invention;

[0048] Figure 4 A schematic diagram of establishing a coordinate system {W} on the workbench provided by the present invention;

[0049] Figure 5 This is a schematic diagram of the measurement layout provided by the present invention.

[0050] Marks and corresponding parts names in the attached drawings:

[0051] 1-Servo cylinder, 2-V-type calibration piece, 3-V-type target seat, 4-target ball, 5-workbench. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0053] Embodiment 1:

[0054] This embodiment 1 provides a device for measuring the linear trajectory guidance accuracy of a robot vision system, such as Figure 2-Figure 5 As shown, it includes: a liftable workbench 5, on which a V-shaped calibration piece 2 is transversely fixed, and the V-shaped calibration piece 2 is linearly arranged; a V-shaped target seat 3 is slidably connected to the V-shaped calibration piece 2, and the V-shaped target seat 3 can slide along the length direction of the V-shaped calibration piece 2; the V-shaped target seat 3 is used to fix the target ball 4. Among them, the measuring device includes the V-shaped calibration piece 2, the V-shaped target seat 3, etc. Figure 2 As shown; there are 4 servo cylinders 1 and a workbench 5 below the workbench 5 as shown Figure 3 As shown; based on the laser tracker, a coordinate system {W} is established on the 5 surfaces of the servo lifting device workbench as shown Figure 4 As shown in Figure 2, the layout of the robot system, laser tracker, and calibration device during the entire measurement process is as follows: Figure 5 The stroke of servo cylinder 1 is 500mm, its repeatability is better than 2μm, and the flatness of worktable 5 is better than 3μm; the length of V-shaped linear calibration piece is 600mm, the height error is better than 2μm throughout the stroke, the straightness of its top generatrix is ​​better than 2μm, and the flatness of the bottom surface of V-shaped linear calibration piece is better than 2μm.

[0055] Embodiment 2:

[0056] This embodiment 2 is further optimized on the basis of embodiment 1, and provides a measurement method for a device for measuring the linear trajectory guidance accuracy of a robot vision system, such as Figure 1-Figure 5 As shown, the robot tool end revolves around the flange coordinate system XF , Y F , Z F Axis rotation fitting ball and space circle Figure 1 As shown, the specific steps include:

[0057] 1. Install the laser tracker to a suitable position, move the target ball 4 on the workbench 5 of the high-precision servo lift device, measure the three non-collinear positions Q1, Q2, and Q3 on the workbench 5, and construct the vector Cross product Get the normal vectors of the five surfaces of the workbench, use point Q1 as the origin of the coordinate system, and the vector The X-axis is the normal vector, the Z-axis is the normal vector, and the right-hand rule is used to establish the measurement coordinate system {W} based on the laser tracker.

[0058] 2. The servo lifting device workbench 5 rises to the fixed position A, the V-shaped calibration piece 2 is fixedly installed on the surface of the servo lifting device workbench 5, the V-shaped target seat 3 is installed at the head end of the V-shaped calibration piece 2, the target ball 4 is adsorbed on the V-shaped target seat 3, and the current center point D1 (X D1 ,Y D1 ,Z D1 ), move the V-shaped target base 3 and the target ball 4 to the end of the V-shaped calibration piece 2, and the laser tracker measures the current center point D2 (X D2 ,Y D2 ,Z D2 ). Set point D1(X D1 ,Y D1 ,Z D1 )、D2(X D2 ,Y D2 ,Z D2 ) along the negative direction of the coordinate system {W}Z axis (R 靶 +H) mm, where R 靶 is the radius of the target ball 4, H is the thickness of the V-shaped target base 3, and the corresponding point after translation is defined as D3(X D3 ,Y D3 ,Z D3 )、D4(X D4 ,Y D4 ,Z D4 ), points D3 and D4 are on the top generatrix of the V-shaped calibration piece 2.

[0059] 3. Move the robot to a suitable position, adsorb the target ball 4 to the target seat at the end of the robot, and teach and record the robot posture P0; the robot moves around the flange coordinate system X F , Y F , Z FThe laser tracker collects the spatial coordinate points of the target ball 4 at the positions of the robot in each posture, and converts the X coordinates around the flange coordinate system into F , Y F , Z F All spatial points of the axis rotation measurement are fitted to obtain a spatial sphere, and the circle and its plane rotating around Rx, Ry, and Rz are fitted.

[0060] The space sphere equation is as follows: (xa) 2 +(yb) 2 +(zc) 2 =R 2 (1)

[0061] The equation transformation is as follows: 2ax+2by+2cz-a 2 -b 2 -c 2 +R 2 =x 2 +y 2 +z 2 (2)

[0062] Let 2a = A 2b = B 2c = Ca 2 +b 2 +c 2 -R 2 =D;

[0063] The above formula can be written in matrix form as follows:

[0064]

[0065] Transform the matrix as follows:

[0066]

[0067] Solve equation (4) to get A, B, C, D, and substitute a=A / 2, b=B / 2, c=C / 2. The coordinates of the center of the sphere Qo(a,b,c) and the radius of the sphere R can be obtained.

[0068] Space plane fitting:

[0069] The spatial plane equation can be expressed as: A1x+B1y+C1z+1=0, (5)

[0070] The equation matrix form is as follows:

[0071]

[0072] After matrix transformation, the following formula can be obtained:

[0073]

[0074] Solving for the coefficients A1, B1, and C1, we can get the spatial plane equation. Combining the spatial plane equation (5) with the sphere equation (1) obtained in the previous step, we can find the spatial center coordinates Ca (a1, b1, c1) and the radius r.

[0075] Construct the normal vector of the circle rotating around Rx, Ry, Rz and its plane Solve for the angle between any two normal vectors, If θ XY ,θ YZ ,θ XZ If any one of the angles is within the range of 90°±0.03°, the above operation process is stopped; if all three angles are not within the range of 90°±0.03°, the above operation process is repeated.

[0076] 4. The robot returns to P0 position. The two normal vectors closest to 90° between the three vectors are used as reference axes, and the coordinate system {F} is established using the right-hand rule with the center of the sphere as the origin; at this time, the coordinate system {F} based on laser tracking coincides with the robot flange coordinate system.

[0077] 5. Measure the coordinate value of target ball 4 at the end of the robot in the laser tracking coordinate system {F}. This value is the offset value of the center of target ball 4 relative to the origin of the robot flange coordinate system (default TCP). Import the coordinate value of target ball 4 into the robot controller. At this time, the tool center point (TCP) of the robot is the center of target ball 4.

[0078] 6. The servo lifting device workbench 5 descends to the fixed position B, and the center point of the robot end tool (the center of the target ball 4) and D3 (X D3 ,Y D3 ,Z D3 ) overlap and teach to record the current point as P1, adjust the robot end tool center point (target sphere 4 center) and D4 (X D4 ,Y D4 ,Z D4 ) overlap and teach to record the current point as P2;

[0079] 7. Use the linear motion trajectory instruction in the robot teaching pendant to write the linear trajectory path program from point P1 to point P2, and set the trajectory running speed to S m / s;

[0080] 8. The laser tracker sets a fixed sampling frequency of Q Hz in the dynamic measurement mode, moves the robot tool center point to point P1, and automatically runs the straight line path program from point P1 to point P2. The laser tracker measures the robot's motion trajectory in real time at a sampling frequency of Q Hz. In the laser tracker measurement system, there are several sampling points C of the robot's straight line trajectory from point P1 to point P2. i (Xc i , Yc i , Zc i ), where i = 1, 2, 3, 4…m, C i (Xc i , Yc i , Zc i ) is the theoretical value of the robot vision system trajectory guidance.

[0081] 9. The servo lifting device workbench 5 rises to the fixed position A, the robot vision system identifies and scans the top busbar of the V-shaped calibration part 2, generates a vision system point cloud based on the top busbar of the V-shaped calibration part 2, and the servo lifting device workbench 5 returns to the fixed position B.

[0082] 10. Set the trajectory running speed S m / s in the robot control program. The robot vision system guides the robot tool center point to move from the front end of the V-shaped calibration piece 2 to the end of the V-shaped calibration piece 2 at a speed of S m / s. The laser tracker dynamically measures the motion trajectory of the robot vision guidance at a sampling frequency of Q Hz. In the laser tracker measurement system, there are several sampling points K of the motion trajectory of the robot vision system. i (X i , Y i , Z i ), where i = 1, 2, 3, 4…m, K i (X i , Y i , Z i ) is the actual value after trajectory guidance by the robot vision system.

[0083] 11. Repeat steps 9 to 10 for n times (n≥10) in total. Through n times of recognition and scanning by the robot vision system, the vision system guides the target ball 4 (TCP) at the end of the robot to run along the track of the top generatrix of the V-shaped calibration piece 2 at a fixed speed S m / s. The laser tracker also performs n times of dynamic real-time measurement of the target ball 4 (TCP) on the robot at a fixed sampling frequency Q Hz, and the coordinates of the n measurement points K can be obtained. ij (X ij , Y ij , Z ij ), where j = 1, 2, 3, 4…n.

[0084] 12. The laser tracking measurement system has both the theoretical value before the robot vision system guidance and the measured value after the robot vision system guidance, so the trajectory accuracy AT after the robot vision system spatial linear trajectory guidance can be calculated. P :in:

[0085]

[0086] Where:

[0087]

[0088] The calculation method of trajectory repeatability after n-time trajectory guidance by the robot vision system is as follows:

[0089]

[0090] Where:

[0091]

[0092] In summary, by designing and manufacturing the corresponding high-precision V-shaped calibration piece 2 and the dedicated V-shaped target seat 3, the laser tracker can conveniently and quickly measure the first and last feature points of the V-shaped calibration piece 2. Through the dynamic monitoring and measurement characteristics of the laser tracker, the target ball 4 at the end of the robot tool is adjusted to enable the robot to teach and record the first and last feature points on the V-shaped calibration piece 2; a fixed running speed S m / s is set to use the straight line trajectory instruction to run the two feature points recorded by the teaching, and the laser tracker measures the straight line trajectory of the robot based on a dynamic measurement method with a fixed sampling frequency Q Hz. The measurement result is the theoretical straight line trajectory before the robot vision system guides; the robot vision system identifies and scans the top busbar of the V-shaped calibration piece 2, and guides the center point of the robot tool to move along the straight line trajectory after the vision system identifies and scans at a fixed running speed S m / s, and the laser tracker measures the straight line trajectory of the robot based on a fixed sampling frequency Q Hz. Hz measures the linear motion trajectory of the robot after vision guidance based on dynamic measurement. In the laser tracking measurement system, it has both the theoretical linear motion trajectory before the robot vision system guides and the actual linear motion trajectory after the robot vision system guides, so the deviation between the two can be easily obtained. Through multiple identification and guidance by the robot vision system and measurement by the laser tracker, the absolute linear trajectory deviation and linear trajectory repeatability deviation of the linear trajectory guidance accuracy of the robot vision system are obtained.

[0093] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for measuring the linear trajectory guidance accuracy of a robot vision system, characterized in that: include: A liftable workbench (5) is provided, wherein a V-shaped calibration piece (2) is transversely fixed on the workbench (5), and the V-shaped calibration piece (2) is arranged linearly; a V-shaped target seat (3) is slidably connected to the V-shaped calibration piece (2), and the V-shaped target seat (3) can slide along the length direction of the V-shaped calibration piece (2); and the V-shaped target seat (3) is used to fix a target ball (4).

2. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 1, characterized in that: The following steps are involved: S1: Raise the workbench (5) to a fixed position A, and establish a coordinate system {W} on the workbench (5) using a laser tracker; S2: respectively measuring the center coordinates D1 and D2 of the target ball (4) when the V-shaped target seat (3) is at the front and rear ends of the V-shaped calibration piece (2), positioning the two center coordinates on the top generatrix of the V-shaped calibration piece (2) along the coordinate axis direction of the coordinate system {W}, and obtaining the current center coordinates D3 and D4; S3: adsorb the target ball onto the target seat at the end of the robot, and calibrate the tool center point of the robot to the center of the target ball; S4: lower the workbench (5) to the fixed position B, and in the dynamic measurement mode of the laser tracker, adjust the center point of the robot end tool to coincide with D3 and teach and record the current position of the robot as P1, and adjust the center point of the robot end tool to coincide with D4 and teach and record the current position of the robot as P2; S5: Control the robot to move from point P1 to point P2 at a fixed speed through a program, and the laser tracker dynamically measures the movement trajectory of the robot in real time at a fixed sampling frequency to obtain a number of sampling points of the straight line trajectory of the robot from point P1 to point P2, and the collected sampling points are used as theoretical values ​​of the linear trajectory guidance of the robot vision system; S6: Control the workbench (5) to rise to a fixed position A, the visual system identifies and scans the top busbar of the V-shaped calibration piece (2), generates a visual system point cloud based on the top busbar of the V-shaped calibration piece (2), and controls the workbench (5) to descend to a fixed position B; then the visual system guides the center point of the robot tool to move along the track of the top busbar of the V-shaped calibration piece (2) at a fixed speed, and the laser tracker dynamically measures the actual motion track of the robot after the visual system guides it at a fixed sampling frequency, and obtains the actual value of the robot visual system after the linear track is guided; S7: According to the theoretical value before the linear trajectory guidance of the robot vision system and the actual value after the linear trajectory guidance of the robot vision system, the trajectory accuracy after the spatial linear trajectory guidance of the robot vision system is obtained.

3. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 1, characterized in that: The step S1 also includes the following specific steps: Install a laser tracker, move the target ball on the workbench (5), measure three non-collinear positions Q1, Q2, Q3 on the workbench, and construct a vector Cross product Get the normal vector of the worktable surface, use point Q1 as the origin of the coordinate system, and the vector The X-axis is the normal vector, the Z-axis is the normal vector, and the right-hand rule is used to establish the measurement coordinate system {W} based on the laser tracker.

4. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 1, characterized in that: The step S3 also includes the following specific steps: S31: Move the robot to a suitable position, adsorb the target ball to the target seat at the end of the robot, teach and record the robot posture P0; the robot moves around the flange coordinate system X F , Y F , Z F The laser tracker collects the spatial coordinate points of the target ball at each posture of the robot and converts the X coordinates of the flange coordinate system into F , Y F , Z F All spatial points of the axis rotation measurement are fitted to obtain a spatial sphere, and the circles and their planes rotating around Rx, Ry, and Rz are fitted, and the normal vectors of the circles and their planes rotating around Rx, Ry, and Rz are constructed. Find the angle between any two normal vectors; S32: The robot returns to P0 position. The two normal vectors closest to 90° between the three vectors are used as reference axes, and the coordinate system {F} is established using the right-hand rule with the center of the sphere as the origin; at this time, the coordinate system {F} based on laser tracking coincides with the robot flange coordinate system; S33: Measure the coordinate value of the target ball at the end of the robot in the laser tracking coordinate system {F}. This value is the offset value of the center of the target ball relative to the origin of the robot flange coordinate system. Import the coordinate value of the target ball into the robot controller. At this time, the tool center point of the robot is the center of the target ball.

5. The measuring method of the measuring device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 4, characterized in that: In step S31, when solving the angle between any two normal vectors, if θ XY ,θ YZ ,θ XZ If any one of the angles is within the range of 90°±0.03°, stop step S31; if all three angles are not within the range of 90°±0.03°, repeat step S31.

6. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 4, characterized in that: The angle between normal vectors is calculated as:

7. The measuring method of the measuring device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 1, characterized in that: In step S5, the specific steps of dynamically measuring the motion trajectory of the robot in real time by a laser tracker to obtain a number of sampling points of the straight line trajectory of the robot from point P1 to point P2 are: The laser tracker is set to a fixed sampling frequency of Q Hz in the dynamic measurement mode, and the robot tool center point is moved to point P1. The robot's straight line trajectory program from point P1 to point P2 is automatically run at a speed of Sm / s. The laser tracker dynamically measures the robot's motion trajectory in real time at a sampling frequency of Q Hz, and collects several sampling points C of the robot's straight line trajectory from point P1 to point P2. i (Xc i , Yc i , Zc i ), where i = 1, 2, 3, 4…m, C i (Xc i , Yc i , Zc i ) is the theoretical value of the linear trajectory guidance of the robot vision system.

8. The measuring method of the measuring device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 1, characterized in that: In step S6, the robot tool center point is then guided to move along the top generatrix trajectory of the V-shaped calibration piece (2), and the specific steps of dynamically and real-time measuring the actual motion trajectory of the robot after being guided by the visual system by a laser tracker are as follows: The trajectory running speed Sm / s is set in the robot control program. The robot vision system guides the center point of the robot tool to move from the head end of the V-shaped calibration piece to the end of the V-shaped calibration piece at a speed of Sm / s. The laser tracker dynamically measures the motion trajectory of the robot after vision guidance at a sampling frequency of Q Hz, and collects several sampling points K of the motion trajectory after the robot vision system guides. i (X i , Y i , Z i ), where i = 1, 2, 3, 4…m, K i (X i , Y i , Z i ) is the actual value after the linear trajectory guidance of the robot vision system.

9. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 8, characterized in that: After collecting several sampling points K of the spatial motion trajectory guided by the robot vision system for the first time i (X i , Y i , Z i ), further comprising the following steps: Repeat step S6 for a total of n times (n≥10). Through n times of recognition and scanning by the robot vision system, the vision system guides the target ball at the end of the robot to run along the track of the top generatrix of the V-shaped calibration piece at a fixed speed Sm / s. The laser tracker also performs n times of dynamic real-time measurement of the target ball (TCP) on the robot at a fixed sampling frequency Q Hz, and the coordinates of the n measurement points K can be obtained. ij (X ij , Y ij , Z ij ), where j = 1, 2, 3, 4…n.

10. The measuring method of the device for measuring the linear trajectory guidance accuracy of a robot vision system according to claim 9, characterized in that: The trajectory accuracy AT P The calculation formula is: Where: i = 1, 2, 3, 4 ... m; The calculation method of trajectory repeatability after n-time linear trajectory guidance by the robot vision system is as follows: Where: i = 1, 2, 3, 4 ... m;

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