A method for positioning a workpiece coordinate system of a polishing industrial robot

Abstract

The application discloses a kind of polishing industrial robot workpiece coordinate system positioning method, it is related to industrial robot automation polishing technical field, and its technical solution points are: the bias calibration in Z direction is realized by robot flange close to known thickness calibration object, the concentricity of robot end flange and measuring head tool is adjusted by micrometer, the bias calibration of two directions of XY is realized, the accurate calibration of workpiece measuring head relative to robot end flange position is realized, according to workpiece measuring head, the measurement and calculation of workpiece coordinate system are realized, and finally the positioning of workpiece coordinate system is completed.The method realizes the accurate calibration of workpiece measuring head relative to robot end flange position, according to workpiece measuring head, the measurement and calculation of workpiece coordinate system are realized, and finally the positioning of workpiece coordinate system is completed, solves the problem of low positioning precision and long time consumption of workpiece measuring head relative to industrial robot relative position measurement method positioning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial robot automatic polishing, and more particularly to a polishing industrial robot workpiece coordinate system positioning method. BACKGROUND

[0002] In recent years, with the orderly implementation of China's national major projects such as the "high-resolution earth observation system", "manned spaceflight and lunar exploration project", etc., space astronomical observation, earth observation, deep space exploration and space strategic equipment technology have entered a period of rapid development, and the demand for large-aperture mirrors for space optical systems is increasing. The manufacturing efficiency of optical elements has become one of the bottlenecks restricting the development of space optics in China. Rapid and efficient high-precision completion of optical element manufacturing tasks is one of the primary tasks of the current industry development.

[0003] Digital optical polishing technology based on industrial robots is a development trend in the field of optical manufacturing in recent years. Robot polishing technology has the advantages of low cost and small footprint. Currently, polishing systems based on industrial robots use workpiece probes to achieve automatic measurement of workpiece positioning. However, since the workpiece probe is an external device, it is difficult to obtain the relative accurate position of the workpiece probe in the industrial robot coordinate system, and there is a problem of inaccurate positioning of the workpiece probe.

[0004] Current industrial robot manufacturers use "three-point method" or "six-point method" to position the workpiece probe, but this method relies on visual judgment, and the workpiece probe still has the problem of poor positioning accuracy.

[0005] Therefore, based on the above problems, the applicant has invented a polishing industrial robot workpiece coordinate system positioning method. SUMMARY

[0006] The purpose of the present application is to provide a polishing industrial robot workpiece coordinate system positioning method, which realizes accurate calibration of the position of the workpiece probe relative to the robot end flange, and according to the workpiece probe, the workpiece coordinate system is measured and calculated, and finally the workpiece coordinate system is positioned, solving the problems of low positioning accuracy and long time consumption of the relative position measurement method of the workpiece probe relative to the industrial robot.

[0007] The above technical purpose of the present application is achieved by the following technical scheme: a polishing industrial robot workpiece coordinate system positioning method, specifically comprising the following steps:

[0008] S1: define the default tool coordinate system of the industrial robot system, and define the initial relative position deviation (X, Y, Z, R x , R y , R z) input into the industrial robot tool coordinate system bias, and define the measuring head coordinate system;

[0009] S2: Fix the measuring head calibration tool, ensure that the measuring head calibration tool is parallel to the industrial robot coordinate system;

[0010] S3: Set the calibration object with a known thickness H on the measuring head calibration tool, switch to the industrial robot system default tool coordinate system, remove the industrial robot polishing tool and workpiece measuring head under the industrial robot system default tool coordinate system, adjust the industrial robot end flange to be parallel to the end face of the calibration tool in a posture close to the calibration object, input the value of the known thickness H into the industrial robot system default tool coordinate system and define it in the Z direction, that is, the Z coordinate value of the tool end face in the industrial robot system default tool coordinate system is H;

[0011] S4: Adjust the horizontal position of the industrial robot end flange to ensure that the flange is concentric with the outer circle of the measuring head calibration tool within a specified error, and record the coordinate origin in the XY direction under the industrial robot system default tool coordinate system as the center of the calibration tool circle;

[0012] S5: Install the industrial robot polishing tool and workpiece measuring head on the industrial robot end flange, and at the same time switch to the workpiece measuring head coordinate system, program control the workpiece measuring head to measure the outer circle and end face of the calibration tool respectively, according to the measurement results, calculate the position coordinates (Dx, Dy, Dz) of the center of the calibration tool end face, that is, the center position coordinates (Dx, Dy, Dz+R) of the tool end face in the workpiece measuring head coordinate system are obtained, R is the radius value of the workpiece measuring head;

[0013] S6: Define the X direction translation deviation of the workpiece measuring head coordinate system relative to the industrial robot system default tool coordinate system as X+Dx, the Y direction translation deviation as Y+Dy, and the Z direction translation deviation as Z+Dz+R-H, and rewrite the above three values into the industrial robot system;

[0014] S7: Switch to the workpiece measuring head coordinate system, and use the workpiece measuring head to measure the position of the workpiece to be polished, that is, to determine the final calculated workpiece coordinate system of the workpiece to be polished under the industrial robot polishing system.

[0015] By adopting the technical scheme, firstly, the bias of the workpiece measuring head relative to the default tool coordinate system of the industrial robot is calibrated, the bias calibration in the Z direction is realized by the robot flange close to the calibration object with a known thickness, the bias calibration in the XY two directions is realized by adjusting the concentricity of the robot end flange and the measuring head tool, the accurate calibration of the position of the workpiece measuring head relative to the robot end flange is completed, the measurement and calculation of the workpiece coordinate system are realized according to the workpiece measuring head, and finally the positioning of the workpiece coordinate system is completed, and the method can realize higher-precision positioning compared with the conventional method.

[0016] The application is further provided that: the method for obtaining the initial relative position deviation (X, Y, Z, R x ,R y ,R z ) of the workpiece measuring head relative to the center of the end flange of the industrial robot in S1 comprises a "three-point method", a "six-point method" built in a traditional industrial robot and a method for modeling the workpiece measuring head and the industrial robot as a whole in three dimensions.

[0017] By adopting the technical scheme, when the relative position deviation of the workpiece measuring head relative to the center of the end flange of the industrial robot is obtained from the model, the "three-point method", the "six-point method" built in the traditional industrial robot and the method for modeling the workpiece measuring head and the industrial robot as a whole in three dimensions can be adopted, accurate motion control of the robot can be realized, and accurate calibration of the position of the workpiece measuring head relative to the robot end flange is realized.

[0018] The application is further provided that: the method for ensuring that the measuring head calibration tool and the geodetic coordinate system of the industrial robot are parallel in S2 adopts the method that a level is placed on the end face of the calibration tool, the posture of the calibration tool is adjusted, the level bubble is located in the level circle, and it is determined that the calibration tool and the geodetic coordinate system of the industrial robot are parallel.

[0019] By adopting the technical scheme, the level is placed on the end face of the calibration tool, the posture of the calibration tool is adjusted, the level bubble is located in the level circle, and the measuring head calibration tool and the geodetic coordinate system of the industrial robot can be conveniently adjusted to be parallel.

[0020] The application is further provided that: the calibration object with a known thickness H in S3 is a regular article with a specific thickness.

[0021] By adopting the above technical scheme, the calibration object with a known thickness is adopted as a regular object with a specific thickness, the pose of the end flange of the industrial robot is adjusted to constantly approach the end face of the calibration tool in a pose parallel to the end face of the calibration tool, and the end face of the end flange of the industrial robot is tightly attached to the calibration object, so that the end face of the calibration tool in the Z coordinate of the default tool coordinate system of the industrial robot system can be quickly and accurately calibrated.

[0022] In summary, the present application has the following advantages:

[0023] 1. First, the offset of the workpiece measuring head relative to the default tool coordinate system of the industrial robot is calibrated, the offset calibration in the Z direction is realized by the robot flange approaching the calibration object with a known thickness, the offset calibration in the XY two directions is realized by adjusting the concentricity of the robot end flange and the measuring head tool, the accurate calibration of the position of the workpiece measuring head relative to the robot end flange is completed, the measurement and calculation of the workpiece coordinate system are realized according to the workpiece measuring head, and finally the positioning of the workpiece coordinate system is completed. This method can realize higher precision positioning than the conventional method.

[0024] 2. When obtaining the relative position deviation of the workpiece measuring head relative to the center of the industrial robot end flange from the model, the traditional industrial robot built-in "three-point method", "six-point method" and the method of modeling the workpiece measuring head and the industrial robot as a whole can be used to realize accurate motion control of the robot and accurate calibration of the position of the workpiece measuring head relative to the robot end flange.

[0025] 3. A level is placed on the end face of the calibration tool, and the pose of the calibration tool is adjusted so that the level bubble is located in the level circle, so that the measuring head calibration tool and the industrial robot geodetic coordinate system can be conveniently adjusted to be parallel.

[0026] 4. The calibration object with a known thickness is adopted as a regular object with a specific thickness, the pose of the end flange of the industrial robot is adjusted to constantly approach the end face of the calibration tool in a pose parallel to the end face of the calibration tool, and the end face of the end flange of the industrial robot is tightly attached to the calibration object, so that the end face of the calibration tool in the Z coordinate of the default tool coordinate system of the industrial robot system can be quickly and accurately calibrated. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of a polishing industrial robot workpiece coordinate system positioning method in an embodiment of the present application;

[0028] Figure 2 is a schematic diagram of S4 in an embodiment of the present application;

[0029] Figure 3 is an enlarged view of Figure 2 in an embodiment of the present application;

[0030] Figure 4 is a schematic diagram of S5 in the embodiment of the present application;

[0031] Figure 5 is a close-up view of Figure 4 in the embodiment of the present application.

[0032] In the figure: 1, industrial robot; 2, workpiece probe; 3, end flange; 4, polishing tool; 5, calibration object; 6, probe calibration tool; 7, workpiece table. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with the accompanying drawings. Figures 1-5 The present application will be further described below in conjunction with the accompanying drawings.

[0034] Embodiment: A polishing industrial robot workpiece coordinate system positioning method, as shown in the figure, specifically comprising the following steps: Figures 1 to 5

[0035] S1: Defining the industrial robot 1 system default tool coordinate system as TCP0, inputting the initial relative position deviation (X, Y, Z, R x ,R y ,R z ) of the workpiece probe 2 relative to the center of the industrial robot 1 end flange 3 to the industrial robot 1 tool coordinate system offset, defining the workpiece probe 2 coordinate system as TCP1, wherein X, Y, Z respectively represent the translational deviation of the workpiece probe 2 relative to the center of the industrial robot 1 end flange 3, R x ,R y ,R z respectively represent the rotational deviation of the workpiece probe 2 pose relative to the center of the industrial robot 1 end flange 3;

[0036] S2: Fix the probe calibration tool 6, and ensure that the probe calibration tool 6 is parallel to the industrial robot 1 geodetic coordinate system;

[0037] S3: Set the calibration object 5 with a known thickness H on the probe calibration tool 6, switch to the industrial robot 1 system default tool coordinate system TCP0, under the coordinate system TCP0, remove the industrial robot 1 polishing tool 4 and the workpiece probe 2, adjust the pose of the industrial robot 1 end flange to continuously approach the end face of the calibration tool in a pose parallel to the end face of the calibration tool, so that the end face of the industrial robot 1 end flange is in close contact with the calibration object 5, input the value of the known thickness H into the industrial robot 1 system default tool coordinate system and define it in the Z direction, i.e. the Z coordinate value of the tool end face under the industrial robot 1 system default tool coordinate system is H;

[0038] ​S4: Adjust the horizontal position of the end flange of the industrial robot 1, ensure that the concentricity between the flange and the outer circle of the probe calibration tool 6 is within 0.01 mm, install a dial gauge at the end of the end flange of the industrial robot 1, operate the robot to rotate the end flange, and adjust the horizontal position of the end flange of the industrial robot 1, when the dial gauge reading or runout is less than 0.01 mm, record the coordinates of the center of the probe calibration tool 6 in the XY direction under the TCP0 coordinate system as (0, 0);

[0039] S5: Install the polishing tool 4 and the workpiece probe 2 of the industrial robot 1 on the end flange of the industrial robot 1, and switch to the TCP1 coordinate system, program and control the workpiece probe 2 to measure the outer circle and end face of the calibration tool respectively, according to the measurement results, calculate the position coordinates (Dx, Dy, Dz) of the center of the end face of the calibration tool, then the position coordinates (Dx, Dy, Dz+R) of the center of the end face of the tool under the TCP1 coordinate system, R is the radius value of the workpiece probe 2;

[0040] S6: Define the X direction translation deviation of the coordinate system TCP1 relative to TCP0 as X+Dx, the Y direction translation deviation as Y+Dy, and the Z direction translation deviation as Z+Dz+R-H, and rewrite the above three values into the system of the industrial robot 1;

[0041] S7: Switch to the tool coordinate system TCP1, and use the workpiece probe 2 to measure the position of the workpiece to be polished, which is the final calculated workpiece coordinate system of the workpiece to be polished under the polishing system of the industrial robot 1.

[0042] In the preferred embodiment of the present embodiment, the method for obtaining the initial relative position deviation (X, Y, Z, R x ,R y ,R z ) of the workpiece probe 2 relative to the center of the end flange plate 3 of the industrial robot 1 in S1 can be obtained by the traditional "three-point method" or "six-point method" built in the industrial robot 1, or the workpiece probe 2 and the industrial robot 1 can be modeled in three dimensions as a whole, and the relative position deviation (X, Y, Z, R x ,R y ,R z ) of the workpiece probe 2 relative to the center of the end flange plate 3 of the industrial robot 1 can be obtained from the model.

[0043] In the preferred embodiment of the present embodiment, the method for ensuring that the probe calibration tool 6 and the industrial robot 1 geodetic coordinate system are parallel in S2 is to place a level on the end face of the calibration tool, adjust the attitude of the calibration tool, and make the level bubble in the level circle, that is, the calibration tool and the industrial robot 1 geodetic coordinate system are parallel.

[0044] Preferably, the S3 known thickness calibration object 5 includes a sheet of paper, a ruler, a standard cylinder, and other regular objects with specific thickness.

[0045] The specific embodiments are only illustrative of the present application, and are not intended to limit the present application. Those skilled in the art can make modifications to the embodiments without creative contribution, as long as the modifications are within the scope of the present application.

Claims

1. A method of positioning a workpiece coordinate system of a polishing industrial robot, characterized by: Specifically comprising the following steps: S1: define the system default tool coordinate system of the industrial robot (1), input the initial relative position deviation (X, Y, Z, R x ,R y ,R z ) of the workpiece measuring head (2) relative to the center of the end flange (3) of the industrial robot (1) into the tool coordinate system offset of the industrial robot (1), and define the measuring head coordinate system; S2: Fix the measuring head calibration tool (6) to ensure that the measuring head calibration tool (6) is parallel to the industrial robot (1) geodetic coordinate system; S3: Set the calibration object (5) with a known thickness H on the measuring head calibration tool (6), switch to the system default tool coordinate system of the industrial robot (1), remove the polishing tool (4) and the workpiece measuring head (2) of the industrial robot (1), adjust the end flange of the industrial robot (1) to be close to the calibration object (5) in a posture parallel to the end face of the calibration tool, input the value of the known thickness H into the system default tool coordinate system of the industrial robot (1) and define it in the Z direction, that is, the Z coordinate value of the tool end face in the system default tool coordinate system of the industrial robot (1) is H; S4: Adjust the horizontal position of the end flange of the industrial robot (1) to ensure that the flange is concentric with the outer circle of the measuring head calibration tool (6) within a specified error, and record the coordinate origin in the XY direction of the system default tool coordinate system of the industrial robot (1) as the center of the calibration tool circle; S5: Install the polishing tool (4) and the workpiece measuring head (2) on the end flange of the industrial robot (1), and at the same time switch to the workpiece measuring head (2) coordinate system, program control the workpiece measuring head (2) to measure the outer circle and end face of the calibration tool respectively, and according to the measurement results, calculate the position coordinates (Dx, Dy, Dz) of the center of the calibration tool end face, that is, the center position coordinates (Dx, Dy, Dz+R) of the tool end face in the workpiece measuring head (2) coordinate system, R is the radius value of the workpiece measuring head; S6: Define the X direction translation deviation of the workpiece measuring head coordinate system relative to the system default tool coordinate system of the industrial robot (1) as X+Dx, the Y direction translation deviation as Y+Dy, and the Z direction translation deviation as Z+Dz+R-H, and rewrite the above three values into the system of the industrial robot (1); S7: Switch to the workpiece measuring head (2) coordinate system, and use the workpiece measuring head (2) to measure the position of the workpiece to be polished, that is, to determine the final calculated workpiece coordinate system of the workpiece to be polished in the polishing system of the industrial robot (1).

2. A method of positioning a workpiece coordinate system of a polishing industrial robot according to claim 1, characterized in that: The method for acquiring the initial relative position deviation (X, Y, Z, R) of the workpiece measuring head (2) relative to the center of the end flange (3) of the industrial robot (1) in the S1 includes the "three-point method", "six-point method" built in the traditional industrial robot (1), and the method of three-dimensionally modeling the workpiece measuring head (2) and the industrial robot (1) as a whole. x y z ) of the workpiece measuring head (2) relative to the center of the end flange (3) of the industrial robot (1) in the S1 includes the "three-point method", "six-point method" built in the traditional industrial robot (1), and the method of three-dimensionally modeling the workpiece measuring head (2) and the industrial robot (1) as a whole.​​ 3. A method of positioning a workpiece coordinate system of a polishing industrial robot according to claim 1, characterized in that: In S2, the method for ensuring that the measuring head calibration tool (6) is parallel to the industrial robot (1) geodetic coordinate system is to place a level on the end face of the calibration tool, adjust the posture of the calibration tool, and make the level bubble in the level circle, that is, to determine that the calibration tool is parallel to the industrial robot (1) geodetic coordinate system.

4. The method of claim 1, wherein: The calibration object (5) with a known thickness H in S3 is a regular object with a specific thickness.

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