A system for measuring robotic 3D vision repeatability accuracy

Abstract

The utility model relates to the field of positioning precision detection, concretely to a kind of system for measuring robot 3D vision repeat positioning precision, robot includes mechanical arm, and the visual device and probe are connected on the mechanical arm, and measuring system includes platform, target, X direction measuring instrument, Y direction measuring instrument and Z direction measuring instrument of measurement direction perpendicular to each other are set on the platform;The axial direction of the measuring axis of the X direction measuring instrument, Y direction measuring instrument and Z direction measuring instrument is in straight line intersection A point, and with the positional relationship of the center B point of the target is relatively fixed. Through positioning plate, visual device and mechanical arm are calibrated to "hand, eye", then coordinate system is established with target and fixed to move to the center of three measuring instruments, sequentially touch three measuring instruments, according to the result of measuring instrument, whether positioning precision is accurate can be directly obtained, solve the instability caused by pure eye, improve equipment precision.

Description

Technical Field

[0001] This utility model relates to the field of positioning accuracy detection technology, and in particular to a system for measuring the 3D vision repeatability accuracy of a robot. Background Technology

[0002] Current methods for measuring the repeatability of robot 3D vision typically involve attaching a pin to the end of the robotic arm's flange as a measuring tool, while simultaneously fixing an identical reference pin on a table. During measurement, the 3D vision system at the robotic arm's end first scans and positions the reference pin. Then, guided by the vision system, the robotic arm moves to align its pin with the fixed pin on the table. The final accuracy assessment relies on the operator visually observing whether the tips of the two pins completely touch and overlap. However, this method has significant limitations: human observation is prone to subjective errors, especially in judging minute deviations, making consistency difficult; prolonged repeated observation can lead to visual fatigue, further reducing the accuracy and reliability of the judgment. Furthermore, manual observation is inefficient, unsuitable for large-scale or high-frequency testing, and lacks objective data recording, hindering subsequent accuracy analysis and system optimization. Therefore, how to measure the repeatability of robots to avoid errors caused by visual observation is a problem that those skilled in the art need to consider. Utility Model Content

[0003] The purpose of this invention is to provide a system for measuring the repeatability accuracy of robot 3D vision, so as to solve the problems of inaccurate repeatability detection of robots in the prior art.

[0004] The technical solution of this utility model is: a system for measuring the 3D visual repeatability accuracy of a robot. The robot includes a robotic arm, on which a vision device and a probe are connected. The measurement system includes a platform, a target set on the platform, and X-axis measuring instruments, Y-axis measuring instruments, and Z-axis measuring instruments with mutually perpendicular measurement directions. The axial directions of the measuring axes of the X-axis measuring instruments, Y-axis measuring instruments, and Z-axis measuring instruments intersect at point A, and their positional relationship with the center point B of the target is relatively fixed.

[0005] Driven by the robotic arm, the vision device acquires information at point B as the origin; then drives the probe to move its end to point A; and sequentially moves a predetermined distance from point A along the X, Y, and Z directions to contact the measuring ends of the X-axis measuring instrument, Y-axis measuring instrument, and Z-axis measuring instrument respectively, and obtains readings.

[0006] Preferably, a calibration plate is provided on the platform, and the vision device collects the information of the calibration plate before collecting the information of point B, in order to perform calibration.

[0007] Preferably, the target is set as a cube.

[0008] Preferably, the distance between the ends of the measuring axes of the X-axis measuring instrument, Y-axis measuring instrument and Z-axis measuring instrument and point B is a preset value.

[0009] Preferably, the probe is cylindrical, and when the probe contacts the X-axis measuring instrument and the Y-axis measuring instrument, the measured value is reduced by the probe radius value.

[0010] Preferably, the end of the probe is spherical, and when the end of the probe contacts the X-axis measuring instrument, the Y-axis measuring instrument, and the Z-axis measuring instrument, the measured value is reduced by the radius of the spherical end.

[0011] Preferably, the plane containing the upper surface of the calibration plate is parallel to the plane containing the upper surface of the target.

[0012] Compared with the prior art, the advantages of this utility model are:

[0013] (1) In this utility model, the vision device and the robotic arm are first calibrated by the positioning plate. Then, the coordinate system is established by the target and fixed to the center of the three measuring instruments. The three measuring instruments are then touched in turn. The positioning accuracy can be intuitively determined based on the results of the measuring instruments. This solves the instability caused by relying solely on human eyes and improves the accuracy of the equipment. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0015] Figure 1 This is a schematic diagram of the system structure for measuring the 3D vision repeatability accuracy of a robot according to the present invention;

[0016] Figure 2 This is a schematic diagram of the measurement system described in this utility model;

[0017] Figure 3 for Figure 2 Enlarged structural diagram at point C.

[0018] Among them: robotic arm 1, vision device 11, probe 12;

[0019] Platform 2, target 21, X-axis measuring instrument 22, Y-axis measuring instrument 23, Z-axis measuring instrument 24, calibration plate 25. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments:

[0021] like Figures 1-3As shown, this utility model is applied to measuring the 3D vision repeatability of a robot. Repeatability is one of the important influencing factors in robot operation, directly affecting product quality and production efficiency. Decreased accuracy will cause the robot's end effector to fail to move strictly and accurately according to the expected pose requirements, leading to a significant drop in product quality or even scrapping. Therefore, it is necessary to measure the repeatability of the robot to ensure its operational stability. Specifically:

[0022] A system for measuring the 3D visual repeatability of a robot is disclosed. The robot includes a robotic arm 1, on which a vision device 11 and a probe 12 are connected. The measurement system includes a platform 2, a target 21 mounted on the platform 2, and X-axis measuring instruments 22, Y-axis measuring instruments 23, and Z-axis measuring instruments 24 with mutually perpendicular measurement directions. The axial directions of the measuring axes of the X-axis measuring instruments 22, Y-axis measuring instruments 23, and Z-axis measuring instruments 24 intersect at point A, and their positions relative to the center point B of the target 21 are relatively fixed. A calibration plate 25 is mounted on the platform 2. Before the vision device 11 acquires information from point B, it first acquires information from the calibration plate 25 for calibration.

[0023] In this embodiment, the calibration plate 25 is a fixed-spacing patterned array plate. By photographing the calibration plate 25 with the vision device 11, lens distortion can be corrected, and the conversion relationship between physical dimensions and pixels can be determined. The specific correction and conversion methods are existing technologies and will not be described in detail in this embodiment. The target 21 is set as a cube, allowing the vision device 11 to quickly calculate the position information of the center point of the target 21 by taking a picture. Of course, it can also be set as a cylinder or other shapes according to actual needs. The plane containing the upper surface of the calibration plate 25 is parallel to the plane containing the upper surface of the target 21 to ensure that the information acquisition of the target 21 after camera calibration is more accurate and stable.

[0024] The distances between the ends of the measuring axes of the X-axis measuring instrument 22, Y-axis measuring instrument 23, and Z-axis measuring instrument 24 and point A are preset values. The measuring instruments can be dial indicators or other measuring devices such as laser rangefinders. In this embodiment, using a dial indicator as an example, the measuring axes of the X-axis measuring instrument 22 and Y-axis measuring instrument 23 are horizontally set, while the measuring axis of the Z-axis measuring instrument 24 is vertically upward. The lines containing the three measuring axes are perpendicular to each other and intersect at point A. It should be noted that the three measuring axes do not contact each other to avoid mutual interference. Furthermore, the distances between the ends of the three measuring axes and point A can be preset to the same value or different values.

[0025] The probe 12 is attached to the robotic arm 1 and can be cylindrical or rotated to be spherical at one end. Of course, other shapes or specifications can also be selected, only requiring a change in the calculation method.

[0026] The measurement principle is as follows:

[0027] Driven by the robotic arm 1, the vision device 11 collects information from the positioning plate to perform lens correction and calibration of physical dimensions and pixels with the robot. Then, the vision device 11 collects information from the target 21 and establishes a virtual coordinate system with the center point B of the target 21 as the origin. Then, according to the preset coordinates of point A, the robotic arm 1 drives the probe 12 to move the end of the probe 12 to point A. After that, the probe 12 is driven to move a predetermined distance from point A along the X, Y and Z directions and contact the measuring ends of the X-axis measuring instrument 22, Y-axis measuring instrument 23 and Z-axis measuring instrument 24 respectively, and obtains readings. Based on the reading information, it is determined whether the repeatability accuracy is accurate or within the error range.

[0028] The specific calculation method is as follows: set the distance between the measuring axis end of X-axis measuring instrument 22, Y-axis measuring instrument 23 and Z-axis measuring instrument 24 and point A to be a. That is, in this state, the readings of X-axis measuring instrument 22, Y-axis measuring instrument 23 and Z-axis measuring instrument 24 are 0.

[0029] When probe 12 is cylindrical, the radius of its cross-sectional circle is r, and the center of the lower end face of probe 12 coincides with point A. Probe 12 moves a preset distance b (the value of b is greater than a) from point A in the X-axis, Y-axis, and Z-axis directions. The readings obtained are: the reading when it contacts the end of the X-axis measuring instrument 22 minus r; the reading when it contacts the end of the Y-axis measuring instrument 23 minus r; and the reading when it contacts the end of the Z-axis measuring instrument 24. If these three values ​​are the same or all within a preset range, the robot's 3D vision repeatability positioning accuracy is qualified.

[0030] When the end of probe 12 is spherical, the radius R at the sphere drives probe 12 until the center of the sphere coincides with point A. Similar to the above method, but when obtaining the values: subtract R from the reading when it touches the end of the X-axis measuring instrument 22, subtract R from the reading when it touches the end of the Y-axis measuring instrument 23, and subtract R from the reading when it touches the end of the Z-axis measuring instrument 24. Compare these three values. If the three values ​​are the same or all within the preset range, it indicates that the robot's 3D vision repeatability is qualified.

[0031] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.

Claims

1. A system for measuring the 3D visual repeatability accuracy of a robot, the robot comprising a robotic arm, wherein a vision device and a probe are connected to the robotic arm, characterized in that, The measurement system includes a platform, a target mounted on the platform, and X-axis measuring instruments, Y-axis measuring instruments, and Z-axis measuring instruments with mutually perpendicular measurement directions. The axial directions of the measuring axes of the X-axis measuring instruments, Y-axis measuring instruments, and Z-axis measuring instruments intersect at point A, and their positional relationship with the center point B of the target is relatively fixed. Driven by the robotic arm, the vision device acquires information at point B as the origin; then drives the probe to move its end to point A; and sequentially moves a predetermined distance from point A along the X, Y, and Z directions to contact the measuring ends of the X-axis measuring instrument, Y-axis measuring instrument, and Z-axis measuring instrument respectively, and obtains readings.

2. The system for measuring the 3D visual repeatability accuracy of a robot according to claim 1, characterized in that: A calibration plate is set on the platform. Before the vision device collects the information of point B, it first collects the information of the calibration plate for calibration.

3. The system for measuring the repeatability of 3D vision positioning of a robot according to claim 2, characterized in that: The target is set as a cube.

4. The system for measuring the 3D visual repeatability accuracy of a robot according to claim 1, characterized in that: The distance between the ends of the measuring axes of the X-axis measuring instrument, Y-axis measuring instrument, and Z-axis measuring instrument and point B is a preset value.

5. A system for measuring the repeatability of 3D vision positioning of a robot according to claim 1, characterized in that: The probe is cylindrical. When the probe touches the X-axis measuring instrument and the Y-axis measuring instrument, the measured value is reduced by the probe radius value.

6. A system for measuring the repeatability of 3D vision positioning of a robot according to claim 1, characterized in that: The probe tip is spherical. When the probe tip contacts the X-axis measuring instrument, Y-axis measuring instrument, and Z-axis measuring instrument, the measured value is reduced by the radius of the spherical end.

7. A system for measuring the repeatability of 3D vision positioning of a robot according to claim 2, characterized in that: The plane containing the upper surface of the calibration plate is parallel to the plane containing the upper surface of the target.

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