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A Calibration Method for the Relative Position of a Three-dimensional Sensor and a Manipulator

A technology of mechanical arm and relative position, which is applied in the direction of instruments, measuring devices, optical devices, etc., can solve the problems that affect the efficiency of large-scale robot application, cannot provide real-time feedback calibration accuracy, and time-consuming and labor-intensive hand-eye calibration process, etc.

Active Publication Date: 2020-11-17
SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the end of the robotic arm as a whole cannot be directly used as a landmark for hand-eye calibration
Moreover, the existing hand-eye calibration method cannot provide real-time feedback on the calibration accuracy and automatically adjust the calibration process
The number of feature points that need to be obtained for hand-eye calibration usually needs to be solved by engineering experience, human intervention and a large number of points. The hand-eye calibration process is time-consuming and labor-intensive, especially affecting the efficiency of large-scale robot applications.

Method used

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  • A Calibration Method for the Relative Position of a Three-dimensional Sensor and a Manipulator
  • A Calibration Method for the Relative Position of a Three-dimensional Sensor and a Manipulator
  • A Calibration Method for the Relative Position of a Three-dimensional Sensor and a Manipulator

Examples

Experimental program
Comparison scheme
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no. 1 example

[0031] see image 3 , the first embodiment of the present invention comprises the following steps:

[0032] S301. Move the end of the robotic arm to the field of view of the 3D sensor, so that the flange at the end faces the 3D sensor without obstruction, record the point cloud information of the flange acquired by the 3D sensor at this time, and extract the flange through a 3D vision algorithm At least one feature point of the disk, and obtain the three-dimensional coordinate value of the extracted feature point relative to the three-dimensional sensor coordinate system;

[0033] It should be noted that the feature points of the flange extracted in the above steps can be the center of the disc of the flange and / or the center of the threaded hole on the flange; when the selected feature points include the disc of the flange When the center and the center of the threaded hole on the flange, there are usually more than three feature points that can be selected, and these featur...

no. 2 example

[0039] see Figure 4 , the second embodiment of the present invention comprises the following steps:

[0040] S401. Move the end of the mechanical arm to the field of view of the three-dimensional sensor, so that the flange at the end faces the three-dimensional sensor without obstruction, record the point cloud information of the flange acquired by the three-dimensional sensor at this time, and extract the flange through a three-dimensional vision algorithm At least one feature point of the disk, and obtain the three-dimensional coordinate value of the extracted feature point relative to the three-dimensional sensor coordinate system and the normal vector of the flange;

[0041] It should be noted that the feature points of the flange extracted in the above steps can be the center of the disc of the flange and / or the center of the threaded hole on the flange; when the selected feature points include the disc of the flange When the center and the center of the threaded hole o...

no. 3 example

[0050] see Figure 5 , the third embodiment of the present invention comprises the following steps:

[0051] S501, move the end of the robotic arm to the field of view of the 3D sensor, and make the flange at the end face the 3D sensor without obstruction, record the point cloud information of the flange acquired by the 3D sensor at this time, and obtain it through the point cloud segmentation algorithm The point cloud image of the flange surface, and then the three-dimensional coordinate value of the center point of the flange disc in the three-dimensional sensor coordinate system and the normal vector of the flange are obtained through the circle fitting algorithm;

[0052] S502, read and record the position of the end of the robot arm relative to the base coordinate system of the robot arm from the controller of the robot arm, and obtain the three-dimensional coordinate value of the center point of the flange in the base coordinate system of the robot arm and the flange met...

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Abstract

The invention discloses a method for calibrating the relative position of a three-dimensional sensor and a mechanical arm, comprising: step 1, moving the mechanical arm so that the flange plate at the end faces the three-dimensional sensor, recording the point cloud information acquired by the three-dimensional sensor at this time, and passing The three-dimensional vision algorithm extracts at least one feature point of the flange, and obtains its three-dimensional coordinate value relative to the three-dimensional sensor coordinate system; Step 2, for the extracted feature point, obtains its three-dimensional coordinate relative to the base coordinate system of the robot arm value; step 3, repeat steps 1 and 2, extract multiple non-coplanar feature points, and obtain multiple sets of three-dimensional coordinate values ​​of each feature point relative to the three-dimensional sensor coordinate system and the base coordinate system of the manipulator, and calculate Optimal hand-eye transformation matrix. The present invention solves the problem of selecting calibration points by adopting the geometric characteristics of the flange at the end of the existing mechanical arm, and does not need to install marker points during calibration, which significantly simplifies the calibration process and greatly reduces the calibration cost.

Description

technical field [0001] The invention relates to the technical field of a hand-eye calibration method for a robotic arm, in particular to a calibration method for the relative positions of a three-dimensional sensor and a robotic arm. Background technique [0002] With the development of Industry 4.0, more and more industrial application scenarios use high-precision robotic arms to replace manual work, such as multi-joint robotic arms and rectangular coordinate system robotic arms. Usually, the robotic arm needs to cooperate with different end effectors to complete specific tasks. The robotic arm referred to in this article does not include the end effector. In recent years, the rapid development and application of high-precision three-dimensional sensors have also made the application of robotic arms no longer limited to a single structured industrial scene and simple repetitive operations. The high-precision point cloud information collected by the 3D sensor contains the s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B11/00
Inventor 宋超阳万芳
Owner SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA