A robot grasping and positioning method

Abstract

The invention relates to a robot grasping and positioning method, which includes the following steps: (1) establishing a system coordinate system and correcting the robot tool coordinate system; (2) installing a camera and completing hand-eye calibration; (3) installing a clamp at the end of the robot and clamping the conveying line (4) Determine the feature area, the feature area includes the first camera scan area, the second camera scan area and the third camera scan area, the robot grabs the workpiece and moves to the first camera scan area, the second camera scan area in turn and the third camera scanning area, create the feature area templates of the above scanning areas respectively, save the feature area template data and the robot scanning starting point position respectively, and express them in matrix respectively; (5) re-scan the image, calculate the feature area relative to the robot base The posture of the system and the rotation offset matrix relative to the robot tool coordinate system; (6) feature point position mapping; (7) establishment of the workpiece coordinate system; (8) new workpiece positioning.

Description

technical field [0001] The invention belongs to the technical field of machining, and in particular relates to a robot grasping and positioning method. Background technique [0002] In the field of robotic grinding, iron castings have the characteristics of large size, poor dimensional consistency, many types and varieties, and heavy workpiece weight. However, the demand for automatic grinding of workpieces is increasing, which is an application trend in the future. When using a robot to load and unload materials, only when the position of the workpiece is known can it be grasped. There are certain requirements for the mechanical structure of the gripper and the position of the workpiece, and not any workpiece can be grasped at will. At present, the commonly used method is to make the position of the workpiece that the robot needs to grab is almost the same through the guide rod or manual operation, or to position the workpiece through vision or a high-precision mechanical s...

AI Technical Summary

Problems solved by technology

The disadvantages of the above technology are as follows: 1. The method of using a binocular structured light 3D camera is firstly that the cost of the camera hardware will increase several times, and secondly, the overall positioning accuracy of the large field of view is not as good as the local positioning accuracy, and the overall will be affected by the quality of the workpiece’s working conditions

2. There is a risk of inaccurate point laser measurement results by using point lasers to measure the position offset before and after the surface change of the workpiece to position the workpiece. The working conditions of the bottom surface of the workpiece and the consistency of the workpiece itself will affect the measurement results. It is very large, and may output wrong results; the reliability of the measurement accuracy is low, and there are only values ​​in the three directions of x, y, and z. If the angle of the workpiece changes, the direct result is to reduce the positioning accuracy of the workpiece, and the positioning result is unreliable.

3. The mechanical mechanism of the tooling fixture installed on the robot is used to realize the positioning of the workpiece. After the gripper grabs the workpiece, the positioning accuracy of the workpiece is ensured by the mechanical structure alignment. Therefore, the positioning accuracy of the mechanical structure directly affects the processing accuracy of the subsequent workpiece. , if the tooling structure design is unreasonable, there may be a slight shift in the workpiece position during the workpiece clamping process, and the tooling will be worn after long-term use, which will eventually affect the machining accuracy of the later workpiece

Images