Welding robot positioning method based on machine vision and laser ranging

Abstract

In order to solve the problem of the accurate positioning of the welding robot in the automatic bar production, this paper proposes a positioning method of the welding robot based on machine vision and laser ranging. The traditional positioning method of welding robot mainly adopts the Hand-eye calibration mode, however, the essence of Hand-eye calibration is to obtain the conversion relationship from camera coordinate system to robot end actuator coordinate system through complex matrix operation. The calculation process of this method is too lengthy, and it is difficult to achieve the required accuracy of welding. The precise positioning of welding robot mainly includes plane coordinate positioning and depth positioning. First of all, this paper is based on the principle that the distance between the camera and the object to be photographed and the size of the camera image are proportional to the size of the object, the pixel coordinates obtained from the image processing are transformed into the plane coordinates of the final target point to be welded by the method of machine vision. At the same time, in view of the distortion caused by the camera in the imaging process, this paper uses the Zhang calibration method to correct the distorted image. Finally, the resistance detection circuit proposed is used to determine the final welding position. The experimental results show that the positioning method of the welding robot has the advantages of easy realization and high positioning accuracy, which can fully meet the welding requirements and improve the efficiency of automatic welding of the label.