Research on Automatic Guidance Technology of Tube-Sheet Welding Based on Vision and Laser Displacement Sensor

Utilizing intelligent sensors to obtain the coordinates of the tube bundle in the robot coordinate system during the tube-sheet welding process represents a current trend in the automated guidance technology for tube-sheet welding. In this paper, a surface array camera and a laser displacement sensor are integrated to establish the three-dimensional pose relationship among the robot, the tube-sheet plane, and the tube bundle, and an automatic welding guidance process based on this fused sensor is proposed. Taking the six-axis robot automatic welding system as an example, the key links affecting the final guidance accuracy are optimized, and ultimately a set of automated guidance technology for tube-sheet welding is developed. The tube bundle positioning process is divided into two steps, namely coarse positioning and fine positioning, to enhance the positioning accuracy. This paper presents the working process and the calibration method of the fused sensor and verifies the accuracy of the sensor. Compensation grids are divided into the motion space of the six-axis robot to increase its absolute positioning accuracy. Experiments indicate that after spatial grid compensation, the accuracy of the tube-sheet welding guidance can increase by 61%,demonstrating the feasibility of the automated guidance technology proposed in this paper.