An On-line Visual Seam Tracking Sensor System During Laser Beam Welding

This paper deals with a seam tracking system of welding of tailored weld blanks based on active laser-triangulation. The system consists of DSP based vision camera and stripe-type laser diode. The total system is assembled into a compact module which can be attached ahead of welding torch and it has high dynamic performance in guiding the robot arm welder accurately over the seam. its structure, basic principle of this system and the main function are introduced . The images taken by the camera are analyzed using image processing algorithms: setting the range of interest, the median filtering and bi-level thresholding. Furthermore, the middle line of the laser stripe is extracted. Finally, a search method is carried out to examine the mid-point. A prototype sensor system has been developed and experimental results show its effectiveness and good performance.