Development of a Multiline Laser Vision Sensor for Joint Tracking in Welding

Abstract

In recent years, laser vision sensors have been widely used to track the weld joint. However, they could not be used to detect the joint precisely for high-speed welding. A multiline laser vision sensor (MLVS), which was used in this work overcame the problem. Five laser lines, which were made by an aspheric lens with a point laser source, provided important information to find the weld joint lines. Clearer images were obtained through the medium, an erosion/dilation filter, and hence, five enhanced range data were obtained by the extraction method. Through the proposed method, 20 images per second could be processed. Experiments were performed with the MLVS attached to a robot. The weld joint line was tracked with speeds of 10, 15, and 20 m/min, and the mean error was 0.3 mm and a maximum error was 0.6 mm. It was found that this MLVS was very reliable for tracking the weld interface.