Visual seam tracking system for butt weld of thin plate

An image-based visual seam tracking system is designed for butt weld of thin plate in this paper. The torch deviation from the joint in the horizontal direction is measured from the seam image. Since the weld seam is so narrow, its image is based on natural lighting. Due to the hardness of measuring depth information using monocular vision, structured laser light is used for detecting the torch deviation in the vertical direction. For steady seam tracking, a robust and fast feature extraction algorithm is developed. Moreover, a reliable controller is designed with error filtering and output pulse verification. Finally, experiments are conducted to verify the proposed seam tracking system.