Automatic and Real-Time Joint Tracking and Three-Dimensional Scanning for a Construction Welding Robot

Although welding is one of the essential steel fabrication processes, the American Welding Society expects that the labor shortage in the United States will reach a deficit of 360,000 welders by 2027. Developing an automatic robotic welding system could potentially alleviate the labor shortage and provide better welding quality. As a first step, this paper designs a system pipeline that can automatically detect different welding joints and plan and track the joints' trajectory with the initial point alignment in real time. There are rare studies that could achieve automatic initial point alignment in real time because the laser stripe's deformation is not obvious at the narrow weld. In this study, the target joint's endpoints were detected once the joint was detected on live video. Then, the joint trajectory was planned, and the robotic arm automatically aligned with the initial point and tracked the planned trajectory while scanning. The results demonstrate the accuracy and effectiveness of the proposed method.