Virtual reality human-robot collaborative welding: A case study of weaving gas tungsten arc welding

To combine the advantages of humans (adaptive intelligence) and robots (higher movement accuracy and physical limitation), we propose a virtual reality human-robot collaborative welding system which allows them to collaborate with each other to complete welding tasks. A common welding method, weaving gas tungsten arc welding (GTAW) is presented as a case study. In this system, a 6-degree of freedom (6-DoF) robot UR-5 carrying the welding torch works as the final performer of weaving welding. A virtual welding environment based on HTC VIVE is built where humans can observe the working scene via a motion-tracked headset without being onsite physically. A mapping model between arc voltage, arc length and welding current is established, and based on this model a seam tracking algorithm is developed which allows the robot to track the weld seam automatically. The robot is pre-programmed to weave the welding torch across the weld seam. The robot travelling along the weld seam is fully controlled by the human operator via motion-tracked handle per the observed working scene. This teleoperation style allows the humans to adjust the travel speed adaptively and freely as needed without suffering onsite danger. The proposed collaborative welding system combines the advantages of humans and robots together, utilizing the intelligence and adaptability of the human operator with precise movement obtained from robots. The welding experiments show that the welded workpiece from human-robot collaboration has better performance compared with that from either humans or robots separately and demonstrated the effectiveness of the proposed virtual reality human-robot collaborative welding system.