Robotic refurbishment of a spherical valve

This paper presents a robotic application for in situ repair of the seal surfaces of a large hydropower spherical valve. The repair involves laser scanning, machining, welding and polishing using the portable track-based Scompi robot. To perform the machining, the robot uses a tool guide mechanism that locates accurately the machining tool and holds it against the work surface despite large disturbance forces. The stiffness with which the tool is held is improved significantly. The method was successfully tested in the field at Rio Tinto Alcan´s Chute-des-Passes generating station in May 2012.