Perimetric sensor for the detection and following of complex seam trajectories in robotic laser welding

Abstract

Laser welding is a process that has high positioning accuracy demands. Such processes are usually performed with velocities of up to 250mm/sec. When robots are used to manipulate the laser welding equipment at such velocities, the robot dynamics can significantly influence the positioning accuracy. The addition of sensors can assist in correcting positioning errors. Nevertheless, the use of sensors imposes additional restrictions on the way that robots are allowed to move over a seam trajectory. For several cases the use of sensors can force robots into positioning errors due to robot dynamics. Thus by fixing one problem another one is created. It is therefore desirable for the sensors to detect and follow a seam without forcing the manipulating robot into dynamic positioning errors. Such a sensor is presented in this paper.