Seam tracking in laser welding using vision sensors

Examples of two different types of vision sensor are described, both capable of being used for seam tracking in laser welding: those based on scanning laser illumination and a linear optical detector (scanning sensors), and those based on structured light illumination and a CCD (charge coupled device) camera (structured light sensors). Their principles, features, performance and availability are described initially. The feasibility of integrating a vision sensor with a motion control unit is discussed, and the requirements of programming languages for seam tracking in laser welding using a vision sensor are outlined. Finally, an experimental seam tracking system for laser welding is presented, which has been successfully used for solving problems in a number of industrial applications.