Design, implementation and testing of a fuzzy control scheme for laser welding

A fuzzy logic controller (FLC) scheme has been developed for laser welding. Process light emissions are measured and combined to determine the current status of the welding process. If the process is not in a desired welding state, the FLC will adapt the laser power. The FLC has been demonstrated for the laser welding of zinc coated steel sheets in an overlap configuration. Experiments showed that the controller is capable of steering the process towards full penetration keyhole welding, avoiding both blowholes as well as lack of penetration. Under the presence of different process disturbances, like changes in focal position and material thickness, the controller proved to be able to maintain full penetration keyhole welding. The architecture of the controller is generic, thus facilitating an implementation for the laser welding process of other materials or configurations.