The control system in our welding cell is based on multiple sensing technology and fuzzy logic algorithm. The first generation of controller is a vision based fuzzy logic controller (FLC). Video signals from weld plume in real time are analyzed to generate information for the fuzzy logic controller to adjust welding speed in order to maintain consistent welds.The second-generation controller incorporates weld fault monitoring technology into the existing FLC to form a self-adapting neural-fuzzy control system. Technology of multiple-color optical emission sensing and neural network analysis is the key feature of this controller. The third-generation controller will add multi-spot detection technology, which detects the gap opening or small offset from the desired beam position on the joint and thus allows for adaptive adjustment of laser beam focal spot size.