Modeling and fuzzy control of the resistance spot welding process

Establishes a welding energy model and describes a fuzzy adaptive process control scheme for a resistance spot welding system. For a welding system, it is not easy to measure online the output, the nugget size, by usual measuring methods. It is also difficult to control the welding process in real time. The paper proposes a method using input welding energy to estimate the nugget size and to assess the welding process. An optimal welding energy reference model is found and compared with different input methods of welding energy. A fuzzy adaptive process control scheme with the model is also described to realize real time control and to improve control performance. The results of simulation and experiments show that the reference model is effective for reducing energy loss and producing a sound nugget and the fuzzy adaptive control scheme may obtain an optimal control process for resistance spot welding.