Modeling and fuzzy control of the resistance spot welding process

This paper 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 with on-line the output, the nugget size, by usual measuring method. And it is also difficult to control the welding process in real time. The paper proposes a new method with input welding energy to estimate the nugget size and to reckon the welding process. An optimal welding energy reference model is founded compared with different input method of welding energy. A fuzzy adaptive process control scheme with the model is also, here, described to realize real time control and to improve control performance. The results of simulation and experiments show that the reference model is effective on reducing loss energy and producing a sound nugget and the fuzzy adaptive control scheme may obtain an optimal control process for resistance spot welding.