ファジィ適応コントローラを用いたスポット溶接機の実時間制御

抄録

This paper describes a control scheme for on-line control of a spot welding machine. From the simulation of the soft-steel welding process by constant current, constant power and variable power methods with numerical analysis by FEM, nugget sizes etc. obtained are compared for these three methods. Variable power method is the best one for obtaining the biggest nugget and is used here as a reference (welding energy) model. And a fuzzy adaptive controller (FAC) instead of an usual fuzzy controller (FC) is developed and used for the improvement of the control accuracy of the spot welding machine. The membership functions of the fuzzy adaptive controller will be modified in real time with the adaptive algorithms according to distinct operating stages and working environment. Combining the reference energy model and FAC, a model reference fuzzy adaptive control (MRFAC) scheme is developed. The results of simulation and experiments with a dummy circuit of the spot welding system show that it is possible to control welding energy with on-line. Simulations also show that the control performance of the welding system with FAC becomes better than that with FC. And the experimental result indicates that the MRFAC system has also robustness for parameters changes, welding stage changes and disturbance.