Stable adaptive fuzzy control of the molten steel level in the strip casting process

A fuzzy control scheme to regulate the molten steel level in the strip casting process is presented, where the parameters of the fuzzy controller are stably adapted by using the Lyapunov-stability theory. A switching controller is also used to deal with the approximation error of the fuzzy logic system. The error in the molten steel level is proved to converge to zero asymptotically. In the simulation, the clogging/unclogging of the stopper nozzle is considered and is shown to be overcome by the proposed controller. The robustness to uncertainty is shown to be superior to that of the conventional proportional integral controller.