On stability of fuzzy control systems using a fuzzy modeling method

The authors present an analysis method on stability of fuzzy control systems using a fuzzy modeling method. A fuzzy neural network (FNN) which is capable of acquiring fuzzy rules is used for obtaining the fuzzy model of the controller object. A new definition of the stability of fuzzy control systems is also presented. Since both the controlled object and the controller are described with linguistic rules, i.e., fuzzy if-then rules, the stability analysis can be done linguistically. Although the new definition of stability is not mathematically rigorous, the process of analysis based on the definition is very simple and easy to understand, even to those who have little knowledge of control theory. For the verification of the proposed method, simulations were carried out by using a simple nonlinear plant