STABILITY ANALYSIS AND DESIGN OF FUZZY CONTROL-SYSTEMS

The stability analysis and the design technique of fuzzy control systems using fuzzy block diagrams are discussed. First, we show the concept of fuzzy blocks and consider the connection problems of fuzzy blocks diagrams. We derive some theorems and corollaries with respect to two basic types of connections of fuzzy blocks. In order to preserve some properties in a connection of fuzzy blocks, continuous piecewise-polynomial membership functions are defined. Secondly, a sufficient condition which guarantees the stability of fuzzy systems is obtained in terms of Lyapunov's direct method. We give an important fact based on this condition. Thirdly, we propose a new design technique of a fuzzy controller. The fuzzy block diagrams and the stability analysis are applied to the design problems of a model-based fuzzy controller.