Design of stable recurrent fuzzy-logic-controllers

Controllers based on fuzzy logic belong to the class of static or memoryless nonlinear controllers and provide better control than is possible using linear control. The major strength of fuzzy controllers lies in the way a nonlinear output mapping of a number of inputs can be specified easily using fuzzy linguistic variables and fuzzy rules. When we use fuzzy logic in feedback control, we in effect have a nonlinear system with feedback and the resulting system could potentially become unstable. In this work, we show how we can design feedback systems (with fuzzy control) that are guaranteed to be stable. This approach can also be used to design stand-alone feedback fuzzy systems (or recurrent fuzzy systems) that are guaranteed to be stable