Design of fuzzy controllers based on stability analysis

Fuzzy systems have been successfully applied to the design of knowledge-based controllers, yielding very good performance in many cases. However, one of the main drawbacks of fuzzy control has been the lack of formal analysis and design techniques that allow the designer to ensure a priori certain features of the closed-loop system, particularly stability. This article presents a systematic procedure for the design of Takagi-Sugeno fuzzy controllers for nonlinear plants in controllable canonical form. Consequent parameters are obtained using linearized plant models and linear design techniques. Premise parameters are computed in such a way that the asymptotic stability of the equilibrium point in the closed-loop system is guaranteed. The proposed design method is illustrated with two examples and simulation results. (C) 2001 Elsevier Science B.V. All rights reserved.