Fuzzy modeling and optimal control of nonlinear second order systems

This paper presents the exact fuzzy modeling and optimal control of a class of second order nonlinear dynamic systems. Input saturation, output slew rate limit and nonlinear stiffness are considered. Conventionally, the TSK fuzzy modeling blends local linear models to represent a nonlinear system, which in general does not exactly represent the nonlinear system under consideration. Here, instead of local linear models, a set of 'boundary linear models' (BLM) and associated membership-functions are so chosen that the fuzzy blending of these models result in an exact representation of the overall nonlinear system. An optimal fuzzy controller is designed based on this exact fuzzy model and the results are compared with a conventional design.