Robust fuzzy control for a class of nonlinear systems using input-output linearization. Real-time implementation for a bot wrist

In this paper, a fuzzy controller enhanced with a H/sub /spl infin// control component is proposed to deal with unmodeled uncertainties for a class of continuous nonlinear systems. The uncertainties are due to fuzzy approximation error and external disturbances. First, we represent the nonlinear plant with a Takagi-Sugeno fuzzy system. Then, a fuzzy controller is designed applying the so-called "input-output linearization" concept. However, this controller cannot guarantee robustness in the presence of uncertainties. In order to deal with this problem, an additive H/sub /spl infin// control component is added to the fuzzy controller to attenuate uncertainty influence on control performances. Finally, in order to demonstrate the feasibility of the proposed methodology, a real-time implementation for controlling a robot wrist is presented.