An empirical study of robustness of fuzzy systems

The authors present intensive empirical studies in fuzzy control systems to investigate, mainly, their robustness properties. The specific problem considered is the speed control of a rotating motor. The desired performance goal of the system is to make the motor speed follow the reference speed with a short rise time and with no overshoot. A fuzzy control system using a controller based on fuzzy if-then rules is proposed. The concept of robustness is formulated theoretically and intensive simulations are used to check its validity. Within this empirical study, the theoretical concept of the approximation capability of fuzzy controllers is also discussed