Fuzzy servocontrollers: the hierarchical approach

On the basis of a study of PI controller functions in servomechanisms, the authors design a two-stage fuzzy servocontroller that accomplishes constant set-point tracking in unknown plants which may be open-loop unstable. A Lyapunov function is used as a performance index in formulating the fuzzy rules. Simulations on an unstable, nonlinear plant justified this approach. >