Novel indirect adaptive fuzzy controller

Adaptive fuzzy control provides an effective approach for the complicate plants, and it gets abroad attention in control field. A new scheme of indirect adaptive fuzzy controller is developed based on Popov hyperstability theory for a class of SISO uncertain nonlinear plants. At first an ideal controller is constructed by plant model, and some fuzzy systems are employed to approximate unknown plant model using universal approximation property of fuzzy systems. Then the close-loop system is converted to an equivalent error model which is composed of a linear constant forward block and a nonlinear time-varying feedback block, and stable adaptive law of parameter is deduced. It can guarantee the convergence of the system output to the given signal, at the same time restriction of minimum approximation error is relaxed, and it can offer more general and flexible form of parameters adjustment. Simulation results illustrate the validity of the proposed scheme to the nonlinear plants.