Adaptive approximation control of nonlinear system based on fuzzy logic with approximation error compensation

This paper deals with the adaptive approximation control of a class of nonlinear dynamics systems without or no considering the compact approximation region. The proposed control scheme is developed to reduce the approximation error. Design of controller for unknown approximation error that has the unknown upper bound is to compensated by the adaptation. The new control scheme ensures the global stability of the adaptive system and achieves desired tracking performance. The control methodology is derived in the sense of Lyapunov theorem so that the stability of the control system is guaranteed. Computer simulation result has been conducted to validate the effectiveness of the proposed control scheme under the occurrence of possible uncertainties and different reference trajectories. The tracking error converges in the small neighborhood of zero and that all signals involved are uniformly bounded (Uniform ultimate boundedness). The merit of the proposed control system is indicated in comparison with a classical control system.