Robust output feedback control of electro- hydraulic servo system using wavelet neural network

Aimed at improving robustness and tracking control performance of electro-hydraulic servo system, an output feedback control scheme is proposed. To estimate the external disturbance and internal parameter uncertainties, the disturbance observer using wavelet neural network is applied. Novel update and control laws are proposed to guarantee that the observer error and the tracking error in the closed-loop control system are uniformly ultimately bounded (UUB) in the sense of Lyapunov, and the tracking error can be kept arbitrarily small. The theoretical results are illustrated in the design of a controller for an electro-hydraulic servo system. Computer simulations show the strong robustness and applicability of the suggested method compared to PID control.