Adaptive position tracking control for electro-hydraulic servo system with input saturation

An adaptive controller is proposed for the position tracking of an electrohydraulic servo system with uncertainties and input saturation. Firstly, fuzzy logic is employed to approximate the unknown nonlinear uncertainties. And a nonlinear tracking controller is developed by combining the adaptive backstepping with H _∞ control method. In addition, in order to tackle the input constraint, an auxiliary design system based on Lyapunov method is presented. The proposed controller not only can effectively avoid the problem of input saturation, but also can guarantee that the output tracking error satisfies the H-infinity performance. Finally, the simulation results testify the effectiveness of the proposed method.