LPV Model-based Robust Controller Design of Electro-hydraulic Servo Systems

In this paper, a Lyapunov-based control algorithm is developed for position tracking control of a class of electro-hydraulic servo systems driven by double-rod hydraulic actuators. By utilizing the nonlinear servo valve flow-pressure characteristics of the hydraulic system, the electro-hydraulic servo system is firstly described as a linear parameter varying (LPV) model. Then the sufficient strict linear matrix inequality (LMI) conditions for the robust stabilizability of the uncertain systems are proposed in terms of LMIs. By solving those LMIs, a parameter-dependent controller is established for the closed-loop system to be stable with a prescribed level of disturbance attenuation. Finally, the numerical simulations demonstrate the usefulness and advantages of the proposed controllers.