Robust Rotational Velocity Controller in Water Hydraulic Servomotor System

Water hydraulic servo system is attractive technology for safety environment. This paper presents a design method of a robust rotational velocity controller of water hydraulic servomotor for the uncertain parameters and the load fluctuation. To overcome the highly nonlinearity of flow equation, we linearize and parametrize it. Considering the effect of uncertain parameter perturbation, e.g. load fluctuation and friction parameters, a method of Lyapunov-based recursive design is applied to construct a robust rotational velocity controller. Simulation results demonstrate the proposed robust controller provides better disturbance rejection and dynamic properties than those achieved by a conventional PID controller.