A new type of control method for electro-hydraulic Servo systems

Internal model control (IMC) has been widely used because of its easily designed method and simple tuning policy. But better performance cannot be obtained when it is used in hydraulic servo system control directly because of the systemspsila uncertainties, time varying and highly nonlinear characteristics due to the flow-pressure relationship, oil leakage, oil temperature variation, load disturbances, integrating characteristic and the high open-loop gain. In this paper a kind of two-degree-of freedom IMC method for Electro-hydraulic servo systems is prompted in which a classical foreword internal model controller and a novel feedback fuzzy controller are designed. The transfer-function-based factorization approach in the frequency domain is used to analyze the stability of the system. Simulation experiments show better dynamic performance and disturbance rejection.