Fex: External load force [N]

In this paper, a typical architecture of Electro-Hydrostatic Actuator (EHA) is described and modeled by the block diagram based on mathematic equations, which is a nonlinear accuracy model. The single PID, cascade PID and state feedback controllers are respectively designed and applied to this model for comparison analysis that focused on system stability, stiffness and dynamic characteristics. It is proven that the state feedback controller along with dynamic pressure feedback strategy could efficiently improve both static and dynamic performance