Block diagram modeling and control of electro-hydrostatic actuator

Power-by-wire (PBW) actuation is the future direction of flight control system in which the need for a central hydraulic system is eliminated. The electro-hydrostatic actuator (EHA) is a kind of PBW actuator that converts the electrical power into local hydraulic power and combines the benefits of the conventional hydraulic system and the direct drive electrical actuators. Based on the mathematic equations, all the EHA components were modeled by the block diagrams and assembled to a fixed-displacement variable-speed architecture, which contained the refeeding circuit and the friction. Furthermore, the single proportion integration differentiation (PID) controller, cascade PID controller and state feedback controller are designed for comparison analysis that focused on the system stability, stiffness and dynamic characteristics. The simulation results prove that the state feedback controller along with dynamic pressure feedback strategy efficiently improves the static and dynamic performance of EHA.