This paper discusses a multi-closed loop control strategy for an active suspension system of a quarter car model operated by an electro-hydrostatic actuator to trade-off between vehicle handling stability and passenger comfort. In order to provide a desirable dynamic behavior of hydraulic active suspension, the closed loop control strategy using fuzzy position feedback controller and linearization force feedback controller and referring to robot compliant control is proposed. The fuzzy position controller is to track a desired body displacement given by the impedance control and the linearization force controller to track a desired force. By using Matlab/Simulink, a vehicle model of suspension system for B road with 0.1 m hump road disturbance is simulated. The result shows that the root mean square values (RMS) of body vertical acceleration, suspension dynamic deflection and tire dynamic load of the active suspension system have been reduced compared to the passive suspension, greatly improving the vehicle handling stability and passenger comfort.

active suspension  /  electro-hydrostatic actuator  /  impedance control  /  position and force feedback control