Motion-based active disturbance rejection control for a non-linear full-car suspension system

This paper investigates the vibration attenuation problem of a non-linear full-car suspension system and aims to stabilize the vehicle attitude to provide a good ride quality. First, with respect to heave motion, pitch motion and roll motion, the full-car suspension system is separated into three interconnected subsystems. For each subsystem, corresponding motion-based controllers are designed to attenuate the vibrations of the sprung mass. A non-linear tracking differentiator is used to track the reference signal and to obtain its derivative. An extended state observer is established to estimate the total disturbance, which includes all the uncertainties and the external disturbance. Based on the principle of active disturbance rejection control, proportional-derivative and fuzzy proportional-derivative controllers are designed to control the resulting linear system with total disturbance compensation. Finally, four actuator forces are computed online using the three motion-based controllers obtained. Simulations are carried out in different road conditions; the results illustrate the merits of the proposed control method.