Active vehicle suspension system and a control method therefor

摘要

In an active vehicle suspension system employing a spring and a hydraulic actuator for supporting a wheel relative to a vehicle body, a control unit actuates the actuator so as to cancel the force applied by the spring force of the spring and a damping force applied by the hydraulic actuator. This damping force is typically produced by the flow resistance which the hydraulic oil encounters in the hydraulic circuit. This control action is carried out according to a signal obtained by processing an output of a displacement sensor between the wheel and the vehicle body with a first-order lead filter circuit. Thus, the control action is based on a readily available and highly responsive detection signal, an accurate and stable vibration control of the sprung mass of the vehicle or the vehicle body is made possible. This control action may be combined with a conventional feedback control based on the acceleration of the sprung mass or the load acting between the suspension system and the vehicle body, and a low-pass filter which ensures the stability of the system even when the first-order lead filter circuit is used.