Hydraulic active suspension system for a vehicle performing vehicle

Abstract

In a hydraulic active suspension system, a plurality of actuators having working fluid chambers are provided corresponding to the vehicle wheels. Each actuator is adapted to increase and decrease vehicle height in response to the pressure within its working chamber, which is controlled by a pressure control device. Vehicle speed and vehicle heights at the locations corresponding to the vehicle wheels are detected by corresponding sensors. A control device is further provided for controlling the pressure control device so that the pressures within the working fluid chambers are driven to substantially the desired pressures, the desired pressures determined by, at least, the sum of the first control parameters corresponding to the differences between the actual vehicle heights detected and the associated desired vehicle heights and the second control parameters corresponding to the changing amounts of the vehicle height differences. The second control parameters are so set that the higher the vehicle speed is, the higher the second quantities are in magnitude, enhancing the controllability and stability of the vehicle under higher vehicle speed conditions and ensuring a greater comfortability level of the vehicle under lower vehicle speed conditions.