Position control device and automotive suspension system employing same

摘要

A position control device includes a fluid-operated directional control valve for controlling the position of the piston of a cylinder assembly under fluid pressure in response to a control signal from an electronic controller. The position of the piston is predicted based on the control signal. A position detector detects when the piston has actually reached a predetermined position. When it is detected that the piston has actually reached the predetermined position, the predicted position of the piston is corrected. The electronic controller applies a control signal to the directional control valve so that the predicted position as corrected will be equalized to a target position for the piston. The predetermined position is a substantially intermediate position of the stroke of the piston. The directional control valve comprises a solenoid-controlled valve for controlling the flow rate of the fluid depending on the magnitude of a current supplied to the solenoid-operated valve. The position of the piston is calculated based on the magnitude of the current and a period of time during which the current is supplied to the solenoid-operated valve. An automotive suspension system incorporating the position control device is also disclosed.