Abstract: Method and apparatus for maintaining vehicular ride height in a vehicle having a body, front and rear wheels and an air suspension including front and rear air springs. The method includes sensing vehicle body height relative to the wheels to obtain front and rear vehicle height signals, and sensing vehicle speed to obtain a vehicle speed signal. The method also includes processing the front height signals to obtain a vehicle roll signal that has been compensated for the natural lean of the vehicle, the vehicle roll signal indicating vehicle roll due to steering adjustments by the vehicle operator. The method further includes processing the vehicle speed signal to obtain a vehicle pitch offset signal, indicating vehicle body height change due to longitudinal vehicle acceleration. The method also includes adjusting the height of the vehicle toward a predetermined target ride height based on the vehicle height sensor signals which have been compensated for vehicle roll and pitch.

Abstract: A method and apparatus for determining a center position of the vehicular steering system includes a steering sensor and a control unit. A dynamic center find routine and a long term center find routine are run simultaneously and the results compared to assure accurate dynamic center position for controlling automotive devices.

Abstract: A feedback control method and system are provided to accurately control the steering assist level in a vehicle steering system. An electric actuator, such as a solenoid, operates a flow control valve that controls the flow of control fluid in a vehicle steering system in relation to driver and vehicle inputs such as vehicle speed and the angular position and velocity of a hand-wheel of the steering system. The flow of the control fluid is utilized by the steering system to provide a power assist steering force. A feedback signal based on the actual measured current of the solenoid is generated after a hardware filter filters the measured current. There is a time lag associated with the filtered feedback signal. A software filter filters an initial control signal which represents the desired steering assist level to maintain a similar time relationship between the feedback signal and the initial control signal.

Abstract: An apparatus and method for determining the steering position of a steering system installed in a vehicle uses a filtering device and technique which operates with a signal representative of the steering system's motion to derive the actual steering system position with respect to a center position.