METHOD AND APPARATUS FOR CONTROLLING AN ELECTRIC POWERED ASSISTED STEERING SYSTEM USING AN ADAPTIVE BLENDING TORQUE FILTER

摘要

An apparatus and method for controlling an electric steering assist system, which system provides assist in response to a steering control signal, comprising: torque sensor (20) operatively connected to steering wheel (12) for providing a torque signal (Ts) blending filter means connected to the torque sensor for providing a blended filtered torque signal having a first functional characteristic at torque frequencies less than the blending frequency and a second functional characteristic at torque frequencies greater than the blending frequency, including a low pass filter (70) which passes all frequencies below the blending frequency and a high pass filter (71) providing said control signal to the steering assist means in response to the blended filtered torque signal whereby high frequency gain of the steering assist system is arranged to be low from on-centre operation of the hand wheel and relatively higher for off-centre operation.