Patent ID: 6729434
Filing Date: 2004-05-04
Classification: B62D

Abstract:
An electric power assisted steering assembly comprising a steering mechanism which operatively connects a steering wheel to roadwheels of a vehicle, a torque sensor adapted to produce a first output signal indicative of a torque T carried by a portion of said steering mechanism, an angular velocity sensing sensor for producing a second output signal indicative of an angular velocity of said portion of said steering mechanism, an electric motor operatively connected to said steering mechanism, a signal processing unit adapted to receive said first output signal and said second output signal and to produce a torque demand signal representative of an assistance torque to be applied to said steering mechanism by said motor, and a motor drive stage adapted to provide a drive current to said motor responsive to said torque demand signal, and in which said torque demand signal includes a damping component that is dependent upon both said first output signal and said second output signal, wherein said damping component is filtered to remove high frequency variations in said damping component caused by high frequency changes in said column torque.