Patent ID: 6863150
Filing Date: 2005-03-08
Classification: B62D

Abstract:
1. An electric power steering control apparatus having an electric motor device that applies assist torque for assisting steering torque of a driver to a steering shaft that is coupled to an axle of a vehicle, comprising: vehicle speed detecting means for detecting a vehicle speed; motor speed detecting means for detecting a rotation speed of the electric motor device; steering shaft reaction torque signal outputting means for outputting a steering shaft reaction torque signal that corresponds to steering shaft reaction torque acting on the steering shaft; and road surface reaction torque detecting means for outputting a road surface reaction torque estimation value to be used for a control on the assist torque by filtering the steering shaft reaction torque signal by a low-pass filter operation, wherein a time constant of the low-pass filter operation is determined in according with the vehicle speed detected by the vehicle speed detecting means and the motor rotation speed detected by the motor speed detecting means.