Patent ID: 6854559

Claim:
An electric power steering controller comprising: a road surface reaction force torque detecting unit for detecting reaction force torque of a road surface on which a vehicle having a steering system including said electric power steering controller travels; a reaction force torque detecting unit for detecting reaction force torque of the steering system, said reaction force torque detecting unit including a steering shaft reaction force torque sensor for detecting the reaction force torque of a steering shaft of the steering system; and a return torque compensator for calculating a compensating return torque superimposed on the reaction force torque in returning a steering wheel of the steering system in a return direction toward a neutral position of the steering wheel, said return torque compensator calculating the compensating return torque by multiplying the reaction force torque of the road surface detected by said road surface reaction torque detecting unit by a feedback gain varying with the reaction force torque so that the compensating return torque superimposed on the reaction force torque changes inversely with magnitude of the reaction force torque of the steering shaft.