Patent ID: 8996251
Filing Date: 2015-03-31
Classification: B62D

Abstract:
1. An electric power-steering control device for an electric power-steering system, the electric power steering system including a motor providing an assist steering power for assisting an operation of turning a steering wheel of a vehicle, the electric power-steering control device comprising: a basic assist quantity generator generating a basic assist quantity for assisting the operation of turning the steering wheel, the basic assist quantity generator including: a basic assist quantity calculator calculating the basic assist quantity for controlling the motor based on a steering torque detected by a steering torque detector of the electric power-steering system, a road surface force estimator estimating a road surface force based on the basic assist quantity and the steering torque detected by steering torque detector, wherein the basic assist quantity generated changes the steering torque according to the road surface force applied to wheels of the vehicle from a road surface, and a target steering torque calculator determining a target steering torque, wherein the target steering torque is a desired value of the steering torque and is based on the road surface force estimated by the road surface force estimator, and the basic assist quantity generated controls the motor such that the steering torque detected by the steering torque detector matches the target steering torque determined by the target steering torque calculator; an assist compensation quantity generator generating an assist compensation quantity for modifying the basic assist quantity generated by the basic assist quantity generator such that an action of the wheels of the vehicle responds to predetermined action characteristics; an assist quantity modifier generating a modified assist quantity by modifying the basic assist quantity generated by the basic assist quantity generator with the assist compensation quantity generated by the assist compensation quantity generator; and a motor driver driving the motor based on the modified assist quantity from the assist quantity modifier.