Patent ID: 8099211

Claim:
An electric power steering apparatus applied to a steering system that transmits a steering operation of a driver to a steerable wheel, the apparatus comprising: a steering force assist device provided with a motor as a driving source, the steering force assist device applying an assist force for assisting the steering operation to the steering system; control means controlling an actuation of the steering force assist device on the basis of a signal indicating a state of the steering system based on a rotation angle of a pinion shaft, wherein the control means computes a target assist force to be generated in the steering force assist device by adding a compensation component based on a differential value of a steering torque to a basic assist component; and extracting means capable of extracting, from the signal indicating the state of the steering system, a specific frequency component corresponding to a vibration generated in the steering system on the basis of a stress applied to the steerable wheel, wherein, when the effective value of the extracted specific frequency component is equal to or more than a predetermined threshold value, the control means increases the compensation component based on the differential value of the steering torque.