Patent ID: 7032706

Claim:
A method for setting a control parameter for an electric power steering device comprising: a first resolver for detecting a first steering angle including a rotation angle of a steering shaft connected to a steering wheel; a second resolver for detecting a second steering angle including a rotation angle of the steering shaft, the second resolver including pole pairs having a different number from the first resolver; a rack and pinion type steering mechanism including a rack shaft geared with a pinion shaft coaxially connected to the steering shaft; a motor for assisting an actuation of the rack shaft; a third resolver for detecting a motor electric angle including a rotation angle of the motor; and a control means for controlling the motor based on an absolute rotational position of the steering wheel obtained from the first steering angle, the second steering angle, and the motor electric angle; the setting method comprising process of: obtaining a speed ratio between the steering shaft and the motor based on a mechanical angle at the steering shaft obtained from the first steering angle and the second steering angle and the motor electric angle of the motor; and setting the speed ratio as a control parameter used for obtaining the absolute rotational position of the steering wheel from the first steering angle, the second steering angle, and the motor electric angle at the control means.