| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress the peak torque to be transmitted to a torque transmission member when an electric power steering device reaches the steering limit position without adding any separate steering angle sensor or the like. <P>SOLUTION: An electric power steering device comprises an electric motor 12 for transmitting the steering assist torque to a steering mechanism, a motor control unit 25 for performing the drive control of the electric motor 12 by the pulse width modulation signal according to the current command value based on the steering torque, a motor torque detection unit 26a for detecting the motor torque of the electric motor 12, a motor torque rate-of-change detection unit 26b for computing the rate of change of the detected motor torque, and a current command value limiting unit 23 which determines that the current command value limiting condition is satisfied when the rate of change of the computed motor torque is not less than the threshold for determining the steering limit, and limits the current command value so as to suppress the torque to be transmitted to the torque transmission member between a steering shaft and a turning wheel of the steering mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT |
