| 摘要 |
<p>PROBLEM TO BE SOLVED: To carry out satisfactory return control without increasing the costs. SOLUTION: A motor 4 for producing a steering assist force to be applied to a steering mechanism is driven in response to PWM drive pulses delivered from a PWM producing part 24. A current detection value of the motor detected by a motor current detecting circuit 6 is offset by an offset producing circuit 8. The degree of the offset corresponds to a PWM duty of the PWM drive pulses. Upon returning of a steering wheel, the motor 4 is rotated through the returning of the steering wheel by a self-aligning torque of a vehicle, so as to generate a power with which the PWM duty is changed. Accordingly, the PWM producing part 24 sets up a PWM duty with which the motor 4 produces a torque for assisting the returning of the steering wheel.</p> |
