| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor-driven power steering device with the safety enhanced by maintaining the advancing direction of a vehicle even in the hand- off condition in which the driver leaves his hands off from the steering wheel. SOLUTION: The steering torque T applied to the steering wheel 2 by the driver is sensed by a torque sensor 10. When the steering torque T lies within a certain specified range, judgement is passed that it is in the hand-off condition. When the steering angleδsensed by a steering angle sensor 11 lies with the specified range near the middle point of steering angle, judgement is passed that the vehicle is in the straight running condition. In the case the vehicle is in the straight running condition and in the hand-off condition, a target amperage setting part 21 sets the target amperage for keeping the steering angleδat the middle point of steering. The motor 13 is controlled on the basis of this target amperage, which allows hindering a variation of the steering angle of vehicle wheels FL and FR resulting from the surface unevenness of the road surface. |
