ELECTRIC POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electric power steering device which can detect a runaway of CPU for a short time without an error. SOLUTION: This device decides the motor current target value of a motor 4 for assisting a steering force based on a detection torque and drives and controlls the motor 4 as the target value of an automatic control. This device is provided with a torque change direction detection part 21 for detecting the change direction of the detection torque, a drive logic judging part 9 for judging whether the detection torque is out of the range of dead zone and the direction to drive the motor 4 by a motor current target value is opposite to the direction of the detection torque and the direction to drive the motor 4 by the motor current target value is opposite to the change direction of the torque or not and an abnormal current judging part 6a for judging that the drive current of the motor 4 is bigger than a prescribed value. When it is judged that the drive logic judging part 9 is the said state and the drive current is larger than the prescribed value, the abnormal current judging part 6a prohibits the drive of the motor 4.