| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device capable of securely discriminating an offset due to a failure and a change with the lapse of time of a motor current detecting means and a disturbance noise from each other. SOLUTION: This electric power steering device has a control means for giving the steering assist force to a steering mechanism on the basis of a current control value computed on the basis of a steering assist command value, which is based on the steering torque and the car speed, and a detected motor current value. The motor is driven by an H-bridge circuit formed of four semiconductor elements on the basis of the current control value, and the power is supplied to the H-bridge circuit through a first switch. The motor is connected to the H-bridge circuit through a second switch. An abnormality detecting means for detecting abnormality of the motor current detecting means on the basis of the output of the motor current detecting means and a third switch connected in parallel with the current detecting element are provided, and the abnormality detecting means detects abnormality of the output value on the basis of an output of the motor detecting means in the condition that the current control value is zero and the third switch is turned on. COPYRIGHT: (C)2003,JPO |
