To provide an electric power steering device for which a failure diagnosis for a motor system is performed before an ignition key is turned on in order to solve problems that failures under an initial state of the motor system cannot surely be detected unless steering is performed, and which can avoid danger from being exerted on a vehicle due to a failure of the motor system.
This electric power steering device performs an assistance for a steering mechanism by controlling a motor which provides a steering assisting force to the steering mechanism based on a current control value which is calculated from a steering assistance commanding value being calculated by a calculating means based on a steering torque generated on a steering shaft, and a current value of the motor. In the electric power steering device, the failure diagnosis for the motor system is performed before the assistance.
SHIMADA KENICHI
NSK STEERING SYS CO LTD
Sadayoshi Igarashi
Susumu Kitano
Akio Ishii
Next Patent: VEHICLE WITH STEER-BY-WIRE TYPE STEERING DEVICE