Patent ID: 7720584

Claim:
A vehicular steering apparatus having a steering wheel which is manipulated by a driver, and a steering mechanism which steers steered wheels by a sub-steering-angle superposition mechanism controllable by an electric motor; comprising transmission-characteristic setting means for setting a transmission characteristic between a steering angle of the steering wheel and a steered angle of the steered wheels, in accordance with a traveling state of the vehicle, steering-wheel-angle detection means for detecting the steering-wheel steering angle of the driver, sub-steering-angle detection means for detecting a sub steering angle which is steered by the sub-steering-angle superposition mechanism, target sub-steering-angle setting means for generating a target sub steering angle which is to be added by the sub-steering-angle superposition mechanism, on the basis of the output of the steering-wheel-angle detection means and the transmission characteristic set by the transmission-characteristic setting means, and drive control means for driving and controlling the sub-steering-angle superposition mechanism so that the target sub steering angle and the output of the sub-steering-angle detection means may agree; wherein the drive control means includes: target-current setting means for setting a target drive current for the electric motor on the basis of an angular deviation between the target sub steering angle and the output of the sub-steering-angle detection means; and current control means having current detection means for detecting a current which flows through the electric motor, and for controlling the current for the electric motor so that the output of the current detection means may agree with the set current of the target-current setting means.