STEERING ANGLE CONTROL DEVICE FOR VEHICLE

PROBLEM TO BE SOLVED: To dissolve wrong steering or non-steering caused by misjudgment so as to improve steering reliability by providing a failure diagnostic means for a steering angle sensor, and a driving force limiting means for a steering angle control motor, and limiting the driving force of the steering angle control motor during the failure diagnosis execution of the steering angle sensor. SOLUTION: A control device 10 is provided with a CPU 22, and an FET driving circuit 23 and an FET circuit 24 for controlling a current to a motor 12. Signals from vehicle speed sensors 11, 21, a steering angle sensor 9 of a steering wheel and steering angle sensor 20M are inputted to the CPU 22. The steering angle and steering acceleration of front wheels are detected from the signal of the steering angle sensor 9, and the travel speed of a body is detected by the vehicle speed sensors 11, 21. On the basis of these detection value, the optimum steering angle value of rear wheels is computed. At the same time, the actual steering angle of the rear wheels is detected by the steering angle sensor 20M. The actual steering angle of the rear wheels is compared with the optimum steering angle computed value, and the rotating direction and driving torque of the motor 12 are determined so as to make both compared value coincide with each other.