Controlling apparatus of steering angle of rear wheels of four-wheel steering vehicle.

摘要

The tuning of the parameters (Kp,Ki,Kd) of a PiD controller for controlling an electric motor (4) of a rear wheel steering device is achieved by first determining the motor transient response to a step input, the motor being disconnected from the steering shaft, and next comparing measured overshoot amount and raising-up time to given values. Further a vibrating state of the electric steering motor under load may be detected by determining that the difference between desired and detected position of the motor repeats positive and negative values more than a predetermined number of times within a preset term. When the unstable vibration of the electric motor is detected a gain to the yaw rate is adjusted. <IMAGE>