Supplementary steering system

Claim 1

A supplementary steering system for rear wheel supplementary steering systems of motor vehicles, having a steering means for controlling the steering angle of front wheels of the vehicle and regulating means which deflects steered rear vehicle wheels as a function of a quantity solely responsive to vehicle; longitudinal velocity, transverse acceleration and yaw velocity for stabilizing the vehicle at skidding situations; on the occurrence of a skidding movement of the vehicle associated with a rapidly increasing transverse velocity of the vehicle, and regulating means deflects the steered rear wheels in the sense of a counter-steering with respect to said steering angle of the front wheels for counteracting the skidding movement; and said regulating means only controls a respective lock angle of the steered rear wheels when a change of vehicle transverse velocity exceeds a theoretical change of vehicle transverse velocity; said regulating means including a computer which determines the steering deflection and steering angle of the rear wheels (δ HA ), by the following equation: ##EQU4## T H is a predetermined time interval; K p , K D and K s are predetermined constants; t is the time; v y is the change of transverse velocity; v y , actual is the actual value of the change of transverse velocity; v y , theoretical is the theoretical value of the change of tranverse velocity, and τ is a time variable; said theoretical value of the change of tranverse velocity (v y , theoretical) is determined by the following equation: ##EQU5## where v x , v x are the longitudinal velocity and the change in longitudinal velocity respectively; l H is the distance between the rear axle of the vehicle and the center of gravity of the vehicle (S p ); 1is the wheel base of the vehicle; and δ VA , δ VA are the steering lock and the change of steering lock of the front wheels respectively.