Supplementary steering system
AssigneeDaimler-Benz Aktiengesellschaft
InventorErich Schindler
Life of this patent
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Abstract
The supplementary steering system operates automatically as a function of the change of the transverse velocity (v.sub.y) of the vehicle to provide compensation steering movements to stabilize a vehicle in skidding situations. The system relies on the fact that a great increase invehicle transverse velocity is characteristic of skidding movements. Critical travel conditions can be stabilized by a rapid reaction to the change of transverse velocity. Under steady travel conditions, i.e., when only a negligible change of transverse vehicle velocity occurs, the supplementary steering system is not actuated, or is reset to its central position.
Claims9
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 (.delta..sub.HA), by the following equation:
- ##EQU4## T.sub.H is a predetermined time interval;
- K.sub.p, K.sub.D and K.sub.s are predetermined constants;
- t is the time;
- v.sub.y is the change of transverse velocity;
- v.sub.y, actual is the actual value of the change of transverse velocity;
- v.sub.y, theoretical is the theoretical value of the change of tranverse velocity, and
- .tau. is a time variable;
- said theoretical value of the change of tranverse velocity (v.sub.y, theoretical) is determined by the following equation:
- ##EQU5## where v.sub.x, v.sub.x are the longitudinal velocity and the change in longitudinal velocity respectively;
- l.sub.H is the distance between the rear axle of the vehicle and the center of gravity of the vehicle (S.sub.p);
- 1is the wheel base of the vehicle;
- and
- .delta..sub.VA, .delta..sub.VA are the steering lock and the change of steering lock of the front wheels respectively.
Dependencies are inferred from the claim text.