Mercedes-benz Aktiengesellschaft

Thomas Wohland

Walter Klinkner

Erich Schindler

Frank-Werner Mohn

Adam Zomotor

A method and apparatus for preventing vehicle handling instabilities, in which a vehicle yaw angular velocity required value (.mu..sub.soll) is formed from measured quantities (vehicle velocity, steering wheel angle). The vehicle yaw angular velocity actual value (.mu..sub.ist) is formed from at least one sensor signal, the difference between the yaw angular velocity required value (.mu..sub.soll) and the yaw angular velocity actual value (.mu..sub.ist) is determined by subtracting the yaw angular velocity actual value (.mu..sub.ist) from the yaw angular velocity required value (.mu..sub.soll), and the handling situation or the vehicle yaw behavior to be detected is determined from this difference. The time derivative of the difference is formed to determine whether the vehicle exhibits understeer or oversteer. The slip threshold value (.sigma..sub.soll) is varied in the direction of the value 0 when it is deduced from the detected handling situation that a changed lateral guidance force is required on the wheels of the vehicle driven axle.

Method and apparatus for preventing vehicle handling instabilities

A method detects the driving situation with respect to the yaw behavior of the vehicle, in which a desired value of the vehicle yaw angle rate .mu..sub.des is derived in a computer unit from measured values (such as vehicle speed, steering wheel angle), and at least one sensor signal is supplied to the computer unit from which the actual value of the vehicle yaw angle rate .mu..sub.act is derived. The difference between the desired value of the yaw angle rate .mu..sub.des and the actual value of the yaw angle rate .mu..sub.act is formed in the computer unit. The actual value of the yaw angle rate .mu..sub.act is subtracted from the desired value of the yaw angle rate .mu..sub.des, and at least one output signal is generated in and emitted by the computer unit from this difference. The output signal represents the detected driving situation with respect to the yaw behavior of the vehicle. The magnitude of the time derivative of the difference is used to derive whether there is a tendency towards an increasingly critical driving situation.

Method for detecting driving situation with respect to vehicle yaw

A method and apparatus prevents instabilities in vehicle handling by forming a desired value of the vehicle yaw angle rate .mu..sub.des from measured values (namely, vehicle speed, steering wheel angle), and forming the actual value of the vehicle yaw angle rate .mu..sub.act from at least one sensor signal. The difference between the desired value of the yaw angle rate .mu..sub.des and the actual value of the yaw angle rate .mu..sub.act is formed by subtracting the actual value of the yaw angle rate .mu..sub.act from the desired value of the yaw angle rate .mu..sub.des. At least one output signal is generated and emitted by the computer unit, from this difference. The output signal represents the detected driving situation with respect to the yaw behavior of the vehicle, with the brake pressure of individual wheels of the vehicle being varied as a function of this output signal, and the output signal being generated in the computer unit as a function of a time derivative of the difference. The output signal contains information on whether the vehicle has understeering or oversteering handling. In the case of oversteering handling, the brake pressure is increased for the vehicle front wheel on the outside of the turn; in the case of understeering handling, the brake pressure is increased for the vehicle rear wheel on the inside of the turn.

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Stuttgart, Germany

Thomas Wohland