Antilock brake control method
First Claim
1. Method for reducing brake pressure in a vehicle equipped with front wheels and rear wheels, each wheel exhibiting a μ
- -slip curve, and an ABS which reduces brake pressure at the wheels when wheel slippage exceeds a working point on the respective μ
-slip curve, said vehicle exhibiting a transverse acceleration and a steering angle, said method comprisingmeasuring the actual steering angle δ
2,measuring the speeds of the wheels,determining a vehicle speed vF based on the wheel speeds,determining wheel slip values based on the wheel speeds and the vehicle speed,measuring the transverse acceleration aq,determining a steering angle value δ
1 based on said vehicle speed vF, said transverse acceleration aq, and constants specific to the vehicle,determining the difference δ
2 -δ
1 between the actual steering angle δ
2 and the determined steering angle value δ
1,displacing the working point on the μ
-slip curve toward smaller slip values based on δ
2 -δ
1, andreducing brake pressure at at least one said wheel when the determined slip value exceeds the working point on the respective μ
-slip curve.
1 Assignment
0 Petitions
Accused Products
Abstract
A difference δ2 -δ1 is formed between the steering angle δ2 actually measured and the steering angle δ1 calculated from the vehicle transverse acceleration, vehicle speed, and a series of constants. This difference (δ2 -δ1) is used to displace the working point on the μ-slip curve in the direction of an increase of the lateral stability, i.e., toward smaller slip values. Response can be improved by making the displacement also dependent on the rate of change of this difference or the rate of change of the actual steering angle. Preferably no reaction is produced when the difference is below a threshold angle unless one of the rates exceeds a respective threshold.
13 Citations
7 Claims
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1. Method for reducing brake pressure in a vehicle equipped with front wheels and rear wheels, each wheel exhibiting a μ
- -slip curve, and an ABS which reduces brake pressure at the wheels when wheel slippage exceeds a working point on the respective μ
-slip curve, said vehicle exhibiting a transverse acceleration and a steering angle, said method comprisingmeasuring the actual steering angle δ
2,measuring the speeds of the wheels, determining a vehicle speed vF based on the wheel speeds, determining wheel slip values based on the wheel speeds and the vehicle speed, measuring the transverse acceleration aq, determining a steering angle value δ
1 based on said vehicle speed vF, said transverse acceleration aq, and constants specific to the vehicle,determining the difference δ
2 -δ
1 between the actual steering angle δ
2 and the determined steering angle value δ
1,displacing the working point on the μ
-slip curve toward smaller slip values based on δ
2 -δ
1, andreducing brake pressure at at least one said wheel when the determined slip value exceeds the working point on the respective μ
-slip curve. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- -slip curve, and an ABS which reduces brake pressure at the wheels when wheel slippage exceeds a working point on the respective μ
Specification