Method and system for controlling the braking force in a vehicle

• US 6,801,862 B2
• Filed: 08/25/2003
• Issued: 10/05/2004
• Est. Priority Date: 05/10/2001
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Arndt, Dietmar, Maier-Landgrebe, Rolf, Grob, Ferdinand
• Primary Examiner(s): SHAH, KAMINI S
• Application Number:
  US10/332,687
• Publication Number:
  US 20040019422A1
• Time in Patent Office: 407 Days
• Field of Search: 702/41, 702/70, 702/76, 702/78, 702/82-84, 738/01, 738/623.81, 738/623.91, 738/624.1, 303/190, 303/191, 303/186
• US Class Current: 702/41
• CPC Class Codes: B60T 8/17636 Microprocessor-based systems
• CPC Class Codes: B60T 8/58 responsive to speed and another condition or to plural speed conditions

Abstract

A method of controlling the braking force in a vehicle has the following steps: determining actual values of controlled variables; determining setpoint values of controlled variables; comparing the actual values with the setpoint values, thereby obtaining comparison results; and influencing wheel forces on the basis of the comparison results, wheel forces being used as controlled variables, the actual values of the wheel forces being determined by a sensor system which measures the wheel force, torques having a modulation frequency being generated at the wheels, whereby the slip of the wheels and the wheel force of the wheels are modifiable, the slip of the wheels and the wheel forces of the wheels are analyzed, and the setpoint values of the wheel forces are determined from the analysis of the slip of the wheels and the wheel forces of the wheels. A system for controlling the braking force in a vehicle is also described.

Claims

1. A method of controlling a braking force in a vehicle, comprising:

determining actual values of controlled variables;

determining setpoint values of the controlled variables;

comparing the actual values with the setpoint values, thereby obtaining comparison results; and

influencing wheel forces on the basis of the comparison results, wherein;

the wheel forces are used as the controlled variables,

the actual values of the wheel forces are determined by a sensor system that measures the wheel forces,

torques having a modulation frequency are generated at wheels, thereby enabling a slip of the wheels and the wheel forces at the wheels to be modifiable,

the slip of the wheels and the wheel forces of the wheels are analyzed, and

the setpoint values of the wheel forces are determined from an analysis of the slip of the wheels and from the wheel forces of the wheels.

2. The method as recited in claim 1, further comprising:

determining longitudinal forces by the sensor system.

3. The method as recited in claim 1, further comprising:

determining transverse forces by the sensor system.

4. The method as recited in claim 1, wherein:

the torques at the wheels are hydraulically generated.

5. The method as recited in claim 1, wherein:

the torques at the wheels are generated by an electric motor.

6. The method as recited in claim 1, wherein:

an amplitude of a modulation frequency is considerably less than the torques occurring in a normal driving operation.

7. The method as recited in claim 1, further comprising:

analyzing the wheel forces and the slip of the wheels in specific frequency ranges of a known modulation frequency.

8. The method as recited in claim 6, wherein:

the modulation frequency is in the range from 50 Hz to 100 Hz.

9. The method as recited in claim 1, further comprising:

determining longitudinal wheel force characteristics of the wheels by analyzing the wheel forces and the slip of the wheels, wherein;

the wheel forces at a maximum of the longitudinal wheel force characteristics are used is wheel force setpoint values.

10. The method as recited in claim 1, further comprising:

determining transverse wheel force characteristics of the wheels by analyzing the wheel forces and the slip of the wheels; and

determining a setpoint slip of particular ones of the wheels at which the setpoint values of transverse wheel forces occur from the transverse wheel force characteristics.

11. The method as recited in claim 1, further comprising:

determining a slip λ

₀ corresponding to a zero longitudinal wheel force by extrapolating a linearly increasing range of a longitudinal wheel force characteristic; and

correcting a determined value of the slip λ

₀ using slip λ

₀.

12. The method as recited in claim 1, further comprising:

determining an increase of a longitudinal wheel force characteristic from a wheel slip modulation divided by a longitudinal wheel force modulation.

13. A system for controlling a braking force in a vehicle, comprising:

an arrangement for determining actual values of controlled variables;

an arrangement for determining setpoint values of the controlled variables;

an arrangement for comparing the actual values with the setpoint values, thereby obtaining comparison results;

an arrangement for modulating torques at the wheels and being provided with a modulation frequency, thereby enabling a slip of the wheels and the wheel forces at the wheels to be modified; and

an arrangement for influencing wheel forces on the basis of the comparison results, wherein;

the controlled variables include the wheel forces,

the arrangement for determining the actual values of the wheel forces are implemented as a sensor system that measures the wheel forces,

the arrangement for determining the setpoint values includes an arrangement for analyzing the slip of the wheels and the wheel forces of the wheels, and

the arrangement for determining the setpoint values uses a result of the analysis of the slip of the wheels and the wheel forces of the wheels.

14. The system as recited in claim 13, wherein:

the sensor system determines longitudinal forces.

15. The system as recited in claim 13, wherein:

the sensor system determines transverse forces.

16. The system as recited in claim 13, wherein:

the arrangement for modulating the torques include a hydraulically arrangement.

17. The system as recited in claim 13, wherein:

the torques at the wheels are generated by an electric motor.

18. The system as recited in claim 13, wherein:

an amplitude of a modulation frequency is considerably less than the torques occurring in a normal driving operation.

19. The system as recited in claim 13, wherein:

the arrangement for analyzing the wheel forces and the slip of the wheels operates in specific frequency ranges of a known modulation frequency.

20. The system as recited in claim 18, wherein:

the modulation frequency is in the range from 50 Hz to 100 Hz.

21. The system as recited in claim 13, further comprising:

an arrangement for determining longitudinal wheel force characteristics of the wheels by analyzing the wheel forces and the slip of the wheels, wherein;

the wheel forces at a maximum of the longitudinal wheel force characteristics are used as wheel force setpoint values.

22. The system as recited in claim 13, further comprising:

an arrangement for determining transverse wheel force characteristics of the wheels by analyzing the wheel forces and the slip of the wheels; and

an arrangement for determining a setpoint slip of particular ones of the wheels at which the setpoint values of transverse wheel forces occur from the transverse wheel force characteristics.

23. The system as recited in claim 13, further comprising:

an arrangement for determining a slip λ

₀ corresponding to a zero longitudinal wheel force by extrapolating a linearly increasing range of a longitudinal wheel force characteristic; and

an arrangement for correcting a determined value of the slip λ

₀ using slip λ

₀.

24. The system as recited in claim 13, further comprising:

an arrangement for determining an increase of a longitudinal wheel force characteristic from a wheel slip modulation divided by a longitudinal wheel force modulation.