Brake control system for actively controlling wheel brakes

• US 6,454,365 B1
• Filed: 01/03/2001
• Issued: 09/24/2002
• Est. Priority Date: 01/03/2001
• Status: Expired due to Fees

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Arwine, Joan B., Zumberge, Jon T.
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US09/754,420
• Publication Number:
  US 20020084692A1
• Time in Patent Office: 629 Days
• Field of Search: 303/155, 303/153, 303/178, 303/DIG.3, 303/DIG.4, 303/113.4
• US Class Current: 303/155
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence

Abstract

Systems and methods are disclosed to control a braking system. One method provides a command signal to a valve to control fluid pressure to a wheel brake in a braking system, includes determining a pressure signal based on a first set for control gains and a pressure command signal, determining a first current signal based upon the pressure command signal, subtracting an actual pressure signal from the pressure command signal to produce an error signal, and determining a second current signal based on the second set of control gains and the error signal. The method further includes subtracting a supply pressure actual signal from a supply pressure nominal signal to produce a pressure differential signal, multiplying the pressure differential signal by a selected gain to produce a third current signal, and summing the first current signal, the second current signal and the third current signal to produce an output signal.

Claims

1. A method for providing a command signal to a valve to control fluid pressure to a wheel brake in a braking system, said method comprising the steps of:

determining a pressure signal based on a first set of control gains and a pressure command signal;

determining a first current signal based upon the pressure signal;

subtracting an actual pressure signal from the pressure command signal to produce an error signal;

determining a second current signal based on a second set of control gains and the error signal;

subtracting a supply pressure actual signal from a supply pressure nominal signal to produce a pressure differential signal;

multiplying the pressure differential signal by a selected gain to produce a third current signal; and

summing the first current signal, the second current signal and the third current signal to produce an output signal.

2. The method of claim 1, further comprising the step of determining the first set of control gains based upon a pressure command signal.

3. The method of claim 1, wherein in the first set of control gains include one of a proportion gain and a derivative gain.

4. The method of claim 1, wherein the step of determining the first current signal is determined using a pressure-current conversion table.

5. The method of claim 1, further comprising the step of filtering a wheel pressure signal to produce the filtered pressure signal.

6. The method of claim 1, wherein the actual pressure signal is determined using a pressure estimation operation.

7. The method of claim 1, wherein the error signal is pre-processed.

8. The method of claim 1, further comprising the step of determining the second set of control gains based upon the actual pressure signal.

9. The method of claim 1, wherein in the second set of control gains include one of a proportion control gain, an integral control gain and a derivative control gain.

10. The method of claim 1, wherein the valve includes one of an apply solenoid valve and a release solenoid valve.

11. The method of claim 1, wherein the brake system comprises an electro-hydraulic braking system.

12. A braking system, comprising:

a master cylinder for delivering pressurized fluid in response to a mechanical input;

a first sensor for providing a pressure signal in response to fluid pressure delivered by an accumulator;

a second sensor for providing a wheel pressure signal in response to fluid pressure applied to at least one wheel brake; and

a controller responsive to the wheel pressure signal and supply pressure signal to produce a pressure command signal, the controller operable to

determine a first current signal based on a first set of control gains and the pressure command signal;

determine an actual pressure signal based upon the wheel pressure signal;

subtract an actual pressure signal from the pressure command signal to produce an error signal;

determine a second current signal based on a second set of control gains and the error signal;

subtract the supply pressure signal from a supply pressure nominal signal to produce a pressure differential signal;

multiply the pressure differential signal by a selected gain to produce a third current signal; and

sum the first current signal, the second current signal and the third current signal to produce an output signal.

13. The braking system of claim 12, further comprising an accumulator for acceptance of pressurized fluid from the master cylinder.

14. The braking system of claim 12, a motor for delivering pressurized fluid to the accumulator in response to a command signal.

15. The braking system of claim 12, further comprising the step of determining the first set of control gains based upon a pressure command signal.

16. The braking system of claim 12, wherein the step of determining the first current signal is determined using a pressure-current conversion table.

17. The braking system of claim 12, wherein the actual pressure signal is determined using pressure estimation and a filtered operation.

18. The braking system of claim 12, further comprising the step of determining the second set of control gains based upon the actual pressure signal.

19. A braking system, comprising:

means for determining a pressure signal based on a first set of control gains and a pressure command signal;

means for determining a first current signal based upon the pressure command signal;

means for subtracting an actual pressure signal from the pressure command signal to produce an error signal;

means for determining a second current signal based on a second set of control gains and the error signal;

means for subtracting a supply pressure actual signal from a supply pressure nominal signal to produce a pressure differential signal;

means for multiplying the pressure differential signal by a selected gain to produce a third current signal; and

means for summing the first current signal, the second current signal and the third current signal to produce an output signal.