METHODS AND SYSTEMS FOR CONTROLLING BRAKING OF A VEHICLE WHEN THE VEHICLE IS STATIONARY

• US 20110015845A1
• Filed: 07/15/2009
• Published: 01/20/2011
• Est. Priority Date: 07/15/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: KIDSTON, KEVIN S., MUI, DANNY Y., MONSERE, PATRICK J.
• Granted Patent: US 8,620,547 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/885 using electrical circuitry

Abstract

A method for controlling braking of a vehicle includes the steps of calculating a first pressure based on a driver request, and providing pressure that does not exceed a predetermined pressure threshold if the vehicle is stationary and the first pressure is less than the predetermined pressure threshold.

Claims

1. A method for controlling braking of a vehicle, the method comprising the steps of:

calculating a first pressure based on a driver request; and

providing pressure that does not exceed a predetermined pressure threshold if the vehicle is stationary and the first pressure is less than the predetermined pressure threshold.

2. The method of claim 1, wherein the vehicle has a wheel, and the method further comprises the steps of:

obtaining a wheel speed value from a wheel speed sensor; and

determining whether the vehicle is stationary based upon the wheel speed value.

3. The method of claim 1, further comprising the step of:

providing pressure that is equal to the first pressure if the vehicle is moving, the first pressure is greater than the predetermined pressure threshold, or both.

4. The method of claim 3, further comprising the step of:

providing pressure that is equal to the first pressure or the predetermined pressure threshold, whichever is less, if the vehicle is stationary and the first pressure is less than the predetermined pressure threshold.

5. The method of claim 1, wherein the request is received during a first period of time during a braking event, and the method further comprises the steps of:

calculating a second pressure based on a second driver request during a second period of time during the braking event, the second period of time being subsequent to the first period of time; and

providing pressure during the second period of time equal to the second pressure if (a) neither the first pressure nor the second pressure are less than the predetermined pressure threshold, (b) the vehicle is moving during the second period of time, or both; and

providing pressure during the second period of time that does not exceed the predetermined pressure threshold if conditions (c) and (d) are both satisfied, namely;

(c) the vehicle is stationary during the second period of time, and

(d) the first pressure, the second pressure, or both, are less than the predetermined pressure threshold.

6. The method of claim 5, further comprising the step of:

providing pressure during the second period of time equal to the first pressure, if conditions (e) and (f) are both satisfied;

(e) the first pressure and the second pressure are both greater than the predetermined pressure threshold; and

(f) the second pressure is greater than the first pressure.

7. The method of claim 5, further comprising the step of:

providing pressure equal to the second pressure or the predetermined pressure threshold, whichever is less, during the second period of time if conditions (e) and (f) are both satisfied, namely;

(e) the vehicle is stationary, and

(f) the first pressure, the second pressure, or both, are less than the predetermined pressure threshold.

8. The method of claim 1, wherein the step of calculating the first pressure comprises the steps of:

obtaining an initial pressure value based on the driver request; and

filtering the initial pressure, to thereby calculate the first pressure.

9. The method of claim 5, further comprising the steps of:

calculating a third pressure based on a third driver request during a third period of time during the braking event, the third period of time being subsequent to the second period of time; and

providing pressure during the third period of time equal to an intermediate pressure value that is greater than the predetermined pressure threshold and less than the third pressure, if each of the following conditions (e)-(g) are satisfied;

(e) the vehicle is moving during the third period of time,

(f) the braking was controlled based on the predetermined pressure threshold during the second period of time, and

(g) the third pressure is greater than the predetermined pressure threshold.

10. A method for controlling braking of a vehicle during a braking event, the method comprising the steps of:

calculating a plurality of pressures during the braking event, each of the plurality of pressures calculated based on a different one of a plurality of driver requests; and

providing pressure that does not exceed a predetermined pressure threshold if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold.

11. The method of claim 10, wherein the vehicle has a wheel, and the method further comprises the steps of:

obtaining a wheel speed value from a wheel speed sensor; and

determining whether the vehicle is stationary based upon the wheel speed value.

12. The method of claim 10, further comprising the step of:

providing pressure equal to a corresponding one of the plurality of pressure values if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold; and

providing pressure equal to the predetermined pressure threshold if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold.

13. The method of claim 12, further comprising the steps of:

providing pressure equal to an intermediate pressure value that is greater than the predetermined pressure threshold and less than the corresponding one of the pressure values., if each of the following conditions (a)-(d) are satisfied, namely;

(a) the vehicle is moving,

(b) the vehicle has been moving for less than a predetermined amount of time,

(c) pressure was provided equal to the predetermined pressure threshold earlier during the braking event, and

(d) the corresponding one of the plurality of pressures is greater than the predetermined pressure threshold.

14. The method of claim 12, further comprising the step of:

providing a constant pressure during a time interval, if conditions (a) and (b) are both satisfied;

(a) the plurality of pressures have each been greater than the predetermined pressure threshold; and

(b) the plurality of pressures are increasing during the time interval.

15. A system for controlling braking of a vehicle during a braking event, the system comprising:

a sensor configured to detect a plurality of driver requests during the braking event; and

a processor coupled to the sensor and configured to at least facilitate;

calculating a plurality of pressures during the braking event, each of the plurality of pressures calculated based on a different one of the plurality of driver requests; and

providing pressure that does not exceed a predetermined pressure threshold if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold.

16. The system of claim 15, wherein the vehicle has a wheel, and the system further comprises:

a second sensor configured to obtain a wheel speed value, wherein the processor is further configured to determine whether the vehicle is stationary based upon the wheel speed value.

17. The system of claim 15, wherein the processor is further configured to at least facilitate:

providing pressure equal to a corresponding one of the plurality of pressure values if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold; and

providing pressure equal to the predetermined pressure threshold if the vehicle is stationary and any of the plurality of pressures are less than the predetermined pressure threshold.

18. The system of claim 17, wherein the processor is further configured to at least facilitate:

providing a constant pressure during a time interval, if conditions (a) and (b) are both satisfied;

(a) the plurality of pressures have each been greater than the predetermined pressure threshold; and

(b) the plurality of pressures are increasing during the time interval.

19. The system of claim 17, wherein the processor is further configured to at least facilitate providing pressure equal to an intermediate pressure value that is greater than the predetermined pressure threshold and less than the corresponding one of the pressure values, if each of the following conditions (a)-(d) are satisfied, namely:

(a) the vehicle is moving,

(b) the vehicle has been moving for less than a predetermined amount of time,

(c) pressure was provided equal to the predetermined pressure threshold earlier during the braking event, and

(d) the corresponding one of the plurality of pressures is greater than the predetermined pressure threshold.

20. The system of claim 19, wherein the processor is further configured to at least facilitate providing pressure equal to the corresponding one of the plurality of pressures if the vehicle has been moving for more than the predetermined amount of time.