System and method for vehicle stability enhancement control with surface estimate

• US 20030062768A1
• Filed: 08/17/2001
• Published: 04/03/2003
• Est. Priority Date: 08/17/2001
• Status: Active Grant

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Loudon, Steven P., Guiet, Julien, Krueger, Eric E., Check, Michael J.
• Granted Patent: US 6,588,859 B2
• Time in Patent Office: Days
• US Class Current: 303/146
• CPC Class Codes: B60T 2270/304 during driver brake actuation
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02

Abstract

A system and method of vehicle stability enhancement control the method comprising the steps of determining a Delta Velocity of the vehicle, determining one of an understeer and an oversteer condition of the vehicle, applying a percentage of the Delta Velocity to an outside front and an outside rear wheel in the oversteer condition, and applying a percentage of the Delta Velocity to an inside front and an inside rear wheel in the understeer condition. The system and method may further comprise the step of applying the Delta Velocity to a rear wheel during the oversteer condition or applying the Delta Velocity to a front wheel during the understeer condition using fluid pressure from a master cylinder when braking is occurring.

Claims

1. A method for vehicle stability enhancement control comprising:

determining a Delta Velocity of the vehicle;

determining one of an understeer and an oversteer condition of the vehicle;

applying a percentage of the Delta Velocity to an outside front and an outside rear wheel in the oversteer condition; and

applying a percentage of the Delta Velocity to an inside front and an inside rear wheel in the understeer condition.

2. The method of claim 1 wherein Delta Velocity includes a yaw rate error term and slip rate error term.

3. The method of claim 1 wherein the Delta Velocity includes a determination of surface adhesion estimate.

4. The method of claim 1 further comprising:

applying the Delta Velocity to a rear wheel during the oversteer condition using fluid pressure from a master cylinder when braking is occurring.

5. The method of claim 1 further comprising:

applying the Delta Velocity to a rear wheel during the oversteer condition using an isolated hydraulic circuit when braking is not occurring.

6. The method of claim 1 further comprising:

applying the Delta Velocity to a front wheel during the understeer condition using fluid pressure from a master cylinder when braking is occurring.

7. The method of claim 1 further comprising:

applying the Delta Velocity to a front wheel during the understeer condition using an isolated hydraulic circuit when braking is not occurring.

8. The method of claim 1 wherein the Delta Velocity is proportioned corresponding to an estimate of surface coefficient.

9. The method of claim 8 wherein the Delta Velocity is proportioned between the affected front and rear wheel corresponding to whether the vehicle is experiencing one of a condition of understeer and oversteer.

10. The method of claim 9 wherein the proportions are selected from lookup tables, vector values of which are predetermined according to an estimate of surface coefficient.

11. The method of claim 10 wherein the applied percentage of the Delta Velocity to the outside front wheel decreases as the estimate of surface coefficient increases.

12. The method of claim 10 wherein the applied percentage of the Delta Velocity to the outside rear wheel increases as the estimate of surface coefficient increases.

13. The method of claim 10 wherein the applied percentage of the Delta Velocity to the inside front wheel increases as the estimate of surface coefficient increases.

14. The method of claim 10 wherein the applied percentage of the Delta Velocity to the inside front wheel remains constant as the lateral velocity increases.

15. A system for vehicle stability enhancement control comprising:

means for determining a Delta Velocity of the vehicle;

means for determining one of an understeer and an oversteer condition of the vehicle;

means for applying a percentage of the Delta Velocity to an outside front and an outside rear wheel in the oversteer condition; and

means for applying a percentage of the Delta Velocity to an inside front and an inside rear wheel in the understeer condition.

16. The system of claim 15 further comprising:

means for applying the Delta Velocity to a rear wheel during the oversteer condition using fluid pressure from a master cylinder when braking is occurring.

17. The system of claim 15 further comprising:

means for applying the Delta Velocity to a rear wheel during the oversteer condition using an isolated hydraulic circuit when braking is not occurring.

18. The system of claim 15 further comprising:

means for applying the Delta Velocity to a front wheel during the understeer condition using fluid pressure from a master cylinder when braking is occurring.

19. The system of claim 15 further comprising:

means for applying the Delta Velocity to a front wheel during the understeer condition using an isolated hydraulic circuit when braking is not occurring.