Method and apparatus for vehicle stability enhancement system

• US 6,813,552 B2
• Filed: 11/18/2002
• Issued: 11/02/2004
• Est. Priority Date: 11/18/2002
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Ghoneim, Youssef Ahmed, Jenny, Thomas, Bielaczek, Christian
• Primary Examiner(s): Nguyen, Thu V.
• Application Number:
  US10/298,895
• Publication Number:
  US 20040098184A1
• Time in Patent Office: 715 Days
• Field of Search: 701/36-37, 701/40-41, 701/44, 701/48, 701/53, 701/65, 701/55-59, 701/70-72, 701/74-75, 701/77-80, 701/83, 180/333-400, 180/415, 280/5.5, 280/5.51, 280/5.512, 280/5.519
• US Class Current: 701/70
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 8/17555 specially adapted for enhancing driver or passenger comfort, e.g. soft intervention or pre-actuation strategies

Abstract

A vehicle stability enhancement (VSE) system for a vehicle having at least one vehicle subsystem includes; at least one sensor for sensing at least one vehicle parameter, at least one vehicle control system for adjusting the at least one vehicle subsystem, a driving mode switch for selecting at least one driving mode, at least one memory comprising at least one set of gain factors, and a controller responsive to the at least one sensor, the driving mode switch, and the at least one set of gain factors for controlling the at least one vehicle control system.

Claims

1. A vehicle stability enhancement system for a vehicle having at least one vehicle subsystem, comprising:

at least one sensor for sensing at least one vehicle parameter;

at least one vehicle control system for adjusting the at least one vehicle subsystem;

a driving mode switch for selecting at least one driving mode;

at least one memory comprising at least one set of gain factors, said at least one memory including a VSE flag register settable to OFF and ON; and

a controller responsive to said at least one sensor, said driving mode switch, and said at least one set of gain factors for controlling said at least one vehicle control system;

wherein the vehicle stability enhancement system is activated in response to said VSE flag being ON, and not activated in response to said VSE flag being OFF;

wherein said at least one memory further comprises;

a vehicle yaw rate error register for storing a vehicle yaw rate error value; and

a vehicle yaw rate error threshold register for storing a vehicle yaw rate error threshold value;

wherein

said VSE flag register is set to ON in response to the absolute value of said vehicle yaw rate error exceeding said vehicle yaw rate error threshold value.

2. The vehicle stability enhancement system of claim 1, wherein said at least one sensor comprises:

a yaw sensor for sensing the vehicle yaw rate;

at least one velocity sensor for sensing the velocity of the vehicle;

a lateral acceleration sensor for sensing the vehicle lateral acceleration;

a steering angle sensor for sensing the vehicle steering angle; and

a pressure sensor for sensing the brake fluid pressure;

wherein signals from said sensors are received at said controller.

3. The vehicle stability enhancement system of claim 1, wherein said at least one vehicle control system comprises:

a steering mechanism control system for adjusting a steering mechanism; and

a braking mechanism control system for adjusting a braking mechanism.

4. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

at least one look-up table comprising said at least one set of gain factors.

5. The vehicle stability enhancement system of claim 1, wherein said at least one set of gain factors comprises:

a yaw rate error threshold gain factor; and

a brake pressure apply rate gain factor.

6. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

at least one vehicle parameter register for storing at least one vehicle parameter value in response to said at least one sensor;

at least one vehicle parameter threshold register for storing at least one vehicle parameter threshold value; and

an OSUS index register settable to at least one value in response to the absolute value of said at least one vehicle parameter exceeding said at least one vehicle parameter threshold value.

7. The vehicle stability enhancement system of claim 6, wherein:

said at least one set of gain factors have values responsive to said at least one value of said OSUS index.

8. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

an SFlag register settable to OFF and ON for indicating the state of a high friction surface flag;

an LFlag register settable to OFF and ON for indicating the state of a limit stability flag; and

an OSUS index register settable to at least one value in response to said SFlag and said LFlag register settings.

9. A method for actively controlling a vehicle stability enhancement system, comprising:

sensing at least one vehicle parameter;

calculating a yaw rate error index in response to the at least one vehicle parameter;

calculating the state of at least one control flag in response to the at least one vehicle parameter;

setting a VSE flag to either a first state representative of an activated VSE system or a second state representative of a non-activated VSE system;

determining the state of a driving mode in response to a driving mode request;

determining the state of the at least one control flag in response to the state of the driving mode;

determining at least one control gain factor in response to the state of the at least one control flag and the yaw rate error index; and

activating the vehicle stability enhancement system in response to the VSE flag being set to the first state;

wherein said calculating the state of at least one control further comprises;

calculating the state of the VSE flag to ON in response to the absolute value of the vehicle yaw rate error exceeding the vehicle yaw rate error threshold value.

10. The method of controlling set forth in claim 9, wherein said sensing at least one vehicle parameter further comprises:

sensing the vehicle yaw rate;

sensing the vehicle velocity;

sensing the vehicle lateral acceleration;

sensing the brake fluid pressure; and

sensing the vehicle steering angle.

11. The method of controlling set forth in claim 9, wherein said calculating a yaw rate error index further comprises:

calculating a yaw rate error index in response to the ratio of vehicle yaw rate error to vehicle yaw rate error threshold.

12. The method of controlling set forth in claim 9, wherein said calculating the state of at least one control flag further comprises:

calculating the state of an SFlag register for indicating the state of a high friction surface flag; and

calculating the state of an LFlag register for indicating the state of a limit stability flag.

13. The method of controlling set forth in claim 12, wherein said calculating the state of an SFlag register comprises:

calculating the SFlag to an ON state.

14. The method of controlling set forth in claim 12, wherein said calculating the state of an LFlag register comprises:

calculating the LFlag to an OFF state.

15. The method of controlling set forth in claim 9, wherein said determining the state of a driving mode further comprises:

determining whether the driving mode is Normal or Sporty.

16. The method of controlling set forth in claim 9, wherein said determining at least one control gain factor further comprises:

determining a yaw rate error threshold gain factor; and

determining a brake pressure apply rate gain factor.

17. A vehicle stability enhancement system for a vehicle having a vehicle subsystem, the vehicle stability enhancement system settable to an active and an inactive state, the vehicle stability enhancement system comprising:

a sensor for sensing a vehicle parameter;

a driving mode switch for selecting a driving mode;

a VSE flag indicative of an activated or a non-activated vehicle stability enhancement system;

a vehicle control system for adjusting the vehicle subsystem; and

a controller responsive to the sensor, the driving mode, and the VSE flag, for controlling the vehicle control system;

wherein the vehicle subsystem is responsive to the controller in response to the vehicle stability enhancement system being activated, and wherein the vehicle subsystem is not responsive to the controller in response to the vehicle stability enhancement system not being activated;

wherein said VSE flag is indicative of an active vehicle stability enhancement system in response to a vehicle yaw rate error exceeding a threshold value, and is indicative of an inactive vehicle stability enhancement system in response to a vehicle yaw rate error not exceeding the threshold value.

18. The vehicle stability enhancement system of claim 17, further comprising:

a memory having at least one set of gain factors, said at least one set of gain factors comprising;

a yaw rate error threshold gain factor; and

a brake pressure apply rate gain factor.

19. The vehicle stability enhancement system of claim 17, further comprising at least one memory, said at least one memory further comprising:

an SFlag register settable to OFF and ON for indicating the state of a high friction surface flag;

an LFlag register settable to OFF and ON for indicating the state of a limit stability flag; and

an OSUS index register settable to at least one value in response to said SFlag and said LFlag register settings.