Damper based vehicle yaw control

• US 6,505,108 B2
• Filed: 09/26/2001
• Issued: 01/07/2003
• Est. Priority Date: 03/01/2000
• Status: Expired due to Fees

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Bodie, Mark Olen, Hac, Aleksander Boguslaw
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/963,765
• Publication Number:
  US 20020128760A1
• Time in Patent Office: 468 Days
• Field of Search: 701/41, 701/38, 701/91, 701/37, 701/72, 280/772, 280/703, 280/707, 280/840, 280/711, 180/41
• US Class Current: 701/41
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 2400/0523 Yaw rate
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/822 Road friction coefficient determination affecting wheel traction
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2600/184 Semi-Active control means
• CPC Class Codes: B60G 2600/1873 Model Following
• CPC Class Codes: B60G 2800/212 Transversal; Side-slip during cornering
• CPC Class Codes: B60G 2800/215 by applying a braking action on each wheel individually
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 2800/244 Oversteer
• CPC Class Codes: B60G 2800/246 Understeer
• CPC Class Codes: B60G 2800/91 Suspension Control
• CPC Class Codes: B60G 2800/922 EBV - Electronic brake force distribution

Abstract

Controllable dampers are used to improve vehicle responses and stability during severe vehicle handling maneuvers. A total handling damping value for the vehicle is derived, preferably from the greatest of a yaw rate error value, a lateral acceleration value and a time derivative of lateral acceleration value. In addition, a control ratio of front axle roll damping to total roll damping is derived, preferably from the yaw rate error value, an oversteer/understeer indication and possibly vehicle speed. From these values, handling damping values are derived for each wheel of the vehicle and blended with damping values for the same wheels derived from suspension component movement to determine a corner damping command for each controllable damper. Preferably, the damping values derived from suspension component movement are shifted away from damping control of the vehicle body toward handling damping control when yaw rate error is large in magnitude.

Claims

1. A method for using controllable dampers to improve vehicle response and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle and a rear axle, the method comprising:

a) responsive to vehicle dynamic variables, deriving a total handling damping value for the vehicle;

b) responsive to vehicle dynamic variables, deriving a control ratio of front axle roll damping to total roll damping for the vehicle;

c) responsive to the total handling damping value and the ratio of front axle roll damping to total roll damping, deriving a handling damping value for the controllable damper; and

d) blending the total handling damping value with a damping value derived from suspension component movement to determine a corner damping command for the controllable damper.

2. The method of claim 1 wherein the total handling damping value is derived responsive to one of a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, a lateral acceleration of the vehicle, and a time derivative of desired lateral acceleration of the vehicle.

3. The method of claim 2 wherein the total handling damping value is derived from the greatest of the yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, the lateral acceleration of the vehicle, and the time derivative of desired lateral acceleration of the vehicle.

4. The method of claim 1 wherein the control ratio is derived from a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle.

5. The method of claim 4 wherein the control ratio increases during an oversteering condition and decreases during an understeering condition.

6. The method of claim 4 wherein the control ratio is further derived from vehicle speed.

7. The method of claim 6 wherein the control ratio increases as the vehicle speed increases.

8. The method of claim 1 wherein the damping value derived from suspension component movement is derived from a body damping value favoring damping control of the vehicle body and a wheel damping value favoring damping control of the wheel and the body damping value is reduced in response to a large magnitude of a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle.

9. A method for using controllable dampers to improve vehicle responses and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle, a rear axle, the method comprising:

a) measuring wheel speeds;

b) estimating vehicle speed

c) measuring lateral acceleration;

d) measuring yaw rate;

e) measuring steering angle;

f) estimating slip angle and slip rate;

g) determining a desired yaw rate, a desired lateral acceleration, a desired slip angle, and a desired slip rate based upon a vehicle reference model;

h) determining an error term derived from the difference between the desired yaw rate, desired slip angle, and the desired slip rate and the measured yaw rate and estimated slip angle and slip rate;

i) determining if the vehicle is in an under steer or over steer condition and generating a steering signal flag;

j) determining a derivative of the desired lateral acceleration by multiplying the desired yaw rate by the vehicle speed then differentiating the product;

k) determining a handling pulse width modulation for each of the at least one controllable damper;

l) determining a handling scale factor;

m) blending the handling pulse-width modulation with a pulse width modulation derived from suspension component movement and having a wheel control component and a body control component multiplied by the handling scale factor to determine a total pulse width modulation for each of the controllable dampers.

10. A method for improving vehicle responses and stability during severe maneuvers, the vehicle including a front axle with a pair of wheels having associated controllable dampers, a rear axle with a pair of wheels having associated controllable dampers, the method comprising:

a) responsive to at least one of a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, a lateral acceleration of the vehicle, and a time derivative of lateral acceleration of the vehicle, deriving a total handling damping value for the vehicle;

b) responsive to the yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, deriving a control ratio of axle roll damping on one of the front axle and the rear axle to total roll damping for the vehicle;

c) responsive to the total handling damping value and the control ratio, deriving a handling damping value for the controllable dampers associated with the wheels of one of the front axle and the rear axle; and

d) controlling the controllable dampers associated with the wheels of one of the front axle and the rear axle in response to their derived handling damping values.

11. The method of claim 10 wherein the control ratio is adjusted by a value having a magnitude derived from the yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle and a sign derived from a determined oversteer/understeer condition of the vehicle.

12. A method for using controllable dampers to improve vehicle response and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle and a rear axle, the method comprising:

a) responsive to vehicle dynamic variables, deriving a total handling damping value for the vehicle;

b) responsive to vehicle dynamic variables, deriving a control ratio of front axle roll damping to total roll damping for the vehicle;

c) responsive to the total handling damping value and the ratio of front axle roll damping to total roll damping, deriving a handling damping value for the controllable damper; and

d) deriving a corner damping command for the controllable damper at least in part from the total handling damping value.

13. The method of claim 12 wherein the total handling damping value is derived responsive to one of a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, a lateral acceleration of the vehicle, and a time derivative of lateral acceleration of the vehicle.

14. The method of claim 13 wherein the total handling damping value is derived from the greatest of the yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, the lateral acceleration of the vehicle, and the time derivative of lateral acceleration of the vehicle.

15. The method of claim 12 wherein the control ratio is derived from a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle.

16. The method of claim 15 wherein the control ratio increases during an oversteering condition and decreases during an understeering condition.

17. The method of claim 15 wherein the control ratio is further derived from vehicle speed.

18. The method of claim 17 wherein the control ratio increases as the vehicle speed increases.