Estimation of vehicle roll rate and roll angle using suspension deflection sensors

• US 7,571,030 B2
• Filed: 04/10/2006
• Issued: 08/04/2009
• Est. Priority Date: 04/10/2006
• 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: Ryu, Jihan, Moshchuk, Nikolai K., Chen, Shih-Ken
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US11/400,844
• Publication Number:
  US 20070239320A1
• Time in Patent Office: 1,212 Days
• Field of Search: 701/1, 701 37- 38, 340/440, 280/5.502, 280/5.506, 280/5.507
• US Class Current: 701/1
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence

Abstract

A system and method for estimating vehicle roll rate and roll angle. The system includes a suspension deflection sensor provided at each wheel of the vehicle that provides suspension measurement signals indicative of the roll of the vehicle. The system also includes a roll rate estimator that uses the suspension measurement signals and an estimated tire deflection of the wheels to provide a roll rate estimation signal. The system also includes a vehicle roll angle and a roll rate estimator that uses the roll rate estimation signal and a dynamic model to estimate the roll angle and refine the roll rate. The roll rate estimator calculates the roll rate one way if none of the vehicle wheels are off of the ground and calculates it another way if any of the wheels are off of the ground.

Claims

1. A system for estimating vehicle roll rate and roll angle of a vehicle, said system comprising:

a suspension deflection sensor provided at each wheel of the vehicle, said suspension deflection sensors providing suspension measurement signals indicative of the roll of the vehicle;

a roll rate estimator responsive to the suspension deflection measurement signals, said roll rate estimator estimating the vehicle roll rate based on the suspension measurement signals and estimated tire deflection rates of the wheels and providing a roll rate estimation signal; and

a vehicle roll angle and roll rate estimator responsive to the roll rate estimation signal, said roll angle and roll rate estimator using a dynamic model to estimate the roll angle and refine the roll rate estimation signal.

2. The system according to claim 1 wherein the roll angle and roll rate estimator uses a Kalman filter.

3. The system according to claim 1 wherein the roll angle and roll rate estimator uses a Luenberger type observer.

4. The system according to claim 1 wherein the roll rate estimator calculates the roll rate estimation signal in a first manner if none of the vehicle wheels are off of the ground and calculates the roll rate estimation signal in a second manner different than the first manner if any of the vehicle wheels are off of the ground.

5. The system according to claim 1 wherein the roll angle and roll rate estimator adjusts an observer gain in the dynamic model with a roll angle non-linearity factor and a wheel lift condition factor to correct for system non-linearities.

6. The system according to claim 1 wherein the roll rate estimator estimates the roll rate for two of the wheels using the equation:

7. The system according to claim 6 wherein the deflection rate values from the suspension sensors are converted to vertical deflection rates using the equation:

Ż

^S =ƒ

₁(Ż

_SUS)

prior to the roll angle being calculated, where Ż

^S is a vertical deflection rate at the wheel and the value ƒ

₁ is a function of the measured deflection rate Ż

_SUS.

8. The system according to claim 6 wherein the tire deflection rates are estimated from the deflection rate values by the equation:

Ż

^T =c₂Ż

^S

where Ż

^T is the tire deflection rate, Ż

^S is the deflection rate value and c₂is a vehicle dependent parameter.

9. The system according to claim 1 where the roll rate estimator estimates the roll rate for two of the wheels using the equation:

{dot over (φ

)}_S=c₃(Ż

_R^S +Ż

_R^T)

when wheel lift is occurring, where {dot over (φ

)}_S is the estimated roll rate, Ż

_R^S is a deflection rate value for one wheel, Ż

_R^T is a tire deflection rate for the one wheel, and c₃ is the vehicle dependent parameter.

10. The system according to claim 1 wherein the suspension sensors are velocity sensors.

11. The system according to claim 1 wherein the suspension sensors are displacement sensors.

12. A system for estimating vehicle roll rate and a roll angle of a vehicle, said system comprising:

a suspension deflection rate sensor provided at each wheel of the vehicle, said suspension deflection rate sensors providing suspension deflection rate signals indicative of the roll of the vehicle;

a roll rate estimator responsive to the suspension deflection rate signals, said roll rate estimator estimating the vehicle roll rate based on the suspension rate signals and estimated tire deflection rates of the wheels, and providing a roll rate estimation signal, said roll rate estimator calculating the roll rate estimation signal in a first manner if none of the vehicle wheels are off the ground and calculates the roll rate estimation signal in a second manner different than the first manner if any of the vehicle wheels are off the ground; and

a roll angle and roll rate estimator responsive to the roll rate estimation signal, said roll angle and roll rate estimator using a dynamic model to estimate the roll angle and refine the estimate roll rate signal, said roll angle and roll rate estimator adjusting an observer gain in the dynamic model with a roll angle non-linearity factor and wheel lift condition factor to correct for system non- linearities.

13. The system according to claim 12 wherein the roll angle and roll rate estimator uses a Kalman filter.

14. The system according to claim 12 wherein the roll angle and roll rate estimator uses a Luenberger type observer.

15. The system according to claim 12 wherein the roll rate estimator estimates the roll rate for two of the wheels using the equation:

16. The system according to claim 12 where the roll rate estimator estimates the roll rate for two of the wheels using the equation:

{dot over (φ

)}_S=c₃(Ż

_R^{S +Ż}

_R^T)

when wheel lift is occurring, where {dot over (φ

)}_S is the vehicle roll rate, Ż

_R^S is a deflection rate value for one wheel, Ż

_R^T is a tire deflection rate for the one wheel, and c₃ is the vehicle dependent parameter.

17. A method for estimating estimated roll rate and roll angle of a vehicle, said method comprising:

measuring the deflection rate of a vehicle suspension at each wheel of the vehicle;

estimating a roll rate of the vehicle using the suspension rate measurements and estimated tire deflection rates of the vehicle wheels; and

estimating the roll angle and refining the roll rate estimation using a 1 degree-of-freedom dynamic model.

18. The method according to claim 17 wherein estimating the roll rate includes estimating the roll rate in a first manner if none of the vehicle wheels are off the ground and estimating the roll rate in a second manner different than the first manner if any of the vehicle wheels are off the ground.

19. The method according to claim 17 wherein estimating the roll angle and refining the roll rate estimation includes adjusting an observer gain in the dynamic model with a roll angle non-linearity factor and a wheel lift condition factor to correct for system non-linearities.

20. The method according to claim 17 wherein the 1 degree-of-freedom dynamic model is a Kalman filter model or a Luenberg type observer.