Vehicle side slip angle estimation using dynamic blending and considering vehicle attitude information

• US 6,671,595 B2
• Filed: 01/08/2002
• Issued: 12/30/2003
• Est. Priority Date: 01/08/2002
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lu, Jianbo, Brown, Todd Allen
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Gibson, Eric M
• Application Number:
  US10/041,246
• Publication Number:
  US 20030130775A1
• Time in Patent Office: 721 Days
• Field of Search: 701/1, 701/36-38, 701/41, 701/42, 701/70-75, 340/438, 340/440, 180/197
• US Class Current: 701/36
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B60W 2520/20 Sideslip angle

Abstract

A method and system (18) for determining a side slip angle for an automotive vehicle (10) includes various sensors such as a yaw rate sensor (28), a speed sensor (20), a lateral acceleration sensor (32), a roll rate sensor (34), a steering angle sensor (35), and a longitudinal acceleration sensor (36). Each of the sensors are coupled to a controller (26) that determines a side slip angle velocity in response to the sensor signals. The side slip angle velocity is compensated for due to gravity and vehicle attitude changes. Also, the side slip angle velocity is compensated for due to the non-linearity of the side slip angle. The side slip angle velocity is integrated, preferably with an anti-drift integration filter (to determine an integrated side slip angle). A steady state side slip angle is also determined based on the sensors such as the yaw rate sensor and the lateral acceleration sensor. The steady state side slip angle is filtered using a steady state recovery filter (74). The integrated side slip angle and the steady state side slip angle are combined to form a side slip angle estimate.

Claims

1. A method of estimating and determining a side slip angle of an automotive vehicle, comprising the steps of:

measuring vehicle dynamic conditions;

determining a first side slip angle due to gravity, a vehicle attitude change, non-linearity of a side slip angle velocity and the dynamic conditions;

generating a steady state side slip angle; and

determining a side slip angle estimation based on the first side slip angle and the steady state side slip angle.

2. A method as recited in claim 1 wherein determining a first side slip angle comprises determining a first side slip angle due to gravity, a vehicle attitude change, non-linearity of a side slip angle velocity and the dynamic conditions and an anti-drift integration filter.

3. A method as recited in claim 1 wherein generating a steady state side slip angle comprises generating a steady state side slip angle in response to a steady state recovery filter.

4. A method as recited in claim 1 wherein determining a first side slip angle comprises determining a first side slip angle due to gravity, a vehicle attitude change, non-linearity of a side slip angle velocity and the dynamic conditions and an anti-drift integration filter;

and wherein generating a steady state side slip angle comprises generating a steady state side slip angle in response to a steady state recovery filter.

5. A method of estimating and determining a side slip angle of an automotive vehicle, comprising the steps of:

measuring the yaw rate of the vehicle;

measuring the lateral acceleration of the vehicle;

calculating the vehicle scaler velocity;

calculating an attitude change;

determining a side slip angle velocity based on the scalar velocity;

determining a first correction to side slip angle velocity due to gravity and the vehicle attitude change;

determining a second correction to side slip angle velocity due to nonlinearity;

forming a corrected side slip angle based on the first correction and the second correction;

integrating the said corrected side slip angle velocity to form an integrated side slip angle;

generating a steady state side slip angle based on the yaw rate and lateral dynamics of the vehicle;

filtering the steady state side slip signal with a steady state recovery filter to obtain a filtered side slip angle; and

determining a side slip angle estimation based on the integrated side slip angle and the filtered side slip angle.

6. A method as recited in claim 5 wherein calculating an attitude change comprises measuring roll rate, and longitudinal acceleration, and determining attitude change based on the roll rate, yaw rate, longitudinal acceleration and lateral acceleration.

7. A method as recited in claim 5 wherein determining a side slip angle velocity based on the scalar velocity and determining a non-linear side slip angle velocity based on the scalar velocity.

8. A method as recited in claim 5 wherein determining a second correction comprises determining the second correction as a function of cos²(β

), cos(2β

), cos(β

) sin(β

), sin(2β

), where β

is the side slip angle.

9. A method as recited in claim 5 wherein the step of integrating comprises integrating through an anti-drift integration filtering (ADI filtering) such that an integration cumulative error is eliminated.

10. A method as recited in claim 5 wherein filtering comprises the steady state recovery filtering.

11. A method as recited in claim 5 wherein the side slip angle velocity {dot over (β

)} has the following formula $\stackrel{.}{\mathrm{\beta <br><br>}}=\frac{{\stackrel{.}{v}}_y}{v_x}<br><br>{\cos }^2<br><br>\left(\mathrm{\beta <br><br>}\right)-\frac{{\stackrel{.}{v}}_x}{v_x}<br><br>\sin <br><br>\left(\mathrm{\beta <br><br>}\right)<br><br>\cos <br><br>\left(\mathrm{\beta <br><br>}\right)$

where {dot over (ν

)}_y is the time derivative of the lateral velocity, ν

_x is the time derivative of the longitudinal velocity, ν

_x is the longitudinal velocity and {dot over (β

)} is the time derivative of the side slip angle β

.

12. A method as recited in claim 5 wherein the velocity of the side slip angle obeys the following differential equation $\stackrel{}{\beta }$

.=[-ω

z+ay-g

 



sin

(θ

x)

cos

(θ

y)vx]

cos2

(β

)-v.xvx

sin

(β

)

cos

(β

)

where ν

_y is the time derivative of the lateral velocity, {dot over (v)}_x is the time derivative of the longitudinal velocity, ν

_x is the longitudinal velocity, and {dot over (β

)} is the velocity of the side slip angle, ω

_z is the yaw rate, θ

_x is the global roll attitude angle of the vehicle body, θ

_y is the global pitch attitude angle of the vehicle body.

13. A method as recited in claim 5 wherein the side slip angle velocity has the following formula $\begin{array}{c}\frac{}{}\end{array}$



t

DSSA= 



[-ω

z+ay-g

 



sin

(θ

x)

cos

(θ

y)vx]

(1+cos

(DSSA))- 



v.xvx

sin

(DSSA)

where ν

_y is the time derivative of the lateral velocity, {dot over (v)}_x is the time derivative of the longitudinal velocity, ν

_x is the longitudinal velocity, and {dot over (β

)} is the side slip angle velocity, ω

_z is the yaw rate, θ

_x is the global roll attitude angle of the vehicle body, θ

_y is the global pitch attitude angle of the vehicle body, and DSSA is the double side slip angle.

14. A method as recited in claim 5 wherein generating a steady state side slip angle comprises generating a steady state side slip angle according to the formula:

15. A control system for an automotive vehicle comprising:

a yaw rate sensor for generating a yaw rate signal;

a lateral acceleration sensor generating a lateral acceleration signal;

a speed sensor for generating a vehicle scalar velocity signal;

a longitudinal acceleration sensor generating a longitudinal acceleration signal;

a roll rate sensor generating a roll rate signal;

a controller coupled to the yaw rate sensor, the lateral acceleration sensor, the longitudinal acceleration sensor and the roll rate sensor, said controller determining an attitude change in response based on the roll rate signal, the yaw rate signal, longitudinal acceleration signal and lateral acceleration signal, determining a side slip angle velocity based on the scalar velocity, the controller determining a first correction to side slip angle velocity due to gravity and the vehicle attitude change, a second correction to side slip angle velocity due to nonlinearity and a corrected side slip angle based on the first correction and the second correction, said controller integrating the corrected side slip angle velocity to form an integrated side slip angle, generating a steady state side slip angle based on the yaw rate and lateral dynamics of the vehicle;

filtering the steady state side slip signal with a steady state recovery filter to obtain a filtered side slip angle, and determining a side slip angle estimation based on the integrated side slip angle and the filtered side slip angle.

16. A system as recited in claim 15 further comprising a handling and safety system, said controller controlling the safety system in response to the integrated side slip angle.

17. A control system as recited in claim 16 wherein said handling and safety system comprises an active brake control system.

18. A control system as recited in claim 16 wherein said handling and safety system comprises an active rear steering system.

19. A control system as recited in claim 16 wherein said handling and safety system comprises an active front steering system.

20. A control system as recited in claim 16 wherein said handling and safety system comprises an active anti-roll bar system.

21. A control system as recited in claim 16 wherein said handling and safety system comprises an active suspension system.

22. A method of estimating and determining a side slip angle of an automotive vehicle comprising:

determining a first side slip angle due to a vehicle attitude change;

generating a steady state side slip angle; and

determining a side slip angle estimation based on the first side slip angle and the steady state side slip angle.

23. A method as recited in claim 22 further comprising measuring vehicle dynamic conditions, wherein the step of determining a first side slip angle comprises determining a first side slip angle due to the vehicle attitude change and the vehicle dynamic conditions.

24. A method as recited in claim 23 wherein the step of determining a side slip angle comprises determining a side slip angle due to the vehicle dynamic conditions, the vehicle attitude change, and a non-linearity of a side slip angle velocity.