INTEGRATED CONTROL OF ACTIVE TIRE STEER AND BRAKES

• US 20020143451A1
• Filed: 01/25/2001
• Published: 10/03/2002
• Est. Priority Date: 01/25/2001
• Status: Active Grant

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: Delphi Automotive Systems LLC (Aptiv PLC)
• Inventors: Hac, Aleksander B., Bedner, Edward J., Chen, Hsien H., Loudon, Steven P.
• Granted Patent: US 6,453,226 B1
• Time in Patent Office: Days
• US Class Current: 701/48
• 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 2800/922 EBV - Electronic brake force distribution
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 2260/022 Rear-wheel steering; Four-wheel steering
• CPC Class Codes: B60T 2260/024 Yawing moment compensation during mu-split braking
• 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
• CPC Class Codes: B60W 2050/0034 Multiple-track, 2D vehicle model, e.g. four-wheel model
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

An integrated active steering and braking control system for providing one or more corrective yaw moments to a vehicle in response to a plurality of signals indicative of operational and environmental conditions related to the vehicle is disclosed. The system comprises a reference model, an estimator, a vehicle level brake/steer controller, and an actuator controller. The reference model provides a feedforward front steering angle correction signal a feedforward rear steering angle correction signal, a desired yaw rate signal, a desired lateral velocity signal, and a desired side slip angle signal. The estimator provides an estimated surface coefficient of adhesion signal, an estimated lateral velocity signal, and an estimated side slip angle signal. In response to the signals from the reference model and the estimator, the vehicle level brake/steer controller provides either a desired speed differential signal, a desired front steering angle signal and/or a desired rear steering angle signal. The actuator controller selectively provides a corrective braking signal to a brake actuator, a corrective front steering signal to a steering actuator, and a corrective rear steering signal to the steering actuator as a function of the desired speed differential signal, the desired front steering angle signal, and the desired rear steering angle signal, respectively.

Claims

1. An integrated active steering and braking control method for a vehicle, the vehicle including an axle, a first tire, a second tire, a steering system, and a braking system, said method comprising:

determining a first corrective yaw moment as a function of a steering angle of the axle;

determining a second corrective yaw moment as a function of a speed differential between the first tire and the second tire;

providing a corrective steering signal to the steering system whereby said first corrective yaw moment is applied to the vehicle; and

providing a corrective braking signal to the braking system whereby said second corrective yaw moment is applied to the vehicle.

2. The method of claim 1, wherein

said corrective steering signal and said corrective braking signal are concurrently provided whereby said first corrective yaw moment and said second corrective yaw moment are concurrently applied to the vehicle.

3. An integrated active steering and braking control method for a vehicle, the vehicle including an axle, a first tire, and a second tire, said method comprising:

determining a desired speed differential between the speed of the first tire and the speed of the second tire; and

determining a desired steering angle of the axle as a function of said desired speed differential.

4. The method of claim 3, further comprising:

determining a corrective braking signal as a function of said desired speed differential.

5. The method of claim 3, further comprising:

determining a corrective steering signal as a function of said desired steering angle.

6. The method of claim 3, further comprising:

applying a limitation to said desired steering angle; and

determining a corrective steering signal as a function of said desired steering angle in view of said limitation.

7. The method of claim 3, further comprising:

selectively determining a corrective braking signal as a function of said desired speed differential; and

determining a corrective steering signal as a function of said desired steering angle.

8. An integrated active steering and braking control method for a vehicle, the vehicle including an axle, a first tire, and a second tire, said method comprising:

receiving a plurality of operational signals indicative of an operational state of the vehicle;

determining a feedforward portion of a corrective front steering angle signal in response to said plurality of operational signals; and

determining a feedforward portion of a corrective rear steering angle signal in response to said plurality of operational signals.

9. The method of claim 8, further comprising:

determining a desired yaw rate in response to said plurality of operational signals;

determining a desired side slip velocity in response to said plurality of operational signals; and

determining a desired side slip angle in response to said plurality of operational signals.

10. The method of claim 8, further comprising:

estimating a surface coefficient of adhesion in response to said plurality of operational signals

estimating a side slip velocity in response to said plurality of operational signals; and

estimating a side slip angle in response to said plurality of operational signals.

11. The method of claim 8, further comprising:

determining a feedback portion of said corrective front steering angle signal in response to said plurality of operational signals; and

determining a feedback portion of said corrective rear steering angle signal in response to said plurality of operational signals.

13. The system of claim 12, wherein

said second controller is operable to concurrently provide said corrective steering signal to the steering system and said corrective braking signal to the braking system whereby said first corrective yaw moment and said second corrective yaw moment are concurrently applied to the vehicle.

15. The vehicle of claim 14, wherein

said system is further operable to determine a corrective braking signal as a function of said desired speed differential.

16. The vehicle of claim 14, wherein

said system is further operable to determine a corrective steering signal as a function of said desired steering angle.

17. The vehicle of claim 14, wherein

said system is further operable to apply a limitation to said desired steering angle and to determine a corrective steering signal as a function of said desired steering angle in view of said limitation.

18. The vehicle of claim 14, wherein

said system is further operable to selectively determine a corrective braking signal as a function of said desired speed differential and to determine a corrective steering signal as a function of said desired steering angle.

20. The system of claim 19, further comprising:

a means for determining a desired yaw rate in response to said plurality of operational signals;

a means for determining a desired side slip velocity in response to said plurality of operational signals; and

a means for determining a desired side slip angle in response to said plurality of operational signals.

21. The system of claim 19, further comprising:

a means for estimating a surface coefficient of adhesion in response to said plurality of operational signals

a means for estimating a side slip velocity in response to said plurality of operational signals; and

a means for estimating a side slip angle in response to said plurality of operational signals.

22. The system of claim 8, further comprising:

a means for determining a feedback portion of said corrective front steering angle signal in response to said plurality of operational signals; and

a means for determining a feedback portion of said corrective rear steering angle signal in response to said plurality of operational signals.

12. An integrated active steering and braking control method for a vehicle including an axle, a first tire, a second tire, a steering system, and a braking system, said method comprising:

a first controller operable to determine a first corrective yaw moment as a function of a steering angle of the axle and to determine a second corrective yaw moment for the vehicle as a function of a speed differential between the first tire and the second tire; and

a second controller operable to provide a corrective steering signal to the steering system whereby said first corrective yaw moment is applied to the vehicle, and to provide a corrective braking signal to the braking system whereby said second corrective yaw moment is applied to the vehicle.

14. A vehicle, comprising:

an axle;

a first tire;

a second tire; and

an integrated active steering and braking control system operable to determine a desired speed differential between a speed of said first tire and a speed of said second tire and to determine a desired steering angle of said axle as a function of said desired speed differential.

19. An integrated active steering and braking control system for a vehicle, comprising:

a means for determining a feedforward portion of a corrective front steering angle signal in response to a plurality of operational signals indicative of an operational state of the vehicle; and

a means for determining a feedforward portion of a corrective rear steering angle signal in response to said plurality of operational signals.