Determination and control of vehicle sideslip using GPS

• US 20020198655A1
• Filed: 01/29/2002
• Published: 12/26/2002
• Est. Priority Date: 01/29/2001
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Bevly, David M., Gerdes, Joseph C.
• Granted Patent: US 6,681,180 B2
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: B60T 2210/36 Global Positioning System [GPS]
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• 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 method for determining a sideslip angle of a terrestrial vehicle that moves on wheels by using a global positioning system (GPS) receiver. The GPS receiver is mounted in the vehicle and measures the horizontal velocity of the vehicle as well as its attitude. The sideslip angle of the vehicle at the GPS receiver is obtained from these measurements. The body sideslip angle and tire sideslip angles are derived by translating the sideslip angle at the GPS receiver to the center of gravity and to the wheels. Alternatively, an on-board gyroscope is provided for measuring vehicle attitude while the horizontal velocity is obtained from the GPS receiver. The method is extended to derive wheel slip and tire cornering stiffness. The vehicle states derived by the method can be used in a stability control system for stabilizing the motion of the vehicle.

Claims

1. A method for determining a sideslip angle in a terrestrial vehicle moving on wheels by using a global positioning receiver having at least two antennas mounted in said terrestrial vehicle, said method comprising:

a) measuring a horizontal velocity of said terrestrial vehicle using said global positioning receiver;

b) measuring an attitude of said terrestrial vehicle using said global positioning receiver; and

c) deriving said sideslip angle at said global positioning receiver from said horizontal velocity and said attitude.

2. The method of claim 1, further comprising translating said sideslip angle from said global positioning receiver to a center of gravity of said terrestrial vehicle to obtain a body sideslip angle β

of said terrestrial vehicle.

3. The method of claim 1, further comprising translating said sideslip angle from said global positioning receiver to at least one of said wheels comprising a tire to obtain a tire sideslip angle α

.

4. The method of claim 3, further comprising deriving a cornering stiffness of said at least one wheel from said tire sideslip angle α

.

5. The method of claim 1, wherein said horizontal velocity is derived by dividing a distance between two position measurements of said vehicle into the time elapsed between said two position measurements.

6. The method of claim 1, wherein said horizontal velocity is derived from a Doppler measurement using said global position receiver.

7. The method of claim 1, wherein said horizontal velocity is derived by dividing the difference between two carrier phase measurements into the time elapsed between said two measurements.

8. The method of claim 1, further comprising:

a) measuring a wheel speed of at least one of said wheels;

b) taking a difference between an x-component of said horizontal velocity and said wheel speed; and

c) determining a wheel slip from said difference.

9. A method for determining a sideslip angle in a terrestrial vehicle moving on wheels by using a global positioning receiver mounted in said terrestrial vehicle, said method comprising:

a) measuring a horizontal velocity of said terrestrial vehicle using said global positioning receiver;

b) providing a gyroscope in said terrestrial vehicle;

c) measuring an attitude of said terrestrial vehicle using said gyroscope; and

d) deriving said sideslip angle of said terrestrial vehicle at said global positioning receiver from said horizontal velocity and said attitude.

10. The method of claim 9, further comprising translating said sideslip angle from said global positioning receiver to a center of gravity of said terrestrial vehicle to obtain a body sideslip angle β

of said terrestrial vehicle.

11. The method of claim 9, further comprising translating said sideslip angle from said global positioning receiver to at least one of said wheels comprising a tire to obtain a tire sideslip angle α

.

12. The method of claim 11, further comprising deriving a cornering stiffness of said at least one wheel from said tire sideslip angle α

.

13. The method of claim 9, wherein said horizontal velocity is derived by dividing a distance between two position measurements of said vehicle into the time elapsed between said two position measurements.

14. The method of claim 9, wherein said horizontal velocity is derived from a Doppler measurement using said global positioning receiver.

15. The method of claim 9, wherein said horizontal velocity is derived by dividing the difference between two carrier phase measurements into the time elapsed between said two measurements.

16. The method of claim 9, further comprising:

a) measuring a wheel speed of at least one of said wheels;

b) taking a difference between an x-component of said horizontal velocity and said wheel speed; and

c) determining a wheel slip from said difference.

17. The method of claim 9, further comprising:

a) determining a time offset for said measurement of said horizontal velocity with respect to said measurement of said attitude; and

b) correcting said measurement of said horizontal velocity for said time offset.

19. The stability control system of claim 18, wherein said control mechanism comprises a Kalman filter.

18. A stability control system for stabilizing the motion of a terrestrial vehicle moving on a set of wheels, said stability control system comprising:

a) a global positioning receiver having at least two antennas mounted in said terrestrial vehicle for measuring a horizontal velocity of said terrestrial vehicle and for measuring an attitude of said terrestrial vehicle;

b) a processing unit for deriving a sideslip angle of said terrestrial vehicle at said global positioning receiver from said horizontal velocity and said attitude; and

c) a control mechanism for using said sideslip angle to stabilize said terrestrial vehicle.

20. A stability control system for stabilizing the motion of a vehicle, said stability control system comprising:

a) a global positioning receiver mounted in said vehicle for measuring a horizontal velocity of said vehicle;

b) a gyroscope mounted in said vehicle for measuring an attitude of said vehicle;

c) a processing unit for deriving a sideslip angle of said terrestrial vehicle at said global positioning receiver from said horizontal velocity and said attitude; and

d) a control mechanism for using said sideslip angle to stabilize said terrestrial vehicle.

21. The stability control system of claim 20, wherein said control mechanism comprises a Kalman filter.