GPS BASED PITCH SENSING FOR AN INTEGRATED STABILITY CONTROL SYSTEM

• US 20110087398A1
• Filed: 09/23/2010
• Published: 04/14/2011
• Est. Priority Date: 10/12/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ryan, Jonathan, Bevly, David M., Prakah-Asante, Kwaku O., Lu, Jianbo, Filev, Dimitar Petrov
• Granted Patent: US 9,403,415 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60G 17/0165 to an external condition, e.g. rough road surface, side wind
• CPC Class Codes: B60G 17/019 characterised by the type of sensor or the arrangement thereof B60G17/01941 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 2400/34 Accelerator pedal position
• CPC Class Codes: B60G 2400/39 Brake pedal position
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2401/16 GPS track data
• CPC Class Codes: B60G 2500/20 Spring action or springs
• CPC Class Codes: B60G 2800/94 Electronic Stability Program (ESP, i.e. ABS+ASC+EMS)
• CPC Class Codes: B60W 2420/905 the sensor being an xyz axis sensor
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 40/11 Pitch movement
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement

Abstract

A system and method for sensing vehicle global pitch angle and rate that uses global velocities measured from a single antenna global positioning system (GPS) receiver together with sensor fusion algorithms involving sensor signals and other computed signals. This constructed, or computed, vehicle body'"'"'s pitch angle may replace the role of a pitch rate sensor in an integrated stability control system. Namely, it achieves enhanced vehicle state estimation without the need for a pitch rate sensor.

Claims

1. A pitch sensing system including pitch computation used by an integrated stability control system of a motor vehicle, the system comprising:

a GPS receiver for acquiring global vehicle velocities in three dimensions; and

a pitch computation estimated from the global vehicle velocities and input to the integrated stability control system.

2. The pitch sensing system as claimed in claim 1 wherein the pitch computation input further comprises a pitch angle and a pitch rate.

3. The pitch sensing system as claimed in claim 2 further comprising:

a roll stability control motion sensor set having a lateral acceleration sensor, a longitudinal acceleration sensor, a yaw rate sensor and a roll rate sensor;

a GPS velocity sampled at a predetermined frequency and integrated with the roll stability control motion sensor set;

an estimate of a vehicle body sideslip angle based on the GPS velocity sample integrated with the roll stability control motion sensor set.

4. The pitch sensing system as claimed in claim 2 further comprising:

a roll stability control motion sensor set having a lateral acceleration sensor, a longitudinal acceleration sensor, a yaw rate sensor and a roll rate sensor;

a GPS velocity sampled at a predetermined frequency and integrated with the RSC motion sensor set;

an estimate of a vehicle body roll angle with respect to sea level based on the GPS velocity sample integrated with the roll stability control motion sensor set.

5. The pitch sensing system as claimed in claim 2, further comprising:

a Kalman filter for estimating a lateral velocity, a lateral velocity derivative, a lateral acceleration bias, and a longitudinal acceleration bias.

6. The pitch sensing system as claimed in claim 2 further comprising:

a pitch angle computation;

a pitch rate computation;

a roll angle computation; and

a lateral velocity computation;

the pitch angle computation, the pitch rate computation, the roll angle computation, and the lateral velocity computation each have a sampling rate that is faster than a sampling rate for the GPS.

7. The pitch sensing system as claimed in claim 2 further comprising:

the global vehicle velocities being sampled at a predetermined sampling rate;

a vertical vehicle body acceleration value;

a longitudinal vehicle body acceleration value;

compensated global vehicle velocities based on a combination of the global vehicle velocities, the vertical vehicle body acceleration value and the longitudinal vehicle body acceleration value; and

a pitch angle estimated from the compensated global vehicle velocities and the GPS global vehicle velocity.

8. The pitch sensing system as claimed in claim 7 further comprising a Kalman filter for estimating the vertical and longitudinal vehicle body acceleration values at a sampling rate which is faster than the predetermined sampling rate.

9. The pitch sensing system as claimed in claim 2 wherein the global vehicle velocities further comprise a global vertical velocity and a global horizontal velocity and the pitch angle is estimated from a ratio of the global vertical velocity and the global horizontal velocity.

10. An integrated stability control system for a motor vehicle having a GPS receiver capable of acquiring three-dimensional vehicle velocity measurements, the integrated stability control system comprising:

a single roll rate sensor for providing a roll rate signal indicative of a roll rate of the motor vehicle;

a pitch computation indicative of the vehicle pitch angle and pitch rate as it is estimated using at least the three-dimensional vehicle velocity measurements acquired from the GPS receiver; and

a controller using at least the roll rate signal and the pitch angle signal for integrated stability control.

11. The integrated stability control system as claimed in claim 10 further comprising a lateral velocity signal estimated using the pitch angle signal, the lateral velocity signal being an input to the controller.

12. The integrated stability control system as claimed in claim 10 further comprising a sideslip angle signal estimated using the estimated pitch angle and input to the controller.

13. The integrated stability control system as claimed in claim 10 wherein a pitch computation indicative of a pitch angle further comprises a pitch angle as it is estimated using the three-dimensional vehicle velocity measurements that are compensated for using body-fixed vehicle accelerations.

14. A method for estimating a pitch computation of a motor vehicle having a GPS receiver and at least one stability control system, the method comprising the steps of:

acquiring three dimensional global vehicle velocity measurements from the GPS receiver;

estimating a pitch angle of a vehicle using the three-dimensional global vehicle velocity measurements;

inputting the estimated pitch angle to the stability control system.

15. The method as claimed in claim 14 wherein the step of inputting further comprises inputting the estimated pitch angle to an integrated stability control system and further comprising the step of controlling a roll stability of the vehicle using the estimated pitch angle.

16. The method as claimed in claim 14 wherein the step of inputting further comprises inputting the estimated pitch angle to an integrated stability control system and further comprising the step of controlling a yaw stability of the vehicle using the estimated pitch angle.

17. The method as claimed in claim 14 wherein the step of inputting further comprises inputting the estimated pitch angle to an integrated stability control system and further comprising the step of controlling a lateral stability of the vehicle using the estimated pitch angle.

18. The method as claimed in claim 14 further comprising the steps of:

estimating a lateral velocity using the estimated pitch angle;

inputting the estimated lateral velocity to the integrated stability control system; and

controlling roll stability of the vehicle using at least the estimated lateral velocity.

19. The method as claimed in claim 14 further comprising the steps of:

estimating a lateral velocity using the estimated pitch angle;

inputting the estimated lateral velocity to the integrated stability control system; and

controlling yaw stability of the vehicle using at least the estimated lateral velocity.

20. The method as claimed in claim 14 further comprising the steps of:

estimating a lateral velocity using the estimated pitch angle;

inputting the estimated vehicle sideslip angle to the control system; and

controlling lateral stability of the vehicle using at least the estimated lateral velocity.

21. The method as claimed in claim 14 further comprising the steps of:

estimating a vehicle sideslip angle using the estimated pitch angle;

inputting the estimated vehicle sideslip angle to the control system; and

controlling roll stability of the vehicle using at least the estimated vehicle sideslip angle.

22. The method as claimed in claim 14 further comprising the steps of:

estimating a vehicle sideslip angle using the estimated pitch angle;

inputting the estimated vehicle sideslip angle to the control system; and

controlling yaw stability of the vehicle using at least the estimated vehicle sideslip angle.

23. The method as claimed in claim 14 further comprising the steps of:

estimating a vehicle sideslip angle using the estimated pitch angle;

inputting the estimated vehicle sideslip angle to the control system; and

controlling lateral stability of the vehicle using at least the estimated vehicle sideslip angle.