Claims
- 1. An apparatus for providing data from which a yaw rate for a wheeled land vehicle can be estimated, the apparatus comprising a pair of spaced apart accelerometers.
- 2. The apparatus of claim 1 wherein the accelerometers are disposed along a common longitudinal axis of the wheeled land vehicle.
- 3. The apparatus of claim 2 wherein one of the accelerometers is disposed forwardly of a center of gravity of the wheeled land vehicle and another one of the accelerometers is disposed rearwardly of the center of gravity of the wheeled land vehicle.
- 4. The apparatus of claim 4 wherein yaw rate obtained is fed to a vehicle stability control system on board the wheeled land vehicle that lack a gyroscope.
- 5. The apparatus of claim 3 wherein each one of the accelerometers has a sensing axis that is disposed transversely and generally perpendicularly relative to the common longitudinal axis of the wheeled land vehicle.
- 6. The apparatus of claim 5 further comprising a processor that processes signals from both of the accelerometers to obtain an estimate of yaw rate.
- 7. The apparatus of claim 6 wherein the processor is configured to obtain an estimate of rate of change of yaw rate that is equal to a first result of an acceleration provided by the accelerometer that is disposed forwardly of the center of gravity of the wheeled land vehicle minus an acceleration provided by the accelerometer that is disposed rearwardly of the center of gravity of the wheeled land vehicle divided by a second result of a first distance between the forwardly disposed accelerometer and the center of gravity plus a second distance between the rearwardly disposed accelerometer and the center of gravity.
- 8. The apparatus of claim 7 wherein the processor is configured to obtain or determine an estimate of acceleration from the signal provided by each accelerometer.
- 9. The apparatus of claim 7 further comprising a steer angle sensor and wherein the processor is configured to take steer angle into account in determining a yaw rate.
- 10. The apparatus of claim 9 wherein the processor is further configured with a statistical estimating filter that helps drive yaw rate estimation error toward zero.
- 11. The apparatus of claim 9 wherein the statistical estimating filter comprises a Lewenberg filter.
- 12. The apparatus of claim 9 wherein the processor is configured with a state estimator.
- 13. The apparatus of claim 6 wherein the processor is configured with the following algorithm for determining an estimate of a rate of change of yaw rate:
- 14. The apparatus of claim 13 wherein error due to super-elevation and roll is ignored when determining an estimate of yaw rate.
- 15. An apparatus for providing data from which a yaw rate for a wheeled land vehicle can be determined, the apparatus comprising:
a pair of spaced apart accelerometers with one of the accelerometers being disposed rearwardly of a center of mass of the wheeled land vehicle and the other one of the accelerometers being disposed forwardly of a center of mass of the wheeled land vehicle and both of the sensors disposed along an axis that is parallel to a vehicle centerline; a steer angle sensor; and a processor configured to process signals or data from the accelerometers and the steer angle sensor and output a yaw rate.
- 16. The apparatus of claim 15 wherein the processor is configured with a state estimation algorithm that is used to process the signals or data from the accelerometers and the steer angle sensor and output a yaw rate.
- 17. The apparatus of claim 16 wherein the state estimation algorithm comprises a statistical estimating filter.
- 18. The apparatus of claim 16 wherein the state estimation algorithm comprises a Lewenberg estimator.
- 19. The apparatus of claim 15 wherein signals or data from the accelerometers and the steer angle sensor are processed in real time during operation of the wheeled vehicle to produce a yaw rate estimate and further comprising a vehicle stability control system that compares the yaw rate estimate with a yaw rate threshold to determine whether to activate the vehicle stability control system to increase vehicle stability.
- 20. A method estimating yaw rate comprising:
(a) providing a wheeled land vehicle having an onboard processor, a steer angle sensor, and a pair of spaced apart accelerometers; (b) obtaining lateral accelerations from the accelerometers; (c) obtaining a steer angle from the steer angle sensor; and (d) estimating a yaw rate using the lateral accelerations and steer angle.
- 21. The method according to claim 20 wherein the processor is configured with a recursive statistical estimating algorithm that processes the steer angle and lateral accelerations.
- 22. The method according to claim 21 wherein the recursive statistical estimating algorithm applies feedback based on the prior estimated yaw rate and the present steer angle.
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. Section 119(e) to U.S Provisional Application Serial No. 60/313,716, filed Aug. 20, 2001, the entirety of which is hereby expressly incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60313716 |
Aug 2001 |
US |