System for dynamically determining axle loadings of a moving vehicle using integrated sensing system and its application in vehicle dynamics controls

1. A method of controlling a vehicle having a sprung mass, a spring rate, a wheel assembly mass, a suspension, a body and a suspension point where the suspension couples to the body, a half track, a center of gravity, a longitudinal distance between the center of gravity and an axle, a vertical distance between the center of gravity and a suspension point, said method comprising:

determining a relative pitch angle;

determining a relative roll angle;

determining a vertical acceleration using the vertical distance between the center of gravity and the suspension point;

determining a heave motion wheel loading in response to the sprung mass and the vertical acceleration;

determining an attitude based wheel loading in response to the spring rate and the half track and the longitudinal distance between the center of gravity and the axle;

determining a vertical motion induced wheel loading in response to the wheel assembly mass and the vertical acceleration;

determining a total wheel normal loading in response to the heave motion wheel loading, the attitude based wheel loading and the vertical motion induced wheel loading; and

controlling a vehicle system in response to the total wheel normal loading.

2. The method of controlling the vehicle as recited in claim 1 wherein determining the vertical acceleration comprises determining a moving-road-frame vertical acceleration.

3. The method of controlling the vehicle as recited in claim 1 wherein controlling the vehicle system comprises controlling a vehicle safety system.

4. The method of controlling the vehicle as recited in claim 1 wherein controlling the vehicle system comprises controlling a vehicle suspension.

5. The method of controlling the vehicle as recited in claim 1 wherein controlling the vehicle system comprises controlling a dynamic control system.

6. The method of controlling the vehicle as recited in claim 5 wherein the dynamic control system comprises a roll stability control system.

7. A method of controlling a vehicle comprising:

determining a relative pitch angle;

determining a relative roll angle;

determining a vertical acceleration;

determining a heave motion generated wheel loading, a body attitude based wheel loading and a vertical motion induced wheel loading in response to the relative pitch angle, the relative roll angle and the vertical acceleration;

determining a total wheel normal loading in response to the heave motion generated wheel loading, the body attitude based wheel loading and the vertical motion induced wheel loading; and

controlling a vehicle system in response to the total wheel normal loading.

8. The method of controlling the vehicle as recited in claim 7 wherein controlling the vehicle comprises controlling a vehicle safety system.

9. The method of controlling the vehicle as recited in claim 7 wherein controlling the vehicle comprises controlling a vehicle suspension.

10. The method of controlling the vehicle as recited in claim 7 wherein controlling the vehicle comprises controlling a dynamic control system.

11. The method of controlling the vehicle as recited in claim 10 wherein the dynamic control system comprises a roll stability control system.

12. An apparatus for controlling a vehicle system comprising:

an integrated sensing system generating a plurality of dynamic signals indicative of a dynamic state of the vehicle;

a controller coupled to the integrated sensing system and using the plurality of dynamic signals to determine a relative pitch angle, a relative roll angle, a vertical acceleration; wherein

a heave motion wheel loading is determined by the controller in response to the relative pitch angle, the relative roll angle, and the vertical acceleration;

a body attitude based wheel loading is determined by the controller in response to the relative pitch angle, the relative roll angle, and the vertical acceleration;

a vertical motion induced wheel loading is determined by the controller in response to a the relative pitch angle, the relative roll angle and the vertical acceleration;

a total wheel normal loading determined by the controller in response to the heave motion wheel loading, the body attitude based wheel loading and the vertical motion induced wheel loading; and

a control signal to control the vehicle system is determined by the controller in response to the total wheel normal loading.

13. The apparatus as recited in claim 12 wherein the vertical acceleration is determined using a vertical distance between a vehicle center of gravity and a suspension point.

14. The apparatus as recited in claim 13 further comprising a moving road frame vertical acceleration determined in response to the vertical acceleration in a body frame, the relative roll angle and the relative pitch angle.

15. The apparatus as recited in claim 12 wherein the control signal controls a vehicle safety system.

16. The apparatus as recited in claim 12 wherein the control signal controls a vehicle suspension.

17. The apparatus as recited in claim 12 wherein the control signal controls a dynamic control system.

18. The apparatus as recited in claim 17 wherein the dynamic control system is a roll stability control system.