System and method for detecting roll rate sensor fault

1. A method for detecting a roll stability control system sensor fault comprising:

generating a compensated roll rate signal having a first threshold;

generating a lateral acceleration signal having a second threshold;

generating a reference velocity signal having a third threshold;

generating a yaw rate signal having a fourth threshold;

generating a small roll rate shift flag in response to at least one of said first threshold, said second threshold, said third threshold, and said fourth threshold exceeded for greater than a predetermined time; and

generating said small roll rate shift flag in response to said second threshold, said third threshold or said fourth threshold exceeded for turning situations or straight driving situations; said second threshold, said third threshold or said fourth threshold having alternate threshold limits for each of said turning situations and said driving situations.

2. A method as in claim 1 wherein generating said small roll rate shift flag further comprises generating said small roll rate shift flag as a function of a small roll rate fault including 3–7 deg/s roll rate fault.

3. A method as in claim 1 wherein generating said small roll rate shift flag further comprises generating said small roll rate shift flag for three situations including straight driving, 0.1 g steady state turns, and 0.2 g steady state turns during which the roll rate ω x term should be zero.

4. The method of claim 1 further comprising disabling the method when RSC, AYC or TCS are in cycle.

5. The method of claim 1 further comprising shutting down roll stability control in response to said small roll rate shift flag.

6. The method of claim 1 further comprising activating a warning lamp in response in response to said small roll rate shift flag.

7. The method of claim 1 further comprising terminating roil stability control in response to said small roll rate shift flag and in response to a detection that there is no double wheel lift.

8. The method of claim 1 further comprising generating a dynamic factor; and

generating a determination of stability as a function at said dynamic factor.

9. The method of claim 8 further comprising low-pass filtering said dynamic factor.

10. The method of claim 1 further comprising generating a dynamic factor;

generating a dynamic threshold; and

generating a determination of vehicle stability or vehicle position on a banked surface as a function of said dynamic factor and said dynamic threshold.

11. The method of claim 1 , further comprising tuning said first threshold, said second threshold, said third threshold, and said fourth threshold for achieving detection of errors at a desired rate and to avoid false error detection.

12. The method of claim 1 further comprising compensating for a valid signal bias in said roll rate signal.

13. The method of claim 1 further comprising generating a residue signal as a function of a reference angle signal and said roll rate signal;

adjusting said residue signal as a function of a sine of bank angle signal;

generating an adjusted residue signal;

generating a fault condition threshold from said adjusted residue signal as a function of at least one of said first threshold, said second threshold, said third threshold, or said fourth threshold;

setting a fault condition in response to said adjusted residue signal larger than a dynamic threshold and a magnitude of said roll rate signal above said fault condition threshold; and

setting a fault flag in response to said fault condition indicated for a predetermined time during which no double wheel lift occurs.

14. A method for detecting a roll stability control system sensor fault comprising:

generating a roll rate fault signal as a function of a reference angle signal, a roll rate signal, and a yaw rate signal;

generating global variables as a function of said reference angle signal;

adding a virtual high frequency component of pitch estimation to one of said global variables;

generating a vehicle dynamic fault threshold as a function of said global variables;

generating a residue signal as a function of said reference angle signal and said roll rate signal;

adjusting said residue signal as a function of a sine of bank angle signal;

generating an adjusted residue signal;

generating a fault condition threshold from said adjusted residue signal as a function of said vehicle dynamic fault threshold;

setting a fault condition in response to said adjusted residue signal larger than a dynamic threshold and a magnitude of said roll rate signal above said fault condition threshold; and

setting a fault flag in response to said fault condition indicated for a predetermined time during which no double wheel lift occurs.

15. The method of claim 14 further comprising applying a deadband to said vehicle dynamic threshold.

16. The method of claim 14 further comprising applying a deadband to said yaw rate signal.

17. The method of claim 16 wherein applying a deadband to said yaw rate signal further comprises filtering said yaw rate signal.

18. The method of claim 14 , wherein generating said vehicle dynamic threshold further comprises generating at least one of a yaw threshold, a pitch threshold, or a roll threshold.

19. The method of claim 14 further comprising passing said roll rate fault signal through a direction dependent low pass filter;

generating a filtered roll rate fault signal; and

generating a dynamic memory from said filtered roll rate fault signal.

20. The method of claim 19 further comprising saturating said filtered roll rate fault signal.

21. The method of claim 14 , wherein generating said roll rate fault signal further comprises generating said roll rate fault signal as a function of at least one of a roll angle signal, a pitch angle signal or a yaw angle signal.

22. A control system for an automotive vehicle having a vehicle body comprising:

a sensor cluster having a housing oriented within the vehicle body;

a roll rate sensor positioned within the housing generating a roll rate sensor signal corresponding to a roll angular motion of said housing; and

a controller receiving said roll rate sensor signal, said controller generating a residue signal in response to a sensor error or a measurement error, said controller setting a fault condition in response to said residue signal larger than a dynamic threshold and a magnitude of said roll rate signal above a fault condition threshold, and said controller setting a fault flag in response to said fault condition indicated for a predetermined time during which no double wheel lift occurs.

23. A system as recited in claim 22 , wherein said controller compensates said roll rate sensor signal for all valid signal faults.

24. A system as recited in claim 22 , wherein said controller is further adapted to shut down a roll over detection system in response to said fault flag.

25. A system as recited in claim 22 , wherein said controller generates a small roll rate shift flag in response to at least one vehicle dynamic threshold exceeded for greater than a predetermined time.

26. A system as recited in claim 25 , wherein said vehicle dynamic threshold of: said mu rate sensor signal, a lateral acceleration signal, a reference velocity signal, or a yaw rate signal.

27. A method for detecting a roll rate sensor fault comprising:

generating a reference velocity signal;

generating a lateral acceleration signal;

generating a compensated rollrate signal;

generating a yaw rate signal;

generating a dynamic factor;

generating a small fault flag as a function of, in excess of a predetermined time, at least one of said reference velocity signal exceeding a reference velocity threshold, said lateral acceleration signal exceeding a lateral acceleration threshold, said compensated rollrate signal exceeding a compensated rollrate threshold, said yaw rate signal exceeding a yaw rate threshold, or said dynamic factor exceeding a dynamic threshold; and

disabling the method when RSC, AYC or TCS are in cycle.

28. A method for detecting a roll rate sensor fault comprising:

generating a residue signal;

generating a global roll plausibility signal;

generating a dynamic factor signal:

generating a compensated rollrate signal;

generating a pitch signal;

generating a small fault flag;

generating a sticking signal fault flag; and

generating a dynamic factor threshold, a plausibility of fault signal, and a plausibility fault flag as a function of said residue signal, said global plausibility signal, said dynamic factor signal, said compensated rollrate signal, said pitch signal, said small fault flag, and said sticking fault flag.

29. The method of claim 28 further comprising setting a fault condition in response to said residue signal larger than said dynamic threshold.

30. The method of claim 29 , wherein setting further comprises setting said fault condition in response to said rollrate signal exceeding a rollrate threshold.

31. The method of claim 29 further comprising setting a fault flag in response to said fault condition set for a predetermined time wherein at least three vehicle tires contact a road surface.