Vehicle safety system with advanced tire monitoring

1. A safety system for a vehicle comprising:

a tire sensor located within each wheel of the vehicle and each generating a tire signal comprising pressure, temperature and multi-axis acceleration data;

at least one vehicle dynamics sensor providing a vehicle dynamics signal; and

a controller communicating with each tire sensor and the at least one vehicle dynamics sensor, the controller, in response to the vehicle dynamics signal;

generating a tire abnormal state value as a function of the multi-axis acceleration data of the tire signal and a comparison of frequency response characteristics of the tire signal; and

transmitting the tire abnormal state to at least one vehicle system controller.

2. A system according to claim 1 wherein the controller generates the tire abnormal state value as a function of the tire signal by comparing frequency response characteristics of the tire signal to stored frequency response characteristics indicative of different tire abnormalities.

3. A system according to claim 2 wherein the controller further generates the tire abnormal state value as a function of the tire signal by comparing frequency response characteristics of one of the tire signals to frequency response characteristics of at least two other tire signals.

4. A system according to claim 2 , wherein the tire abnormal state value is a loose wheel value.

5. A system according to claim 4 wherein the controller further generates the loose wheel value as a function of the tire signal by comparing amplitude response characteristics of the tire signal to stored amplitude response characteristics indicative of a loose wheel condition.

6. A system according to claim 3 wherein the controller further generates the loose wheel value as a function of the tire signal by comparing frequency response characteristics of one of the tire signals to frequency response characteristics of at least two other tire signals.

7. A system according to claim 1 wherein the controller generates the tire abnormal state value as a function of the tire signal by comparing frequency response characteristics of one of the tire signals to frequency response characteristics of at least two other tire signals.

8. A system according to claim 7 , wherein the tire abnormal state value is a loose wheel value.

9. A system according to claim 1 wherein the controller communicates with each tire sensor by wireless transmission.

10. A system according to claim 1 further comprising an indicator for signaling the tire abnormal state value.

11. A system according to claim 1 wherein the at least one vehicle dynamics sensor comprises a vehicle speed sensor and a braking sensor.

12. A system according to claim 1 wherein the at least one vehicle system controller comprises a stability control system.

13. A system according to claim 12 wherein the stability control system is adapted to modify stability control parameters in response to the tire abnormal state value.

14. A system according to claim 1 wherein the controller communication with each tire sensor also generates a roadway departure signal as a function of the multi-axis acceleration data of the tire signals and transmits the roadway departure signal to at least one vehicle system controller.

15. A system according to claim 14 wherein the controller generates the roadway departure signal as a function of the tire signals by comparing frequency and amplitude response characteristics of the tire signal to stored frequency and amplitude response characteristics indicative of different roadway surfaces.

16. A system according to claim 15 wherein the controller also generates a lateral tire force signal for each of the vehicle wheels as a function of the respective multi-axis acceleration data of the tire signal, generates an oversteer/understeer signal as a function of the lateral tire force signals, and transmits the brake signal to the brake system in response to the oversteer/understeer signal.

17. A system according to claim 16 wherein the controller generates the oversteer signal by detecting a sudden drop in lateral tire forces for both of the rear tires, in the presence of lateral tire forces in the same direction on the front tires.

18. A system according to claim 16 wherein the controller generates the understeer signal by detecting a sudden drop in lateral tire forces for both of the front tires, in the presence of lateral tire forces in the same direction on the rear tires.

19. A system according to claim 16 wherein the vehicle dynamics signal comprises a vehicle speed signal and a steering wheel angle signal.

20. A system according to claim 14 wherein the controller generates the roadway departure signal as a function of the tire signals by comparing frequency response characteristics of the left tire signals to frequency response characteristics of the right tire signals.

21. A system according to claim 14 wherein the at least one vehicle system controller comprises a stability control system.

22. A system according to claim 21 wherein the stability control system is adapted to modify stability control parameters in response to the roadway departure signal.

23. A safety system for a vehicle comprising:

a tire sensor located within each wheel of the vehicle and generating a tire signal comprising pressure, temperature and multi-axis acceleration data;

at least one vehicle dynamics sensor providing a vehicle dynamics signal; and

a controller communicating with each tire sensor and the at least one vehicle dynamics sensor, the controller, in response to the vehicle dynamics signal, generating a roadway departure signal as a function of the multi-axis acceleration data of the tire signals as a comparison of frequency and amplitude response characteristics of the tire signal; and

transmitting the roadway departure signal to at least one vehicle system controller.

24. A system according to claim 23 wherein the controller generates the roadway departure signal as a function of the tire signals by comparing frequency and amplitude response characteristics of the tire signal to stored frequency and amplitude response characteristics indicative of different roadway surfaces.

25. A system according to claim 23 wherein the controller generates the roadway departure signal as a function of the tire signals by comparing frequency response characteristics of the left tire signals to frequency response characteristics of the right tire signals.

26. A system according to claim 23 wherein the at least one vehicle system controller comprises a stability control system.

27. A system according to claim 26 wherein the stability control system is adapted to modify stability control parameters in response to the roadway departure signal.

28. A safety system for a vehicle comprising:

a tire sensor located within each wheel of the vehicle and generating a tire signal comprising pressure, temperature and multi-axis acceleration data;

at least one vehicle dynamics sensor providing a vehicle dynamics signal;

a brake system for applying a braking torque to each of the vehicle wheels in response to a brake signal; and

a controller communicating with each tire sensor and the at least one vehicle dynamics sensor, the controller, in response to the vehicle dynamics signal, generating a lateral tire force signal for each of the vehicle wheels as a function of the respective multi-axis acceleration data of the tire signal as a comparison of frequency response characteristics of the tire signal, generating an oversteer/understeer signal as a function of the lateral tire force signal, and transmitting the brake signal to the brake system in response to the oversteer/understeer signal.

29. A system according to claim 28 wherein the controller generates the oversteer signal by detecting a sudden drop in lateral tire forces for both of the rear tires, in the presence of lateral tire forces in the same direction on the front tires.

30. A system according to claim 28 wherein the controller generates the understeer signal by detecting a sudden drop in lateral tire forces for both of the front tires, in the presence of lateral tire forces in the same direction on the rear tires.

31. A system according to claim 28 wherein the vehicle dynamics signal comprises a vehicle speed signal and a steering wheel angle signal.