Seat load measuring system that automatically makes a self diagnosis and zero point adjustment in response to a vehicle crash

• US 6,643,575 B2
• Filed: 06/20/2002
• Issued: 11/04/2003
• Est. Priority Date: 06/25/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kuwahara, Sadayuki, Ishida, Shoichi
• Primary Examiner(s): Chin, Gary
• Application Number:
  US10/175,401
• Publication Number:
  US 20020198645A1
• Time in Patent Office: 502 Days
• Field of Search: 701/45, 701/46, 701/47, 180/271, 180/273, 180/282, 280/734, 280/735, 307/10.1
• US Class Current: 701/45
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60R 2021/01184 Fault detection or diagnostic circuits in power circuits B60R2021/01129
• CPC Class Codes: B60R 2021/01197 Warning devices
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/015 including means for detecting the presence or position of passengers, passenger seats or child seats , and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015

Abstract

An occupant protection system of a vehicle comprises a seat load measuring subsystem and an occupant protection subsystem. The seat load measuring subsystem includes a controller and weight sensors attached to a vehicle seat, each weight sensor providing a weight signal. The controller provides information determined by a weight of an occupant of the vehicle seat. In response to a detection of a crash, the occupant protection subsystem provides a crash signal determined by a magnitude of the crash. In response to a reception of the crash signal, the controller automatically decides whether a weight sensor under diagnosis is normal, abnormal or intermediate between normal and abnormal on the basis of a level of the crash signal and the weight signals obtained from the weight sensor before and after the crash.

Claims

1. An occupant protection system of a vehicle, the system comprising:

a seat load measuring subsystem which includes

a plurality of weight sensors attached to a vehicle seat, each weight sensor providing a weight signal responsive to a weight load applied thereto;

crash sensing means, responsive to a crash of said vehicle, for outputting a magnitude of said crash;

a controller, responsive to said magnitude of said crash for providing a crash signal determined by said magnitude and, responsive to a decision that said crash signal has reached a predetermined level for providing control information on the basis of said weight signals from said plurality of weight sensors; and

occupant protection means, response to said control information, for executing a protection operation, wherein said seat load measuring subsystem further includes;

means responsive to a reception of said crash signal for automatically making a diagnosis on each weight sensor or a zero adjustment of said each weight sensor.

2. An occupant protection system as defined in claim 1, wherein said seat load measuring subsystem further includes:

decision means for deciding whether said diagnosis is necessary or not;

a set of parameters of which at least a part is used as a criterion for diagnosis based on said crash signal; and

diagnosis means, responsive to a decision that said diagnosis is necessary, for deciding whether said each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of said set of parameters.

3. An occupant protection system as defined in claim 2, wherein said seat load measuring subsystem further includes:

means responsive to a decision that said diagnosis is not necessary for making said zero adjustment of said each weight sensor.

4. An occupant protection system as defined in claim 2, wherein said decision means includes auxiliary means for detecting a presence or a position of an occupant of said vehicle seat.

5. An occupant protection system as defined in claim 2, wherein said seat load measuring subsystem further includes means response to a decision made by said diagnosis means that said each weight sensor is intermediate for making said zero adjustment of said each weight sensor.

6. An occupant protection system as defined in claim 2, further including means, response to a decision made by said diagnosis means that said each weight sensor is abnormal, for providing an alert to a user.

7. An occupant protection system as defined in claim 2, wherein said diagnosis means comprises:

means operative in the event that said level of said crash signal is smaller than a first predetermined value for deciding that said each weight sensor is normal; and

means operative in the event that said level of said crash signal is larger than a second predetermined value which is larger than said first predetermined value for deciding that said each weight sensor is abnormal.

8. An occupant protection system as defined in claim 7, wherein said diagnosis means further comprises:

means operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value for, regardless of an output level of said each weight sensor, deciding that said each weight sensor is intermediate between normal and abnormal.

9. An occupant protection system as defined in claim 7, wherein said set includes parameters used as a criterion for diagnosis based on said crash signal and said weight signals obtained from said each weight sensor before and after said crash, and wherein said diagnosis means further comprises:

means, operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value and that a difference between said weight signals before and after said crash is in a larger weight sensor output range defined in said set but is out of a smaller weight sensor output range which is defined in said set and completely included in said larger weight sensor output range, for deciding that said each weight sensor is intermediate.

10. An occupant protection system as defined in claim 9, wherein said larger and smaller weight sensor output ranges remain constant throughout said range from said first predetermined value to said second predetermined value.

11. An occupant protection system as defined in claim 9, wherein said larger and smaller weight sensor output ranges, when expressed in a graph, change in tapered shapes as said level of said crash signal increases from said first predetermined value to said second predetermined value.

12. An occupant protection system as defined in claim 2, wherein said seat load measuring subsystem further comprises:

means for calculating a sum of said weight signals from said plurality of said weight sensors; and

a second set of parameters which is different from said set, said set being adapted to said sum which is larger than a threshold weight value, while said second set being adapted to said sum which is not larger than said threshold weight value, wherein said means for automatically making a diagnosis or a zero adjustment includes;

means for making an arrangement to use suitable one of said set and said second set depending on whether said sum is larger than said threshold weight value.

13. An occupant protection system as defined in claim 2, wherein said means for automatically making a diagnosis or a zero adjustment comprises:

a plurality of diagnosis parameters sets for use in diagnosing all of said weight sensors;

said plurality of diagnosis parameter sets adapted for said weight sensors;

global diagnosis means responsive to a reception of said crash signal for automatically deciding whether all of said weight sensors is normal, abnormal or intermediate between normal and abnormal on the basis of said plurality of diagnosis parameter sets;

means for deciding whether each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of one of said diagnosis parameter sets adapted for said each weight sensor to provide an interim result; and

means for calculating a logical product or sum between the decision of said global diagnosis means and said interim result for said each weight sensor to provide a final diagnosis result for said each weight sensor.

14. An integrated circuit for use in an occupant protection system of a vehicle wherein the occupant protection system includes a plurality of weight sensors attached to a vehicle seat, each weight sensor providing a weight signal responsive to a weight load applied thereto;

a crash sensor for providing a magnitude of a crash; and

occupant protection means responsive to control information from the external for providing a protection, the integrated circuit comprising;

means responsive to said magnitude of said crash for providing a crash signal;

mean responsive to said crash signal for generating said control information on the basis of said weight signals from said plurality of weight sensors;

means responsive to a reception of said crash signal for automatically making a diagnosis on said each weight sensor or a zero adjustment of said each weight sensor.

15. An integrated circuit as defined in claim 14, further including:

decision means for deciding whether said diagnosis is necessary or not;

a set of parameters of which at least a part is used as a criterion for diagnosis based on said crash signal; and

diagnosis means, responsive to a decision that said diagnosis is necessary, for deciding whether said each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of said set.

16. An integrated circuit as defined in claim 15, further including:

means responsive to a decision that said diagnosis is not necessary for making said zero adjustment of said each weight sensor.

17. An integrated circuit as defined in claim 15, wherein said set includes parameters used as a criterion for diagnosis based on said crash signal and said weight signals obtained from said each weight sensor before and after said crash.

18. A seat load measuring system for use in an occupant protection system of a vehicle wherein the occupant protection system includes means responsive to a detection of a crash for providing a crash signal and means responsive to said crash signal for executing a protection operation on the basis of control information provided by the seat load measuring system, the seat load measuring system including;

a plurality of weight sensors attached to a vehicle seat, each weight sensor providing a weight signal responsive to a weight load applied to said each weight sensor, said weight signal being used either as said control information or for generating said control information; and

means responsive to a reception of said crash signal for automatically making a diagnosis on each weight sensor or a zero adjustment of said each weight sensor.

19. A seat load measuring system as defined in claim 18, wherein said means for automatically making a diagnosis further includes:

decision means for deciding whether said diagnosis is necessary or not;

a set of parameters of which at least a part is used as a criterion for diagnosis based on said crash signal; and

diagnosis means, responsive to a decision that said diagnosis is necessary, for deciding whether said each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of said set of parameters.

20. A seat load measuring system as defined in claim 18, further including means response to a decision that said each weight sensor is intermediate for making a zero adjustment of said each weight sensor.

21. A seat load measuring system as defined in claim 18, further including means response to a decision that said each weight sensor is abnormal for providing an alert to a user.

22. A seat load measuring system as defined in claim 18, wherein said diagnosis means comprises:

means operative in the event that a level of said crash signal is smaller than a first predetermined value for deciding that said each weight sensor is normal; and

means operative in the event that said level of said crash signal is larger than a second predetermined value which is larger than said first predetermined value for deciding that said each weight sensor is abnormal.

23. A seat load measuring system as defined in claim 22, wherein said diagnosis means further comprises:

means operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value for, regardless of an output level of said each weight sensor, deciding that said each weight sensor is intermediate between normal and abnormal.

24. A seat load measuring system as defined in claim 22, wherein a set of parameters includes parameters used as a criterion for diagnosis based on said crash signal and said weight signals obtained from said each weight sensor before and after said crash, and wherein said diagnosis means further comprises:

means, operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value and that a difference between said weight signals before and after said crash is in a larger weight sensor output range defined in said set but is out of a smaller weight sensor output range which is defined in said set and completely included in said larger weight sensor output range, for deciding that said each weight sensor is intermediate.

25. A seat load measuring system as defined in claim 24, wherein said larger and smaller weight sensor output ranges remain constant throughout said range from said first predetermined value to said second predetermined value.

26. A seat load measuring system as defined in claim 24, wherein said larger and smaller weight sensor output ranges, when expressed in a graph, change in tapered shapes as said level of said crash signal increases from said first predetermined value to said second predetermined value.

27. A seat load measuring system as defined in claim 19, further including:

means for calculating a sum of said weight signals from said plurality of said weight sensors; and

a second set of parameters which is different from said set, said set being adapted to said sum which is larger than a threshold weight value, while said second set being adapted to said sum which is not larger than said threshold weight value, wherein said means for automatically making a diagnosis or a zero adjustment includes;

means for making an arrangement to use suitable one of said set and said second set depending on whether said sum is larger than said threshold weight value.

28. A seat load measuring system as defined in claim 19, wherein said means for automatically making a diagnosis or a zero adjustment comprises:

a plurality of diagnosis parameter sets for use in diagnosing all of said weight sensors;

said plurality of diagnosis parameter sets adapted for said weight sensors;

global diagnosis means responsive to a reception of said crash signal for automatically deciding whether all of said weight sensors is normal, abnormal or intermediate between normal and abnormal on the basis of said plurality of diagnosis parameter sets;

means for deciding whether each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of one of said diagnosis parameter sets adapted for said each weight sensor to provide an interim result; and

means for calculating a logical product or sum between the decision of said global diagnosis means and said interim result for said each weight sensor to provide a final diagnosis result for said each weight sensor.

29. An integrated circuit for use in a seat load measuring device of an occupant protection system of a vehicle wherein the seat load measuring device includes a plurality of weight sensors attached to a vehicle seat, each weight sensor providing a weight signal responsive to a weight load applied thereto, wherein the occupant protection system includes means responsive to a detection of a crash for providing a crash signal determined by a magnitude of the crash and means responsive to a detection of the crash for executing a protection operation on the basis of information provided by the integrated circuit, the integrated circuit including;

means for providing said information that is calculated from said weight signals from said plurality of weight sensors; and

means responsive to a reception of said crash signal for automatically making a diagnosis on said each weight sensor or a zero adjustment of said each weight sensor.

30. An integrated circuit as defined in claim 29, wherein said means for automatically making a diagnosis or a zero adjustment includes:

decision means for deciding whether said diagnosis is necessary or not;

a set of parameters of which at least a part is used as a criterion for diagnosis based on said crash signal; and

diagnosis means, responsive to a decision that said diagnosis is necessary, for deciding whether said each weight sensor is normal, abnormal or intermediate between normal and abnormal on the basis of said set of parameters.

31. An integrated circuit as defined in claim 30, wherein said means for automatically making a diagnosis or a zero adjustment includes:

means response to a decision made by said diagnosis means that said each weight sensor is intermediate for making said zero adjustment of said each weight sensor.

32. An integrated circuit as defined in claim 30, wherein said diagnosis means includes:

means operative in the event that a level of said crash signal is smaller than a first predetermined value for deciding that said each weight sensor is normal; and

means operative in the event that said level of said crash signal is larger than a second predetermined value which is larger than said first predetermined value for deciding that said each weight sensor is abnormal.

33. An integrated circuit as defined in claim 32, wherein said diagnosis means further includes:

means operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value for, regardless of an output level of said each weight sensor, deciding that said each weight sensor is intermediate between normal and abnormal.

34. An integrated circuit as defined in claim 32, wherein said set includes parameters used as a criterion for diagnosis based on said crash signal and said weight signals obtained from said each weight sensor before and after said crash, and wherein said diagnosis means further includes:

means, operative in the event that said level of said crash signal is in a range from said first predetermined value to said second predetermined value and that a difference between said weight signals before and after said crash is in a larger weight sensor output range defined in said set but is out of a smaller weight sensor output range which is defined in said set and completely included in said larger weight sensor output range, for deciding that said each weight sensor is intermediate.