Analog signal processing system for determining airbag deployment

• US 6,175,299 B1
• Filed: 03/04/1996
• Issued: 01/16/2001
• Est. Priority Date: 03/04/1996
• Status: Expired due to Term

• Current Assignee: Loopback Technologies, Inc. (Marathon Patent Group, Inc.)
• Original Assignee: Delco Electronics Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Liu, Jiyao, Manlove, Gregory Jon, Kosiak, Walter Kirk, Ravas, Richard Joseph
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US08/610,021
• Time in Patent Office: 1,779 Days
• Field of Search: 364/424.055, 364/424.056, 364/424.01, 364/424.03, 340/426, 340/429, 340/665, 340/669, 340/903, 280/735, 280/734, 180/268
• US Class Current: 340/436
• 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 21/01332 by frequency or waveform analysis
• CPC Class Codes: B60R 21/01336 using filtering

Abstract

An analog signal processing system for determining airbag deployment includes a first low pass filter receiving a conditioned analog accelerometer signal and providing an analog acceleration signal therefrom. A first comparator/latch circuit receives the analog acceleration signal and provides a first signal to a logic circuit. The analog acceleration signal is further provided to a first integrator which converts the signal to a first velocity signal and provides the first velocity signal to a second comparator/latch circuit which provides a second logic level signal to the logic circuit. A second low pass filter receives the analog acceleration signal and provides a low frequency analog acceleration signal to a third comparator/latch circuit which provides a third signal to the logic circuit. The low frequency analog acceleration signal is further received by a second integrator circuit which converts the signal to a second velocity signal and provides the second velocity signal to a fourth comparator/latch circuit which provides a fourth signal to the logic circuit. The logic circuit performs a logic operation on the various logic level signals to provide an airbag deployment signal therefrom. Each comparator/latch circuit has a comparator threshold value associated therewith provided by a threshold circuit. The system is enabled for a preset time period after detecting a predefined acceleration level to provide a time-independent analog algorithm for evaluating the analog acceleration signal for possible airbag deployment.

Claims

1. An analog signal processing system for generating an airbag deployment signal from an analog acceleration signal comprising:

means for converting the analog acceleration signal to a first analog velocity signal;

means for providing a first deployment signal if the first analog velocity signal exceeds a first analog reference signal independent of the analog acceleration signal; and

means responsive to said first deployment signal for generating the airbag deployment signal.

2. The system of claim 1 further including means for providing a low frequency band representation of a conditioned analog acceleration signal, said low frequency band representation of said conditioned analog acceleration signal corresponding to the analog acceleration signal.

3. The system of claim 2 further including:

means responsive to acceleration for providing a differential analog acceleration signal corresponding thereto; and

means responsive to said differential analog acceleration signal for providing said conditioned analog acceleration signal.

4. The system of claim 3 further including means for providing said first analog reference signal.

5. The system of claim 4 further including means for enabling said means for converting the analog acceleration signal to a first analog velocity signal and said means for providing a first deployment signal for a predetermined time period if the analog acceleration signal exceeds a second analog reference signal.

6. The system of claim 1 further including:

means for providing a low frequency band representation of the analog acceleration signal;

means for converting the low frequency band representation of the analog acceleration signal to a second analog velocity signal; and

means for providing a second deployment signal if said second analog velocity signal exceeds a second analog reference signal, wherein said means responsive to said first deployment signal for generating the airbag deployment signal is further responsive to said second deployment signal for generating the airbag deployment signal.

7. The system of claim 6 further including means for providing a third deployment signal if the analog acceleration signal exceeds a third analog reference signal, wherein said means responsive to said first and second deployment signals for generating the airbag deployment signal is further responsive to said third deployment signal for generating the airbag deployment signal.

8. The system of claim 7 further including means for providing a fourth deployment signal if said low frequency band representation of the analog acceleration signal exceeds a fourth analog reference signal, wherein said means responsive to said first, second and third deployment signals for generating the airbag deployment signal is further responsive to said fourth deployment signal for generating the airbag deployment signal.

9. The system of claim 8 further including means for enabling said means for converting the analog acceleration signal to a first analog velocity signal, said means for converting the analog acceleration signal to a second analog velocity signal, said means for providing a first deployment signal, said means for providing a second deployment signal, said means for providing a third deployment signal, and said means for providing a fourth deployment signal for a predetermined time period if the analog acceleration signal exceeds a fifth analog reference signal.

10. The system of claim 9 further including means for providing said first, second, third, fourth and fifth analog reference signals.

11. The system of claim 1 further including means for providing a second deployment signal if the analog acceleration signal exceeds a second analog reference signal, wherein said means responsive to said first deployment signal for generating the airbag deployment signal is further responsive to said second deployment signal for generating the airbag deployment signal.

12. The system of claim 1 further including:

means for providing a low frequency band representation of the analog acceleration signal; and

means for providing a second deployment signal if said low frequency band representation of the analog acceleration signal exceeds a second analog reference signal, wherein said means responsive to said first deployment signal for generating the airbag deployment signal is further responsive to said second deployment signal for generating the airbag deployment signal.

13. An analog signal processing system for generating an airbag deployment signal from an analog acceleration signal comprising:

a first analog signal processing circuit having a first analog reference signal associated therewith corresponding to a first velocity, said analog reference signal independent of the analog acceleration signal, said first circuit receiving the analog acceleration signal and providing a first analog velocity signal corresponding thereto;

said first circuit further providing a first output signal if said first analog velocity signal exceeds said first analog reference signal, and otherwise providing a second output signal; and

a logic circuit receiving said first and second output signals and performing a logic operation thereon to provide the airbag deployment signal.

14. The system of claim 13 wherein said first analog signal processing circuit includes:

a signal integrating circuit having an input receiving the analog acceleration signal and an output, said signal integrating circuit converting the analog acceleration signal to said first analog velocity signal;

a level detecting circuit having an input connected to said output of said signal integrating circuit and an output, said level detecting circuit providing said first output signal at said level detecting circuit output when said first analog velocity signal exceeds said first analog reference signal, and providing said second output signal at said level detecting circuit output when said first analog velocity signal is below said first analog reference signal; and

a latch circuit having an input connected to said output of said level detecting circuit and an output, said latch circuit providing said first output signal at said latch circuit output if said level detecting circuit provides said first output signal to said latch circuit input, and otherwise providing said second output signal to said latch circuit output.

15. The system of claim 13 further including:

an analog signal filter receiving the analog acceleration signal and providing a low frequency analog acceleration signal corresponding thereto; and

a second analog signal processing circuit having a second analog reference signal associated therewith corresponding to a second velocity, said second circuit receiving the low frequency analog acceleration signal and providing a second analog velocity signal corresponding thereto, said second circuit further providing a third output signal if said second analog velocity signal exceeds said second analog reference signal, and otherwise providing a fourth output signal, herein said logic circuit further receives said third and fourth output signals and performs a logic operation thereon to provide the airbag deployment signal.

16. The system of claim 15 wherein said second analog signal processing circuit includes:

a signal integrating circuit having an input receiving the low frequency analog acceleration signal and an output, said signal integrating circuit converting the low frequency analog acceleration signal to said second analog velocity signal;

a level detecting circuit having an input connected to said output of said signal integrating circuit and an output, said level detecting circuit providing said third output signal at said level detecting circuit output when said second analog velocity signal exceeds said second analog reference signal, and providing said fourth output signal at said level detecting circuit output when said second analog velocity signal is below said second analog reference signal; and

a latch circuit having an input connected to said output of said level detecting circuit and an output, said latch circuit providing said third output signal at said latch circuit output if said level detecting circuit provides said third output signal to said latch circuit input, and otherwise providing said fourth output signal to said latch circuit output.

17. The system of claim 15 further including a third analog signal processing circuit having a third analog reference signal associated therewith corresponding to a first acceleration level, said third circuit receiving the analog acceleration signal and providing a fifth output signal if the acceleration signal exceeds said third analog reference signal, and otherwise providing a sixth output signal, wherein said logic circuit further receives said fifth and sixth output signals and performs a logic operation thereon to provide the airbag deployment signal.

18. The system of claim 17 wherein said third analog signal processing circuit includes:

a level detecting circuit having an input receiving the analog acceleration signal and an output, said level detecting circuit providing said fifth output signal at said level detecting circuit output when said analog acceleration signal exceeds said third analog reference signal, and providing said sixth output signal at said level detecting circuit output when said analog acceleration signal is below said third analog reference signal; and

a latch circuit having an input connected to said output of said level detecting circuit and an output, said latch circuit providing said fifth output signal at said latch circuit output if said level detecting circuit provides said fifth output signal to said latch circuit input, and otherwise providing said sixth output signal to said latch circuit output.

19. The system of claim 17 further including a fourth analog signal processing circuit having a fourth analog reference signal associated therewith corresponding to a second acceleration level, said fourth circuit receiving the low frequency analog acceleration signal and providing a seventh output signal if the low frequency acceleration signal exceeds said fourth analog reference signal, and otherwise providing an eighth output signal, wherein said logic circuit further receives said seventh and eighth output signals and performs a logic operation thereon to provide the airbag deployment signal.

20. The system of claim 19 wherein said fourth analog signal processing circuit includes:

a level detecting circuit having an input receiving the low frequency analog acceleration signal and an output, said level detecting circuit providing said seventh output signal at said level detecting circuit output when said analog acceleration signal exceeds said fourth analog reference signal, and providing said eighth output signal at said level detecting circuit output when said analog acceleration signal is below said fourth analog reference signal; and

a latch circuit having an input connected to said output of said level detecting circuit and an output, said latch circuit providing said seventh output signal at said latch circuit output if said level detecting circuit provides said seventh output signal to said latch circuit input, and otherwise providing said eight output signal to said latch circuit output.

21. The system of claim 19 wherein said first, third, fifth and seventh output signals are each high level signals, and said second, fourth, sixth and eighth signals are each low level signals.

22. The system of claim 19 wherein each of said first, second, third and fourth analog signal processing circuits further includes a circuit enable input;

and wherein said system further includes an enabling circuit having a circuit enable output connected to each of said circuit enable inputs and a fifth analog reference signal associated therewith corresponding to a third acceleration level, said enabling circuit receiving the analog acceleration signal and providing a circuit enable signal to said circuit enable output for a predefined time period to thereby permit operation of each of said analog signal processing circuits if the analog acceleration signal exceeds said fifth analog reference signal.

23. The system of claim 19 wherein said third acceleration level is equal to said first acceleration level;

and wherein said fifth analog reference signal is equivalent to said third analog reference signal.

24. The system of claim 19 further including a reference signal circuit operable to provide said first, second, third, fourth and fifth analog reference signals.

25. The system of claim 19 wherein said logic circuit includes a logic select input, said logic circuit responsive to any one of a plurality of predefined signal levels at said logic select input to perform any one of a corresponding plurality of separate logic operations upon said output signals of said first, second, third and fourth analog signal processing circuits to provide the airbag deployment signal.

26. A time independent method of determining an airbag deployment signal from an airbag acceleration signal, the method comprising the steps of:

converting the analog acceleration signal to a first analog velocity signal;

comparing said first analog velocity signal to a first analog reference signal independent of the analog acceleration signal and corresponding to a first analog velocity, and providing a first output signal if said first velocity signal exceeds said first analog reference signal, and otherwise providing a second output signal; and

performing a logic operation upon the first and second output signals and providing the airbag deployment signal therefrom.

27. The method of claim 26 further including the steps of:

passing the analog acceleration signal through a first low pass filter to provide a low frequency analog acceleration signal corresponding thereto;

converting the low frequency analog acceleration signal to a second analog velocity signal; and

comparing said second analog velocity signal to a second analog reference signal corresponding to a second velocity and providing a third output signal if said second analog velocity signal exceeds said second analog reference signal, and otherwise providing a fourth output signal,

and wherein the logic operation step further includes performing the logic operation upon the third and fourth output signals and providing the airbag deployment signal therefrom.

28. The method of claim 26 further including the step of comparing the analog acceleration signal to a second analog reference signal corresponding to a predetermined acceleration level and providing a third output signal if said analog acceleration signal exceeds said second analog reference signal, and otherwise providing a fourth output signal;

and wherein the logic operation step further includes performing the logic operation upon the third and fourth output signals and providing the airbag deployment signal therefrom.

29. The method of claim 26 further including the steps of:

passing the analog acceleration signal through a low pass filter to provide a low frequency analog acceleration signal corresponding thereto; and

comparing the low frequency analog acceleration signal to a second analog reference signal corresponding to a predetermined acceleration level and providing a third output signal if said low frequency analog acceleration signal exceeds said second analog reference signal, and otherwise providing a fourth output signal;

and wherein the logic operation step further includes performing the logic operation upon the third and fourth output signals and providing the airbag deployment signal therefrom.

30. The method of claim 27 further including the steps of:

comparing the analog acceleration signal to a third analog reference signal corresponding to a first acceleration level and providing a fifth output signal if said analog acceleration signal exceeds said third analog reference signal, and otherwise providing a sixth output signal; and

comparing the low frequency analog acceleration signal to a fourth analog reference signal corresponding to a second acceleration level and providing a seventh output signal if said low frequency analog acceleration signal exceeds said fourth analog reference signal, and otherwise providing an eighth output signal;

and wherein the logic operation step further includes performing the logic operation upon the fifth, sixth, seventh and eighth output signals and providing the airbag deployment signal therefrom.

31. The method of claim 30 wherein said first, third, fifth and seventh output signals correspond to high level output signals, and said second, fourth, sixth and eighth output signals correspond to low level output signals.

32. The method of claim 30 further including the step of passing a conditioned analog accelerometer signal through a second low pass filter to provide the analog acceleration signal.