Method and apparatus for sensing a vehicle crash in the frequency domain

• US 5,109,341 A
• Filed: 05/29/1991
• Issued: 04/28/1992
• Est. Priority Date: 11/03/1989
• Status: Expired due to Term

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Blackburn, Brian K., Gentry, Scott B.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/708,830
• Time in Patent Office: 335 Days
• Field of Search: 364/424.05, 180/274, 180/282, 280/734, 280/735, 307/10.1, 340/436, 340/438, 340/669
• US Class Current: 701/47
• 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 21/0133 by integrating the amplitude of the input signal
• CPC Class Codes: B60R 21/01334 using Fourier analysis
• CPC Class Codes: B60R 21/01336 using filtering

Abstract

A method and apparatus is disclosed for controlling actuation of an air bag restraint system. The apparatus includes a sensor securable to the vehicle for providing a vibratory electric signal having various frequency components indicative of whether the vehicle is in a deployment condition. The particular frequency components indicative of an deployment condition are not present when the vehicle is in a non-deployment condition. A filter circuit is connected to the sensor for providing an electric signal having a value indicative of the value of the particular frequency components indication of the occurrence of a deployment condition that are present in the signal provided by the sensor. A signal generator provides the actuation signal when the signal from the filtering circuit exceeds a predetermined value.

Claims

1. An apparatus for providing an actuation signal for a passenger restraint system in a vehicle upon an occurrence of one of a plurality of predetermined types of vehicle crash conditions, said apparatus comprising:

sensing means securable to the vehicle for providing a vibratory electric signal having frequency components upon the occurrence of a crash condition, each of said predetermined types of vehicle crash conditions having an identifiable frequency component which, for that type of vehicle, has been empirically determined to be indicative of that type of crash condition; and

filter means connected to said sensing means for providing said actuation signal when said sensing means provides a signal that includes one of said identifiable frequency components which has been empirically determined to be indicative of that type of vehicle being in an associated one of said plurality of predetermined types of vehicle crash conditions, each of said identifiable frequency components having a value less than 3000 hertz.

2. The apparatus of claim 1 wherein said identifiable frequency components are not present unless the vehicle is in the predetermined type of vehicle crash condition.

3. The apparatus of claim 1 wherein said sensing means is a mass suspended by cantilever members from a frame secured to the vehicle so that when the vehicle is subjected to a crash condition, said mass vibrates, said sensing means further including resistive elements operatively coupled to said cantilever members, the resistance value of each of said resistive elements varying as said mass vibrates.

4. The apparatus of claim 3 wherein said filter means includes a bandpass filter connected to an output of said sensing means for passing electric signals from said sensing means having said identifiable frequency components indicative of said predetermined types of vehicle crash conditions, said filter means further including an envelope detector for providing a voltage value responsive to the passed frequency components.

5. The apparatus of claim 4 wherein said apparatus further includes a one-shot connected to said envelope detector for providing a pulse signal of a predetermined duration, said pulse being said actuation signal.

6. The apparatus of claim 1 wherein the passenger restraint system is an air bag restraint system.

7. An apparatus for providing an actuation signal for a passenger restraint system in a vehicle upon an occurrence of a predetermined type of vehicle crash condition, said apparatus comprising:

sensing means securable to the vehicle for providing a vibratory electric signal having various frequency components upon the occurrence of a vehicle crash condition;

first filter means connected to said sensing means for passing an electric signal from said sensing means when the signal from said sensing means has particular frequency components indicative of the vehicle being in said predetermined type of crash condition;

first envelope detector means connected to said first filter means for providing a voltage value responsive to the value of the signal from said first filter means;

second filter means connected to said sensing means for passing an electric signal from said sensing means when the signal from said sensing means has particular frequency components indicative of the vehicle not being in said predetermined type of crash condition;

second envelope detector means connected to said second filter means for providing a voltage value responsive to the value of the signal from said second filter means;

summing circuit means connected to said first envelope detector means and to said second envelope detector means for providing a signal having a value indicative of the sum of output signals from said first and second envelope detector means; and

comparative means connected to the summing circuit means and to a voltage reference signal for providing said actuation signal when the value of the signal from said summing circuit means is greater than the value of the reference signal.

8. The apparatus of claim 7 wherein said sensing means is a mass suspended by cantilever members from a frame secured to the vehicle so that when the vehicle is subjected to a crash condition, said mass vibrates, said sensing means further including resistive elements operatively coupled to said cantilever members, the resistance value of each of said resistive elements varying as said mass vibrates.

9. The apparatus of claim 8 wherein said first filter means includes a bandpass filter connected to an output of said sensing means for passing electric signal from said sensing means having said particular frequency components indicative of said predetermined type of vehicle crash condition, and wherein said second filter means includes a bandpass filter connected to an output of said sensing means for passing electric signals from said sensing means having said particular frequency components not indicative of said predetermined type of vehicle crash condition.

10. The apparatus of claim 9 wherein said apparatus further includes a one-shot connected to said comparator means for providing a pulse signal of a predetermined duration, said pulse being said actuation signal.

11. The apparatus of claim 7 wherein the passenger restraint system is an air bag restraint system.

12. An apparatus for providing an actuation signal for a passenger restraint system in a vehicle upon an occurrence of a plurality of possible predetermined types of vehicle crash conditions, said apparatus comprising:

sensing means securable to the vehicle for providing vibratory electric signals having various frequency components indicative of particular types of crash conditions to which the vehicle is subjected;

a plurality of first filter means connected to said sensing means, each said first filter means passing an electric signal from said sensing means when the signal from said sensing means has a particular frequency component indicative of the vehicle being in an associated one of said predetermined types of vehicle crash conditions;

a plurality of first envelope detector means, each said first envelope detector means connected to an associated one of said first filter means for providing a voltage value responsive to the value of the signal passed from its associated first filter means;

a plurality of second filter means connected to said sensing means, each said second filter means passing an electric signal from said sensing means when the signal from said sensing means has a particular frequency component indicative of the vehicle not being in one of said predetermined types of vehicle crash conditions;

a plurality of second envelope detector means, each said second envelope detector means connected to an associated one of said second filter means for providing a voltage value responsive to the value of the signal passed from its associated second filter means;

summing circuit means connected to said plurality of first envelope detector means and to said plurality of second envelope detector means for providing a signal having a value indicative of the sum of output signals from said plurality of first and second envelope detector means; and

comparator means connected to the summing circuit means and to a voltage reference signal for providing said actuator signal when the value of the signal from said summing circuit means is greater than the value of the reference signal.

13. The apparatus of claim 12 wherein said sensing means is a mass suspended by cantilever members from a frame secured to the vehicle so that when the vehicle is subjected to a crash condition, said mass vibrates, said sensing means further including resistive elements operatively coupled to said cantilever members, the resistance value of each of said resistive elements varying as said mass vibrates.

14. The apparatus of claim 13 wherein each said first filter means includes a bandpass filter connected to an output of said sensing means for passing electric signals from said sensing means having said particular frequency component indicative of one of said predetermined types of vehicle crash conditions, and wherein each said second filter means includes a bandpass filter connected to an output of said sensing means for passing electric signals from said sensing means having said particular frequency component not indicative of said predetermined types of vehicle crash conditions.

15. The apparatus of claim 14 wherein said apparatus further includes a one-shot connected to said comparator means for providing a pulse signal of a predetermined duration, said pulse being said actuation signal.

16. The apparatus of claim 12 wherein the passenger restraint system is an air bag restraint system.

17. A method for providing an actuation system for a passenger restraint system in a vehicle upon an occurrence of one of a plurality of predetermined types of vehicle crash conditions, said method comprising the steps of:

providing a vibratory electric signal having particular frequency components upon the occurrence of said predetermined type of crash condition, each of the predetermined types of crash conditions having an identifiable frequency component which, for that type of vehicle, has been empirically determined to be indicative of that type of vehicle crash condition, each of said identifiable frequency components having a value less than 3000 hertz;

filtering said vibratory signal to pass said identifiable frequency components; and

providing said actuation signal when said filtering step passes one of said identifiable frequency components indicative of the vehicle being in one of said predetermined types of vehicle crash conditions.