Crash sensing via piezoelectric sensors

• US 7,702,439 B2
• Filed: 06/24/2004
• Issued: 04/20/2010
• Est. Priority Date: 06/25/2003
• Status: Active Grant

• Current Assignee: Methode Electronics Incorporated
• Original Assignee: Methode Electronics Incorporated
• Inventors: Kithil, Philip
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US10/562,442
• Publication Number:
  US 20060241834A1
• Time in Patent Office: 2,126 Days
• Field of Search: 701 45- 47, 280/728.1, 280734-735, 340/438
• US Class Current: 701/45
• CPC Class Codes: B60R 2021/01302 monitoring vehicle body vibrations or noise
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

A system and method for characterizing piezoelectric sensor responses for automotive vehicle crash analysis, is disclosed. The method employs Daubechies wavelet analysis (1006) to plot signal response amplitudes (1008) in three-dimensional space of at least one piezoelectric sensor. A cluster, signifying a combination of Daubechies amplitudes of the at least one piezoelectric sensor in three-dimensional space, is compared to reference clusters (1010) stored in the automotive vehicle. Based on results from comparing the cluster to the reference clusters, instructions are transmitted to an occupant restraint control system (1013) in the vehicle to deploy a specific airbag at a specific power level.

Claims

1. A method for characterizing piezoelectric sensor signal responses for automotive vehicle crash analysis, said method comprising:

providing at least one piezoelectric sensor mounted at a predetermined locations on the automotive vehicle;

sampling a response from the piezoelectric sensor for a predetermined period of time;

subjecting the response from the piezoelectric sensor to a wavelet analysis and obtaining signal amplitudes;

plotting the signal amplitudes in three-dimensional space and forming a cluster of signal amplitudes;

comparing a most recent cluster to reference clusters that are indicative of both crash and non-crash events; and

providing instructions to an occupant restraint control system in the automotive vehicle.

2. The method of claim 1, further comprising providing three polyvinylidene fluoride piezoelectric sensors mounted at predetermined locations on a transparency product of the automotive vehicle.

3. The method of claim 2, wherein the transparency product is a windshield.

4. The method of claim 3, comprising applying a Daubechies transfer function in the wavelet analysis.

13. The method of claim 1, further comprising:

combining the signal amplitudes and plotting a commonality point of the signal amplitudes in three-dimensional space;

comparing commonality points of most recent signal amplitudes to a library including a memory of reference commonality points of signal amplitudes; and

instructing deployment of at least one airbag using results from comparing the most recent commonality points of signal amplitudes to the reference commonality points of signal amplitudes.

5. A method for characterizing piezoelectric sensor signal responses for automobile crash analysis, said method comprising:

providing at least three polyvinylidene fluoride piezoelectric sensors;

mounting the three polyvinylidene fluoride piezoelectric sensors on a windshield of the automobile;

sampling responses from the three polyvinylidene fluoride piezoelectric sensors to a Daubechies wavelet analysis and obtaining Daubechies amplitudes for each polyvinylidene fluoride piezoelectric sensor;

aggregating the Daubechies amplitudes from the three polyvinylidene fluoride piezoelectric sensors and plotting the intersection of the Daubechies amplitudes and forming a cluster of the Daubechies amplitudes.

6. The method of claim 5, comprising providing a fourth polyvinylidene fluoride piezoelectric sensor.

7. The method of claim 5, comprising incorporating the fourth polyvinylidene fluoride piezoelectric sensor into a rear-view mirror mounting button of the automobile.

8. The method of claim 5, further comprising using orthogonal single-axis polyvinylidene fluoride piezoelectric sensors.

9. The method of claim 5, further comprising using a dual signal path integrated circuit for sampling responses from the polyvinylidene fluoride piezoelectric sensors.

10. The method of claim 5, wherein at least one application-specific integrated circuit controls the method.

11. The method of claim 10, further comprising locating the at least one application-specific integrated circuit in at least one piezoelectric sensor.

12. The method of claim 10, further comprising locating the at least one application-specific integrated circuit within the occupant restraint control system.

14. A method for characterizing a response from a sensor used for automotive vehicle crash analysis, said method comprising:

providing at least one sensor mounted at a predetermined location on the automotive vehicle;

sampling a response from the sensor for a predetermined period of time;

subjecting the response from the sensor to a wavelet analysis and obtaining signal amplitudes;

plotting the signal amplitudes in three-dimensional space and forming a cluster of signal amplitudes;

comparing a most recent cluster to reference clusters that are indicative of both crash and non-crash events; and

providing instructions to an occupant restraint control system in the automotive vehicle.

15. The method of claim 14, wherein the sensor is a piezoelectric sensor.