IMPACT SENSOR CALIBRATION TOOL

• US 20120130586A1
• Filed: 11/18/2010
• Published: 05/24/2012
• Est. Priority Date: 11/18/2010
• Status: Active Grant

• Current Assignee: Id Systems Incorporated (PowerFleet, Inc.)
• Original Assignee: Id Systems Incorporated (PowerFleet, Inc.)
• Inventors: EHRMAN, MICHAEL, EHRMAN, KENNETH, SMAIL, SCOTT, CHARITONOS, MICHAEL
• Granted Patent: US 8,762,009 B2
• Time in Patent Office: Days
• US Class Current: 701/32.2
• CPC Class Codes: B60R 21/01 Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents electrical circuits for transmission of signals between steering wheel and the vehicle itself B60R16/027; for electrically actuating belt retractor locking means B60R22/343

Abstract

An impact sensor calibration tool, wherein an impact sensor is installed on a vehicle and in wireless communication with a processor, which analyzes data reported by the impact sensor. Specifically, the impact sensor of the present invention continuously measures two dimensional acceleration of a vehicle. Changes in vehicle acceleration create impulse data and the impact sensor reports this data to a processor. The processor performs statistical calculations on the data to identify the vehicle'"'"'s normal use operation and from this, develops an impact threshold wherein impulses exceeding this threshold are identified as impacts. The impacts may be further characterized as real impacts and stored in memory for subsequent analysis.

Claims

1. A method of determining vehicle impact events, comprising:

sensing vehicle acceleration data;

determining vehicle impulse data based on changes in vehicle acceleration;

performing statistical calculations on impulse data;

setting an impact threshold based on the statistical calculations;

identifying vehicle impulse data that exceeds the impact threshold as impacts;

characterizing the impact as normal use or a real impact; and

recording real impacts for subsequent analysis.

2. The method of claim 1, wherein the impact threshold is continuously set based on current vehicle impulse data and historical vehicle impulse data.

3. The method of claim 1, wherein sensing vehicle acceleration data comprises sensing two-dimensional vehicle acceleration data.

4. The method of claim 1, wherein performing statistical calculations on impulse data comprises:

calculating a recursive average; and

calculating a recursive standard deviation

5. The method of claim 4, wherein calculating the recursive standard deviation comprises utilizing a function that approximates standard deviation, wherein the function returns an integer approximation.

6. The method of claim 4, wherein impulses less than or substantially equal to a sum of the recursive average and the recursive standard deviation are normal use events.

7. The method of claim 4, wherein impulses greater than a sum of the recursive average and the recursive standard deviation are impacts.

8. The method of claim 1, wherein characterizing the impact as a normal use impact or a real impact comprises:

identifying a duration of time a vehicle impulse lasts; and

comparing vehicle impulse data to a sustain sample.

9. The method of claim 1, further comprising calculating an impulse energy level of real impacts.

10. The method of claim 9, wherein calculating the impulse energy level of real impacts comprises:

identifying a maximum impulse of the real impact;

identifying a duration of real impact impulses; and

comparing real impact impulses with a sustain sample.

11. The method of claim 1, further comprising:

tracking a vehicle using a global positioning system, wherein the global positioning system is adapted to assist with setting the impact threshold.

12. The method of claim 1, further comprising:

uploading the impacts with a confidence level, wherein the confidence level provides an indication of how effectively the statistical calculations are working.

13. The method of claim 1, further comprising categorizing the impacts by impact direction.

14. A method of determining vehicle impact events, comprising:

sensing vehicle acceleration data;

determining vehicle impulse data based on changes in vehicle acceleration;

performing statistical calculations on impulse data;

setting an impact threshold based on the statistical calculations;

identifying vehicle impulse data that exceeds the impact threshold as impacts;

characterizing the impact as normal use or a real impact;

calculating an impulse energy level of real impacts; and

recording real impacts for subsequent analysis.

15. A computer readable medium having program instructions tangibly stored thereon executable by a processor to perform a method for continuously sensing vehicle impact events, comprising:

receiving vehicle impulse data from an impact sensor based on changes in vehicle acceleration;

performing statistical calculations on impulse data;

setting an impact threshold based on the statistical calculations;

identifying vehicle impulse data that exceeds the impact threshold as impacts;

characterizing the impact as normal use or a real impact; and

recording real impacts for subsequent analysis.

16. The computer readable medium of claim 15, wherein the impact threshold is continuously set based on current vehicle impulse data and historical vehicle impulse data.

17. The computer readable medium of claim 15, wherein performing statistical calculations on impulse data comprises:

calculating a recursive average; and

calculating a recursive standard deviation

18. The computer readable medium of claim 17, wherein calculating the recursive standard deviation comprises utilizing a function that approximates standard deviation, wherein the function returns an integer approximation.

19. The computer readable medium of claim 17, wherein impulses less than or substantially equal to a sum of the recursive average and the recursive standard deviation are normal use events.

20. The computer readable medium of claim 17, wherein impulses greater than a sum of the recursive average and the recursive standard deviation are impacts.

21. The computer readable medium of claim 15, wherein characterizing the impact as a normal use impact or a real impact comprises:

identifying a duration of time a vehicle impulse lasts; and

comparing vehicle impulse data to a sustain sample.

22. The method of claim 15, further comprising calculating an impulse energy level of real impacts.