Magnetic crash sensing method

• US 20050096881A1
• Filed: 09/20/2004
• Published: 05/05/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Watson, William Todd, Cech, Leonard S., Rice, Debra A.
• Granted Patent: US 7,113,874 B2
• Time in Patent Office: Days
• US Class Current: 702/190
• CPC Class Codes: B60R 2021/0006 Lateral collision
• CPC Class Codes: B60R 2021/01177 Misdeployment, e.g. during assembly, disassembly, accident salvage or recycling
• 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 signal generated responsive to a magnetic field in a magnetic circuit is decomposed into first and second filtered signals, wherein, at at least one first frequency, a magnitude of a component of the first filtered signal is greater than that of the second filtered signal, and at at least one second frequency greater than the at least one first frequency, a magnitude of a component of the second filtered signal is greater than that of the first filtered signal. A condition of a magnetic circuit is sensed responsive to the first and second filtered signals. In one embodiment, actuation of a safety restraint actuator of a vehicle is controlled responsive to the sensed condition of the magnetic circuit that includes a portion of the vehicle susceptible to a crash. A deployment threshold is adjusted responsive to a door opening state.

Claims

1. A method of sensing a condition of a magnetic circuit, comprising:

a. generating at least one signal responsive to at least one magnetic field in at least one magnetic circuit;

b. filtering said at least one signal with at least one first filter so as to generate a corresponding at least one first filtered signal;

c. filtering said at least one signal with at least one second filter so as to generate a corresponding at least one second filtered signal, wherein said at least one first filter and said at least one second filter are adapted so that a magnitude of a component of said at least one first filtered signal at at least one first frequency is greater than a magnitude of a component of said at least one second filtered signal at said at least one first frequency, and a magnitude of a component of said at least one second filtered signal at at least one second frequency is greater than a magnitude of a component of said at least one first filtered signal at said at least one second frequency, wherein said at least one second frequency is greater than said at least one first frequency; and

d. sensing a condition of said at least one magnetic circuit responsive to said at least one first filtered signal and responsive to said at least one second filtered signal.

2. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein said at least one signal is generated by at least one magnetic sensor operatively associated with at least one first location of said at least one magnetic circuit and at least a portion of said at least one magnetic field is generated by at least one first coil operatively associated with a second location of said at least one magnetic circuit.

3. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein said at least one signal is responsive to a self-inductance of at least one first coil operatively associated with said at least one magnetic circuit.

4. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein said at least one signal is responsive to at least one time-varying magnetic field, and at least a portion of said at least one time-varying magnetic field is generated in said at least one magnetic circuit by at least one first coil operatively associated with said at least one magnetic circuit responsive to at least one time-varying signal operatively associated with said at least one first coil.

5. A method of sensing a condition of a magnetic circuit as recited in claim 4, wherein the operation of generating said at least one signal comprises demodulating at least one signal responsive to said at least one magnetic field.

6. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein said at least one magnetic circuit comprises a body of a vehicle.

7. A method of sensing a condition of a magnetic circuit as recited in claim 6, wherein said at least one magnetic circuit comprises at least one door of said vehicle.

8. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein the operation of sensing a condition of said at least one magnetic circuit comprises a sensing algorithm with an entrance criteria and an exit criteria, upon or after satisfaction of said entrance criteria, said sensing algorithm is entered, and upon or after satisfaction of said exit criteria, said sensing algorithm is exited.

9. A method of sensing a condition of a magnetic circuit as recited in claim 8, wherein said satisfaction of said entrance criteria is responsive to said at least one first filtered signal.

10. A method of sensing a condition of a magnetic circuit as recited in claim 8, wherein upon or after said satisfaction of said entrance criteria, at least one data element associated with said sensing algorithm is initialized.

11. A method of sensing a condition of a magnetic circuit as recited in claim 8, wherein the operation of filtering said at least one signal with at least one second filter commences after said entrance criteria is satisfied.

12. A method of sensing a condition of a magnetic circuit as recited in claim 8, further comprising detecting an opening state of at least one door of said vehicle from said at least one first filtered signal, and not entering said sensing algorithm if said opening state of said at least one door comprises either an open said at least one door or a recent forceful closure of said at least one door.

13. A method of sensing a condition of a magnetic circuit as recited in claim 1, further comprising generating at least one AC measure responsive to said at least one signal and to said at least one second filtered signal, wherein the operation of sensing said condition of said at least one magnetic circuit is responsive to said at least one AC measure.

14. A method of sensing a condition of a magnetic circuit as recited in claim 13, wherein said at least one AC measure comprises a summation of an absolute value of a difference between said at least one signal and said at least one second filtered signal, and said summation extends over a recent period of time.

15. A method of sensing a condition of a magnetic circuit as recited in claim 1, further comprising generating at least one first metric as a corresponding at least one combination of said at least one first filtered signal and said at least one AC measure, wherein the operation of sensing said condition of said at least one magnetic circuit is responsive to said at least one first metric.

16. A method of sensing a condition of a magnetic circuit as recited in claim 15, wherein a relative weighting of said at least one first filtered signal and said at least one AC measure in said at least oner combination is responsive to said at least one first filtered signal.

17. A method of sensing a condition of a magnetic circuit as recited in claim 16, wherein if said at least one first filtered signal does not exceed a threshold, then said at least one first metric is set equal to said at least one first filtered signal.

18. A method of sensing a condition of a magnetic circuit as recited in claim 15, wherein a relative weighting of said at least one first filtered signal and said at least one AC measure in said at least one combination is responsive to transition-smoothing factor, wherein said transition-smoothing factor is incremented or decremented responsive to whether or not said at least one first filtered signal exceeds a threshold.

19. A method of sensing a condition of a magnetic circuit as recited in claim 18, wherein said transition-smoothing factor is bounded.

20. A method of sensing a condition of a magnetic circuit as recited in claim 15, further comprising damping said at least one first metric over time.

21. A method of sensing a condition of a magnetic circuit as recited in claim 1, further comprising generating at a second metric, wherein said second metric is a combination of a first said first metric and a second said first metric, wherein said first said first metric is responsive to a condition of a first door of a vehicle, and a second said first metric is responsive to a condition of a second door of said vehicle, wherein said first and second doors are on a same side of said vehicle.

22. A method of sensing a condition of a magnetic circuit as recited in claim 21, further comprising damping said second metric over time.

23. A method of sensing a condition of a magnetic circuit as recited in claim 1, wherein said at least one magnetic circuit comprises at least a portion of a vehicle susceptible to a crash, further comprising determining whether or not to actuate a safety restraint actuator responsive to the operation of sensing a condition of said at least one magnetic circuit.

24. A method of sensing a condition of a magnetic circuit as recited in claim 23, further comprising detecting an opening state of at least one door of said vehicle from said at least one first filtered signal, and preventing actuation of said safety restraint actuator if said opening state of said at least one door comprises either an open said at least one door or a recent forceful closure of said at least one door.

25. A method of sensing a condition of a magnetic circuit as recited in claim 23, wherein the operation of determining whether or not to actuate said safety restraint actuator is responsive to a deployment threshold, and said deployment threshold is responsive to at least one door opening state of at least one door of said vehicle.

26. A method of sensing a condition of a magnetic circuit as recited in claim 23, further comprising determining if a safing criteria is satisfied, wherein the operation of determining whether or not to actuate a safety restraint actuator responsive to the operation of determining if said safing criteria is satisfied.

27. A method of sensing a condition of a magnetic circuit as recited in claim 26, wherein the operation of determining if a safing criteria is satisfied is responsive to a plurality said signals responsive to said at least one magnetic field, wherein at least two of said plurality of said signals are associated with different magnetic circuits.

28. A method of sensing a condition of a magnetic circuit as recited in claim 26, wherein the operation of determining if a safing criteria is responsive to at least one signal used to generate at least a portion of said at least one magnetic field in said at least one magnetic circuit.

29. A method of providing for sensing a condition of a magnetic circuit, comprising:

a. providing for generating at least one signal responsive to at least one magnetic field in at least one magnetic circuit;

b. providing for filtering said at least one signal with at least one first filter so as to generate a corresponding at least one first filtered signal;

c. providing for filtering said at least one signal with at least one second filter so as to generate a corresponding at least one second filtered signal, wherein said at least one first filter and said at least one second filter are adapted so that a magnitude of a component of said at least one first filtered signal at at least one first frequency is greater than a magnitude of a component of said at least one second filtered signal at said at least one first frequency, and a magnitude of a component of said at least one second filtered signal at at least one second frequency is greater than a magnitude of a component of said at least one first filtered signal at said at least one second frequency; and

d. providing for sensing a condition of said at least one magnetic circuit responsive to said at least one first filtered signal and responsive to said at least one second filtered signal.