MAGNETIC CRASH SENSOR

• US 20090001976A1
• Filed: 09/11/2006
• Published: 01/01/2009
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Smith, Richard, Merrick, William, Watson, W., Bauer, Scott, Bomya, Timothy, Baal, James, Cech, Leonard
• Granted Patent: US 7,514,917 B2
• Time in Patent Office: Days
• US Class Current: 324/228
• CPC Class Codes: B60R 2021/0006 Lateral collision
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• 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 time-varying signal is applied to at least one coil in magnetic communication with at least a portion of a vehicle susceptible to deformation responsive to a crash. A sense resistor in series with the at least one coil provides for detecting a current therethrough responsive to a voltage thereacross. The current is responsive to a magnetic condition affecting the magnetic field generated by the at least one coil, responsive to the reluctance of a magnetic circuit with which the at least one coil is in magnetic communication, and responsive to associated eddy currents in proximal conductive elements, responsive to the magnetic field generated by the at least one coil.

Claims

1. A magnetic crash sensor, comprising:

a. at least one coil in magnetic communication with at least a portion of a vehicle, wherein said portion of said vehicle is susceptible to deformation responsive to a crash;

b. a signal source operatively associated with said at least one coil, wherein said signal source provides for generating a first time-varying signal, and said first time-varying signal is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field; and

c. at least one circuit, wherein said at least one circuit comprises at least one sense resistor in series with said at least one coil, said current through said at least one coil and through said at least one sense resistor is responsive to said first signal, said first signal comprises a time-varying voltage applied by said signal source, said current through said at least one coil and through said at least one sense resistor is also responsive to a magnetic condition of said at least one coil, said magnetic condition is responsive to said magnetic communication of said at least one coil with said portion of said vehicle, said at least one circuit generates a second signal responsive to a voltage across said at least one sense resistor.

2. A magnetic crash sensor as recited in claim 1, wherein said at least one coil comprises a plurality of coil elements, wherein said plurality of coil elements are electrically interconnected in series with one another, and said plurality of coil elements are proximate to and are adapted to span a substantial region of a body or structural element of said vehicle, wherein said body or structural element of said vehicle is susceptible to deformation responsive to a crash.

3. A magnetic crash sensor as recited in claim 2, wherein said plurality of coil elements are operatively coupled to a substrate.

4. A magnetic crash sensor as recited in claim 1, further comprising a conductive element adapted to cooperate said at least one coil so as to provide for shaping, controlling or limiting said magnetic field generated by said at least one coil.

5. A magnetic crash sensor as recited in claim 1, wherein said at least one coil is adapted to cooperate with a gap between two portions of a body or structure of said vehicle.

6. A magnetic crash sensor as recited in claim 5, wherein said gap is in series with a magnetic circuit of said vehicle.

7. A magnetic crash sensor as recited in claim 5, wherein at least one axis of a corresponding said at least one coil is oriented substantially perpendicular to a surface bounding said gap.

8. A magnetic crash sensor as recited in claim 5, wherein at least one axis of a corresponding said at least one coil is oriented substantially parallel to a surface bounding said gap.

9. A magnetic crash sensor as recited in claim 5, wherein said at least one coil is bonded to a surface bounding said gap.

10. A magnetic crash sensor as recited in claim 1, wherein said at least one coil comprises a ferromagnetic core.

11. A magnetic crash sensor as recited in claim 1, wherein said at least one coil is operatively coupled to said body or structure of said vehicle with a fastener through a central portion of said at least one coil.

12. A magnetic crash sensor as recited in claim 1, wherein said at least one coil is located between an outward facing surface of said body or structure of said vehicle and an inward facing surface of a proximate door of said vehicle.

13. A magnetic crash sensor as recited in claim 1, wherein at least one said coil comprises a toroidal helical coil.

14. A magnetic crash sensor as recited in claim 1, wherein said signal source comprises a oscillator.

15. A magnetic crash sensor as recited in claim 14, wherein said first time-varying signal comprises a sinusoidal signal.

16. A magnetic crash sensor as recited in claim 1, further comprising at least one conductive element, wherein said at least a portion of said vehicle comprises a first portion of said vehicle, said at least one conductive element is operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said magnetic field generated by said at least one coil induces at least one eddy current in said at least one conductive element.

17. A magnetic crash sensor as recited in claim 16, wherein said at least one conductive element comprises a metal sheet, film or coating of paramagnetic or diamagnetic material that is relatively highly conductive.

18. A magnetic crash sensor as recited in claim 16, wherein said at least one conductive element is operatively coupled to or a part of a portion of said vehicle that is susceptible to deformation responsive to a crash.

19. A magnetic crash sensor as recited in claim 18, wherein said at least one conductive element is operatively coupled to or at least a part of a bumper of said vehicle.

20. A magnetic crash sensor as recited in claim 18, wherein said at least one coil is operatively associated with a first portion of a door of said vehicle, and said at least one conductive element is operatively associated with or at least a part of a second portion of said door of said vehicle.

21. A magnetic crash sensor as recited in claim 18, wherein at least one said conductive element is operatively associated with or at least a part of an outer skin of said door of said vehicle.

22. A magnetic crash sensor as recited in claim 18, wherein at least one said conductive element is operatively associated with or at least a part of a door beam of said door of said vehicle.

23. A magnetic crash sensor as recited in claim 1, wherein said at least one circuit comprises at least one demodulator adapted to generate a third signal responsive to said second signal, and said third signal is responsive to a component of said second signal that is in-phase with said first signal.

24. A magnetic crash sensor as recited in claim 1, wherein said at least one circuit comprises at least one demodulator adapted to generate third and fourth signals responsive to said second signal, said third signal is responsive to a component of said second signal that is in-phase with said first signal, and said fourth signal is responsive to a component of said second signal that is in quadrature-phase with respect to said first signal.

25. A magnetic crash sensor as recited in claim 24, wherein said third signal and fourth signals are responsive to, or provide a measure of, a self-impedance of said at least one coil.

26. A magnetic crash sensor as recited in claim 1, further comprising a safety restraint system, wherein an actuation of said safety restraint system is controlled responsive to said second signal.

27. A magnetic crash sensor as recited in claim 23, wherein an actuation of said safety restraint system is controlled responsive to at least said third signal.

28. A magnetic crash sensor as recited in claim 24, wherein an actuation of said safety restraint system is controlled responsive to at least said third and fourth signals.

29. A magnetic crash sensor as recited in claim 1, wherein said first time-varying signal comprises at least one pulse, said at least one circuit is adapted to charge said at least one coil through said at least one sense resistor with said pulse when said pulse is activated, and said at least one circuit is adapted to discharge said at least one coil through a second resistor after said at least one pulse is deactivated.

30. A magnetic crash sensor as recited in claim 29, wherein said at least one pulse is mono-polar, and said at least one circuit comprises a diode in series with said second resistor, wherein said diode is reverse biased by said at least one pulse.

31. A magnetic crash sensor as recited in claim 29, wherein said at least one pulse is bi-polar, and said at least one circuit comprises a switch in series with said second resistor, wherein said switch is turned off when said at least one pulse is activated, and said switch is turned off when said at least one pulse is deactivated.

32. A magnetic crash sensor as recited in claim 29, wherein said at least one pulse is mono-polar, said at least one circuit comprises a diode in series with said second resistor, wherein said diode is reverse biased by said at least one pulse, and said at least one circuit comprises an H-switch, wherein said H-switch is adapted to control a direction of current through said at least one coil, and said H-switch is adapted to periodically reverse a flow of current through said at least one coil responsive to said at least one pulse.

33. A magnetic crash sensor as recited in claim 1, wherein said first time-varying signal comprises a plurality of sinusoidal signals at a corresponding plurality of different oscillation frequencies.

34. A magnetic crash sensor as recited in claim 1, wherein said at least one circuit comprise at least one of a discrete electrical component, an analog circuit element, a logic circuit element, a logic array, and a computer processor.

35. A magnetic crash sensor, comprising:

a. at least one coil in magnetic communication with at least a portion of a vehicle, wherein said portion of said vehicle is susceptible to deformation responsive to a crash;

b. a signal source operatively associated with said at least one coil, wherein said signal source provides for generating a first time-varying signal, and said first time-varying signal is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field; and

c. at least one circuit, wherein said at least one first circuit comprises a four-arm bridge, a first arm of said four-arm bridge comprises a first resistor connected between a first node and a second node of said four-arm bridge, a second arm of said four-arm bridge comprises said at least one coil connected between said second node and a third node of said four-arm bridge, a third arm of said four-arm bridge comprises an inductance gyrator connected between said third node and a fourth node of said four-arm bridge, a fourth arm of said four-arm bridge comprises a second resistor connected between said first node and fourth nodes of said four-arm bridge, said first signal is operatively coupled across said first and third nodes of said four-arm bridge, and a second signal is generated across said second and fourth nodes of said four-arm bridge, said second signal is responsive to a magnetic condition of said at least one coil, and said magnetic condition is responsive to said magnetic communication of said at least one coil with said portion of said vehicle.

36. A magnetic crash sensor, comprising:

a. at least one coil operatively associated with a first portion of a vehicle;

b. a signal source operatively associated with said at least one coil, wherein a first signal from said signal source is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field;

c. at least one conductive element operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said magnetic field generated by said at least one coil induces at least one eddy current in said at least one conductive element;

d. at least one magnetic sensor adapted to generate a second signal responsive to said magnetic field from said at least one coil responsive to an influence by said at least one eddy current induced in said at least one conductive element by said magnetic field; and

e. at least one circuit adapted to generate a third signal from said second signal, wherein said third signal is at least partially in-phase with said signal source.

37. A magnetic crash sensor as recited in claim 36, wherein said first portion of said vehicle comprises a front cross beam of said vehicle.

38. A magnetic crash sensor as recited in claim 37, wherein at least one said coil is located proximate to a central portion of said front cross beam of said vehicle.

39. A magnetic crash sensor as recited in claim 36, wherein said signal source comprises an oscillator.

41. A magnetic crash sensor as recited in claim 36, wherein said at least one conductive element is operatively coupled to or a part of a portion of said vehicle that is susceptible to deformation responsive to a crash.

42. A magnetic crash sensor as recited in claim 41, wherein said at least one conductive element is operatively coupled to or at least a part of a bumper of said vehicle.

43. A magnetic crash sensor as recited in claim 36, wherein at least one said magnetic sensor comprises a corresponding at least one said coil, and said second signal is responsive to a self-impedance of said corresponding at least one said coil.

44. A magnetic crash sensor as recited in claim 36, wherein at least one said magnetic sensor comprises a coil, a Hall-effect sensor or a giant magnetoresistive (GMR) sensor.

47. A magnetic crash sensor as recited in claim 36, further comprising a safety restraint system, wherein said safety restraint system is actuated responsive to a signal from said at least one magnetic sensor.

48. A magnetic crash sensor as recited in claim 41, wherein said at least one coil is operatively associated with a first portion of a door of said vehicle, and said at least one conductive element is operatively associated with or at least a part of a second portion of said door of said vehicle.

49. A magnetic crash sensor as recited in claim 48, wherein at least one said conductive element is operatively associated with or at least a part of an outer skin of said door of said vehicle.

50. A magnetic crash sensor as recited in claim 49, wherein at least one said conductive element is operatively associated with or at least a part of a door beam of said door of said vehicle.

51. A magnetic crash sensor as recited in claim 48, wherein at least one said conductive element is operatively associated with or at least a part of a door beam of said door of said vehicle.

52. A magnetic crash sensor as recited in claim 48, further comprising at least one accelerometer operatively coupled to said vehicle, wherein a detection of a crash is responsive to a signal from said at least one magnetic sensor and is responsive to a signal from said accelerometer.

53. A magnetic crash sensor as recited in claim 52, wherein said accelerometer is operatively coupled to a structural element of said vehicle proximate to said door of said vehicle.

40. A magnetic crash sensor, comprising:

a. at least one coil operatively associated with a first portion of a vehicle;

b. a signal source operatively associated with said at least one coil, wherein a first signal from said signal source is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field;

c. at least one conductive element operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said magnetic field generated by said at least one coil induces at least one eddy current in said at least one conductive element, and said at least one conductive element comprises a metal sheet, film or coating of paramagnetic or diamagnetic material that is relatively highly conductive; and

d. at least one magnetic sensor adapted to generate a second signal responsive to said magnetic field from said at least one coil responsive to an influence by said at least one eddy current induced in said at least one conductive element by said magnetic field.

45. A magnetic crash sensor, comprising:

a. at least one coil operatively associated with a first portion of a vehicle;

b. a signal source operatively associated with said at least one coil, wherein a first signal from said signal source is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field;

c. at least one conductive element operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said magnetic field generated by said at least one coil induces at least one eddy current in said at least one conductive; and

d. at least one magnetic sensor adapted to generate a second signal responsive to said magnetic field from said at least one coil responsive to an influence by said at least one eddy current induced in said at least one conductive element by said magnetic field, wherein said at least one magnetic sensor is displaced from said at least one coil.

46. A magnetic crash sensor, comprising:

a. at least one coil operatively associated with a first portion of a vehicle;

b. a signal source operatively associated with said at least one coil, wherein a first signal from said signal source is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field;

c. at least one conductive element operatively associated with or at least a part of a second portion of said vehicle, wherein said at least one conductive element is located so that said magnetic field generated by said at least one coil induces at least one eddy current in said at least one conductive; and

d. at least one magnetic sensor adapted to generate a second signal responsive to said magnetic field from said at least one coil responsive to an influence by said at least one eddy current induced in said at least one conductive element by said magnetic field, wherein said at least one magnetic sensor comprises a plurality of magnetic sensors that are relatively distal with respect to said at least one coil.

54. A method of sensing a crash, comprising:

a. generating at least one magnetic field in a vehicle, wherein the operation of generating said at least one magnetic field is responsive to a first time-varying signal;

b. operatively associating at least one conductive element with a portion of a vehicle that is susceptible to a crash;

c. generating at least one eddy current in said conductive element responsive to said at least one magnetic field; and

d. sensing said magnetic field responsive to said at least one eddy current, wherein the operation of sensing said magnetic field comprises sensing at least an in-phase component of at least one second time-varying signal responsive to said magnetic field, and said in-phase component is in-phase relative to said first time-varying signal.