Method and installation for detecting certain parameters concerning an auxiliary child seat with a view to controlling the operation of the airbags of a vehicle

• US 5,851,026 A
• Filed: 03/26/1997
• Issued: 12/22/1998
• Est. Priority Date: 10/17/1994
• Status: Expired due to Term

• Current Assignee: IEE - International Electronics & Engineering S.A.
• Original Assignee: IEE - International Electronics & Engineering S.A.
• Inventors: Schoos, Aloyse, Witte, Michel
• Primary Examiner(s): English, Peter C.
• Application Number:
  US08/829,702
• Time in Patent Office: 636 Days
• Field of Search: 280/735, 280/734, 280/732, 280/730.1, 280/728.1, 180/273, 180/272, 340/572, 340/667, 340/666, 297/250.1, 297/216.11
• US Class Current: 280/735
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/28 Seats readily mountable on, and dismountable from, existing seats or other parts of the vehicle
• CPC Class Codes: B60N 2/2863 backward facing
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/01556 Child-seat detection systems

Abstract

A system to detect certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system. The system uses inductive electromagnetic emitter, inductive electromagnetic receiver, and resonant circuits to detect various parameters concerning the child seat. Some of the parameters include the presence of a child seat, the orientation of the child seat, and the type of child seat present. These parameters are transmitted to an airbag control unit for adapting the deployment of the airbag to the specific circumstances as indicated by the inductive and resonant circuits. The transmitted information allows the airbag control unit to disable the airbag in certain situations where it is not needed.

Claims

1. A method for detecting certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system, said parameters being used to adapt the deployment of the airbag protection system associated with said passenger seat to specific circumstances determined by these parameters, said method using at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit being incorporated into the passenger seat of the vehicle which is protected by the airbag protection system, and at least one resonant circuit incorporated into a base of said child seat, provided that there are used at least two electromagnetic induction emitter circuits or at least two electromagnetic induction receiver circuits or at least two resonant circuits, said method comprising the steps of;

detecting presence of the child seat irrespective of orientation by detecting an influence on an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit, said coupling being influenced by said at least one resonant circuit, and

detecting orientation of the child seat when the child seat is present by analyzing the influence of said at least one resonant circuit on the electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit.

2. A method according to claim 1, wherein said at least one electromagnetic emitter circuit emits an excitation frequency, the excitation frequency being varied periodically within a band of predetermined frequencies.

3. A method according to claim 1, comprising the step of modulating the electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit with a characteristic modulation.

4. A method according to claim 3, comprising the step of analyzing the modulation of a signal of said at least one electromagnetic induction receiver circuit.

5. A method according to claim 3, wherein the modulation of the electromagnetic coupling is achieved by switching the resonant frequency of said at least one resonant circuit.

6. A method according to claim 3, wherein the modulation of the electromagnetic coupling is achieved with a subcarrier frequency synchronous with an excitation frequency of said at least one electromagnetic induction emitter circuit.

7. A method according to claim 3, comprising the step of using a demodulation circuit to demodulate a signal of said at least one electromagnetic induction receiver circuit.

8. A method according to claim 7, comprising the step of synchronizing the demodulation circuit with an excitation signal produced by said at least one electromagnetic induction emitter circuit, and comparing the excitation signal produced by said at least one electromagnetic induction emitter circuit for coincidence with a signal received by said at least one electromagnetic induction receiver circuit.

9. A method according to claim 3, comprising the step of modulating an inductive coupling of said at least one resonant circuit using a pseudo-random binary sequence imposed on said at least one resonant circuit.

10. A method according to claim 1, further comprising the step of detecting the lateral and/or longitudinal position of the child seat with respect to the passenger seat.

11. A method according to claim 1, further comprising the step of detecting the vertical position of the child seat with respect to the passenger seat.

12. A method according to claim 1, further comprising the step of detecting a deviation of the longitudinal axis of the child seat from the longitudinal axis of the passenger seat.

13. A system for detecting certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system, said parameters being used to adapt the deployment of the airbag protection system associated with said passenger seat to specific circumstances determined by these parameters, comprising:

at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit being incorporated into the passenger seat of the vehicle which is protected by the airbag protection system;

at least one resonant circuit incorporated into a base of said child seat and positioned, when the child seat is placed on the passenger seat, to influence an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit so as to cause said at least one electromagnetic induction receiver circuit to deliver a signal representing at least one of the parameters;

wherein the system comprises at least two electromagnetic induction emitter circuits or at least two electromagnetic induction receiver circuits or at least two resonant circuits, the arrangement of said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit in the passenger seat and the arrangement of said at least one resonant circuit in the child seat being in such a way that;

presence of the child seat is detectable irrespective of orientation, and

orientation of the child seat is detectable when the child seat is present.

14. A system according to claim 13, wherein said at least one resonant circuit incorporated into the child seat includes a flat coil associated with an electronic circuit intended to modulate the electromagnetic coupling with characteristic information.

15. A system according to claim 13, wherein said at least one resonant circuit incorporated into the child seat has a resonant frequency and includes means for switching the resonant frequency of said at least one resonant circuit, the switching of the resonant frequency thereby modulating the electromagnetic coupling.

16. A system according to claim 13, wherein said at least one electromagnetic induction emitter circuit includes at least one elongate inductive structure extending over a lateral side of the passenger seat, said at least one resonant circuit includes at least one inductive coil situated laterally in the base of the child seat, and said at least one elongate inductive structure in the passenger seat and said at least one inductive coil in the child seat are sized such that their superficial dimensions are greater than or comparable with the vertical distance between said at least one elongate inductive structure in the passenger seat and said at least one inductive coil in the child seat.

17. A system according to claim 16, wherein each lateral side of the passenger seat contains at least one inductive emitter structure.

18. A system according to claim 16, wherein each inductive emitter structure is formed on a flexible thin film incorporated into the seat.

19. A system according to claim 13, wherein said at least one electromagnetic induction receiver circuit includes at least one elongate inductive structure extending over a lateral side of the passenger seat, said at least one resonant circuit includes at least one inductive coil situated laterally in the base of the child seat, and said at least one elongate inductive structure in the passenger seat and said at least one inductive coil in the child seat are sized such that their superficial dimensions are greater than or comparable with the vertical distance between said at least one elongate inductive structure in the passenger seat and said at least one inductive coil in the child seat.

20. A system according to claim 19, wherein each lateral side of the passenger seat contains at least one inductive receiver structure.

21. A system according to claim 19, wherein each inductive receiver structure is formed on a flexible thin film incorporated into the seat.

22. A system according to claim 13, including at least two resonant circuits, each resonant circuit including at least one inductive coil situated laterally in the base of the child seat, wherein each lateral side of the child seat contains at least one inductive coil.

23. A system for detecting certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system, said parameters being used to adapt the deployment of the airbag protection system associated with said passenger seat to specific circumstances determined by these parameters, comprising:

at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, wherein the system comprises at least two electromagnetic emitter circuits if only one receiver circuit is present and at least two receiver circuits if only one emitter circuit is present, said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit being incorporated into the passenger seat of the vehicle which is protected by the airbag protection system; and

at least one resonant circuit incorporated into a base of said child seat and positioned, when the child seat is placed on the passenger seat, to influence an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit so as to cause said at least one electromagnetic induction receiver circuit to deliver a signal providing means for determining the location of the resonant circuit with respect to said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit.

24. A system according to claim 23, comprising two electromagnetic induction emitter circuits and one electromagnetic induction receiver circuit, said electromagnetic induction receiver circuit being arranged so that coupling between each of the two electromagnetic induction emitter circuits and said electromagnetic induction receiver circuit occurs.

25. A system according to claim 23, comprising one electromagnetic induction emitter circuit and two electromagnetic induction receiver circuits, said electromagnetic induction emitter circuit being arranged so that coupling between said electromagnetic induction emitter circuit and each of the two electromagnetic induction receiver circuits occurs.

26. A system according to claim 23, wherein said at least one resonant circuit is associated with electronic modulation circuit means for modulating the electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit with a characteristic modulation.

27. A system according to claim 26, wherein the means for modulating the electromagnetic coupling comprises means for switching of a resonant frequency of said at least one resonant circuit.

28. A system according to claim 27, wherein the modulation of the electromagnetic coupling is achieved with a subcarrier frequency synchronous with an excitation generator.

29. A system according to claim 28, wherein the electronic modulation circuit means comprises at least one frequency divider for providing of a synchronous subcarrier frequency.

30. A system according to claim 28, wherein means is provided for modulating an inductive coupling by said at least one resonant circuit using a pseudo-random binary sequence imposed on said at least one resonant circuit.

31. A system according to claim 26 comprising at least two resonant circuits, wherein distinct resonant circuits comprise means for modulating the electromagnetic coupling with a distinct modulation, the distinct modulation of each resonant circuit providing means for distinguishing between the respective resonant circuits.

32. A system according to claim 31, wherein the modulation of the electromagnetic coupling by each of the resonant circuits is achieved with a subcarrier frequency synchronous with an excitation generator and wherein the subcarrier frequencies of each of the resonant circuits are different.

33. A system according to claim 23, wherein said at least one electromagnetic induction emitter circuit incorporates an oscillator operating at a given frequency.

34. A system according to claim 33, wherein said at least one electromagnetic induction receiver circuit incorporates a demodulation circuit.

35. A system according to claim 34, including means for synchronizing the demodulation circuit with an excitation signal produced by the oscillator, and wherein the excitation signal produced by the oscillator is compared for coincidence with a signal received by said at least one electromagnetic induction receiver circuit.

36. A system according to claim 23, wherein said at least one electromagnetic emitter circuit emits an excitation frequency and means is provided for periodically varying the excitation frequency within a band of predetermined frequencies.

38. A system according to claim 31, wherein the means for modulating the electromagnetic coupling comprises at least one frequency divider providing a synchronous subcarrier frequency.

39. A system according to claim 38, wherein each resonant circuit has a distinct subcarrier frequency.

37. A system for detecting certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system so that the parameters are used to adapt the deployment of the airbag protection system associated with the seat supporting said auxiliary seat according to the parameters detected, comprising:

at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit being incorporated into the passenger seat of the vehicle which is protected by the airbag protection system;

at least two resonant circuits incorporated into a base of the child seat and positioned, when the child seat is placed on the passenger seat, to influence an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit so as to cause said at least one electromagnetic induction receiver circuit to deliver a signal representing at least one of the parameters;

wherein each resonant circuit is associated with electronic modulation circuit means for modulating the electromagnetic coupling with a distinct modulation, the distinct modulation of each resonant circuit providing means for distinguishing between the respective resonant circuits, said at least one electromagnetic induction emitter circuit incorporating an oscillator operating at a given frequency and each resonant circuit in the child seat modulating the resonant frequency with a subcarrier frequency synchronous with the oscillator.

40. A system according to claim 37, wherein said at least one electromagnetic induction receiver circuit incorporates a demodulation circuit.

41. A system according to claim 40, including means for synchronizing said demodulation circuit with an excitation signal produced by said oscillator, and wherein the excitation signal produced by said oscillator is compared for coincidence with a signal received by said at least one electromagnetic induction receiver circuit.

42. A system for detecting certain parameters concerning an auxiliary child seat placed on a passenger seat of a motor vehicle equipped with an airbag protection system so that the parameters are used to adapt the deployment of the airbag protection system associated with the seat supporting said auxiliary seat according to the parameters detected, comprising:

at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit being incorporated into the passenger seat of the vehicle which is protected by the airbag protection system;

at least two resonant circuits incorporated into a base of the child seat and positioned, when the child seat is placed on the passenger seat, to influence an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit so as to cause said at least one electromagnetic induction receiver circuit to deliver a signal representing at least one of the parameters;

wherein each resonant circuit is associated with electronic modulation circuit means for modulating the electromagnetic coupling with a distinct modulation, the distinct modulation of each resonant circuit providing means for distinguishing between the respective resonant circuits, and means is provided for modulating an inductive coupling of the resonant circuits using a pseudo-random binary sequence imposed on the resonant circuits.

43. An auxiliary child seat for installing on a passenger seat of a motor vehicle, the passenger seat having at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, the child seat comprising at least two resonant circuits incorporated therein and arranged for cooperating with said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit in order to determine certain parameters concerning said auxiliary child seat.

44. An auxiliary child seat according to claim 43, wherein an electromagnetic coupling exists between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit, said at least two resonant circuits comprising means adapted for influencing the electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit so as to cause said at least one electromagnetic induction receiver circuit to deliver a signal representing at least one of the parameters.

45. An auxiliary child seat according to claim 44, wherein each resonant circuit is associated with electronic modulation circuit means adapted for modulating the electromagnetic coupling with a distinct modulation, the distinct modulation of each resonant circuit providing means for distinguishing between the respective resonant circuits.

46. An auxiliary child seat according to claim 45, wherein each resonant circuit has a resonant frequency and includes means for switching the resonant frequency of each resonant circuit, the switching of the resonant frequency thereby adapted for modulating the electromagnetic coupling.

47. An auxiliary child seat according to claim 46, wherein said at least one electromagnetic induction emitter circuit in the passenger seat of the vehicle has an exciting frequency, each resonant circuit in the child seat modulating the resonant frequency with a subcarrier frequency adapted to be synchronous with the exciting frequency.

48. An auxiliary child seat according to claim 47, wherein the electronic modulation circuit means comprises at least one frequency divider for providing of a synchronous subcarrier frequency.

49. An auxiliary child seat according to claim 48, wherein each resonant circuit has a distinct subcarrier frequency.

50. An auxiliary child seat according to claim 45, wherein means is provided for modulating an inductive coupling of the resonant circuits using a pseudo-random binary sequence imposed on the resonant circuits.

51. An auxiliary child seat according to claim 44, wherein each resonant circuit comprises a flat coil associated with an electronic circuit adapted for modulating the electromagnetic coupling with characteristic information.

52. A resonant circuit adapted for installation in an auxiliary child seat installed on a passenger seat of a vehicle, the passenger seat having at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, the passenger seat having at least two emitter circuits if only one receiver circuit is present and at least two receiver circuits if only one emitter circuit is present, the resonant circuit comprising means adapted for influencing an electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit.

53. A resonant circuit according to claim 52 wherein the electromagnetic coupling exists between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit in the passenger seat, said resonant circuit being associated with electronic modulation circuit means adapted for modulating the electromagnetic coupling with a characteristic modulation.

54. A resonant circuit according to claim 53, comprising a flat coil associated with an electronic circuit adapted for modulating the electromagnetic coupling with characteristic information.

55. A resonant circuit according to claim 53, having a resonant frequency and comprising means for switching said resonant frequency, the switching of the resonant frequency thereby adapted for modulating the electromagnetic coupling.

56. A resonant circuit according to claim 55, wherein said at least one electromagnetic induction emitter circuit of the passenger seat has an exciting frequency, the resonant circuit modulating the resonant frequency with a subcarrier frequency adapted to be synchronous with the exciting frequency.

57. A resonant circuit according to claim 56, wherein the electronic modulation circuit means comprises at least one frequency divider for providing of a synchronous subcarrier frequency.

58. A resonant circuit according to claim 55, wherein means is provided for modulating an inductive coupling of the resonant circuit using a pseudo-random binary sequence imposed on the resonant circuit.

59. A pair of resonant circuits for incorporating in an auxiliary child seat for installing on a passenger seat of a motor vehicle, the passenger seat having at least one electromagnetic induction emitter circuit and at least one electromagnetic induction receiver circuit, an electromagnetic coupling existing between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit, said pair of resonant circuits adapted for influencing the electromagnetic coupling between said at least one electromagnetic induction emitter circuit and said at least one electromagnetic induction receiver circuit, wherein the resonant circuits of said pair of resonant circuits have different resonant frequencies.

61. A pair of resonant circuits according to claim 59, each resonant circuit comprising means for switching the respective resonant frequency, the switching of the respective resonant frequency thereby adapted for modulating the electromagnetic coupling.

62. A pair of resonant circuits according to claim 59 in which said at least one electromagnetic induction emitter circuit in the passenger seat has an exciting frequency, each of said resonant circuits modulating the respective resonant frequency with a subcarrier frequency adapted to be synchronous with the exciting frequency.

63. A pair of resonant circuits according to claim 62, wherein the different resonant circuits of said pair of resonant circuits modulate the respective resonant frequency with a different subcarrier frequency.

60. A pair of resonant circuits according to claim each resonant circuit being associated with electronic modulation circuit means adapted for modulating the electromagnetic coupling with a characteristic modulation, the different resonant circuits of said pair of resonant circuits providing for different characteristic modulations.