Method and apparatus for sensing a vehicle crash using energy and velocity as measures of crash violence

• US 5,216,607 A
• Filed: 05/11/1990
• Issued: 06/01/1993
• Est. Priority Date: 05/30/1989
• Status: Expired due to Term

• Current Assignee: TRW Technar, Inc. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Ross, Mark A., Diller, Robert W., Mazur, Joseph F., Blackburn, Brian K.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Auchterlonie, Thomas S.
• Application Number:
  US07/520,417
• Time in Patent Office: 1,117 Days
• Field of Search: 364/424.01, 364/424.05, 364/557, 340/436, 340/438, 280/728, 280/734, 280/735, 180/232, 180/268, 180/271, 180/274, 180/282, 307/9.1, 307/10.1
• US Class Current: 701/45
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• 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 method and apparatus is disclosed for providing a passenger restraint actuation signal for use in an actuatable passenger restraint system in a vehicle is provided. The method comprises a sensor for providing a time varying electric signal proportional to vehicle deceleration. A crash energy is determined and compared against a predetermined limit. If the determined crash energy equals or exceeds the predetermined limit, a passenger restraint actuation signal is provided.

Claims

1. An apparatus for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said apparatus comprising:

sensing means mounted to the vehicle body for sensing a vehicle crash condition, said sensing means providing a time varying electric signal having an electrical characteristic functionally related to the vehicle crash deceleration;

means for determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body;

timing means for providing a time signal;

means for comparing within a time period timed by said timing means the determined at least one energy value against an associated limit indicative of a maximum energy level beyond which the passenger restraint device needs to be actuated to maximize protection of the passengers; and

means for providing said passenger restraint actuation signal when said comparing means indicates that at least one of the compared energy values is equal to or greater than its associated limit within said time period.

2. The apparatus of claim 1 wherein said means for determining said at least one energy value includes means for determining the RMS value of the analog voltage value of said electric signal from said sensing means, the RMS value being functionally related to the crash energy of the vehicle during a crash condition.

3. The apparatus of claim 1 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for summing the absolute value of each of said digital values to determine a summed digital value functionally related to the total energy value dissipated in the vehicle body, said comparing means comparing the summed digital value against the associated limit for the at least one energy value.

4. The apparatus of claim 3 further comprising means for multiplying each determined at least one energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, means for summing the weighted energy values together to determine a sum total value, said comparing means comparing the sum total value against a predetermined value.

5. The apparatus of claim 4 wherein the weighting factors are selected to give the most weight to the most recent acquired data.

6. The apparatus of claim 1 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for determining an averaging value functionally related to the mean value of a predetermined number of the most recent of the measured values of the electric signal from said sensing means, means for subtracting the averaging value from each of the measured values, means for summing the absolute value of each of said digital values minus the averaging value to determine a sum functionally related to the total energy value of the crash dissipated in the vehicle body excluding the energy resulting from the zero hertz frequency of the time varying electronic signal, said comparing means comparing the resultant summed absolute value against the associated limit for the energy value.

7. The apparatus of claim 6 further comprising means for multiplying each determined energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, means for summing the weighted energy values together to determine a sum total value, said comparing means comparing the sum total value against the associated limit for the energy value.

8. The apparatus of claim 7 wherein the weighting factors are selected to give the most weight to the most recent acquired data.

9. The apparatus of claim 1 further including means for measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, means for converting each of the measured analog voltage values into a digital value, means for determining the energy value, means for storing a predetermined number of said values in memory, means for combining the stored values into a sum total value, said comparing means comparing the sum total value against the associated limit for the energy value.

10. The apparatus of claim 9 further including means to update a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said means for determining the sum total value making their determinations based upon the updated stored digital values.

11. The apparatus of claim 1 wherein said means for determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body includes means for excluding from said energy determination energy resulting from zero hertz frequency in said time varying signal.

12. The apparatus of claim 1 wherein said means for determining said at least one energy value includes means for determining the integral of the power spectral density over all frequencies of the analog voltage value of said electric signal from said sensing means, the integral of the power spectral density being functionally related to the crash energy of the vehicle during a crash condition.

13. The apparatus of claim 12 wherein said means for determining said integral of the power spectral density includes means for excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal.

14. The apparatus of claim 13 wherein the frequency eliminated is zero hertz.

15. The apparatus of claim 1 wherein said means for determining said at least one energy includes means for sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said at least one energy value against an associated limit not beginning until said sensed vehicle deceleration is greater than said predetermined value.

16. The apparatus of claim 1 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said comparing means comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

17. An apparatus for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said apparatus comprising:

sensing means mounted to the vehicle body for sensing a vehicle crash condition, said sensing means providing a time varying electric signal having an electrical characteristic proportional to the vehicle crash deceleration;

means for determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body;

means for determining from said time varying electric signal a vehicle velocity value;

means for comparing the determined at least one energy value and the vehicle velocity value against associated limits; and

means for providing said passenger restraint actuation signal when said comparing means indicates that each of the compared values is equal to or greater than its associated limit.

18. The apparatus of claim 17 further comprising timing means for providing a timing signal and wherein said means for comparing compares said at least one energy value and said velocity value against their associated limits within associated time periods.

19. The apparatus of claim 18 wherein said means for determining said velocity value is reset to a predetermined value when said timing signal times out.

20. The apparatus of claim 17 wherein said means for determining said at least one energy value includes means for determining the RMS value of the analog voltage value of said electric signal from said sensing means, the RMS value being functionally related to the crash energy of the vehicle during a crash condition.

21. The apparatus of claim 17 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for summing the absolute value of each of said digital values to determine a summed digital value functionally related to the total energy value dissipated in the vehicle body, said comparing means comparing the summed digital value against the associated limit for the at least one energy value.

22. The apparatus of claim 21 further comprising means for multiplying each determined at least one energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, means for summing the weighted energy values together to determine a sum total value, said comparing means comparing the sum total value against a predetermined value.

23. The apparatus of claim 17 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for determining an averaging value functionally related to the mean value of a predetermined number of the most recent of the measured values of the electric signal from said sensing means, means for subtracting the averaging value from each of the measured values, means for summing the absolute value of each of said digital values minus the averaging value to determine a sum functionally related to the total energy value of the crash dissipated in the vehicle body excluding the energy resulting from the zero hertz frequency of the time varying electronic signal, said comparing means comparing the resultant summed absolute value against the associated limit for the energy value.

24. The apparatus of claim 23 further comprising means for multiplying each determined at least one energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, means for summing the weighted energy values together to determine a sum total value functionally related to the energy value dissipated in the vehicle body minus energy at zero hertz, said comparing means comparing the sum total value against a predetermined value.

25. The apparatus of claim 17 further including means for measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, means for converting each of the measured analog voltage values into a digital value, means for determining the energy value, means for storing a predetermined number of said values in memory, means for combining the stored values into a sum total value, said comparing means comparing the sum total value against the associated limit for the energy value.

26. The apparatus of claim 25 further including means to update a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said means for determining the sum total value making their determinations based upon the updated stored digital values.

27. The apparatus of claim 17 wherein said means for determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body includes means for excluding from said energy determination energy resulting from at least one predetermined frequency in said time varying signal.

28. The apparatus of claim 27 wherein the frequency eliminated is zero hertz.

29. The apparatus of claim 17 wherein said means for determining said at least one energy value includes means for determining the integral of the power spectral density over all frequencies of the analog voltage value of said electric signal from said sensing means, the integral of the power spectral density being functionally related to the crash energy of the vehicle during a crash condition.

30. The apparatus of claim 29 wherein said means for determining said integral of the power spectral density includes means for excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal.

31. The apparatus of claim 30 wherein the frequency eliminated is zero hertz.

32. The apparatus of claim 17 wherein said means for determining said at least one energy includes means for sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said at least one energy value against an associated limit not beginning until said sensed vehicle deceleration is greater than said predetermined value.

33. The apparatus of claim 17 wherein said means for determining said at least one energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said comparing means comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

34. An apparatus for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said apparatus comprising:

sensing means mounted to the vehicle body for sensing a vehicle crash condition, said sensing means providing a time varying electric signal having an electrical characteristic proportional to the vehicle crash deceleration;

means for determining from said time varying electric signal a first energy value functionally related to the total energy of the crash dissipated in the vehicle body;

means for determining from said time varying electric signal a second energy value functionally related to the energy of the crash dissipated in the vehicle body minus the energy associated with at least one predetermined frequency band;

means for determining a vehicle velocity value from said time varying electric signal;

means for comparing the determined first energy value, the second energy value, and the vehicle velocity value against associated limits; and

means for providing said passenger restraint actuation signal when said comparing means indicates that each of the compared values is equal to or greater than its associated limit.

35. The apparatus of claim 34 further comprising timing means for providing a timing signal and wherein said means for comparing compares said first energy value, said second energy value, and said velocity value against their associated limits within associated time periods.

36. The apparatus of claim 35 wherein said means for determining said velocity value are reset to a predetermined values when said timing signal times out.

37. The apparatus of claim 35 wherein said means for determining said second energy value, and said means for determining said velocity value are reset to associated predetermined values when said timing signal times out.

38. The apparatus of claim 34 wherein said means for determining said first energy value includes means for determining the RMS value of the analog voltage value of said electric signal from said sensing means, the RMS value being functionally related to the total crash energy of the vehicle during a crash condition.

39. The apparatus of claim 34 wherein said means for determining said first energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for summing the absolute value of each of said digital values to determine a summed digital value, said comparing means comparing the summed digital value against the associated limit for the first energy value.

40. The apparatus of claim 39 further comprising means for multiplying each determined first energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined first energy values, means for summing the weighted energy values together to determine a sum total value first energy value, comparing means comparing the sum total value against a predetermined value.

41. The apparatus of claim 34 wherein said means for determining said second energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for determining an averaging value functionally related t the mean value of a predetermined number of the most recent of the measured values of the electric signal from said sensing means, means for subtracting the averaging value from each of the measured values, means for summing the absolute value of each of said digital values minus the averaging value to determine a summed absolute value functionally related to the energy value dissipated in the vehicle body minus energy resulting from the presence of predetermined frequency components, said comparing means comparing the resultant summed absolute value against the associated limit for the second energy value.

42. The apparatus of claim 41 further comprising means for multiplying each determined second energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined second energy values, means for summing the second weighted energy values together to determine a sum total value, said comparing means comparing the sum total second energy value against an associated limit for the second energy value.

43. The apparatus of claim 34 further including means for measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, means for converting each of the measured analog voltage values into a digital value, means for determining the first and second energy values, means for storing a predetermined number of said values in memory, means for combining the stored values into a sum total first energy value and a sum total second energy value, said comparing means comparing the sum total values against each associated limit for the energy value.

44. The apparatus of claim 43 further including means to update a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said means for determining the total first and second energy values making their associated determinations based upon the updated stored digital values.

45. The apparatus of claim 44 wherein said means for determining from said time varying electric signal said second energy value functionally related to the energy of the crash dissipated in the vehicle body includes means for excluding from said second energy determination energy resulting from at least one predetermined frequency in said time varying signal.

46. The apparatus of claim 45 wherein the frequency eliminated is zero hertz.

47. The apparatus of claim 34 wherein said means for determining said first energy value includes means for determining the integral of the power spectral density over all frequencies of the analog voltage value of said electric signal from said sensing means, the integral of the power spectral density being functionally related to the total crash energy of the vehicle during a crash condition.

48. The apparatus of claim 34 wherein said means for determining said second energy value includes means for determining the integral of the power spectral density over selected frequencies of the analog voltage value of said electric signal from said sensing means, the integral of the power spectral density being functionally related to part of the crash energy of the vehicle during a crash condition.

49. The apparatus of claim 48 wherein said means for determining said integral of the power spectral density includes means for excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal.

50. The apparatus of claim 49 wherein the frequency eliminated is zero hertz.

51. The apparatus of claim 34 wherein said means for determining said first energy, said second energy, and said velocity includes means for sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said first energy, said second energy, and said velocity value against an associated limit not beginning until said sensed vehicle deceleration is greater than said predetermined value.

52. The apparatus of claim 34 wherein said means for determining said first energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said comparing means comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

53. The apparatus of claim 34 wherein said means for determining said second energy value includes means for measuring the analog voltage value of said electric signal from said sensing means at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, means for determining the mean value of the measured values, means for subtracting the mean value from the measured values, means for squaring the individual digital values, means for squaring the result of the subtraction, summing the squared values and taking the square root of the sum of the squares, said comparing means comparing the square root of the sum of the squares against the associated limit for the second energy value.

54. A method for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said method comprising the steps of:

mounting a sensor to the vehicle for sensing a vehicle crash condition, said sensor providing a time varying electric signal having an electrical characteristic functionally related to the vehicle crash deceleration;

providing a timing signal for timing out a predetermined time period;

determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body;

comparing within said predetermined time period said determined at least one energy value against an associated limit indicative of a maximum energy level beyond which the passenger restraint device needs to be actuated to maximize protection of the passengers; and

providing said passenger restraint actuation signal when said comparing step indicates that at least one of the compared energy values is equal to or greater than its associated limit within said predetermined time period.

55. The method of claim 54 wherein said step of determining said at least one energy value includes determining the RMS value of the analog voltage value of said time varying electric signal, the RMS value being functionally related to the crash energy of the vehicle during a crash condition.

56. The method of claim 54 wherein said step of determining said at least one energy value includes the steps of measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, summing the absolute value of each of said digital values to determine a summed digital value functionally related to the total energy value dissipated in the vehicle body, and comparing the summed digital value against the associated limit for the at least one energy value.

57. The method of claim 56 further comprising the steps of multiplying each determined at least one energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, summing the weighted energy values together to determine a sum total value, and wherein the step of comparing compares the sum total value against a predetermined value.

58. The method of claim 54 wherein said step of determining said at least one energy value includes the steps of measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, determining an averaging value functionally related to the mean value of a predetermined number of the most recent the measured values of the time varying electric, subtracting the averaging value from each of the measured values, summing the absolute value of each of said digital values minus the averaging value to determine a sum functionally related to the total energy value of the crash dissipated in the vehicle body excluding the energy resulting from the zero hertz frequency of the time varying electronic signal, and wherein the step of comparing compares the resultant summed absolute value against the associated limit for the energy value.

59. The method of claim 58 further comprising the steps of multiplying each determined energy value by a weighting factor so as to give certain of the acquired data measurements a value greater than other of the energy values, summing the weighted energy values together to determine a sum total value, said step of comparing comparing the sum total value against the associated limit for the energy value.

60. The method of claim 54 further including steps of measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, converting each of the measured analog voltage values into a digital value, determining the energy value, storing a predetermined number of said values in memory, combining the stored values into a sum total value, said step of comparing comparing the sum total value against the associated limit for the energy value.

61. The method of claim 60 further including the steps of updating a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said step of determining the sum total value making the determinations based upon the updated stored digital values.

62. The method of claim 54 wherein said step of determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body includes the step of excluding from said energy determination energy resulting from zero hertz frequency in said time varying signal.

63. The method of claim 54 wherein said step of determining said at least one energy value includes determining the integral of the power spectral density over all frequencies of the time varying electric signal, the integral of the power spectral density being functionally related to the crash energy of the vehicle during a crash condition.

64. The method of claim 63 wherein said step of determining said integral of the power spectral density includes excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal;

65. The method of claim 64 wherein the frequency eliminated is zero hertz.

66. The method of claim 54 wherein said step of determining said at least one energy includes sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said at least one energy value against an associated limit not beginning until said sensed vehicle deceleration is greater than said predetermined value.

67. The method of claim 54 wherein said step of determining said at least one energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said step of comparing comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

68. A method for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said method comprising the steps of:

mounting a sensor to the vehicle for sensing a vehicle crash condition, said sensor providing a time varying electric signal having an electrical characteristic proportional to the vehicle crash deceleration;

determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body;

determining from said time varying electric signal a vehicle velocity value;

comparing the determined at least one energy value and the vehicle velocity value against associated limits; and

providing said passenger restraint actuation signal when said comparing step indicates that each of the compared values is equal to or greater than its associated limit.

69. The method of claim 68 further comprising the steps of providing a timing signal and said step of comparing compares said at least one energy value and said velocity value against their associated limits within associated time periods.

70. The apparatus of claim 69 wherein said step of determining said velocity value are reset to a predetermined value when said timing signal times out.

71. The method of claim 68 wherein said step of determining said at least one energy value includes determining the RMS value of the analog voltage value of said time varying electric signal, the RMS value being functionally related to the crash energy of the vehicle during a crash condition.

72. The method of claim 68 wherein said step of determining said at least one energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, summing the absolute value of each of said digital values to determine a summed digital value functionally related to the total energy value dissipated in the vehicle body, said step of comparing comparing the summed digital value against the associated limit for the at least one energy value.

73. The method of claim 72 further comprising the steps of multiplying each determined at least one energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, summing the weighted energy values together to determine a sum total value, said step of comparing comparing the sum total value against a predetermined value.

74. The method of claim 68 wherein said step of determining said at least one energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, means for converting each of said measured analog voltage values into a corresponding digital value, determining an averaging value functionally related to the mean value of a predetermined number of the measured values of the time varying electric signal, subtracting the averaging value from each of the measured values, summing the absolute value of each of said digital values minus the averaging value to determine a sum functionally related to the total energy value of the crash dissipated in the vehicle body excluding the energy resulting from the zero hertz frequency of the time varying electronic signal, said step of comparing comparing the resultant summed absolute value against the associated limit for the energy value.

75. The method of claim 74 further comprising the step of multiplying each determined energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined energy values, summing the weighted energy values together to determine a sum total value, said step of comparing comparing the sum total value against the associated limit for the energy value.

76. The method of claim 68 further including the steps of measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, converting each of the measured analog voltage values into a digital value, determining the energy value, storing a predetermined number of said values in memory, combining the stored values into a sum total value, said step of comparing comparing the sum total value against the associated limit for the energy value.

77. The method of claim 76 further including the steps of updating a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said step of determining the sum total value making the determinations based upon the updated stored digital values.

78. The method of claim 68 wherein said step of determining from said time varying electric signal at least one energy value functionally related to the energy of the crash dissipated in the vehicle body includes excluding from said energy determination energy resulting from at least one predetermined frequency in said time varying signal.

79. The method of claim 78 wherein the frequency eliminated is zero hertz.

80. The method of claim 68 wherein said step of determining said at least one energy value includes determining the integral of the power spectral density over all frequencies of the analog voltage value of said time varying electric signal, the integral of the power spectral density being functionally- related to the crash energy of the vehicle during a crash condition.

81. The method of claim 80 wherein said step of determining said integral of the power spectral density includes excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal.

82. The method of claim 81 wherein the frequency eliminated is zero hertz.

83. The method of claim 68 wherein said step of determining said at least one energy includes sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said at least one energy value against an associated limit not beginning until said sensed vehicle deceleration is greater than said predetermined value.

84. The method of claim 68 wherein said step of determining said at least one energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said step of comparing comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

85. A method for providing a passenger restraint actuation signal for use in controlling actuation of a passenger restraint system in a vehicle, said method comprising the steps of:

mounting a sensor to the vehicle for sensing a vehicle crash condition, said sensor providing a time varying electric signal having an electrical characteristic proportional to the vehicle crash deceleration;

determining from said time varying electric signal a first energy value functionally related to the total energy of the crash dissipated in the vehicle body;

determining from said time varying electric signal a second energy value functionally related to the total energy of the crash dissipated in the vehicle body minus the energy associated with at least one predetermined frequency band;

determining a vehicle velocity value from said time varying electric signal;

comparing the determined first energy value, the second energy value, and the vehicle velocity value against associated limits; and

providing said passenger restraint actuation signal when said comparing step indicates that each of the compared values is equal to or greater than its associated limit.

86. The method of claim 85 further comprising the steps of providing a timing signal and wherein said step of comparing compares said first energy value, said second energy value, and said velocity value against their associated limits within associated time periods.

87. The apparatus of claim 86 wherein said step of determining said velocity value are reset to a predetermined values when said timing signal times out.

88. The apparatus of claim 86 wherein said step of determining said second energy value, and said step of determining said velocity value are reset to associated predetermined values when said timing signal times out.

89. The method of claim 85 wherein said step of determining said first energy value includes determining the RMS value of the analog voltage value of said time varying electric signal, the RMS value being functionally related to the total crash energy of the vehicle during a crash condition.

90. The method of claim 85 wherein said step of determining said first energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, summing the absolute value of each of said digital values to determine a summed digital value functionally related to the total energy value dissipated in the vehicle body, said step of comparing comparing the summed digital value against the associated limit for the first energy value.

91. The method of claim 90 further comprising the step of multiplying each determined first energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined first energy values previously determined, summing the weighted energy values together to determine a sum total first energy value, said step of comparing comparing the sum total first energy value against an associated predetermined value.

92. The method of claim 85 wherein said step of determining said second energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, determining an averaging value functionally related to the mean value of a predetermined number of the most recent of the measured values of the time varying electric signal, subtracting the averaging value from each of the measured values, summing the absolute value of each of said digital values minus the averaging value to determine a summed absolute value functionally related to the energy value of the crash dissipated in the vehicle body minus energy resulting from the presence of predetermined frequency components, said step of comparing comparing the resultant summed absolute value against the associated limit for the second energy value.

93. The method of claim 92 further comprising the steps of multiplying each determined energy value by a weighting factor so as to give certain acquired data measurements a value greater than other determined second energy values, summing the weighted second energy values together to determine a sum total value, said step of comparing comparing the sum total second energy value against the associated limit for the second energy value.

94. The method of claim 85 further including the steps of measuring an analog voltage value of said time varying electric signal at a plurality of discrete times over a predetermined time interval, converting each of the measured analog voltage values into a digital value, determining the first and second energy values, storing a predetermined number of said values in memory, combining the stored values into a sum total first energy value and a sum total second energy value,. said step of comparing comparing the sum total values against the associated limit for each energy value.

95. The method of claim 94 further including the steps of updating a portion of said stored digital values by replacing a portion of the stored digital values with newly determined digital values, said step of determining the total first and second energy values making the associated determinations based upon the updated stored digital values.

96. The method of claim 85 wherein said step of determining from said time varying electric signal said second energy value functionally related to the energy of the crash dissipated in the vehicle body includes excluding from said second energy determination energy resulting from at least one predetermined frequency in said time varying signal.

97. The method of claim 96 wherein the frequency eliminated is zero hertz.

98. The method of claim 85 wherein said step of determining said first energy value includes determining the integral of the power spectral density over all frequencies of the analog voltage value of said time varying electric signal, the integral of the power spectral density being functionally related to the total crash energy of the vehicle during a crash condition.

99. The method of claim 85 wherein said step of determining said second energy value includes determining the integral of the power spectral density over selected frequencies of the analog voltage value of said time varying electric signal, the integral of the power spectral density being functionally related to part of the crash energy of the vehicle during a crash condition.

100. The method of claim 99 wherein said step of determining said integral of the power spectral density includes excluding from said determination energy resulting from at least one predetermined frequency in said time varying signal.

101. The method of claim 100 wherein the frequency eliminated is zero hertz.

102. The method of claim 85 wherein said step of determining said first energy, said second energy, and said velocity includes sensing when the vehicle deceleration is greater than a predetermined value, a comparison of said first energy, said second energy, and said velocity value against associated limits not beginning until said sensed vehicle deceleration is greater than said predetermined value.

103. The method of claim 85 wherein said step of determining said first energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, squaring the individual digital values, summing the squared values and taking the square root of the sum of the squares, said step of comparing comparing the square root of the sum of the squares against the associated limit for the at least one energy value.

104. The method of claim 85 wherein said step of determining said second energy value includes measuring the analog voltage value of said time varying electric signal at a plurality of different times, converting each of said measured analog voltage values into a corresponding digital value, determining the mean value of the measured values, subtracting the mean value from the measured values, squaring the individual digital values, squaring the result of the subtraction, summing the squared values and taking the square root of the sum of the squares, said step of comparing comparing the square root of the sum of the squares against the associated limit for the second energy value.