Crash/non-crash discrimination using frequency components of acceleration uniquely generated upon crash impact
First Claim
1. A crash detection apparatus for operating an inflatable occupant restraint system, comprising:
- an accelerometer for producing an accelerometer signal representative of acceleration/deceleration of the vehicle during a vehicle crash;
Integrator means for integrating said accelerometer signal at intervals and producing a velocity signal;
bandpass filter means for detecting frequency components of said accelerometer signal which appear uniquely during said vehicle crash;
squaring means for squaring the amplitude of the bandpass filtered accelerometer signal and producing an impact energy signal; and
decision means for producing a deployment signal in accordance with said velocity signal and said impact energy signal and applying said deployment signal to said occupant restraint system,
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Accused Products
Abstract
In a crash detection apparatus, the output signal of an accelerometer is integrated at intervals and a velocity signal is produced. Those frequency components of the accelerometer output which appear uniquely during a vehicle crash are extracted and their amplitude is squared to produce an impact energy signal. An airbag is operated when the velocity signal exceeds a first threshold, or when a sum of the velocity and impact energy signals exceeds a second threshold, or operated when the impact energy signal exceeds a third threshold. In a modified embodiment, the accelerometer output is integrated both at longer and shorter intervals to produce a long-term and a short-term velocity signal. The airbag is operated when the long-term velocity signal exceeds a first threshold, or when the short-term velocity signal and the impact energy signal simultaneously exceed a second and a third threshold, respectively.
109 Citations
15 Claims
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1. A crash detection apparatus for operating an inflatable occupant restraint system, comprising:
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an accelerometer for producing an accelerometer signal representative of acceleration/deceleration of the vehicle during a vehicle crash; Integrator means for integrating said accelerometer signal at intervals and producing a velocity signal; bandpass filter means for detecting frequency components of said accelerometer signal which appear uniquely during said vehicle crash; squaring means for squaring the amplitude of the bandpass filtered accelerometer signal and producing an impact energy signal; and decision means for producing a deployment signal in accordance with said velocity signal and said impact energy signal and applying said deployment signal to said occupant restraint system, - View Dependent Claims (2, 3, 4)
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5. A crash detection apparatus for operating an inflatable occupant restraint system, comprising:
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an accelerometer for producing an accelerometer signal representative of acceleration/deceleration of the vehicle during a vehicle crash; long-term integrator means for integrating said accelerometer signal at longer intervals and producing a long-term velocity signal; short-term integrator means for integrating said accelerometer signal at shorter intervals and producing a short-term velocity signal; bandpass filter means for detecting frequency components of said accelerometer signal which appear uniquely during said vehicle crash; squaring means for squaring the amplitude of the bandpass filtered accelerometer signal and producing an impact energy signal; and decision means for producing a deployment signal in accordance with said long-term and short-term velocity signals and said impact energy signal and applying said deployment signal to said occupant restraint system. - View Dependent Claims (6, 7, 8, 9)
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10. A crash detection apparatus for operating an inflatable occupant restraint system, comprising:
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an accelerometer for producing an accelerometer signal representative of acceleration/deceleration of the vehicle during a vehicle crash; lowpass filter means for removing aliasing components of the accelerometer signal; sampling means for sampling an output signal of said lowpass filter means at constant intervals to produce analog samples; analog-to-digital converter means for converting the analog samples to digital samples; integrator means for integrating said digital samples at intervals and producing a velocity signal; bandpass filter means for detecting frequency components of said digital samples which appear uniquely during said vehicle crash; squaring means for squaring the amplitude of the bandpass filtered digital samples and producing therefrom an impact energy signal; first weighting means for weighting said velocity signal to produce a weighted velocity signal; second weighting means for weighting the impact energy signal to produce a weighted impact energy signal; and decision means for producing a deployment signal in accordance with said weighted velocity signal and said weighted impact energy signal and for applying said deployment signal to said occupant restraint system. - View Dependent Claims (11, 12)
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13. A crash detection apparatus for operating an inflatable occupant restraint system, comprising:
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an accelerometer for producing an accelerometer signal representative of acceleration/deceleration of the vehicle during a vehicle crash; lowpass filter means for removing aliasing components of the accelerometer signal; sampling means for sampling an output signal of said lowpass filter means at constant intervals to produce analog samples; analog-to-digital converter means for converting the analog samples to digital samples; long-term integrator means for integrating said analog samples at longer intervals and producing a long-term velocity signal; short-term integrator means for integrating said analog samples at shorter intervals and producing a short-term velocity signal; bandpass filter means for detecting frequency components of said digital samples which appear uniquely during said vehicle crash; squaring means for squaring the amplitude of the bandpass filtered digital samples and producing therefrom an impact energy signal; first weighting means for weighting said long-term velocity signal to produce a weighted long-term velocity signal; second weighting means for weighting said short-term velocity signal to produce a weighted short-term velocity signal; third weighting means for weighting the impact energy signal to produce a weighted impact energy signal; and decision means for producing a deployment signal in accordance with said weighted long-term and weighted short-term velocity signals and said weighted impact energy signal and applying said deployment signal to said occupant restraint system. - View Dependent Claims (14, 15)
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Specification