Crash/non-crash discrimination using frequency components of acceleration uniquely generated upon crash impact

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;
• 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.

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;
• 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.

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;
• 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.