Method for determining frequency components in a vehicle crash

A method for designing filter circuits for an actuatable vehicle passenger restraint system having a deceleration sensor that provides an electric signal that is responsive to, and has frequency component values indicative of, a plurality of different types of crashes of a predetermined class of vehicles, said filter circuits monitoring when frequency components are present which are indicative of a particular type of vehicle crash and for which it is desirable to actuate the passenger restraint system and providing a signal indicative thereof, said method comprising the steps of:

• (a) mounting a first deceleration sensor to a first vehicle of the predetermined class, said first deceleration sensor providing an electric signal having frequency components indicative of a particular type of crash condition;
• (b) crashing said first vehicle of the predetermined class under a condition in which it is not desirable to actuate the vehicle passenger restraint system;
• (c) recording the signal from said first deceleration sensor for said vehicle crash of step (b);
• (d) mounting a second deceleration sensor to a second vehicle of the predetermined class, said second deceleration sensor providing an electric signal having frequency components indicative of a particular type of crash condition;
• (e) crashing a second vehicle of the predetermined class under a condition in which it is desirable to actuate the vehicle passenger restraint system;
• (f) recording signal from said second deceleration sensor for said vehicle crash of step (e);
• (g) performing a frequency domain transform function on said signals recorded in steps (c) and (f);
• and
• (h) designing the filter circuits to pass those frequencies determined to be present in step (g) only for said crash in step (e).

A method for designing filter circuits for an actuatable vehicle passenger restraint system having a deceleration sensor that provides an electric signal that is responsive to, and has frequency component values indicative of, a plurality of different types of crashes of a predetermined class of vehicles, said filter circuits monitoring when frequency components are present which are indicative of a particular type of vehicle crash and for which it is desirable to actuate the passenger restraint system and monitoring when frequency components are present which are indicative of other types of vehicle crashes and for which it is not desirable to actuate the passenger restraint system, and providing a signal indicative thereof, said method comprising the steps of:

• (a) crashing individual vehicles of the predetermined class, having an associated deceleration sensor mounted thereto, under a plurality of conditions in which it is not desirable to actuate the vehicle passenger restraint system;
• (b) recording the signals from said associated deceleration sensors for said vehicle crashes of step (a);
• (c) crashing individual vehicles of the predetermined class, having an associated deceleration sensor mounted thereto, under a plurality of conditions in which it is desirable to actuate the vehicle passenger restraint system;
• (d) recording signals from said associated deceleration sensors for said vehicle crashes of step (c);
• (e) performing a frequency domain transform function on each of said signals recorded in steps (b) and (d);
• (f) designing the filter circuits to pass those frequencies determined to be present in step (e) only for crashes in step (c);
• and
• (g) designing the filter circuits to pass those frequencies determined to be present in step (e) only for crashes in step (a).