Dynamic occupant position detection system and method for a motor vehicle

Abstract

An improved occupant position detection system and method in which a periodically updated position output of an occupant recognition system (ORS) is dynamically augmented for purposes of determining if the occupant is out-of-position (OOP) so as to inhibit or allow deployment of occupant restraints in a timely manner. Vehicle acceleration data developed by an accelerometer of the restraint system is double integrated to form an incremental occupant displacement value. The incremental displacement value is reset to zero each time the ORS updates its position output, and between updates is used to modify the last position output to provide a dynamic position value for OOP determination. If the occupant is not wearing a seat belt, the incremental displacement value is combined with the last ORS position output both prior to and during the crash event. If the occupant is wearing a seat belt, the incremental displacement value is combined with the last ORS position output so long as the measured acceleration level is below a threshold at which the seat belt should begin to exert a significant restraining force; if the measured acceleration is above the threshold, the seat belt tension is detected to determine if the belt is in fact restraining the occupant. If the belt is not restraining the occupant, the incremental displacement value is combined with the last ORS position output; if the belt is restraining the occupant, the last ORS position output is used for OOP determination.