Distance Corrected Capacitive Sensors for Advanced Air Bag Applications

The Federal Motor Vehicle Safety Standards No 208 now includes directives rendering the morphological estimation of passengers mandatory for Advanced Air Bag systems. The Dynamic Automatic Suppression System, which is part of the advanced air bag system uses both the morphological and positional information about the passenger to allow or prevent air bag deployment. Various solutions have been proposed to obtain these information by using for instance capacitive sensors. The response of this kind of sensors depends drastically on their distance from the passenger. This paper presents a method, now implemented in the BIOVOLUME technology developed by Faurecia in partnership with Hitachi computer products, to render those sensors independent from this distance.