A methodology for out of position occupant identification from pressure sensors embedded in a vehicle seat

The airbag deployment against an out of position (OP) occupant is critical. The OP condition can be hardly expected during design, while a too close airbag deployment can cause serious injuries instead of mitigating the crash effects. An adaptive airbag system would be capable to adjust its deployment to the inside scenario. However, the integration between human passengers and intelligent vehicle requires the airbag control unit to be aware of the actual occupant(s) position. In the present research, a methodology for monitoring the occupant(s) position is developed and tested with a seat prototype. A layout of thin film sensors monitors the interface pressure between the occupant and the seat cover. An inertial measurement unit (IMU) monitors the accelerations of the vehicle, considered the reference moving platform. A microcontroller is programmed for pressure sensors calibration, IMU alignment with the vehicle reference system, signals processing, OP detection, and identification. Real driving experiments on a race track were performed in the correct position and in three different OPs. The comparison of the pressure center in longitudinal and transversal directions with the vehicle acceleration enables to identify the OPs.