Advanced Microsystems for Automotive Applications 2000

Part of the series VDI-Buch pp 147-155

The BMW SBE2 Child Seat Detection System

  • L. EisenmannAffiliated withBMW AG
  • , C. MarschnerAffiliated withBMW AG
  • , Y. LuAffiliated withBMW AG
  • , S. SauerAffiliated withBMW AG
  • , H. HowardAffiliated withBMW AG

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Besides a measure of crash-severity the smart airbag system of the future needs information about the actual seat-occupation. For the driver seat, two parameters are to be evaluated:
  • Approximate weight of driver (occupant classification)

  • Drivers distance to airbag (out of position sensor)

For the passenger seat, two additional aspects are relevant:
  • Is the seat occupied at all? (seat occupation detection)

  • Is it occupied by a child seat? (child seat detection)

Child seat detection is especially important in two-seat vehicles like the Z3 roadster. This challenge is adressed by the upcoming BMW SBE2 system. Unlike some competitors strategies to install manual airbag deactivation switches or to develop a system that recognises only certain child seats equipped with electronic resonators, the BMW SBE2 system generally discriminates between adults and child restraints.

The sensor-principle is based on the measurement of two distinct physical properties, pressure profile and capacity. The employment of digital signal processing and pattern recognition algorithms enables a redundant, selfsupervising and fully-automatic detection system.


child seat detection system capacitive-system occupant classification field detection system electric field smart airbag