Signal analyses of airbag sensor by side impact

Abstract

Due to the nature of MEMS sensor, the signal characteristics of the impact sensor are strongly influenced by the module packaging type. In this paper, performances of MEMS airbag sensors were analyzed under side impact using two different module packaging types. The first type was a new sensor packaging on the flexible circuit board was introduced to attach directly on the frame surface using adhesive. The second sensor type was a conventional packaging structure, and composed of the accelerometer MEMS sensor mounted on a printed circuit board, which is assembled inside a plastic housing. And the entire module is mechanically installed by bolts on the automobile frame. For the signal characterizations, impact tests were performed on the center pillar, a.k.a. b-pillar, where the sensors were installed for the pendulum test. It was found that the housing module had great effects on the signal generation due to the vibration interaction with the automobileframe. Numerical analyses were also carried out for the detail investigation. The results indicated that the system of the airbag sensor packaging requires the comprehensive engineering consideration.