Resonant accelerometer with self-test

A new resonant accelerometer is presented consisting of a doubly clamped be am coupled to a seismic mass. The beam is thermally excited by an implanted resistor and its vibration is sensed piezoresistively. An acceleration whi ch deflects the seismic mass leads to characteristic strains inside the res onator, shifting its resonance frequency. We studied the oscillation charac teristics of the resonant beam. The non-linearity at high excitation amplit udes is treated theoretically and experimentally. Further, it is shown that the electrical and thermal cross-talk can be eliminated. The resonant sens ing principle ensures a quasi-digital output signal, high sensitivity and a mechanical integrity test. Advanced automotive safety systems and x-by wir e applications require a high reliability of the employed sensors. The sens or presented here allows an on-going self-test without any constructive cha nges of the sensor element. The self-test concept, we developed also finds applications in other sensors with resonant structures. (C) 2001 Elsevier S cience B.V. All rights reserved.