| 摘要 |
A low-cost pendular non-serviced accelerometer comprises a base, a pendular seismic mass connected to the base by a hinged connection for pivotal movement of the seismic mass about an axis along a sense direction perpendicular to the hinged connection and a sensor connecting the seismic mass to the base. The sensor comprises at least two vibrating beams of piezo-electric material, each connected to the base at an end thereof and to the seismic mass at the other end thereof, and each provided with electrodes for vibrating the respective beam at a tuning frequency thereof. The beams are directed orthogonally to the sense axis and are located symmetrically with respect to the seismic mass on both sides of the hinged connection, whereby any acceleration along the sense axis creates tractive stresses in one beam and compression stresses in the other beam. A circuit connected to the electrodes and is arranged for delivering a signal which is responsive to the difference between the resonant frequencies of the two beams when the seismic mass is subjected to an acceleration.
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