Double tuning-fork resonant accelerometer

Abstract

The structure of a novel resonant accelerometer has been designed and fabricated; it includes: two double-ended tuning forks (DETF), a proof mass surrounding and extending around the two tuning forks; a four-leverage system amplifying inertial force; drive/sense combs. Each tuning fork is electrostatically actuated and sensed at resonance using the comb electrodes. When an external acceleration is applied to the device, one tuning fork is subjected to a tensile force which raises its natural frequency, and the other tuning fork experiences a compressive force, lowering its frequency. The output of the accelerometer is the frequency difference between the two tuning forks. The device has been fabricated using MEMS bulk-silicon technology, the sensitivity of the accelerometer sample is 27.3 Hz/g, the resolution is 167.8 /spl mu/g.