PRELIMINARY-RESULTS ON A SILICON GYROMETER BASED ON ACOUSTIC MODE-COUPLING IN SMALL CAVITIES

A silicon vibratory gas angular rate sensor has been developed by mean s of micromachining techniques, It is a shock-proof sensor because it has no movable part. This device is a miniaturized form of an instrume nt, which has been previously fabricated in a conventional technology format and called the acoustic gyrometer, The working principle of thi s sensor is based on acoustic coupling between two orthogonal modes of a closed cavity, due to Coriolis forces effect on vibrating gas parti cles, The gyrometer, which is presented in this paper, was fabricated by a silicon process, It is constituted by an acoustic cavity and four microphones: one to generate an acoustic wave, one to slave the cavit y at its first resonance frequency, and two for the measurement of the angular rate effect, Finite-element modeling (FEM) modal analyses wer e performed on two cavity shapes: cylindrical and trapezoidal, corresp onding to the fabricated devices, The results are compared with availa ble analytic solutions and with measurements.