A mechanically amplified angular rate MEMS sensor using V -shaped springs

Abstract

We propose a quad mass Z-axis angular rate sensor, vibrating at 8.4kHz and with improved sensitivity. The drive blocks are capacitively actuated to a displacement of 6.5um with stresses in the suspension springs smaller than 250MPa. A displacement amplification system based on V-shaped springs transforms the drive movement to a large movement of 20um of the proof masses. A second pair of V-shaped springs is used to transform the Coriolis movement of the proof masses to a movement of the sense blocks with a five-fold amplification. An analytical model is proposed for the V-shaped springs. A finite element model is used to finely tune the drive and sense frequencies and to estimate the frequencies of higher resonances, all above 13kHz.