Virtually Rotated Multiple Mass Resonator Enabled by Electrostatic Frequency and Q-factor Tuning

This paper reports a two-axis symmetric multiple mass resonator with an enhanced frequency and Q-factor tuning capability for rate integrating gyroscope. The stiffness and damping mismatches can be compensated by electrostatic softening the suspension stiffness of the main proof masses and the inner stiffness of the inside proof masses, respectively. The as-fabricated frequency mismatch between two orthogonal modes was firstly measured as 145 Hz, which was decreased to 24 Hz by focus ion beam (FIB). Then the DC bias was applied on a pair of diagonal sensing electrodes for compensating the nonorthogonal stiffness components and the remained anisoelasticity. The anisodamping was then eliminated by adding the DC bias on the coupling proof masses, which mainly modified the squeeze film damping with a minor effect on the frequency. Finally, a free precession of the resonator could be observed and the rate detection was performed by removing the angle drifts from the self-precession.