Dynamicaly balanced degenerate mode gyro with sub-hz frequency symmetry and temperature robustness

We designed, fabricated, and experimentally demonstrated a dynamically balanced z-axis MEMS vibratory gyroscope utilizing the concentrated suspension architecture. This architecture allows for a high degree of structural symmetry (degeneracy of modes), potentially enabling high precision Rate Gyroscopes (RG) and Rate Integrating Gyroscopes (RIG). The full dynamic balance of the design is enabled by two concentric masses that oscillate in anti-phase as an unconstrained tuning fork, in any direction in-plane of the substrate. Experiments demonstrated a sub-Hz, as fabricated, frequency split (Δf) of 190mHz (0.19Hz) confirming the objective of the architecture. The high level of symmetry makes the gyro robust against temperature variations, demonstrating less than 50mHz variation of Δf in a broad range of temperatures, from -30°C to 100°C.