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Abstract: This paper reports a new MEMS vibratory rate gyroscope designed with increased robustness to fabrication imperfections and variations in environmental conditions. The proposed architecture utilizes a single degree-of-freedom (DOF) drive-mode and a fully coupled 2-DOF sense-mode. The drive-mode operational frequency and the sense-mode bandwidth can be set independently, relaxing the tradeoff between the gain, die size, and detection capacitance inherent to the previously reported robust gyroscopes with dynamic vibration absorber (DVA) architecture of the 2-DOF sense-mode. Prototypes with 2.5kHz operational frequency were extensively characterized in air and demonstrated sense-mode 3dB bandwidth of 250Hz. The uncompensated temperature coefficients of bias and scale factor were 313(/h)/C and 351ppm C, respectively. Using off-chip detection electronics, the rate sensitivity was 28 V/(/s), ARW – 0.09(/s)/, bias instability – 0.08(/s), and ARRW – 0.03(/s) . Detailed time domain, Allan variance, and probability density function analysis revealed that both ARW and ARRW are of Gaussian type and Coriolis-uncorrelated, showing stable in-operational noise performance of the reported gyroscope. [Copyright &y& Elsevier]

Abstract: We report detailed characterization of a vacuum sealed rate integrating silicon MEMS gyroscope. The new gyroscope utilizes geometrically symmetric, dynamically balanced quadruple mass architecture, which provides a combination of maximized quality (Q) factors and isotropy of both the resonant frequency and damping. The vacuum sealed SOI prototype with a 2kHz operational frequency demonstrated virtually identical X- and Y-mode Q-factors of 1.2 million. Due to the stiffness and damping symmetry, and low energy dissipation, the gyroscope can be instrumented for direct angle measurements with fundamentally unlimited rotation range and bandwidth. Experimental characterization of the mode-matched gyroscope operated in whole-angle mode confirmed linear response in a ±450°/s range and 100Hz bandwidth (limited by the experimental setup), eliminating both bandwidth and range constraints of conventional open-loop Coriolis vibratory rate gyroscopes. [Copyright &y& Elsevier]