Ultra-high Q silicon gyroscopes with interchangeable rate and whole angle modes of operation

Abstract

We report a new family of ultra-high Q silicon MEMS tuning fork gyroscopes demonstrating angle rate and, for the first time, rate integrating (whole angle) operation. The novel mechanical architecture eliminates low frequency in-phase modes and maximizes the Q-factors. A vacuum packaged SOI dual mass gyroscope with a 1.7 kHz operational frequency demonstrated drive-and sense-mode Q-factors of 0.31 and 0.64 million, respectively. A completely symmetric, dynamically balanced quadruple mass gyroscope with a 2.2 kHz operational frequency demonstrated identical drive-and sense-mode Q-factors of 0.45 million. Due to the stiffness and damping symmetry, the new gyroscope can be instrumented to measure the angle of rotation directly, eliminating the bandwidth and dynamic range limitations of conventional MEMS vibratory rate gyroscopes. The technology may enable silicon micromachined devices for inertial guidance applications previously limited to precision-machined quartz hemispherical resonator gyroscopes.

A novel technique for extracting parametric models from MEM resonator test data

“…VALIDATION For the purpose of validation and establishing utility, the procedure presented in Section II is applied to a pair of planar concentric ring resonators (URES) [3] as well as a quadruple mass gryoscope (QMG) [4]. The data obtained from each of the devices exhibit distinctive qualities, in turn permitting several aspects of the parametric modeling capability to be highlighted.…”

“…In Sec. III, the ringdown-based modeling approach is validated by application to MEM resonators: first, using a pair of UCLA-designed planar concentric ring resonators (URES) [3], model competency and immunity to input-output parasitics is established; next, using a quadruple mass gryo (QMG) [4], short-segment parametrizations for long ringdown devices are demonstrated. Section IV summarizes the work and comments on limitations of the LTI parametrization in application to MEM resonators.…”

Energy Dissipation Contribution Modeling of Vibratory Behavior for Silicon Micromachined Gyroscope

“…In order to achieve high performance of the MCVG, analysis of energy dissipation mechanisms of the Q value of the MCVG during vibration becomes an important issue [13][14][15][16]. For the single-mode mass-damping-stiffness resonator, the value has been widely regarded as a combination of five energy dissipation mechanisms and inverse proportion to the total energy dissipation [17][18][19].…”

“…In summary, influencing factors on damping losses can contribute to three aspects: vacuum packaging technology, materials properties, and mechanical structure topology. First, vacuum packaging scheme as the 2 Shock and Vibration most common one is used to greatly decrease air damping, such as epi-seal encapsulation process [20][21][22][23][24][25], hermetic lid sealing process [13,[26][27][28], Through-Silicon Via (TSV) process [29,30], and SPIL MEMS WLP process [31]. Second, some different kinds of materials are tried to yield lower the thermoelastic, surface deflect, and Akhiezer damping.…”

Resonant pitch and roll silicon gyroscopes with sub-micron-gap slanted electrodes: Breaking the barrier toward high-performance monolithic inertial measurement units

“…However, because different designs are involved, it is difficult to obtain consistent high performance for all three sensing axes. Different types of high quality factor (Q) resonant yaw gyroscopes (z axis) have demonstrated promising performance for navigation applications [10][11][12] . However, development of high-performance resonant pitch/roll gyroscopes (x/y axis) with OOP degrees of freedom is known to be challenging due to fabrication non-idealities.…”