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

Wen, Haoran; Daruwalla, Anosh; Ayazi, Farrokh

doi:10.1038/micronano.2016.92

Cited by 32 publications

(9 citation statements)

References 20 publications

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“…Capacitive bulk acoustic wave (BAW) gyroscopes circumvent this problem by increasing the resonance frequency of the device using stiff bulk vibration modes of the structure at the cost of intricate fabrication processing to realize high-aspect-ratio gaps [13][14][15][16] . Bulk-mode resonant devices in the megahertz frequency range have also been proven to offer superior shock and vibration immunity [17][18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Eigenmode operation of piezoelectric resonant gyroscopes

Hodjat-Shamami

Ayazi

2020

Microsyst Nanoeng

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The theory of eigenmode operation of Coriolis vibratory gyroscopes and its implementation on a thin-film piezoelectric gyroscope is presented. It is shown analytically that the modal alignment of resonant gyroscopes can be achieved by applying a rotation transformation to the actuation and sensing directions regardless of the transduction mechanism. This technique is especially suitable for mode matching of piezoelectric gyroscopes, obviating the need for narrow capacitive gaps or DC polarization voltages. It can also be applied for mode matching of devices that require sophisticated electrode arrangements for modal alignment, such as electrostatic pitch and roll gyroscopes with slanted electrodes utilized for out-of-plane quadrature cancellation. Gyroscopic operation of a 3.15 MHz AlN-on-Si annulus resonator that utilizes a pair of high-Q degenerate in-plane vibration modes is demonstrated. Modal alignment of the piezoelectric gyroscope is accomplished through virtual alignment of the excitation and readout electrodes to the natural direction of vibration mode shapes in the presence of fabrication nonidealities. Controlled displacement feedback of the gyroscope drive signal is implemented to achieve frequency matching of the two gyroscopic modes. The piezoelectric gyroscope shows a mode-matched operation bandwidth of ~250 Hz, which is one of the largest open-loop bandwidth values reported for a mode-matched MEMS gyroscope, a small motional resistance of ~1300 Ω owing to efficient piezoelectric transduction, and a scale factor of 1.57 nA/°/s for operation at atmospheric pressure, which greatly relaxes packaging requirements. Eigenmode operation results in an ~35 dB reduction in the quadrature error at the resonance frequency. The measured angle random walk of the device is 0.86°/√h with a bias instability of 125°/h limited by the excess noise of the discrete electronics.

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Section: Introductionmentioning

confidence: 99%

Eigenmode operation of piezoelectric resonant gyroscopes

Hodjat-Shamami

Ayazi

2020

Microsyst Nanoeng

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“…Since the virtual precession is already discussed, so the overall control effort in the based band will be eventually synthesized based on ( 20 ), ( 23 ) and ( 24 ): L is the indicator for the resonant frequency tracking and it’s a phase lock loop (PLL) type implementation in this design. The two modes of the HRG can be fine tuned through the electrostatic spring softening effect that 27 . The generated digital sinusoidal signal is also used to up convert the control signals in ( 25 ).…”

Section: Asymmetry Error Analysis and Calibration Techniquesmentioning

confidence: 99%

High sensitivity rate-integrating hemispherical resonator gyroscope with dead area compensation for damping asymmetry

Zhao

Hao²,

Liu³

et al. 2021

Sci Rep

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The rate-integrating gyroscope (RIG) operation is considered as the next generation architecture for hemispherical resonator gyroscopes (HRGs) with advantages of direct angle measurement and unlimited dynamic range. However, this RIG operation requires high symmetry for the HRG device and the damping mismatch of the two gyroscopic modes will result in a dead area problem. This work analyzes the error mechanism of the damping asymmetry induced dead area and proposed a novel virtual procession compensation method for HRG RIG. The simulation proves the existence of the dead area as the theory predicted. More importantly, the experimental HRG RIG platform with the proposed compensation method can significantly expand the dynamic range with accurate angle measurement and overcome the problem of dead area. The earth rotation is accurate measured which is the first time that captured by a RIG scheme as a state-of-the-art result.

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“…Specifically, the Brownian mechanical noise scales as Q −1/2 where Q or Q -factor is inversely proportional to energy dissipation. To achieve the lowest possible Brownian mechanical noise and high signal-to-noise ratio, advanced structural designs have been developed in silicon (Si) resonators to minimize energy dissipation and bind Q to intrinsic quantum-based losses combining bulk thermoelastic damping ( Q TED ) and Akhiezer damping ( Q AKHIEZER ) in the megahertz frequency range 5,6 . For example, energy dissipation in substrate-decoupled gyroscopic-mode silicon (Si) disk resonators approaches the overall quantum limit 7,8 while TED-free Lamé resonators cooled down to 120 K have reached the Akhiezer limit of Si 9 .…”

Section: Introductionmentioning

confidence: 99%

Monocrystalline Silicon Carbide Disk Resonators on Phononic Crystals with Ultra-Low Dissipation Bulk Acoustic Wave Modes

Hamelin

Yang

Daruwalla

et al. 2019

Sci Rep

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Micromechanical resonators with ultra-low energy dissipation are essential for a wide range of applications, such as navigation in GPS-denied environments. Routinely implemented in silicon (Si), their energy dissipation often reaches the quantum limits of Si, which can be surpassed by using materials with lower intrinsic loss. This paper explores dissipation limits in 4H monocrystalline silicon carbide-on-insulator (4H-SiCOI) mechanical resonators fabricated at wafer-level, and reports on ultra-high quality-factors (Q) in gyroscopic-mode disk resonators. The SiC disk resonators are anchored upon an acoustically-engineered Si substrate containing a phononic crystal which suppresses anchor loss and promises QANCHOR near 1 Billion by design. Operating deep in the adiabatic regime, the bulk acoustic wave (BAW) modes of solid SiC disks are mostly free of bulk thermoelastic damping. Capacitively-transduced SiC BAW disk resonators consistently display gyroscopic m = 3 modes with Q-factors above 2 Million (M) at 6.29 MHz, limited by surface TED due to microscale roughness along the disk sidewalls. The surface TED limit is revealed by optical measurements on a SiC disk, with nanoscale smooth sidewalls, exhibiting Q = 18 M at 5.3 MHz, corresponding to f · Q = 9 · 1013 Hz, a 5-fold improvement over the Akhiezer limit of Si. Our results pave the path for integrated SiC resonators and resonant gyroscopes with Q-factors beyond the reach of Si.

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

Cited by 32 publications

References 20 publications

Eigenmode operation of piezoelectric resonant gyroscopes

Eigenmode operation of piezoelectric resonant gyroscopes

High sensitivity rate-integrating hemispherical resonator gyroscope with dead area compensation for damping asymmetry

Monocrystalline Silicon Carbide Disk Resonators on Phononic Crystals with Ultra-Low Dissipation Bulk Acoustic Wave Modes

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