Z-Axis Micromachined Tuning Fork Gyroscope with Low Air Damping

Nguyen, Minh Ngoc; Ha, Nhat Sinh; Nguyen, Long; Chu, Hoang Manh; Vu, Hung V.

doi:10.3390/mi8020042

Cited by 19 publications

(12 citation statements)

References 21 publications

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“…The capacitance change measured through Equation (36) is

. If the same device is operated at vacuum, the value of the measured capacitance change is increased and is measured to be

for the same angular rate of

due to the fact that decreasing the pressure inside the encapsulated device package results in low energy dissipation due to both slide and squeeze film damping phenomena [ 37 ]. The results of the capacitance change show that the sensitivity of the device can be improved by 10 manifolds by operating the device in vacuum.…”

Section: Fem-based Electro-thermal-structural Analysismentioning

confidence: 99%

Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope

et al. 2018

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This paper presents the design and analysis of a multi degree of freedom (DOF) electro-thermally actuated non-resonant MEMS gyroscope with a 3-DOF drive mode and 1-DOF sense mode system. The 3-DOF drive mode system consists of three masses coupled together using suspension beams. The 1-DOF system consists of a single mass whose motion is decoupled from the drive mode using a decoupling frame. The gyroscope is designed to be operated in the flat region between the first two resonant peaks in drive mode, thus minimizing the effect of environmental and fabrication process variations on device performance. The high gain in the flat operational region is achieved by tuning the suspension beams stiffness. A detailed analytical model, considering the dynamics of both the electro-thermal actuator and multi-mass system, is developed. A parametric optimization is carried out, considering the microfabrication process constraints of the Metal Multi-User MEMS Processes (MetalMUMPs), to achieve high gain. The stiffness of suspension beams is optimized such that the sense mode resonant frequency lies in the flat region between the first two resonant peaks in the drive mode. The results acquired through the developed analytical model are verified with the help of 3D finite element method (FEM)-based simulations. The first three resonant frequencies in the drive mode are designed to be 2.51 kHz, 3.68 kHz, and 5.77 kHz, respectively. The sense mode resonant frequency is designed to be 3.13 kHz. At an actuation voltage of 0.2 V, the dynamically amplified drive mode gain in the sense mass is obtained to be 18.6 µm. With this gain, a capacitive change of 28.11 fF and 862.13 fF is achieved corresponding to the sense mode amplitude of 0.15 sans-serifμnormalm and 4.5 sans-serifμnormalm at atmospheric air pressure and in a vacuum, respectively.

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“…The capacitance change measured through Equation (36) is

. If the same device is operated at vacuum, the value of the measured capacitance change is increased and is measured to be

for the same angular rate of

Section: Fem-based Electro-thermal-structural Analysismentioning

confidence: 99%

Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope

et al. 2018

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“…As is known, the smaller the cross-axis errors between two different sense modes, the better [ 29 , 30 ]. Since the main source of the cross-axis error from Yaw Mode to Pitch Mode is the coupling stiffness terms 2 k 5 xy α + k 9 zx α and k 7 zx θ + k 9 zx θ , more specifically, the coupling stiffness terms of crab-leg beams Y 11 , Y 12 , U-shaped beams Y 7 , Y 8 , Y 9 , Y 10 , trampoline beams P 1 , P 2 , P 3 and P 4 , that the equivalent fabrication angle α and θ matters most ( Figure 4 ), should be decreased as much as possible to reduce the value of cross-axis error S yaw 2 pitch .…”

Section: Mechanical Coupling Stiffness Analysismentioning

confidence: 99%

Coupling Mechanism Analysis and Fabrication of Triaxial Gyroscopes in Monolithic MIMU

Xia

2017

Micromachines

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A novel fully decoupled micro inertial measurement unit (MIMU) is presented in this paper. The proposed MIMU structure, mostly focusing on the gyroscope unit, is highly symmetrical and can be limited to an area of 10,000 μm × 10,000 μm. Both the tri-axis gyroscope and tri-axis accelerometer structures are fabricated on the same single silicon chip, which can differentially detect three axes’ angular velocities and linear accelerated velocities at the same time. By elaborately arranging different decoupling beams, anchors and sensing frames, the drive and sense modes of the tri-axis gyroscope are fully decoupled from each other. Several dynamic models, including decoupling beams with fabrication imperfections, are established for theoretical analysis. The numerical simulation made by MATLAB shows the structural decoupling of three sense modes, and indicates that the key decoupling beams, which affect the quadrature error, can be improved in design. The whole fabrication process, including silicon on glass (SOG) process, dry/wet etching as well as the methods for improving the fabrication quality, is then shown. Experiments for mode frequency and quality factors of four modes (drive, yaw, pitch and roll) have been performed, and are found to be 455 (6950.2 Hz), 66 (7054.4 Hz), 109 (7034.2 Hz) and 107 (7040.5 Hz) respectively. The analysis and experiment both prove that this novel MIMU has the potential value of further intensive investigation.

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“…Based on the working principle, the MEMS gyroscopes are divided into two main categories including resonant and non-resonant gyroscopes. In resonant MEMS gyroscopes, the device is operated at resonance and both the drive and sense mode resonant frequency values are generally matched which leads to high mechanical sensitivity [ 7 ]. The reliability of resonant MEMS gyroscopes is of major concern since a mismatch between the drive and sense mode resonant frequencies occurs due to microfabrication process tolerances and fluctuations in the operating temperature and pressure conditions [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Microfabrication Process-Driven Design, FEM Analysis and System Modeling of 3-DoF Drive Mode and 2-DoF Sense Mode Thermally Stable Non-Resonant MEMS Gyroscope

et al. 2020

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This paper presents microfabrication process-driven design of a multi-degree of freedom (multi-DoF) non-resonant electrostatic microelectromechanical systems (MEMS) gyroscope by considering the design constraints of commercially available low-cost and widely-used silicon-on-insulator multi-user MEMS processes (SOIMUMPs), with silicon as a structural material. The proposed design consists of a 3-DoF drive mode oscillator with the concept of addition of a collider mass which transmits energy from the drive mass to the passive sense mass. In the sense direction, 2-DoF sense mode oscillator is used to achieve dynamically-amplified displacement in the sense mass. A detailed analytical model for the dynamic response of MEMS gyroscope is presented and performance characteristics are validated through finite element method (FEM)-based simulations. The effect of operating air pressure and temperature variations on the air damping and resulting dynamic response is analyzed. The thermal stability of the design and corresponding effect on the mechanical and capacitive sensitivity, for an operating temperature range of −40 °C to 100 °C, is presented. The results showed that the proposed design is thermally stable, robust to environmental variations, and process tolerances with a wide operational bandwidth and high sensitivity. Moreover, a system-level model of the proposed gyroscope and its integration with the sensor electronics is presented to estimate the voltage sensitivity under the constraints of the readout electronic circuit.

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Z-Axis Micromachined Tuning Fork Gyroscope with Low Air Damping

Cited by 19 publications

References 21 publications

Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope

Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope

Coupling Mechanism Analysis and Fabrication of Triaxial Gyroscopes in Monolithic MIMU

Microfabrication Process-Driven Design, FEM Analysis and System Modeling of 3-DoF Drive Mode and 2-DoF Sense Mode Thermally Stable Non-Resonant MEMS Gyroscope

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