Design and Implementation of a Multiple-Beam Tuning-Fork Gyroscope

2011 ◽  
Author(s):  
Ren Wang ◽  
Peng Cheng ◽  
Fei Xie ◽  
Zhili Hao ◽  
Darrin Young
Keyword(s):  
Tuning Fork ◽  
Rate Sensitivity ◽  
Silicon On Insulator ◽  
Sense Mode ◽  
Thermoelastic Damping ◽  
Quality Factors ◽  
Drive Mode ◽  
Multiple Beam ◽  
Equivalent Impedance ◽  
Mode Vibration

This paper presents the design, fabrication, and experimental results of a multiple-beam tuning-fork gyroscope (MB-TFG). Based on a numerical model of thermoelastic damping, a multiple-beam tuning-fork structure is designed with high Quality factors (Qs) in its two operation modes. A simple mask that defines the device through trenches is employed to implement this MB-TFG design on silicon-on-insulator wafers. The highest measured Qs of the fabricated MB-TFGs in vacuum are 255,000 in the drive-mode and 103,000 in the sense-mode, at a frequency of 15.7kHz. Under a frequency difference of 4Hz between the two modes (operation frequency is 16.8kHz) and a drive-mode vibration amplitude of 3.0μm, the measured rate sensitivity is 80μVPP/°/s with an equivalent impedance of 2.5MΩ. The calculated overall rate resolution of this device is 0.377hr°/√Hz.

A Multiple-Beam Tuning-Fork Gyroscope With High Quality Factors

2009 ◽  
Author(s):  
Ren Wang ◽  
Shiva Krishna Durgam ◽  
Zhili Hao ◽  
Linda Vahala
Keyword(s):  
Tuning Fork ◽  
Rate Sensitivity ◽  
Sense Mode ◽  
Quality Factors ◽  
Drive Mode ◽  
High Quality ◽  
Multiple Beam ◽  
Frequency Split ◽  
Operation Frequency ◽  
Mask Fabrication

This paper reports on the design, fabrication, and testing of a multiple-beam tuning-fork gyroscope featuring high Quality factors (Q). A multiple-beam tuning-fork structure is designed to achieve high Qs in its drive mode and sense mode. The gyroscope is fabricated on a 30μm-thick SOI wafer using a one-mask fabrication process. The measured Qs of the fabricated gyroscope are 162,060 in the drive-mode and 85,168 in the sense mode at an operation frequency of 16.8kHz. Under a frequency split of 6Hz, the prototype device demonstrates a rate sensitivity of 0.02mV/°/sec.

A Numerical and Experimental Investigation of Energy Loss Mechanisms in Tuning-Fork Gyroscopes

2008 ◽  
Author(s):  
Yang Xu ◽  
Shiva Krishna Durgam ◽  
Zhili Hao ◽  
Frances Williams
Keyword(s):  
Experimental Investigation ◽  
Energy Loss ◽  
Tuning Fork ◽  
Numerical Models ◽  
Critical Factor ◽  
Thermoelastic Damping ◽  
Quality Factors ◽  
Transfer Method ◽  
Anchor Loss ◽  
Loss Mechanisms

This paper presents a comprehensive investigation of energy loss mechanisms in tuning-fork gyroscopes from both numerical and experimental perspectives. Two main energy loss mechanisms, anchor loss and thermoelastic damping (TED), are investigated through numerical models and later experimental investigation. In order to predict the qualify factor of tuning-fork gyroscopes, a separation-and-transfer method is employed to predict anchor loss and a thermal energy method is utilized to calculate thermoelastic damping. The experimental investigation is conducted to verify the developed models. It is found that HF release in fabricating these devices is a critical factor to the measured quality factor of tuning-fork gyroscopes. The calculated Quality factors are compared with the measured data, showing good agreement.

A multiple-beam tuning-fork gyroscope with high quality factors

2011 ◽  
Vol 166 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Ren Wang ◽  
Peng Cheng ◽  
Fei Xie ◽  
Darrin Young ◽  
Zhili Hao
Keyword(s):  
Tuning Fork ◽  
Quality Factors ◽  
High Quality ◽  
Multiple Beam

Investigation of the Measured Quality Factor Versus Polarization Voltage of a Multiple-Beam Tuning-Fork Gyroscope

2012 ◽  
Author(s):  
Peng Cheng ◽  
Yujie Zhang ◽  
Wenting Gu ◽  
Zhili Hao
Keyword(s):  
Quality Factor ◽  
Tuning Fork ◽  
Factor Versus ◽  
Mechanical Quality Factor ◽  
Thermoelastic Damping ◽  
Polarization Voltage ◽  
Multiple Beam ◽  
Mechanical Quality ◽  
Quality Factor Q ◽  
Anchor Loss

In light of the importance of the mechanical Quality factor (Q) to the ultimate performance of tuning-fork gyroscopes, this paper presents an investigation on the effect of polarization voltage on the Q of a multiple-beam tuning-fork gyroscope. An experimental study is conducted to quantify the relation of the measured Q of the gyroscope to polarization voltage. The two loss mechanisms, thermoelastic damping and anchor loss, in the device are analyzed to identify the reason behind the Q drop with polarization voltage. Using a numerical model of thermoelastic damping built upon thermal-energy method, polarization voltage is found to have a negligible effect on the Q of the gyroscope. Due to the asymmetry of the fabricated devices resulting from fabrication variations, anchor loss is identified as the cause of the Q drop with polarization voltage and an analytical model of anchor loss is further proposed to take polarization voltage into account.

scholarly journals 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

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 862 ◽  
Author(s):  
Syed Ali Raza Bukhari ◽  
Muhammad Mubasher Saleem ◽  
Umar Shahbaz Khan ◽  
Amir Hamza ◽  
Javaid Iqbal ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Microelectromechanical Systems ◽  
System Modeling ◽  
Silicon On Insulator ◽  
System Level ◽  
Voltage Sensitivity ◽  
Thermally Stable ◽  
Sense Mode ◽  
Drive Mode ◽  
Mems Gyroscope

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.

scholarly journals A Resonant Pressure Microsensor with a Wide Pressure Measurement Range

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 382
Author(s):  
Chao Xiang ◽  
Yulan Lu ◽  
Chao Cheng ◽  
Junbo Wang ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Chemical Mechanical Planarization ◽  
Measurement Range ◽  
Silicon On Insulator ◽  
Anodic Bonding ◽  
Pressure Measurements ◽  
Quality Factors ◽  
Deep Reactive Ion Etching ◽  
Wide Range ◽  
Form Pressure ◽  
Silicon Islands

This paper presents a resonant pressure microsensor with a wide range of pressure measurements. The developed microsensor is mainly composed of a silicon-on-insulator (SOI) wafer to form pressure-sensing elements, and a silicon-on-glass (SOG) cap to form vacuum encapsulation. To realize a wide range of pressure measurements, silicon islands were deployed on the device layer of the SOI wafer to enhance equivalent stiffness and structural stability of the pressure-sensitive diaphragm. Moreover, a cylindrical vacuum cavity was deployed on the SOG cap with the purpose to decrease the stresses generated during the silicon-to-glass contact during pressure measurements. The fabrication processes mainly contained photolithography, deep reactive ion etching (DRIE), chemical mechanical planarization (CMP) and anodic bonding. According to the characterization experiments, the quality factors of the resonators were higher than 15,000 with pressure sensitivities of 0.51 Hz/kPa (resonator I), −1.75 Hz/kPa (resonator II) and temperature coefficients of frequency of 1.92 Hz/°C (resonator I), 1.98 Hz/°C (resonator II). Following temperature compensation, the fitting error of the microsensor was within the range of 0.006% FS and the measurement accuracy was as high as 0.017% FS in the pressure range of 200 ~ 7000 kPa and the temperature range of −40 °C to 80 °C.

scholarly journals A Resonant Pressure Microsensor Based on Double-Ended Tuning Fork and Electrostatic Excitation/Piezoresistive Detection

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2494 ◽  
Author(s):  
Xiaoqing Shi ◽  
Yulan Lu ◽  
Bo Xie ◽  
Yadong Li ◽  
Junbo Wang ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Single Crystal Silicon ◽  
Open Loop ◽  
Quality Factors ◽  
Accuracy Rate ◽  
Crystal Silicon ◽  
Piezoresistive Sensors ◽  
Pressure Sensitive ◽  
Tuning Forks ◽  
Stress Buildup

This paper presents a resonant pressure microsensor relying on electrostatic excitation and piezoresistive detection where two double-ended tuning forks were used as resonators, enabling differential outputs. Pressure under measurement caused the deformation of the pressure sensitive membrane, leading to stress buildup of the resonator under electrostatic excitation with a corresponding shift of the resonant frequency detected piezoresistively. The proposed microsensor was fabricated by simplified SOI-MEMS technologies and characterized by both open-loop and closed-loop circuits, producing a quality factor higher than 10,000, a sensitivity of 79.44 Hz/kPa and an accuracy rate of over 0.01% F.S. In comparison to the previously reported resonant piezoresistive sensors, the proposed device used single-crystal silicon as piezoresistors, which was featured with low DC biased voltages, simple sensing structures and fabrication steps. In addition, the two double-ended tuning forks were used as resonators, producing high quality factors and differential outputs, which further improved the sensor performances.

High and Moderate-Level Vacuum Packaging of Vibratory MEMS

2013 ◽  
Vol 2013 (1) ◽  
pp. 000705-000710 ◽  
Author(s):  
Igor P. Prikhodko ◽  
Brenton R. Simon ◽  
Gunjana Sharma ◽  
Sergei A. Zotov ◽  
Alexander A. Trusov ◽  
...  
Keyword(s):  
Vacuum Packaging ◽  
Moderate Level ◽  
Silicon On Insulator ◽  
Quality Factors ◽  
High Q ◽  
Hermetic Sealing ◽  
Hemispherical Resonator ◽  
Q Factors ◽  
Grade Performance

We report vacuum packaging procedures for low-stress die attachment and versatile hermetic sealing of resonant MEMS. The developed in-house infrastructure allows for both high and moderate-level vacuum packaging addressing the requirements of various applications. Prototypes of 100 μm silicon-on-insulator Quadruple Mass Gyroscopes (QMGs) were packaged using the developed process with and without getters. Characterization of stand-alone packaged devices with no getters resulted in stable quality factors (Q-factors) of 1000 (corresponding to 0.5 Torr vacuum level), while devices sealed with activated getters demonstrated Q-factors of 1.2 million (below 0.1 mTorr level inside the package). Due to the high Q-factors achieved in this work, we project that the QMG used in this work can potentially reach the navigation-grade performance, potentially bridging the gap between the inertial silicon MEMS and the state-of-the-art fused quartz hemispherical resonator gyroscopes.

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

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 577 ◽  
Author(s):  
Muhammad Saqib ◽  
Muhammad Mubasher Saleem ◽  
Naveed Mazhar ◽  
Saif Awan ◽  
Umar Shahbaz Khan
Keyword(s):  
Resonant Frequency ◽  
Analytical Model ◽  
Actuation Voltage ◽  
High Gain ◽  
Sense Mode ◽  
Drive Mode ◽  
Mass System ◽  
Mems Gyroscope ◽  
Flat Region ◽  
Thermally Actuated

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   f F and 862.13   f F is achieved corresponding to the sense mode amplitude of 0.15   μ m and 4.5   μ m at atmospheric air pressure and in a vacuum, respectively.

scholarly journals Frequency Modulated Magnetometer Using a Double-Ended Tuning Fork Resonator

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1028 ◽  
Author(s):  
Eurico Esteves Moreira ◽  
João Gaspar ◽  
Luis Alexandre Rocha
Keyword(s):  
Lorentz Force ◽  
Tuning Fork ◽  
Force Transducer ◽  
Silicon On Insulator ◽  
Input Current ◽  
Experimental Characterization ◽  
Total Input ◽  
Out Of Plane ◽  
Sensor Configuration

A Lorentz force MEMS magnetometer based on a double-ended tuning fork (DETF) for out-of-plane sensing is presented here. A novel configuration using a hexagonal-shaped Lorentz force transducer is used, which simplifies the sensor configuration and improves its sensitivity. Frequency modulated devices were fabricated in an in-house process on silicon on insulator wafers (SOI) and then tested in vacuum. The final devices have a differential configuration and experimental characterization shows a sensitivity of 4.59 Hz/mT for a total input current (on the Lorentz bar) of 1.5 mA.

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