scholarly journals An Improved Phase-Robust Configuration for Vibration Amplitude-Phase Extraction for Capacitive MEMS Gyroscopes

Micromachines ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 362 ◽  
Author(s):  
Xudong Zheng ◽  
Siqi Liu ◽  
Yiyu Lin ◽  
Haibin Wu ◽  
Lai Teng ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
Microelectromechanical Systems ◽  
Phase Variation ◽  
Phase Information ◽  
Side Band ◽  
Deviation Analysis ◽  
Mems Gyroscopes ◽  
Capacitive Mems ◽  
Bias Instability ◽  
Improved Algorithm

This paper presents for the first time an improved algorithm for vibration amplitude-phase information extraction of capacitive microelectromechanical systems (MEMS) gyroscopes. Amplitude and phase information resulting from the improved algorithm is insensitive to the phase variation of an interface capacitance-voltage (CV) circuit, thus both long time drift of the gyroscope and bias instability have been improved. Experimental results show that both the phase and amplitude information extracted using this improved algorithm is insensitive to phase variation of CV circuit which is in accordance with theory. Bias instability using this improved configuration is 0.64°/h, which is improved two times more than the configuration using traditional double-side-band (DSB) demodulation configuration, and 4.3 times more than the configuration using single-side-band (SSB) demodulation, respectively. Allan deviation analysis shows that the slow varying drift term using D&S configuration is effectively reduced due to its robustness to CV phase variation compared to test results using DSB or SSB configuration.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

Interface Circuits for Capacitive MEMS Gyroscopes

MEMS ◽  
2017 ◽  
pp. 161-181
Author(s):  
Hongzhi Sun ◽  
Huikai Xie
Keyword(s):  
Interface Circuits ◽  
Mems Gyroscopes ◽  
Capacitive Mems

Decoupled Quadrature and Force Feedback Control of Capacitive MEMS Gyroscopes*

2011 ◽  
Vol 44 (1) ◽  
pp. 13534-13539 ◽  
Author(s):  
Markus Egretzberger ◽  
Florian Mair ◽  
Andreas Kugi
Keyword(s):  
Feedback Control ◽  
Force Feedback ◽  
Mems Gyroscopes ◽  
Capacitive Mems

scholarly journals A Decoupling Design with T-Shape Structure for the Aluminum Nitride Gyroscope

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 244
Author(s):  
Yang ◽  
Si ◽  
Han ◽  
Zhang ◽  
Ning ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Microelectromechanical Systems ◽  
Sense Mode ◽  
Drive Mode ◽  
Aln Film ◽  
Shape Structure ◽  
Mems Gyroscopes ◽  
Sense Electrode ◽  
Working Principle ◽  
Novel Design

This paper reports a novel design for the decoupling of microelectromechanical systems (MEMS) gyroscopes. The MEMS gyroscope is based on piezoelectric aluminum nitride (AlN) film, and the main structure is a mass hung by T-shape beams. A pair of parallel drive electrodes are symmetrically placed on the surface of the vertical bar for driving the oscillating mass. A serpentine sense electrode is placed on the lateral bar. When the gyroscope is oscillating in drive mode, charges with equal quantity and opposite sign will be polarized and distributed symmetrically along the lateral bar. These charges neutralize each other at the sense electrode. Therefore, no coupling signals can be detected from the sense electrode. This design can realize the decoupling between the drive mode and sense mode. In this work, the T-shape decoupled structure was designed as the key component of an AlN piezoelectric gyroscope and the whole structure was simulated by COMSOL Multiphysics 5.2a. The working principle of the decoupling is described in detail. Electrical properties were characterized by the dynamic signal analyzer. According to the test results, the drive mode and the sense mode are decoupled. The coefficient of orthogonal coupling is 1.55%.

Design Optimization for Non-Resonant MEMS Gyroscope

2009 ◽  
Author(s):  
Wei Cui ◽  
Xiaolin Chen ◽  
Wei Xue
Keyword(s):  
Device Performance ◽  
Sense Mode ◽  
Drive Mode ◽  
Resonant Frequencies ◽  
Frequency Matching ◽  
Wide Range ◽  
Mems Gyroscopes ◽  
Capacitive Mems ◽  
Effective Design ◽  
Model Approach

Conventional capacitive MEMS gyroscopes require close matching between the resonant frequencies of drive mode and sense mode. However, the uncertainties in the microfabrication process impair the robustness of the gyroscopes and often lead to unpredictable device performance. This paper analyzes a 4 degree-of-freedom (DOF) non-resonant gyroscope which is less vulnerable to the fabrication perturbations. Unlike the conventional resonant gyroscope which has only one resonant frequency for drive and sense modes, the 4-DOF gyroscope includes two resonant frequencies for each mode. The non-resonant gyroscope design aims to reduce resonance frequency matching, namely to minimize the effect of the inevitable fabrication uncertainties as well as to increase the bandwidth with less sacrifice to the sensitivity. The device performance is analyzed and optimized by the behavior model approach in CoventorWare which significantly accelerates the simulation compared to the traditional finite element method. The optimized non-resonant gyroscope with higher fabrication tolerance as well as enhanced device performance is proven to be an effective design and can be used in a wide range of applications.

scholarly journals Research on a 3D Encapsulation Technique for Capacitive MEMS Sensors Based on Through Silicon Via

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
Meng Zhang ◽  
Jian Yang ◽  
Yurong He ◽  
Fan Yang ◽  
Fuhua Yang ◽  
...  
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Anodic Bonding ◽  
Mems Sensors ◽  
Through Silicon Via ◽  
Hermetic Packaging ◽  
Order Of Magnitude ◽  
Capacitive Mems

A novel three-dimensional (3D) hermetic packaging technique suitable for capacitive microelectromechanical systems (MEMS) sensors is studied. The composite substrate with through silicon via (TSV) is used as the encapsulation cap fabricated by a glass-in-silicon (GIS) reflow process. In particular, the low-resistivity silicon pillars embedded in the glass cap are designed to serve as the electrical feedthrough and the fixed capacitance plate at the same time to simplify the fabrication process and improve the reliability. The fabrication process and the properties of the encapsulation cap were studied systematically. The resistance of the silicon vertical feedthrough was measured to be as low as 263.5 mΩ, indicating a good electrical interconnection property. Furthermore, the surface root-mean-square (RMS) roughnesses of glass and silicon were measured to be 1.12 nm and 0.814 nm, respectively, which were small enough for the final wafer bonding process. Anodic bonding between the encapsulation cap and the silicon wafer with sensing structures was conducted in a vacuum to complete the hermetic encapsulation. The proposed packaging scheme was successfully applied to a capacitive gyroscope. The quality factor of the packaged gyroscope achieved above 220,000, which was at least one order of magnitude larger than that of the unpackaged. The validity of the proposed packaging scheme could be verified. Furthermore, the packaging failure was less than 1%, which demonstrated the feasibility and reliability of the technique for high-performance MEMS vacuum packaging.

Performance of MEMS Vibratory Gyroscope under Harsh Environments

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000633-000654 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Temperature Effect ◽  
High Frequency ◽  
Microelectromechanical Systems ◽  
Rate Of Change ◽  
Harsh Environments ◽  
Harsh Environment ◽  
Thermal Cycles ◽  
Mems Gyroscope ◽  
Vibratory Gyroscope ◽  
Mems Gyroscopes

Microelectromechanical systems (MEMS) gyroscope is a sensor that measures the rate of change in an angular position of an object. MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers.With advances in fabrication technologies, the low-cost MEMS gyroscope has opened up a wide variety of applications with environmental conditions ranging from medium to harsh. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the effects of high mechanical shock, high frequency vibration and high frequency acoustic environment on the MEMS gyroscopes,the effects of sustained exposure to temperature combined withother harsh environment stresseshave not been well researched.Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions.This research reviews current harsh environment studies anddemonstrates the effects of an elevated temperature and sustained exposure to temperature combined humidity on the MEMS vibratory gyroscope. In order to quantify such effects, several tests have been performed. A short-term temperature effect on MEMS gyroscope was examined through temperature characterization test forfive thermal cycles at wider temperature ranges. A long-term temperature effect on the MEMS gyroscope was inspected through 500 thermal cycles; while, combined effects of temperature and humidity was studied through temperature humidity bias(THB) test and highly accelerated stress test (HAST).

scholarly journals The Characteristics and Locking Process of Nonlinear MEMS Gyroscopes

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 233
Author(s):  
Yan Su ◽  
Pengfei Xu ◽  
Guowei Han ◽  
Chaowei Si ◽  
Jin Ning ◽  
...  
Keyword(s):  
Harmonic Balance ◽  
Vibration Amplitude ◽  
Harmonic Balance Method ◽  
Micro Electro Mechanical System ◽  
Drive Mode ◽  
Iterative Calculation ◽  
Start Up ◽  
Mems Gyroscopes ◽  
Order Of Magnitude ◽  
Frequency Curves

With the miniaturization of micro-electro-mechanical system (MEMS) gyroscopes, it is necessary to study their nonlinearity. The phase-frequency characteristics, which affect the start-up time, are crucial for guaranteeing the gyroscopes’ applicability. Nevertheless, although the amplitude-frequency (A-f) effect, one of the most obvious problems in nonlinearity, has been well studied, the phase response of nonlinear gyroscopes is rarely mentioned. In this work, an elaborate study on the characteristics and locking process of nonlinear MEMS gyroscopes is reported. We solved the dynamic equation using the harmonic balance method and simulated the phase-locked loop (PLL) actuation process with an iterative calculation method. It was shown that there existed an apparent overhanging and multi-valued phenomenon in both the amplitude–frequency and phase–frequency curves of nonlinear gyroscopes. Meanwhile, it was ascertained by our simulations that the locking time of PLL was retarded by the nonlinearity under certain conditions. Moreover, experiments demonstrating the effect of nonlinearity were aggravated by the high quality factor of the drive mode due to the instability of the vibration amplitude. A nonlinear PLL (NPLL) containing an integrator was designed to accelerate the locking process. The results show that the start-up time was reduced by an order of magnitude when the appropriate integral coefficient was used.

scholarly journals Strapdown Inertial Navigation Systems for Positioning Mobile Robots—MEMS Gyroscopes Random Errors Analysis Using Allan Variance Method

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4841 ◽  
Author(s):  
Andrii V. Rudyk ◽  
Andriy O. Semenov ◽  
Natalia Kryvinska ◽  
Olena O. Semenova ◽  
Volodymyr P. Kvasnikov ◽  
...  
Keyword(s):  
Inertial Navigation ◽  
Allan Variance ◽  
Measurement Unit ◽  
Navigation Systems ◽  
Random Errors ◽  
Inertial Navigation Systems ◽  
Mems Gyroscopes ◽  
Bias Instability ◽  
Errors Analysis ◽  
Strapdown Inertial Navigation

A problem of estimating the movement and orientation of a mobile robot is examined in this paper. The strapdown inertial navigation systems are often engaged to solve this common obstacle. The most important and critically sensitive component of such positioning approximation system is a gyroscope. Thus, we analyze here the random error components of the gyroscope, such as bias instability and random rate walk, as well as those that cause the presence of white and exponentially correlated (Markov) noise and perform an optimization of these parameters. The MEMS gyroscopes of InvenSense MPU-6050 type for each axis of the gyroscope with a sampling frequency of 70 Hz are investigated, as a result, Allan variance graphs and the values of bias instability coefficient and angle random walk for each axis are determined. It was found that in the output signals of the gyroscopes there is no Markov noise and random rate walk, and the X and Z axes are noisier than the Y axis. In the process of inertial measurement unit (IMU) calibration, the correction coefficients are calculated, which allow partial compensating the influence of destabilizing factors and determining the perpendicularity inaccuracy for sensitivity axes, and the conversion coefficients for each axis, which transform the sensor source codes into the measure unit and bias for each axis. The output signals of the calibrated gyroscope are noisy and offset from zero to all axes, so processing accelerometer and gyroscope data by the alpha-beta filter or Kalman filter is required to reduce noise influence.

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