Design of Proof Mass and System-Level Simulation of a Micromachined Electrostatically Suspended Accelerometer

2011 ◽  
Vol 317-319 ◽  
pp. 1631-1634
Author(s):  
Zhen Wan ◽  
Feng Cui ◽  
Yun Kui Zhang ◽  
Wu Liu ◽  
Wen Yuan Chen ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Proof Mass ◽  
Sacrificial Layer ◽  
Perforated Plate ◽  
Element Model ◽  
System Level ◽  
Squeeze Film ◽  
System Level Simulation ◽  
Squeeze Film Damping ◽  
Level Model

A six-axis Micromachined Electrostatically Suspended Accelerometer (MESA) which is based on LIGA-type microfabrication was designed. MESA employs a levitated perforated plate as its proof mass. Three main purposes are considered for the design of the perforated proof mass: (1) reducing squeeze-film effect; (2) improving the dynamic response of MESA; (3) facilitating the etching of sacrificial layer under the plate. This paper utilized a finite element model for evaluating air squeeze film damping effect of perforated proof mass. Among several designs of perforated proof mass, the best choice was found. Besides, a system-level model created in CoventorWare is used to evaluate the effect of squeeze film damping and the dynamic response of the MESA.

Modeling of Capacitive Microaccelerometers with Squeeze Film Damping and Electrostatic Effects Using Model Order Reduction

2009 ◽  
Vol 60-61 ◽  
pp. 213-218
Author(s):  
Ya Fei Zhang ◽  
Wei Zheng Yuan ◽  
Hong Long Chang ◽  
Jing Hui Xu
Keyword(s):  
Model Order Reduction ◽  
Order Reduction ◽  
System Level ◽  
Squeeze Film ◽  
Electrostatic Effects ◽  
Model Order ◽  
Circuit Simulator ◽  
System Level Simulation ◽  
Squeeze Film Damping ◽  
Hardware Description

Model order reduction is an effective method to generate macromodels for system-level simulation. But it is difficult to deal with the electro-mechanical-damping coupling problems. So we presents a new approach to model the capacitive microaccelerometers with squeeze film damping and electrostatic effects using model order reduction (MOR) method. In this approach, the mechanical, squeeze film damping and electrostatic domains of the devices are modeled separately and then coupled at system-level. The macromodel for squeezed film damping effects could account for slip condition of the flow at low pressure and edge effects. In addition, some important parameters are preserved as symbol. The extracted macromodels are translated into the hardware description language and imported into a circuit simulator. An accelerometer is used to demonstrate the feasibility and efficiency of the proposed approach. Numerical simulation results show that the extracted macromodel can dramatically reduce the computation cost while capturing the device behavior accurately.

scholarly journals System-Level Model and Simulation of a Frequency-Tunable Vibration Energy Harvester

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 91 ◽  
Author(s):  
Sofiane Bouhedma ◽  
Yongchen Rao ◽  
Arwed Schütz ◽  
Chengdong Yuan ◽  
Siyang Hu ◽  
...  
Keyword(s):  
Energy Harvester ◽  
Element Model ◽  
Industrial Applications ◽  
System Level ◽  
Dual Frequency ◽  
Frequency Range ◽  
Vibration Energy Harvester ◽  
Resonance Frequencies ◽  
Level Model ◽  
System Level Model

In this paper, we present a macroscale multiresonant vibration-based energy harvester. The device features frequency tunability through magnetostatic actuation on the resonator. The magnetic tuning scheme uses external magnets on linear stages. The system-level model demonstrates autonomous adaptation of resonance frequency to the dominant ambient frequencies. The harvester is designed such that its two fundamental modes appear in the range of (50,100) Hz which is a typical frequency range for vibrations found in industrial applications. The dual-frequency characteristics of the proposed design together with the frequency agility result in an increased operative harvesting frequency range. In order to allow a time-efficient simulation of the model, a reduced order model has been derived from a finite element model. A tuning control algorithm based on maximum-voltage tracking has been implemented in the model. The device was characterized experimentally to deliver a power output of 500 µW at an excitation level of 0.5 g at the respected frequencies of 63.3 and 76.4 Hz. In a design optimization effort, an improved geometry has been derived. It yields more close resonance frequencies and optimized performance.

Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

2007 ◽  
Author(s):  
Daniel E. Jordy ◽  
Mohammad I. Younis
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Squeeze Film ◽  
Dynamical Response ◽  
Mems Devices ◽  
Damping Coefficients ◽  
Squeeze Film Damping ◽  
Out Of Plane ◽  
Gap Width

Squeeze film damping has a significant effect on the dynamic response of MEMS devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering the damping. By decreasing the size of the holes, the damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze-film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, we consider a G-sensor, which is a sort of a threshold accelerometer, employed in an arming and fusing chip. We study the effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate. We use a multi-physics finite-element model built using the software ANSYS. First, a modal analysis is conducted to calculate the out-of-plane natural frequency of the G-sensor. Then, a squeeze-film damping finite-element model, for both the air underneath the structure and the flow of the air through the perforations, is developed and utilized to estimate the damping coefficients for several hole sizes. Results are shown for various models of squeeze-film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. The extracted damping coefficients are then used in a transient structural-shock analysis. Finally, the transient shock analysis is used to determine the shock loads that induce contacts between the G-sensor and the underlying substrate. It is found that the threshold of shock to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.

The Effect of Squeeze-Film Damping on Suppressing the Shock Response of MEMS

2009 ◽  
Author(s):  
Hadi Yagubizade ◽  
Mohammad I. Younis ◽  
Ghader Rezazadeh
Keyword(s):  
Reynolds Equation ◽  
Element Model ◽  
Squeeze Film ◽  
Beam Equation ◽  
Mechanical Shock ◽  
Shock Loads ◽  
Reduced Order ◽  
Squeeze Film Damping ◽  
Nonlinear Finite Element Model ◽  
Euler Bernoulli Beam

This paper presents an investigation into the response of a clamped-clamped microbeam to mechanical shock under the effect of squeeze-film damping (SQFD). In this work, we solve simultaneously the nonlinear Reynolds equation, to model squeeze-film damping, coupled with a nonlinear Euler-Bernoulli beam equation. A Galerkin-based reduced-order model and a finite-deference method (FDM) are utilized for the solid domain and for the fluid domain, respectively. Several results showing the effect of gas pressure on the response of the microbeams are shown. Comparison with the results of a multi-physics nonlinear finite-element model is presented. The results indicate that squeeze-film damping has more significant effect on the response of microstructures in the dynamic shock loads compared to the quasi-static shock loads.

Design and System Level Simulation of Double-Mass Silicon Micro Gyroscope

2011 ◽  
Vol 138-139 ◽  
pp. 681-686
Author(s):  
Qin Shi ◽  
An Ping Qiu ◽  
Su Yan ◽  
Rui Feng
Keyword(s):  
System Level ◽  
Performance Parameters ◽  
System Level Simulation ◽  
Bias Stability ◽  
Signal Characteristics ◽  
Double Mass ◽  
Level Model ◽  
Working Principle ◽  
System Level Model ◽  
Electrostatic Coupling

The double-mass silicon micro gyroscope prototype, mechanical structure and working principle are introduced, which has high sesitivity. According to dynamic equations, the signal characteristics are analyzed and the mathematical models of scale factro and bias are established. Then the system level model is established on Simulink platform, including mechanical errors and electrostatic coupling errors and the performance are evaluated. Finally, five gyroscope prototypes are tested, and the performance parameters are as follows, the scale factor is 15.63~19.210mV/°/s, bias stability is 8.9~23.9°/h, bias repeatability is 7.5~19.4°/h.

Squeeze film damping effect on the dynamic response of a MEMS torsion mirror

1998 ◽  
Vol 8 (3) ◽  
pp. 200-208 ◽  
Author(s):  
Feixia Pan ◽  
Joel Kubby ◽  
Eric Peeters ◽  
Alex T Tran ◽  
Subrata Mukherjee
Keyword(s):  
Dynamic Response ◽  
Squeeze Film ◽  
Damping Effect ◽  
Squeeze Film Damping

A Comparative Study of Thin-Film and Reynolds Equation Simulation Models for Squeeze Film Damping in MEMS Plate Structures

2011 ◽  
Vol 403-408 ◽  
pp. 4580-4587
Author(s):  
Wei Guo Liu ◽  
Wei Wang ◽  
Shou Jun Peng
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Knudsen Number ◽  
Parallel Plate ◽  
Reynolds Equation ◽  
Perforated Plate ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Knudsen Numbers ◽  
Viscosity Modification

Squeeze film damping effect of MEMS parallel plate structure was analyzed based on thin film and Reynolds Equation in ANSYS under the different Knudsen numbers. Perforation effect of parallel plate with certain size and operating frequency was achieved under the different Knudsen numbers, the simulation results of two methods are very close. For unperforated plate, when Knudsen number is below 0.01, the discrepancy of two simulations is nonsignificant, and it grows up with Knudsen number. But gas rarefaction effects related with Knudsen number was considered in heat transfer analogy theory and used viscosity modification according to Veijola model, two simulations get the same result. For perforated plate, the simulation discrepancy of two methods will be great because of channel flow's effect and also grow up with Knudsen number, it can't be avoided even if the channel flow's effect and viscosity modification were concerned in heat transfer analogy theory.

Dynamic Response of a Piezoelectric Flextensional Microactuator

2005 ◽  
Author(s):  
Jongpil Cheong ◽  
Srinivas Tadigadapa ◽  
Christopher D. Rahn
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Natural Frequencies ◽  
Rf Mems ◽  
Squeeze Film ◽  
Beam Shape ◽  
Initial Beam ◽  
Carbon Tape ◽  
Squeeze Film Damping ◽  
Soft Carbon

Microactuators capable of providing high resolution displacement and controlled force have many applications in RF MEMS, microfluidics, and motion control. This paper theoretically and experimentally investigates the dynamic response of a piezoelectric flextensional microactuator consisting of a clamped beam that buckles in response to contraction of a bonded PZT support. The DRIE and solder bonding fabrication process produces beams with initial curvature that affects their dynamic response. Unlike previous research where sinusoidal initial beam shapes are analyzed, polynomial initial beam shape enables more accurate prediction of beam natural frequencies and frequency response when compared with experimental results. The inclusion of squeeze film damping between the beam and PZT support enables the model to predict frequency response. Experiments show that mounting the PZT with soft carbon tape limits PZT vibration.

Displacement Amplifying Compliant Mechanisms for Two-Axis High-Resolution Monolithic Inertial Sensors

2008 ◽  
Author(s):  
M. Dinesh ◽  
G. K. Ananthasuresh
Keyword(s):  
High Resolution ◽  
Building Block ◽  
Proof Mass ◽  
Compliant Mechanisms ◽  
Inertial Sensors ◽  
System Level ◽  
Optimal Parameters ◽  
Mass Sensitivity ◽  
System Level Simulation ◽  
Single Piece

Novel designs for two-axis, high-resolution, monolithic inertial sensors are presented in this paper. Monolithic, i.e., joint-less single-piece compliant designs are already common in micromachined inertial sensors such as accelerometers and gyroscopes. Here, compliant mechanisms are used not only to achieve de-coupling between motions along two orthogonal axes but also to amplify the displacements of the proof-mass. Sensitivity and resolution capabilities are enhanced because the amplified motion is used for sensing the measurand. A particular symmetric arrangement of displacement-amplifying compliant mechanisms (DaCMs) leads to de-coupled and amplified motion. An existing DaCM and a new topology-optimized DaCM are presented as a building block in the new arrangement. A spring-mass-lever model is presented as a lumped abstraction of the new arrangement. This model is useful for arriving at the optimal parameters of the DaCM and for performing system-level simulation. The new designs improved the performance by a factor of two or more.

DYNAMIC PULL-IN INSTABILITY AND VIBRATION ANALYSIS OF A NONLINEAR MICROCANTILEVER GYROSCOPE UNDER STEP VOLTAGE CONSIDERING SQUEEZE FILM DAMPING

2013 ◽  
Vol 05 (03) ◽  
pp. 1350032 ◽  
Author(s):  
M. MOJAHEDI ◽  
M. T. AHMADIAN ◽  
K. FIROOZBAKHSH
Keyword(s):  
Differential Equations ◽  
Natural Frequencies ◽  
Proof Mass ◽  
Dynamic Instability ◽  
Squeeze Film ◽  
Electrostatically Actuated ◽  
Damping Coefficients ◽  
Step Voltage ◽  
Runge Kutta Method ◽  
Squeeze Film Damping

In this paper, a nonlinear model is used to analyze the dynamic pull-in instability and vibrational behavior of a microcantilever gyroscope. The gyroscope has a proof mass at its end and is subjected to nonlinear squeeze film damping, step DC voltages as well as base rotation excitation. The electrostatically actuated and detected microgyroscopes are subjected to coupled flexural-flexural vibrations that are related by base rotation. In order to detune the stiffness and natural frequencies of the system, DC voltages are applied to the proof mass electrodes in drive and sense directions. Nonlinear integro differential equations of the system are derived using extended Hamilton principle considering nonlinearities in curvature, inertia, damping and electrostatic forces. Afterward, the Gelerkin decomposition method is implemented to reduce partial differential equations of microgyroscope deflection to a system of nonlinear ordinary equations. By using the 4th order Runge–Kutta method, the nonlinear ordinary equations are solved for various values of damping coefficients, air pressures, base rotation and various initial gaps between the proof mass electrodes and the substrates. Results show that the geometric nonlinearity increases the dynamic pull-in voltage and also consideration of the base rotation gives an improved evaluation of the dynamic instability. It is shown that the squeeze film damping has a considerable influence on the dynamic deflection of the microgyroscopes.

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