In-situ Compensation on Temperature Coefficient of the Scale Factor for a Single-axis Nano-g Force-balance MEMS Accelerometer

2021 ◽  
pp. 1-1
Author(s):  
Dandan Liu ◽  
Wenjie Wu ◽  
Shitao Yan ◽  
Qiangwei Xu ◽  
Yuanlei Wang ◽  
...  
Keyword(s):  
Temperature Coefficient ◽  
Scale Factor ◽  
Force Balance ◽  
Mems Accelerometer

A Microactuation and Sensing Platform With Active Lockdown for In Situ Calibration of Scale Factor Drifts in Dual-Axis Gyroscopes

2015 ◽  
Vol 20 (2) ◽  
pp. 934-943 ◽  
Author(s):  
Ethem Erkan Aktakka ◽  
Jong-Kwan Woo ◽  
Daniel Egert ◽  
Robert J. M. Gordenker ◽  
Khalil Najafi
Keyword(s):  
Scale Factor ◽  
Sensing Platform

scholarly journals Rheology of till beneath Storglaciären, Sweden

1997 ◽  
Vol 43 (143) ◽  
pp. 172-179 ◽  
Author(s):  
Roger LeB. Hooke ◽  
Brian Hanson ◽  
Neal R. Iverson ◽  
Peter Jansson ◽  
Urs H. Fischer
Keyword(s):  
Strain Rate ◽  
Water Pressure ◽  
Force Balance ◽  
Surface Velocity ◽  
Shear Strain Rate ◽  
Effective Pressure ◽  
Frictional Material ◽  
Image Position ◽  
Gain Access

AbstractIn order to study, in situ, the rheology of a deforming subglacial till, various instruments were emplaced in till beneath Storglaciären, Sweden. Boreholes were used to gain access to the till beneath about 100 m of ice. Tiltmeters provided an estimate of the shear strain rate in the till. Two other instruments yielded measures of till strength. In addition, water pressures were recorded in boreholes and in the till, a computer-controlled distance meter provided an effectively continuous record of the surface velocity and data from frequent surveys of a stake network were used to estimate the mean basal drag, based on a force-balance calculation.Tilt rates varied directly with effective pressure, so decreases in water pressure apparently increased the coupling between the glacier and the bed. Surface speed was either out of phase with tilt or varied independently of tilt. Thus, increases in speed were apparently a consequence either of longitudinal coupling or of reduced coupling between the glacier and the bed; they were not a result of till deformation! Till strength varied directly with effective pressure, which is consistent with it being a Mohr – Coulomb, or frictional material. The devices measuring till strength are presumed to have been pulled through the till at a speed that varied in phase with the surface speed but till strength did not vary systematically with surface speed. This implies that the residual strength of the till is insensitive to strain rate. Thus, the appropriate constitutive equation for till rheology may be of the form:where k is a constant. This is consistent with experimental data reported in the geotechnical literature.

Three-position characterization for the adjustment of MEMS accelerometer scale factor

2020 ◽  
Vol 32 (3) ◽  
pp. 035020
Author(s):  
Tongxu Xu ◽  
Xiang Xu ◽  
Feng Bu ◽  
Dacheng Xu ◽  
Heming Zhao
Keyword(s):  
Scale Factor ◽  
Mems Accelerometer

Effect of excitation voltage on bias temperature coefficient of MEMS sandwich accelerometer

2019 ◽  
Vol 33 (12) ◽  
pp. 1950112 ◽  
Author(s):  
Xianshan Dong ◽  
Qinwen Huang ◽  
Junhua Zhu ◽  
Wei Xu ◽  
Ping Lai
Keyword(s):  
Temperature Coefficient ◽  
Design Parameter ◽  
Closed Loop ◽  
Excitation Voltage ◽  
Temperature Drift ◽  
Mems Accelerometer ◽  
Bias Drift ◽  
Performance Indexes ◽  
Sensor Structure ◽  
Important Design

In MEMS closed-loop accelerometer, excitation voltage is an important design parameter that is related to many performance indexes, and the bias temperature coefficient is a key point for MEMS accelerometer. But the effect of excitation voltage on bias temperature coefficient is not clear and their relation has not yet been established. This paper studies the effect of excitation voltage on bias temperature coefficient of MEMS sandwich accelerometer. The mechanism of their relation is point out, and experiments of bias temperature drift with different excitation voltages are carried out. The measured results show that the excitation voltage influences the bias temperature coefficient of MEMS sandwich accelerometer greatly, and the frame of sensor structure is the main source of bias temperature drift in MEMS sandwich accelerometer. This paper is also helpful for researchers to further understand the source of bias drift in MEMS sandwich accelerometer and make corresponding improvement.

scholarly journals Calibration Method of Accelerometer Based on Rotation Principle Using Double Turntable Centrifuge

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 62
Author(s):  
Xianshan Dong ◽  
Xinlong Huang ◽  
Guizhen Du ◽  
Qinwen Huang ◽  
Yixiong Huang ◽  
...  
Keyword(s):  
Calculation Method ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Scale Factor ◽  
Centripetal Acceleration ◽  
Mems Accelerometer ◽  
Key Technology ◽  
Acceleration Vector ◽  
Back Calculation ◽  
Input Acceleration

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To solve installation errors and obtain the input acceleration in the calibration of the accelerometer, a calibration method based on the rotation principle using a double turntable centrifuge is proposed in this work. The key operation is that the sub-turntable is rotated to make the input axis of the accelerometer perpendicular to the direction of the centripetal acceleration vector. Models of installation errors of angle and radius were built. Based on these models, the static radius and input acceleration can be obtained accurately, and the calibration of the scale factor, nonlinearity and asymmetry can be implemented. Using this method, measurements of the MEMS accelerometer with a range of ±30 g were carried out. The results show that the discrepancy of performance obtained from different installation positions was smaller than 100 ppm after calibrating the input acceleration. Moreover, the results using this method were consistent with those using the back-calculation method. These results demonstrate that the effectiveness of our proposed method was confirmed. This method can measure the static radius directly eliminating the installation errors of angle and radius, and it simplifies the accelerometer calibration procedure.

Surfactant replacement increases compliance in premature lamb lungs during partial liquid ventilation in situ

1998 ◽  
Vol 84 (4) ◽  
pp. 1316-1322 ◽  
Author(s):  
Peter Tarczy-Hornoch ◽  
Jack Hildebrandt ◽  
Thomas A. Standaert ◽  
J. Craig Jackson
Keyword(s):  
Force Balance ◽  
Exogenous Surfactant ◽  
Partial Liquid Ventilation ◽  
Liquid Ventilation ◽  
Lung Inflation ◽  
Surfactant Replacement ◽  
Improve Compliance ◽  
Alveolar Surface ◽  
Force Balance Equation

Treatments available to improve compliance in surfactant-deficient states include exogenous surfactant (ES) and either partial (PLV) or total liquid ventilation (TLV) with perfluorochemical (PFC). Because of the additional air-lung and air-PFC interfaces introduced during PLV compared with TLV, we hypothesized that compliance would be worse during PLV than during TLV. Because surfactant is able to reduce interfacial tension between air and lung as well as between PFC and lung, we further hypothesized that compliance would improve with surfactant treatment before PLV. In excised preterm lamb lungs, we used Survanta for surfactant replacement and perflubron as the PFC. Compliance during PLV was intermediate between TLV and gas inflation, both with and without surfactant. Surfactant improved compliance during PLV, compared with PLV alone. Because of the force-balance equation governing the behavior of immiscible droplets on liquid surfaces, we predict that PFC droplets spread during PLV to cover the alveolar surface in surfactant-deficient lungs during most of lung inflation and deflation but that the PFC would retract into droplets in surfactant-sufficient lungs, except at end inspiration.

Interaction Mechanism between In Situ Nb2C-V2C Nanoparticles and S/L Interface during the Rapid Solidification of Fe-Nb-V Alloy

2011 ◽  
Vol 415-417 ◽  
pp. 285-288
Author(s):  
Chun Xiang Cui ◽  
Yan Chun Li ◽  
Tie Bao Wang ◽  
Shuang Jin Liu ◽  
Suek Bong Kang
Keyword(s):  
Rapid Solidification ◽  
High Speed ◽  
Interaction Mechanism ◽  
Force Balance ◽  
Viscous Force ◽  
Alloy Matrix ◽  
Buoyant Force ◽  
Solid Liquid Interface ◽  
Solid Liquid

This paper deals with the interaction mechanism between in situ Nb2C-V2C nanoparticles and solid/liquid interface during the rapid solidification of Fe-Nb-V alloy ribbons. In situ Nb2C-V2C nanoparticles reinforced Fe alloy matrix composite were carried out by in situ reaction and melt spun with a high-speed centrifugal spray. According to the setting of a force balance for the in situ nanoparticles in front of the S/L interface during the high-speed centrifugal spray of Fe-Nb-V alloy melt as following: F = Fbuoyant force + Frepulsive + Fviscous force + Fcentrifugal force, authors get the critical velocity that S/L interface engulfs particles is proportional to the radius of particles. TEM observation indicates that the less the size of particle is, the more easily S/L interface engulfs particles.

Friction Under Transient Mixed Regime of Lubrication in Conjunction of an Elastic Ring Within a Real Cylinder

2012 ◽  
Author(s):  
C. E. Baker ◽  
S. Theodossiades ◽  
H. Rahnejat
Keyword(s):  
Combustion Engine ◽  
Fuel Efficiency ◽  
Development Program ◽  
Force Balance ◽  
Implicit Assumption ◽  
Cross Sectional ◽  
Compression Ring ◽  
Mixed Regime ◽  
Engine Development

Fuel efficiency is now the over-riding engine development objective. With approximately 50–60% of the input fuel energy in an internal combustion engine lost through thermal and mechanical inefficiencies, friction has been targeted as the arch nemesis in any engine development program. A significant portion of the parasitic frictional losses is due to the top compression ring. This suggests that optimization of tribological performance of the compression ring conjunction warrants much more attention that it has been hitherto afforded. Studies reported thus far take into account ring-bore conformance, based on static fitment of the ring within an out-of-round bore, whose out-of-circularity is affected by manufacturing processes, surface treatment and assembly. The various static fitment analyses presume quasi-static equilibrium between ring tension and gas pressure loading with the generated conjunctional pressures. This is an implicit assumption of ring rigidity whilst in situ, which is in fact not the case in practice. The transient nature of combustion variation means that mere static or quasi-static force balance is inappropriate. Furthermore, the bore is not a right circular cylinder. Thus, its radial cross-sectional out-of-roundness and its axial variation introduce further transience in the ring-bore conformance. Consequently, the net force applied to the ring induces its modal behaviour, which accounts for its instantaneous in situ shape within the bore. These considerations are not taken into account in the often idealized ring-bore tribology. The paper provides transient solution of ring-bore conjunction, when subjected to ring in-plane modal behavior, when the conjunction is subjected to a mixed regime of lubrication, comprising hydrodynamic viscous action and boundary interactions.

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