Measurement and analysis of certain flight parameters based on MEMS sensors

Abstract. Gyroscopes established one of the fundamental references for attitude and heading in aerospace applications. The information about angular velocities gives input not only for autopilot, but also damping devices, such as yaw or pitch dampers for example. The MEMS (micro-electro-mechanical system) gyroscopes are much less reliable than their laser or fibre-optic cousins. Nevertheless, the availability and low price of MEMS components make this a growing area of application in avionics for general aviation aeroplanes. This paper presents certain results of flight data analysis registered during the flight testing campaign of the new experimental low-power single-engine turbo-propeller utility aeroplane I-31T. The research was focused on identification of oscillation modes, distinctive for the new aeroplane, such as engine precession or shimmy. The data came from a three-axis MEMS gyroscope and accelerometer recorder, placed near to the centre of gravity. Wavelet transform, which was used for analysis, gave better precision in time domain than Fourier transform, especially for signals of low frequency.

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A New Asymptotic Treatment of g-modes of a Star

International Astronomical Union Colloquium ◽

10.1017/s025292110003712x ◽

1995 ◽

Vol 155 ◽

pp. 285-286

Author(s):

P. Smeyers ◽

T. Van Hoolst ◽

I. De Boeck ◽

L. Decock

Keyword(s):

Singular Perturbation ◽

Fourth Order ◽

Asymptotic Expansions ◽

Equilibrium Model ◽

Asymptotic Representation ◽

Radial Displacement ◽

Low Frequency ◽

Order System ◽

Oscillation Modes ◽

Perturbation Problems

An asymptotic representation of low-frequency, linear, isentropic g-modes of a star is developed without the usual neglect of the Eulerian perturbation of the gravitational potential. Our asymptotic representation is based on the use of asymptotic expansions adequate for solutions of singular perturbation problems (see, e.g., Kevorkian & Cole 1981).Linear, isentropic oscillation modes with frequency different from zero are governed by a fourth-order system of linear, homogeneous differential equations in the radial parts of the radial displacement ξ(r) and the divergence α(r). These equations take the formThe symbols have their usual meaning. N2 is the square of the frequency of Brunt-Väisälä. The functions K1 (r), K2 (r), K3 (r), K4 (r), depend on the equilibrium model, e.g.,We introduce the small expansion parameterand assume, for the sake of simplification, N2 to be positive everywhere in the star so that the star is everywhere convectively stable.

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Refactoring and Optimization of Bridge Dynamic Displacement Based on Ensemble Empirical Mode Decomposition

Sensors ◽

10.3390/s19143125 ◽

2019 ◽

Vol 19 (14) ◽

pp. 3125

Author(s):

Zou ◽

Chen ◽

Liu

Keyword(s):

Empirical Mode Decomposition ◽

Field Experiments ◽

Low Frequency ◽

Vibration Signal ◽

Micro Electro Mechanical System ◽

Ensemble Empirical Mode Decomposition ◽

Reconstruction Method ◽

Monitoring Methods ◽

Dynamic Displacement ◽

Mode Decomposition

Considering the lack of precision in transforming measured micro-electro-mechanical system (MEMS) accelerometer output signals into elevation signals, this paper proposes a bridge dynamic displacement reconstruction method based on the combination of ensemble empirical mode decomposition (EEMD) and time domain integration, according to the vibration signal traits of a bridge. Through simulating bridge analog signals and verifying a vibration test bench, four bridge dynamic displacement monitoring methods were analyzed and compared. The proposed method can effectively eliminate the influence of low-frequency integral drift and high-frequency ambient noise on the integration process. Furthermore, this algorithm has better adaptability and robustness. The effectiveness of the method was verified by field experiments on highway elevated bridges.

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Measurement and Analysis of Extremely Low Frequency Electromagnetic Field Exposure in Oman

Journal of Electromagnetic Analysis and Application ◽

10.4236/jemaa.2012.48046 ◽

2012 ◽

Vol 04 (08) ◽

pp. 333-339 ◽

Cited By ~ 1

Author(s):

Abdullah H. Al-Badi

Keyword(s):

Electromagnetic Field ◽

Low Frequency ◽

Field Exposure ◽

Extremely Low Frequency ◽

Measurement And Analysis

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Measurement and Analysis of Low Frequency Magnetic Shielding Performance of Open-Cell Nickel Foam

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/394/3/032122 ◽

2018 ◽

Vol 394 ◽

pp. 032122

Author(s):

Jie He ◽

Hong Ye

Keyword(s):

Nickel Foam ◽

Low Frequency ◽

Magnetic Shielding ◽

Open Cell ◽

Measurement And Analysis

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EFFECTS OF BOUNDARY-LAYER THICKNESS ON FLOW OSCILLATIONS INSIDE OPEN CAVITIES AT SUPERSONIC SPEEDS

Modern Physics Letters B ◽

10.1142/s021798491002255x ◽

2010 ◽

Vol 24 (04n05) ◽

pp. 487-493

Author(s):

DANG-GUO YANG ◽

ZHAO-LIN FAN ◽

JIANG-QIANG LI ◽

DAN YAO

Keyword(s):

Boundary Layer ◽

Layer Thickness ◽

Boundary Layer Thickness ◽

Low Frequency ◽

Cavity Depth ◽

Oscillation Modes ◽

Open Cavities ◽

Flow Oscillations ◽

Unsteady Characteristics ◽

Modified Equation

An experiment was conducted in a wind-tunnel to study the internal acoustic field and flow oscillations inside rectangular-box cavities. The length-to-depth ratio of the cavities was 8. The data presented herein was obtained over a Mach number of 1.5 at a Reynolds number of 2.26×107 per meter with different boundary-layer thicknesses of approximately 24 mm and 5.5 mm. The experimental angle of attack, yawing and rolling angles were 0°. The rules were revealed as governing the effects of boundary-layer thickness on flow oscillations and unsteady characteristics by comparing the experimental results with flow oscillation modes predicated by Rossiter's and Heller's modified equation. The results indicate that a decrease in the ratio of boundary-layer thickness to cavity-depth (δ/D) induces flow oscillations amplification, peak oscillation frequency splitting and shifting phenomena of open cavity tones in the low-frequency region.

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Automotive-grade MEMS sensors used for general aviation

IEEE Aerospace and Electronic Systems Magazine ◽

10.1109/maes.2004.1365012 ◽

2004 ◽

Vol 19 (10) ◽

pp. 13-16 ◽

Cited By ~ 3

Author(s):

L. Sherry ◽

C. Brown ◽

B. Motazed ◽

D. Vos

Keyword(s):

General Aviation ◽

Mems Sensors

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The Earth’s Free Spherical Oscillations of the Great Japan Earthquake

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.622-623.1664 ◽

2012 ◽

Vol 622-623 ◽

pp. 1664-1669 ◽

Cited By ~ 2

Author(s):

Ye Wu ◽

Yong Ge Wan ◽

Liang Ding

Keyword(s):

Free Oscillation ◽

Low Frequency ◽

Earth Model ◽

Frequency Signal ◽

The Earth ◽

Oscillation Modes ◽

Spectral Splitting ◽

Earth’S Free Oscillations ◽

Earth’S Free Oscillation ◽

Digital Seismic Network

An M9.0 earthquake struck Japan on March 11, 2011 and the strong earthquake made continuous oscillation of the Earth. We first studied the Earth’s free oscillations using observations of VHZ channel of China Digital Seismic Network (CDSN). Since the frequency response of seismograph in CDSN suppresses the information of low frequency signal, we do not need to remove the solid tide in our data processing. We extracted 72 clear spherical modes of (0S0,0S2to0S72) of the Earth’s free oscillation and 21 harmonic modes and they are consistent and nearly same with the frequencies of the modes of Preliminary Reference Earth Model (PREM). Spectral splitting phenomenon is observed obviously in0S2,0S3,0S4and1S2free oscillation modes.

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Mockup Investigation of Lightweight Timber Floor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.899.499 ◽

2014 ◽

Vol 899 ◽

pp. 499-504

Author(s):

Juraj Medveď ◽

Bart Ingeleare ◽

Lieven de Geetere

Keyword(s):

Low Cost ◽

Low Frequency ◽

Sound Insulation ◽

Light Weight ◽

Test Results ◽

Lightweight Construction ◽

Frequency Bands ◽

Timber Frame ◽

Measurement And Analysis ◽

The Impact

This paper dealt with measurement and analysis of different floor structures and their acoustic optimization towards the improvement of the impact sound insulation. Special attention goes to light weight timber frame constructions with taking in account the low frequency bands. The aim of the research is to create or design acoustic optimized lightweight floor constructions and mainly to find a good solution to achieve the best possible impact sound insulation for lightweight floors with the lowest possible thickness and low cost. Following contribution is first part of mentioned investigation and deal about test results on mockup lightweight construction.

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