Article

# Measuring displacement signal with an accelerometer

Journal of Mechanical Science and Technology (Impact Factor: 0.7). 06/2010; 24(6):1329-1335. DOI: 10.1007/s12206-010-0336-1

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**ABSTRACT:**Vibration measurement and its real-time graphical representation is often required for analysis of physical conditions of machines, engines as well as in scientific researches, earth-quake amplitude measurement etc. This project work was intended to develop a system for measurement and real-time visualization of vibration. An electronic accelerometer sensor facilitates the vibration sensing procedure. The measured value is then transmitted to the visualization software installed in a personal computer which provides quantitative and qualitative information about the vibration phenomena in addition with a real-time graphical visualization feature. Two test cases were selected to verify the performance of the system. The first one was implemented to visualize and measure vibration parameters of a simple plastic stand, and the second one was intended to test the system performance on an induction motor for measurement and visualization of its horizontal vibration parameters. The performance analysis in the above mentioned cases confirms the stability and reliability of the system in vibration analysis for frequency range up to 5 kHz. This concludes to a low cost vibration analysis system for uses in medium range vibration analysis like earth quake monitoring, machine vibration level monitoring etc. Though there are many available vibrations analysis systems are available, this paper work is intended to derive the process of building a low cost PIC microcontroller and C# .NET based vibration analysis system for general purpose uses like laboratory equipment or study material from commercially available equipmentInternational Conference on Electrical Engineering and Information & Communication Technology (ICEEICT) 2014; 04/2014 - [Show abstract] [Hide abstract]

**ABSTRACT:**Accelerometers are used to measure velocity and displacement in many applications such as ship motion, monitoring of civil and mechanical structure, seismology and machine condition monitoring. However, using direct numerical integration to calculate velocity and displacement from the acceleration signal is known to suffer from low frequency noise amplification and wind-up. In this paper, a Kalman filter based method is proposed for calculating displacement from measured acceleration. Integration wind-up is eliminated by incorporating an additional state variable, namely the integral of the displacement whose "measured" value is assumed to be equal to the known average value of the displacement. In many applications, such as those in marine environment, this average value can be assumed to be constant, usually conveniently assigned to be zero if non-linear behaviour and permanent deformations are deemed negligible. The paper describes the technique and investigates its performance under different conditions of amplitude and frequency of vibrations and sampling rate and validates it by conducting two laboratory experiments. In the first experiment the displacement of a small shaker is calculated from a relatively high frequency (tens of Hz) acceleration signal sampled at 1 kHz with a resolution of 1 g. The calculated displacement of the shaker is found to agree well with that measured using a high resolution laser. In the second experiment, the proposed method is applied to the calculation of the vertical displacement of a boat from a low frequency (less than 1 Hz) acceleration signal sampled at 5 Hz and a resolution of 0.01g. An experimental set up designed to mimic typical motion of a boat is used to validate the results. Although the method explained in this paper is used to calculate the vertical displacement of a boat, it can be applied for calculating the displacement in a wide range of applications with reciprocating movement.Marine Engineering Frontiers (MEF). 08/2014; - [Show abstract] [Hide abstract]

**ABSTRACT:**In many respects, accelerometers are convenient for measuring the lateral vibrations of a gun tube under impulse loads. Reliable measurements by accelerometers must overcome two issues: exceedingly large acceleration at high frequencies due to stress waves, and the elimination of drifts accumulating through the integration of acceleration signals. In this paper, we use a mechanical filter that reduces the effect of stress waves. Also, we propose a new double integration algorithm based on multi-resolution wavelet decomposition. Using a test-rig, we measure the vibration characteristics of commercially-available damping materials. Based on the test results, we design a mechanical filter and experimentally verify the performance of the filter. The proposed double integration algorithm is shown to be as effective as other existing algorithms without arbitrary selection of parameters.Journal of Mechanical Science and Technology 12/2012; 25(12). · 0.70 Impact Factor

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