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Optical Engineering

New oscillation detector system based on the moiré technique
Author(s): Shamseddin Esmaeili; Anooshiravan Ansari; Hosseain Hamzehloo
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Paper Abstract

We have described a method to detect characteristics of an oscillation system based on the moiré technique. We can determine amplitude, resonance frequency, and damping coefficient of an oscillating system both in vertical and horizontal directions. For this approach, the displacement of the oscillatory mass must be accurately determined. The displacement is recorded by the moiré detecting procedure. A spring-suspended mass, whose position is monitored by moiré technique, is used to test this idea. Our detecting system consists of a pair of similar gratings which are installed near each other without physical contact. The planes of the gratings are parallel and the lines of gratings have a small angle with respect to each other. Also, a laser diode, a silicon photo-diode, and a narrow slit have been used and fixed to the frame to illuminate fringes’ displacement due to the suspended mass movement. The displacement of the mass relative to the fixed grating changes the light intensity on the detector. The intensity of the light is recorded as voltage by the light detector. The output voltage can be used to measure the oscillator movement. This method can detect displacements of the order of microns. Also, the experimental result and theoretical simulation are compared.

Paper Details

Date Published: 12 October 2015
PDF: 6 pages
Opt. Eng. 54(10) 105103 doi: 10.1117/1.OE.54.10.105103
Published in: Optical Engineering Volume 54, Issue 10
Show Author Affiliations
Shamseddin Esmaeili, International Institute of Earthquake Engineering and Seismology (Iran)
Anooshiravan Ansari, International Institute of Earthquake Engineering and Seismology (Iran)
Hosseain Hamzehloo, International Institute of Earthquake Engineering and Seismology (Iran)

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