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Proceedings Paper

System for noncontact measurement of torsional vibrations of shafts
Author(s): Steen Gruner Hanson
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Paper Abstract

A method for measurement of rotational speed and torsional vibrations for semireflective targets is presented. The method is parallel to time-of-flight velocimetry in that a delay time between the passage of a speckle pattern between two detectors is tracked. In this setup the delay corresponds to the passage of scattering structures positioned angularly on the target, here a cylindrical shaft. This is facilitated by observing the subjective speckles in the Fourier plane with respect to the object. The method is proven independently of the location of the object, as well as independently of the diameter of the object. Further, the signal strength is considerably higher than compared with previous laser-based noncontact systems. An implementation is presented and the specifications are given. Tracking of the time delay giving the maximum crosscovariance between the two signals is facilitated by a delay locked loop based on a one-bit digitization of the two input signals.

Paper Details

Date Published: 13 February 1996
PDF: 9 pages
Proc. SPIE 2729, Optical Velocimetry, (13 February 1996); doi: 10.1117/12.233002
Show Author Affiliations
Steen Gruner Hanson, Riso National Lab. (Denmark)

Published in SPIE Proceedings Vol. 2729:
Optical Velocimetry
Maksymilian Pluta; Jan Karol Jabczynski; Mariusz Szyjer, Editor(s)

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