Correction of laser Doppler vibrometry measurements affected by steering mirror vibration submitted 13-07-15.pdf (1.77 MB)
Correction of laser Doppler vibrometry measurements affected by steering mirror vibration
conference contribution
posted on 2016-01-26, 13:35 authored by Ben Halkon, Steve RothbergThe laser Doppler vibrometer (LDV) is now well-established as an effective non-contact
alternative to traditional contacting vibration transducers. LDVs are technically well suited to general application but they offer special benefits in a variety of challenging measurement scenarios. A limitation in this respect is sensitivity to vibration of the instrument itself or of any steering optics used to orient the probe laser beam. Making use of a general vectorial framework for modelling the measured velocity, this paper will present a mathematical treatment of the velocity measured in the scenario where the laser beam direction is manipulated by a vibrating mirror. It will be shown that, by knowing the steering mirror vibration, it is possible to completely correct for the
perturbation of the measured signal. A complementary experimental investigation is described. The LDV, the target and the
mirror were relatively carefully aligned with respect to one another enabling three
alternative angles of 90°, 60° and 30° between the instrument and the target vibration
direction. The vibrating target and the steering mirror assemblies were each
instrumented with an accelerometer; the target measurement being the reference or
“true” measurement while the mirror measurement is used to perform the required
correction to the LDV measurement. Simultaneous measurements were taken with either
the target or the mirror vibrating at “high” and “low” broadband levels; the LDV is
shown to over-estimate in the mirror vibration only cases by over 22000 and 11000%
respectively. Post-processing steps are presented which enabled the measurement to be
corrected by circa 35dB.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Published in
Optical Measurement Techniques for Systems & Structures IIIPages
117 - 126Citation
HALKON, B.J. and ROTHBERG, S., 2016. Correction of laser Doppler vibrometry measurements affected by steering mirror vibration. IN: Dirckx, J.J.J. (ed.) Optical Measurement Techniques for Systems & Structures III, Antwerp, Belgium: Shaker Press, pp. 117-126.Publisher
Skaker PressVersion
- SMUR (Submitted Manuscript Under Review)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
2016Notes
This is a conference paper.ISBN
9789042304390Publisher version
Language
- en