Halkon, Ben J.
Rothberg, Steve
Continuous scanning laser vibrometry for measurements on rotating structures
It is readily accepted that a Laser Vibrometer measures target velocity in the direction of
the incident laser beam but it is essential that, for correct measurement interpretation, the target
velocity be considered in terms of the various target motion components. This paper begins with a
review of the theoretical description of the velocity sensed by a dual mirror scanning Laser
Vibrometer incident in an arbitrary direction on a rotating target of flexible cross-section
undergoing arbitrary vibration. This comprehensive velocity sensitivity model can be applied to any
Laser Vibrometer measurement configuration on any target and is sufficiently versatile to
incorporate time dependent beam orientation. This is described in this paper with particular
reference to continuous circular scanning Laser Doppler Vibrometry.
The velocity sensitivity model allows a detailed analysis of the form of the measurement that is
obtained in actual scan configurations. For example, additional components occur in a circular
scanning Laser Vibrometer measurement on a rotating target that can be shown to be due to a
combination of instrument configuration and target misalignment. In this paper, the measured data
obtained from a circular scanning measurement on a rotating target undergoing axial vibration is
investigated as a means of demonstrating the usefulness of the comprehensive velocity sensitivity
model.
Laser Doppler vibrometry;Scanning;Tracking;Velocity sensitivity;Vibration measurement;Rotating machinery
2009-12-07
https://repository.lboro.ac.uk/articles/Continuous_scanning_laser_vibrometry_for_measurements_on_rotating_structures/9549539