Vibration measurements using continuous scanning laser Doppler vibrometry: theoretical velocity sensitivity analysis with applications

Abstract

It is readily accepted that a laser vibrometer measures target velocity in the direction of the incident laser beam, but this measured velocity must be considered in terms of the various components of the target velocity. This paper begins with a review of the theoretical description of the velocity sensed by a single laser beam incident in an arbitrary direction on a rotating target undergoing arbitrary vibration. The measured velocity is presented as the sum of six terms, each the product of a combination of geometric parameters, relating to the laser beam orientation, and a combination of motion parameters—the 'vibration sets'.