Primary accelerometer calibration by scanning laser Doppler vibrometry

Abstract

A primary calibration system for vibration transducers based on laser Doppler vibrometry was complemented by a commercial scan unit. The data acquisition and analysis were optimized for accuracy and a novel procedure to visualize and compensate parasitic rigid-body motion was developed. Additionally, effects related to drift during the calibration process were explicitly taken into account and compensated, thereby allowing an automated measurement of spatial sensitivity distributions at hundreds of measurement positions with the same accuracy as a single-point primary calibration. The system was applied to study the influence of rocking and deforming motion on the apparent sensitivity of back-to-back vibration transducers during the calibration process. New insights were gained by interpreting the measured spatial sensitivity distributions as operational deflection shapes.