Vibration measurements by tracking laser doppler vibrometer on automotive components

Abstract

This paper describes the application of a Tracking Laser Doppler Vibrometer (TLDV) to the measurement of vibration of some typical automotive component. After a presentation and discussion of the measurement technique, the attention is focused on the development of specific version optimised for each application. The first component analysed is the sidewall of a tire during its rotation in a typical drum test-bench. An optimised version of the TLDV was developed for the specific application adding a trajectory assessment tool based on image analysis, in order to fulfil the accuracy specifications imposed by tire manufacturer. The second automotive component is a timing belt. This application presents problems related to the high-speed linear motion and to data processing for noise rejection. The third application is on windscreen wipers. In this case the tracking approach fully demonstrate his capabilities, representing the only technique able to give information in the time domain on the dynamic behaviour of the rubber blade in operative conditions. All the application shows as the TLDV allows to obtain realistic results on the dynamic characteristics under simulated operative conditions. A Lagrangian approach was adopted: data were acquired with the target in continuously changing conditions and that impose a not traditional approach on LDV data such as a joint time-frequency analysis.