Abstract
Vibration measurements on rolling tires are of increasing interest in the automotive industry, because tires play a fundamental rule in vehicles handling and performance. Moreover tires also produce noise, which is strictly related to their vibrational behaviour. To obtain realistic results on the dynamic characteristics of the tire, laboratory tests should be performed under simulated operative conditions, that is, when the tire is rolling. This task is not easy to achieve with traditional measurement techniques. In this paper a Lagrangian approach, using a modified Laser Doppler Vibrometer, is proposed. Scanning hardware and control software have been design to measure the sidewall vibration of a tire with respect to a moving reference frame, in order to obtain a tracking synchronised with the rotating structure. Results on two different types of tire and at two different velocities are presented. Vibration data are analysed in the time domain, in the frequency domain and in the time-scale plane, using wavelets.