Hand-arm vibration measurement by a laser scanning vibrometer

Measurement of hand-arm transmitted vibration is a relevant issue for human health and safety. Many measurement problems occur with conventional transducers. In this paper, new measurement techniques are proposed. The methodology is based on a laser scanning vibrometer. Those techniques can be applied in laboratory tests and also to perform field tests on hand-guided vibrating tools, vehicles, and machines. Results of tests performed on different subjects with their hand on three laboratory test devices, designed according to ISO standards, are presented. Comparison of simultaneous measurements performed by the vibrometer and by conventional techniques (accelerometer) has been carried out. Further work has been done in order to test film sensors for measurement of the contact force between the hand and the vibrating surface. First results are here illustrated of film sensor characterisation and mechanical impedance measurements at some points of hands of different subjects, obtained by the laser Doppler vibrometer and by the film sensor.