Experimental analysis of friction-induced vibrations at the finger contact surface

When a finger moves to scan the surface of an object, the sliding contact generates vibrations that propagate in the finger skin and transmit the information about the object characteristics to mechanoreceptors. Mechanoreceptors convert vibrations into electric impulses sent to the brain. In this context, by appropriate experiments, a frequency analysis of the signal characterizing the surface scanning can be carried out to investigate the vibration spectrum measured on the finger and to highlight how the tactile sense is connected to the measured frequency spectra. Although the correlation between the surface roughness with respect to the tactile sensation is deeply analysed in the literature, the vibration spectra induced by the finger—surface scanning and the consequent activation of mechanoreceptors on the skin were rarely investigated. In particular, in this paper, interests will be focused on the changes shown in the vibration spectra, caused by variations in the characteristic contact parameters such as scanning velocity and roughness.