Investigation of the role of contact-induced vibrations in tactile discrimination of textures

Tactile perception of texture is meaningful for numerous industrial and social applications. While the sense of touch is provided by several contributing factors, each related to different sensory cutaneous units, textures with non-low spatial gradients can be appreciated only by the relative motion between the finger and the object. This work focuses on investigating the role that the vibrations induced during sliding contact play in the origin of tactile perception and surface texture discrimination. We shall focus in particular on the effect of the different spectral contents of the induced vibrations. To this end, first the vibration signals produced by touching different sample surfaces are recovered and analysed under controlled boundary conditions. Then, a collection of data from different subjects is recorded and reproduced by a dynamic exciter. Finally, the reproduced signals are randomly submitted to a panel of subjects in order to test their ability to distinguish the different surfaces only through their perception of the reproduced vibrations. The results, while highlighting the key role played by the spectral distribution of friction-induced vibrations, simultaneously reveal the limits of taking only vibrational signals into account if we are to achieve satisfactory recognition of the whole panel of tested textures.