A model for vibration-mediated tactile perception

Tactile perception originates from scanning the fingertip on object surfaces: in this condition, pressure and/or interaction between fingertip and surface ridges induce stresses and vibrations in the mechanoreceptors located in the skin, allowing the brain to identify objects and to perceive information about the surfaces [1-3]. In addition, many experimental investigations have shown that low wavelength surface patterns (with the respect to the fingerprint spatial period) are perceived by pressure, while high wavelength patterns are sensed by means of vibrations (duplex perception mechanism). In the present work, a numerical model describing finger-surface scanning is introduced. The model takes into account finger and surface shapes, material properties, normal contact force, and scanning velocity. The proposed model describes the vibration induced by a sliding contact between two sinusoidal surfaces, and it is capable to explain the duplex perception mechanism on a mathematical basis. Validation has been fulfilled by comparison with experimental results present in the literature; a parametrical investigation is performed in non-dimensional formulation in order to clarify the role played by contact/scanning parameters on the induced vibration, and to investigate the influence of material and contact properties on tactile perception.