Study On The Frictional Tactile Perception Of Bionic Hexagonal Textures

In this thesis,we designed and prepared a bionic hexagonal texture on the surface of the material based on the hexagonal texture characteristics of the surface of living organisms.By combining cognitive behavior,tribology and EEG method,we systematically studied the influence of the bionic hexagonal texture on the subjective sense of touch,skin frictional touch and tactile EEG characteristics from the "sense" of skin,"knowledge" of brain and subjective "evaluation" :1.Bionic hexagonal convex texture structures with different diameters & spacing and different height characteristics were designed,and the corresponding bionic hexagonal texture specimens were prepared on PVC and PMMA surfaces by laser processing and hot embossing molding process.2.For all hexagonal texture specimens,with the increase of speed and decrease of pressure,the friction coefficient shows a decreasing trend and the slippery feeling shows an increasing trend because the volume of finger embedded in the texture decreases and the adhesive friction and deformation friction decreases;with the increase of hexagonal texture diameter & spacing,the contact area between finger and texture depression increases and the adhesive friction increases,so the friction coefficient shows an increasing trend and the slippery feeling decreases.With the increase of hexagonal texture height,the hysteresis friction and interlocking friction increase due to the gradual increase of finger deformation and the overall increase of finger embedded volume,so the friction coefficient shows an increasing trend and the slipperiness decreases;the power of vibration signal generated by the finger in the frequency band of 2-16 Hz increases with the increase of diameter & spacing and height characteristic parameters,the roughness sense gradually increases.3.The P100 component amplitude of EEG ERP signals evoked by bionic hexagonal textures with different diameter & spacing features and height features textures had significant differences,with the increase of texture diameter & spacing,the peak of P100 component showed an increasing trend due to the gradual increase of adhesive friction,the decrease of slippery sense,the increase of rough sense,and the increase of activation intensity of brain neurons;different diameter & spacing The P300 amplitudes of both feature and height feature textures were significantly different,and textures with high discriminability and low comfort induced higher brain attentional resources and larger peaks of the P300 component;δ rhythm accounted for the main component of the tactile EEG signal evoked by the bionic hexagonal texture,and the EEG rhythms evoked by the bionic hexagonal texture specimens with different diameter & spacing feature textures and different height feature textures were not There was no significant difference in the EEG rhythms evoked by different diameter & spacing texture and different height texture specimens.4.The Lyapunov exponents of the EEG ERP signals evoked by the bionic hexagonal texture specimens with different variable diameter & spacing feature textures and different variable height feature textures are greater than zero,indicating that the ERP signals have chaotic properties.the recursive qualitative and recursive quantitative analyses of the ERP signals show that the recurrence maps can qualitatively characterize the tactile changes during touch,and the diagonal length means and clustering coefficients can quantitatively characterize the tactile comfort and discrimination.