Study Of Frictional Tactile Perception Between Fingerprints And Fine Textures

Tactile sensation plays an important role in human perception of the external world,but human understanding of tactile sensation remains limited due to the complexity of its mechanisms and the large number of perceptual units involved.In this thesis,we investigated the frictional vibration characteristics and the tactile activation response of the brain involved in fine texture tactile depth and width recognition thresholds,and the role of fingerprints in fine texture tactile perception by using cognitive-behavioral,tribological,and EEG methods.The role of fingerprints in fine texture tactile perception was investigated,and the effects of texture stimulus intensity and neuronal excitability on tactile perception were initially verified by a single-channel tactile neuron population model.The main findings are as follows:1.As the texture depth and width increase,the texture sense excited by the surface texture increases,the correct texture recognition rate increases,and the percentage of deformation friction for finger touch increases.The average depth recognition threshold for touch sensation was 11.6 μm,and the average width recognition threshold for touch sensation was 45.4 μm.Both surface texture depth and width were significantly and positively correlated with the maximum amplitude of the touch vibration spectrum,the entropy of the recurrence parameter,and the length of the longest vertical line segment.When the texture depth and width exceeded the haptic recognition threshold,the spectral amplitude and nonlinear characteristic parameters of the touch vibration signal increased significantly,the main frequency of the vibration signal increased to the perceived frequency range of the Pasini voxel,the stability of the system vibration signal became worse,the complexity increased,and the vibration signal system changed from the steady-state mode to the abrupt change mode.2.The average depth recognition thresholds for tactile perception in the three fingerprint states of normal,shallow and no fingerprints were 11.6 μm,13.9 μm and18.8 μm,respectively,and the average width recognition thresholds were 45.4 μm,57.6μm and 66.3 μm,respectively.The tactile perception depth thresholds and width thresholds increased as the depth of the fingerprint decreased,indicating that the human body’s ability to recognize fine textures decreased with fingerprint depth decreases.At the same time,the main frequency and maximum amplitude of the touch vibration signal spectrum increased with the increase of fingerprint depth,and the stability of the vibration system became less stable and more complex.3.With increasing texture depth and width,the intensity and area of tactile perceptually activated brain areas gradually increased.The fine texture depth,width and P300 peak of tactile ERP EEG signal showed a significant positive correlation and a significant negative correlation with P300 latency.When the texture depth and width exceeded the perceptual threshold,the excitation P300 peak was significantly increased and the latency period was significantly decreased,indicating that the neuronal activity of the brain and the processing intensity of tactile information were significantly enhanced and the speed of tactile recognition was significantly increased.The lower the fingerprint depth evoked lower P300 peak and longer the latency period,indicating that fingerprints could enhance the processing intensity of tactile information and the speed of fine texture recognition by the brain during touching fine textures and enhance tactile perception.4.The single-channel neural mass model can effectively simulate the real EEG signal.The main frequency amplitude of the simulated EEG signal increases with the increase of the mean value <ω>,and its trend is consistent with the real EEG signal,indicating that the enhanced tactile intensity excited by the increase of texture depth and width is one of the reasons for the increase of the frequency amplitude of the tactile EEG signal.The main frequency of the simulated EEG signal decreased with the increase of A/B,and the trend was consistent with the real EEG signal,indicating that the increase of "excitability" of neuronal populations excited by the increase of texture depth and width was one of the reasons for the decrease of the main frequency of the tactile EEG signal.