Research On Adhesive Frictional Tactile Mechanism Of Material Surface

People often grasp objects in daily life.The stickiness of material surface is an important factor affecting its contact comfort and grip safety.In this thesis,silicone is taken as the research object,and the method of combining subjective cognition,tribology and electroencephalography is used to study the friction contact behavior between different adhesive surfaces and the skin and the tactile feedback mechanism of the brain stimulated by the adhesive surface.The brain neuron group model is established to simulate the feedback of the brain neurons to the tactile sensation,and the formation mechanism of the adhesive sensation is revealed.The main research results are as follows:1.The subjective cognition and tribological studies show that the friction between the sample with high adhesion and the finger is mainly adhesive friction,while the friction between the sample with low adhesion and the finger is affected by adhesive friction and deformation friction.The sample with high adhesion degree and strong surface adhesion has obvious stick-slip phenomenon in the friction process,large average friction coefficient,large maximum value of vibration signal spectrum diagram and strong adhesion.The larger the diameter of pits and the smaller the spacing,the smaller the proportion of adhesive friction and the larger the proportion of deformation friction.With the increase of pit diameter,the average friction coefficient and vibration amplitude increase,and the adhesive feeling decreases.With the increase of pit spacing,the average friction coefficient increases,the vibration frequency decreases and the adhesive feeling increases.In the presence of a small amount of sweat,the friction coefficient and adhesion increase;In the presence of a large amount of sweat,the friction coefficient and adhesion decreased.Artificial sebum can effectively reduce the friction between the finger and the sample and reduce the adhesive feeling of the sample.2.The results of EEG research show that the brain regions stimulated by touch are located in the parietal and occipital lobes in the middle and rear of the brain,and the higher the degree of adhesion,the greater the area and intensity of the activated brain regions.The P300 latency and the P300 amplitude of the samples with high surface adhesion were small,which indicated that the processing time for the brain to recognize the touch was short,and the brain attention resources were large.The larger the pit diameter is,the larger the latency of P300 is,and the slower the brain processes and recognizes it.When the pit diameter is 2 mm,the P300 amplitude is the smallest and the brain allocates the least attention resources.The P300 latency and the P300 amplitude of the samples with large pit spacing were large,which indicated that the brain had a long time to process the tactile sensation and allocated less attention resources.The δ rhythm is the main rhythm,followed by θ and α rhythm,indicating that the energy of the EEG is mainly concentrated in the low frequency part,and the high frequency part is relatively small.3.The simulation results of the adhesive touch neuron group model show that:the stronger the adhesive sensation is,the stronger the stimulation intensity is on the brain,the stronger the brain excitability is caused,and the corresponding EEG signal amplitude is larger and frequency is lower;The dual-channel three-dynamic adhesive touch neuron group model can effectively simulate the real EEG signal,and compared with the single-channel model,the output signal of the dual-channel group model is more similar to the real EEG signal in the lower frequency band.When the sense of adhesion is enhanced,the corresponding weight coefficient w1 decreases and w2 increases,and the frequency of EEG signal increases.When the two channels are coupled in one direction,the stronger the adhesion is,the larger the coupling coefficient is,and the larger the EEG amplitude is.When the two channels were coupled bidirectional,the EEG amplitude increased more than that when the two channels were coupled unidirectional,and the brain responded more strongly.