The Influence Of Finger Tribological Behavior On Tactile Perception Under Different Grooved Surface

Fingers play an important role in human life as one of the main tactile organs of the body.Human beings perceive the external environment through finger sliding touch.During the touch process,many variables such as friction signals,vibration signals and skin deformation are generated,to help the human to identify the details of the objects.To further understand the mechanism of the tactile perception and improve the cognition of human tactile system,the generation of these variables in finger sliding touch and their impact on tactile perception are studied from the perspective of tribology.In this paper,tribological perception experiments were carried out under seven different grooved surfaces.During the tactile perception process,many variables(such as the geometric dimensions of grooved surface,touch zones,touch gestures,scanning speed,the normal force and so on)can affect the results of the experiment.The influence of the above experimental variables on the finger tactile perception is analyzed to explain the differences of tactile perception under different grooved surfaces.The results of the present work provide several possible explanations for the differences of finger tactile perception when perceiving the detailed information of the surface texture.These findings also provide experimental basis for revealing the mechanism of the finger tactile perception.The main conclusions are as follows:1.The degree of the frictional fluctuation and the skin deformation increase as the groove width increases,thus improving the accuracy of the tactile perception.However,there is a relative small increase in the friction fluctuation and the skin deformation as the ridge width increases.Therefore,the accuracy of the tactile perception does not significantly increase in the group of samples with variable ridge width.In addition,as the groove width and the ridge width increase,the single cycle time of the frictional fluctuation becomes longer.It may provide some guidance for improving the ability of the finger tactile perception.In addition,vibration oscillation may be one of the factors that enhance the finger tactile perception.2.The tactile perception ability of finger tip contact is significantly stronger than that of finger pulp contact.The primary cause is that a stronger friction fluctuation and vibration oscillation appear on finger tip contact.Besides,when the finger tip touches the test sample,the deformation signals of the finger skin in different grooves are significantly different from each other,whereas the deformation signals of the finger skin in different grooves are similarunder finger pulp contact.Consequently,it could be considered that the skin deformation signals which exist a big difference may further enhance the accuracy of the tactile perception.3.Compared with the longitudinal touch gesture,the degree of the frictional fluctuation is stronger under the transverse touch gesture.It provides an explanation for the fact that the tactile perception ability of the transverse touch gesture is better than that of the longitudinal touch gesture.Due to the high Young's modulus value in the lateral zone of the finger skin,the transverse touch gesture could enhance the human pallesthesia,thereby improving the accuracy of the tactile perception.Moreover,the lateral zone of finger is more likely to produce a strong change in stress,which enhances the intensity of mechanical stimulation of finger skin.It would further enhance the ability of finger tactile perception.4.Increasing the scanning speed would reduce the perception time,then reducing the accuracy of the tactile perception.The friction force and vibration acceleration increase as the normal force increases,which would further improve the accuracy of the tactile perception.However,when the normal force increases to 1.5 N,the degree of the frictional fluctuation is nearly unchanged.Hence,the accuracy of the tactile perception is not significantly enhanced after the normal force increases to 1.5 N.