Study On The Tactile Perception On Material Propertities During Reciprocating Sliding And Tactile Signal Acquisition

The stick-slip phenomenon generated between the sliding interfaces is one of the basic contents of friction-induced vibration study in tribology.It is expressed in the form of a jagged fluctuation with the sliding distance or time.In recent years,the research results show that human fingertip can sense the vibrational stimulates during the interaction with a surface.The microscopic vi scoelastic model is established by the sliding friction microscopic visco-slip model can explain the mechanism of the friction induced vibration and the tactile perception of the contact system.Research on load,sliding speed,surface roughness and waviness of the material,adhesion characteristics of the friction pair,and the lubricating film can realize the identification of the material properties by the vibrational tactile signals.The research of such vibrational tactile perception has a significance theoretical and practical value for the development of robotic tactile sensors.In the research of vibrational tactile perception on identification on material properties,basing on the interfacial frictional vibration mechanism,it is found that the material properties have a great influence on the stick-slip phenomenon in sliding friction.The mechanism of friction and vibration between the contact interfaces in the sliding motion of the fingertip was studied.Based on the adhesion friction and ratchet friction mechanism,the relationship between elastic modulus,hardness,normal load,roughness and dynamic/static friction coefficient and stick-slip motion is established for elastic contact and plastic contact in two contact models with and without consideration of the surface topography.The influence of surface topography on vibration signals was studied,the spectral integral variation of the tactile vibration signal is positively correlated with the material hardness and surface roughness.In the POD vibrational tactile perception tribology system device,the tactile sensor with a crossed-beam structure was designed by imitating the finger structure.The relationship between material properties and frictional force,normal load and vibration signals were studied in the time and frequency domain with various sliding velocity and normal load.A method for material property identification based on the spectral integral slope of vibration acceleration signal with velocity and normal load increasing is proposed.Experiments are carried out on various samples with different roughness and hardness.The tactile perception and material properties of complex friction vibration are established.The relationship between the vibration acceleration signal and the veloc ity integral slope method is used to identify the roughness and hardness of the material,then a material property identification coordinate system based on the spec tral integral slope values of kv and kw is established.Aiming at the problems in the tactile recognition of textiles,a method for identifying the characteristics of textile materials by vibrational tactile signals is proposed for improving the accuracy and stability of textile recognition.Firstly,based on the weight of the textile wire,the textile process,and the characteristics of the textile material,human fingertip tactile recognition contrast experiment was carried out to verify the accuracy and limitations of the human hand recognition.The frictional tactile perception experiment wa s carried out on several of textile samples by steel ball probe.The variation of the tactile signal and material properties of textile vibration was studied by a new method of energy spectrum integral slope.The experimental results shows this method has higher accuracy compared with human hand contact recognition.The skin's perception of frictional characteristics and vibrational tactile signals during the process of frictional touch was studied with and without skin cream treatment on animal skin and artificial skin.The effects of sliding speed,normal load,and treatment time on vibrational tactile perception were explored.The artificial skin applied with skin cream showed slightly different vibrational characteristics.The vibration signal frequency remained unchanged and the amplitude was significantly reduced.It was verified that the artificial skin was softened by the skin cream,but the surface roughness has not been affected significantly.The effect of normal load on the skin before and after t he application of skin care products is greater than the sliding velocity,indicating that the skin is mainly affected by the hardness parameters.After applying the cosmetics,the vibration frequency is affected by the speed more than the positive pressur e change,indicating that the surface topography changes after the skin absorbs the skin cream.