Analysis And Experimental Studies On Contact Mechanics Of Mimicking Geckos' Foot Setae Array

Geckos have evolved adhesive structures which allow them to move on the ground, vertical walls and ceilings .It's demonstrated by scientists that this special adhesion ability is arose by the van der walls interaction between the hairy system on the gecko foot and the contacted surface. The design and manufacture for surface climbing robots are inspired by the contact mechanics of the geckos'foot setae array.Based on JKR theory and GW model, we simulate the microscale contact of the synthetic gecko-foot hair material-Polyurethane(PU).The contact of sapphire-ball with PU is considered to be single point contact, and the contact of the glass with PU is considered to be multi-point contacts .We model and simulate the contact mechanics by the computer. The preliminary results show that the adhesion increases with the normal force at the logarithmic rule .On this basis, we regard the PU micro-protrusion as the seta array, and glass as a plane with roughness Finally, the result shows that adhesion increases with the roughness decreasing, and the adhesion reaches the maximum at the degree of 30 with the same roughness.Additionally, we put forward two study plots to test the gecko setae'adhesion by wear and abrasion test machine .The relations between tangent force and speed, preload, surface roughness are studied respectively. By the means of data points fitting and regression analysis, we conclude that the tangent force increases with the preload at the logarithmic rule, with the speed at the linear rule, with the surface roughness at the power rule. And all of the results are conform to the theoretical analysis.