Bionic Study On Adhesive Structure Of Frog Toe Pad And Development Of Mechanical Measuring System

Tree-frog possesses elliptical adhesive discs, which enable tree-frog to adhere to the vertical wall. The study of tree-frog adhesive discs will provide great inspiration to the development of adhesive devices.This thesis focuses on the microstructure of adhesive discs surface of the China Big Tree-frog,using some kinds of microscopes such as bio-microscope, scanning electron microscope (SEM) and atomic force microscope (AFM). Results show that the surface of adhesive discs consists of many regular hexagonal protuberances and some scattered holes. The surface consists of protuberant epidermal tissue which are only founded in the surface of adhesive discs, zonal subcutaneous tissue and connective tissue according to the profile of adhesive discs.Having tested mechanical performance of adhesive discs of tree-frog, the results show that the larger positive pressure applied by adhesive discs, the larger normal adsorption force; the faster sliding speed of adhesive discs or the larger contact area, the larger friction force; the morphology of contact surface influences the adhesive ability of tree-frog scrambling on the vertical plane; the adhesion of tree-frog's discs is considered as the combined action of wet adhesive mechanism and mechanical interlocking of adhesive discss surface by the capillarity.By the application of the high-speed video camera, we found that tree-frog utilizes multilevel joints of palms and foots in the forme of wheel to accomplish the dynamic attachment and detachment by adhesive discs during the locomotion of tree-frog.The testing system for 3D-force is designed, including 3D-force sensor, signal processing circuit and acquisition program, to be measurement tool for further studying the adhesive mechanism and motion law of tree-frog during the locomotion.