Study On Bio-Mimic Gecko Pad Adhesive Material And Actuating Material

Gecko can climb freely on the smooth wall, and it even can move quickly on the ceiling. Gecko's single foot has three nerves which can control the pad's abduction,adduction and rotation respectively, so it can perform simple, effective and precise control. In the mean time, under microscope, it can be clearly observed that there are about 500 thousand setae whose diameter is from scores to hundreds nanometer padded in the gecko's toes. The combination of size effect from gecko's pad micro-nano scale setae and precise control from gecko's pad movement can contribute to gecko's leap onto roofs and over walls. So, to achieve the bio-mimic gecko pad's effective movement and control, it is necessary to fabricate the size effect biomimetic micro/nano-meter seta array and then develop a kind of controllable adhesive mechanism adapting to all circumstance and surface.In this subject, Gecko.gecko (gekkonidae) is regarded as the bio-mimic object, from the view of structure-actuating integration, the pad adhesive mechanism and smart actuating materials which are the crucial parts for 3DOF wall-climbing robot have been deeply studied. In the mean time, based on the internal principle understanding of gecko's extraordinary all round space physical ability, contact mechanics between soft material and rough surface has been researched in detail, which can provide theoretical support for the key technique in bio-mimic gecko robot development. The main research content is summarized as follows:1. To meet the adhesive property demand of bio-mimic gecko robot pad, performance improved Polyurethane/Silicone rubber polymer material has been successfully fabricated. According to gecko's space movement mechanical relation, the mutual relation between adhesive and tangential forces tested from fabricated Polyurethane samples has been fully analyzed, modeling and analysis were also achieved based on the JKR theory and GW model, from this ,the impact of contact points on the Polyurethane material under adhesive elastic contact condition has been concluded, which can provide theoretical fundamental for the parameter selection of bio-mimic gecko robot pad material and the geometric size designation for artificial seta array. 2. Wire material seta-planting, laser etching, laser model casting and lithography model casting technology have been experimentally explored respectively to develop bio-mimic gecko pad seta array material. Seta entangling model has been established according to the fabrication experiment. Geometric condition which must be satisfied to avoid seta entangling was analyzed from the view of energy. The PET"island"structure ending grafting Polyurethane and ablation method were first proposed in the world in this dissertation, so it can hopefully obtain the secondary structure micro-nano scale bio-mimic seta. This fabrication of micro-nano scale complicated structure is currently the international frontier and the technique difficulty in this filed, and it can take a great effect in fabricating bio-mimic gecko secondary structure micro-nano scale seta.3. According to the previous IPMC (Ionic Polymer Metal composite) research, it has been found that IPMC artificial muscle's controllable flexible swing under several voltages can realize gecko's pad abduction and adduction movement effectively. The concept of using IPMC material as bio-mimic gecko pad was first proposed internationally in this dissertation, and IPMC artificial muscle fabricating research has been experimentally carried out in the subject, at the same time, fabricated IPMC samples generated force, displacement and current were tested and analyzed with different actuating signal wave, voltage and frequency, which can provide support for the key technique of active control in developing wall-climbing robot using bio-mimic gecko pad.4. IPMC artificial muscle can generate large displacement at a low voltage, but the generated fore is relatively small. How to improve IPMC output force has become a key and tough point in IPMC application. To improve IPMC output force, Nafion thick film casting technique, electrode manufacturing process and muti-layer process have been experimentally studied in the subject, and the results show these methods can improve IPMC output force effectively.