【作者】 于敏；

【导师】 戴振东；

【作者基本信息】 南京航空航天大学 ， 机械设计及理论， 2008， 博士

【摘要】 自然界中壁虎能在光滑的墙壁上行走自如,甚至能贴在天花板上快速爬行。壁虎单腿上有3条神经控制脚趾的外翻、内收和脚掌的扭转三种运动模式,从而进行简单、有效和精巧的运动控制。同时显微镜下可以看到壁虎脚掌上有近50万根直径为几十到几百纳米的刚毛。壁虎脚底微纳米刚毛所产生的尺寸效应与壁虎脚趾外翻内收的精巧运动控制的结合,最终成就了壁虎“飞檐走壁”的绝活。因此,模仿壁虎脚趾的运动对仿壁虎脚掌实现简单有效的驱动,研制具有尺寸效应的仿生微纳刚毛阵列,进而获得一种对各种环境和各种表面具有良好适应性的可控的粘附机构十分必要。本课题以壁虎科的大壁虎为仿生对象,从结构-驱动一体化角度入手,研制爬壁机器人实现三维空间运动的关键部件-脚掌的粘附结构和智能驱动材料(IPMC人工肌肉材料)。同时,在理解壁虎具有非凡的全空间运动能力的内在本质上,认识软材料与粗糙表面间的接触力学规律,为仿壁虎爬壁机器人研制中的关键技术提供支持。本文主要研究内容如下:1.针对仿壁虎机器人脚掌粘附性能的需求,设计了性能改良的聚氨酯/硅橡胶聚合体材料的配方。比照壁虎空间运动受力关系,对所制备的聚氨酯等试样进行粘着力和切向力相互关系的分析。以JKR接触理论和GW模型为基础,进行建模分析,得出在粘着弹性接触下接触点数对聚氨酯材料粘着力的影响关系。为仿壁虎机器人脚掌材料弹性模量等指标的选择、刚毛阵列几何尺寸的设计提供依据。2.对仿壁虎脚掌刚毛阵列的研制进行了丝材植毛法、激光刻蚀法、激光模型浇铸法、光刻模型浇铸法等多种方法的探索。并针对制备实验,建立刚毛缠结的力学模型,从能量角度分析刚毛阵列克服缠结必须满足的几何条件。首次提出PET“海岛”结构端部接枝聚氨酯及消融方法,有望获得二级结构的微纳米级的仿生刚毛。这种微纳复杂结构的制备是目前国际上该领域的最前沿的还未突破的难点技术。PET“海岛”结构端部接枝聚氨酯及消融方法为制备仿壁虎刚毛二级阵列结构提供了一个很好的设计思路。3.IPMC人工肌肉材料的制备和应用研究目前是国际上智能材料研究的热点之一。通过对IPMC的前期研究,发现IPMC材料在几伏电压驱动下的软性可控往复摆动恰好可实现类似壁虎脚趾外翻和内收的运动。论文首次提出了用IPMC材料驱动仿生壁虎脚掌的思路,进行了IPMC材料的制备研究,实验摸索总结了从Nafion基体的厚膜浇铸工艺到IPMC表面电极化学镀的一套IPMC制备完整工艺。并测试研究了不同波形、电压、频率激励信号对IPMC试样位移、力和电流输出的影响。从而为解决爬壁机器人用仿壁虎脚掌主动控制的关键技术提供支持。4.IPMC在低电压驱动下能产生大的位移,但其输出力却相对较小。如何提高输出力就成为IPMC驱动器应用的一个关键和难点。为增加IPMC力输出,从Nafion厚膜浇铸、电极制备工艺及多片叠加工艺三个方面进行探索实验,进一步提高了IPMC的力输出能力。更多还原

【Abstract】 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.更多还原