自然界中的壁虎、蜗牛和螳螂等生物的攀爬运动使它们具有了更广阔的生存空间，用以逃避天敌和捕获食物。对机器人而言，攀爬能力将赋予其在复杂场景下救援、危险场景内探测以及隐蔽场景内信息获取等应用潜能。以往的柔性攀爬机器人大多依赖于静电吸附足垫，对地形适应能力较低，且需借助外界主动控制来实现地形感知以完成不同角度表面之间的跨越运动。本文希望借助具有单向摩擦性能的微结构足垫，实现柔性机器人在无地图情形下的全地形攀爬。本文首先设计了一种具有单向摩擦性能的单向摩擦足垫。其前进-后退两个方向的摩擦比达到了破纪录的100倍以上。足垫极大的摩擦比既提高了机器人的全地形通过能力，又减小了滑动摩擦损耗，提高了机器人攀爬效率。在单向摩擦足垫设计过程中，本文结合了两种机理以提高其摩擦比：通过不对称图形调节足垫在前进与后退方向上与攀爬表面之间的接触面积，以及通过倾斜结构调节足垫在前进与后退方向上参与接触的微棱柱个数。在不对称图形的设计上，本文利用黏附-摩擦模型逼近范德华力的方法，通过有限元模拟的方法定性研究了微棱柱结构倾斜方向与微棱柱高度对接触面积的影响，并据此制定了微棱柱结构。在微棱柱参与接触个数的调节上，本文提出了“拉近-脱开”原理，解释了倾斜结构在不同加载方向时出现棱柱接触参与率变化的原因，并通过近似实验观察验证了此原理。随后，本文通过倾斜曝光和软光刻等方法制作了单方向摩擦机器人足垫。在倾斜曝光过程中，本文着重解决了SU-8型光刻胶的厚胶（~ 200 μm）的小尺寸孔（~ 35 μm）阵列化加工问题。通过喷涂显影液整平、掩模版无缝贴附、光刻胶释放及翻转转移等创新过程制备了高质量的微棱柱单向摩擦单向摩擦足垫。最终，本文设计并制作了一种具有昆虫尺寸（55 mm × 42mm × 7mm）的柔性压电攀爬机器人。该机器人通过开环方波驱动，首次实现了柔性机器人在无地图情况下5s内完成角度差别最高60°的表面之间的跨越攀爬以及粗糙度差别大于10 μm表面之间的自主跨越攀爬。除此之外，机器人还能够攀爬80°的光滑（Ra = 0.1 μm）表面和粗糙（Ra = 3.0 μm）塑料表面、60°的塑料积木表面、60°的带孔钢板表面，60°的塑料圆管表面。不仅如此，本文还制作了小尺寸的带有单向足垫的压电柔性机器人，此机器人具有10身位/秒的直线奔跑能力，以及在之字形表面、连续台阶上和0.7倍身高狭缝内的穿行能力。
The climbing movements of animals such as geckos, snails, and praying mantises in nature have enabled them to have a wider living space to escape predators and capture food. For robots, climbing ability will give them potential applications in rescue operations in complex environments, detection in dangerous situations, and information gathering in hidden scenes. Previous soft climbing robots have mostly relied on electrostatic adhesive pads, which have low terrain adaptation and require external control to achieve terrain perception in order to complete cross-surface movements at different angles. This article hopes to achieve all-terrain climbing of soft robots on unmapped terrains by using micro-structured footpads with unidirectional frictional performance.This article first designs a directional foot pad with one-way friction, where the frictional force in the backward direction is more than 100 times greater than in the forward direction. The high friction ratio of the foot pad greatly improves the robot‘s all-terrain passing ability and reduces sliding frictional loss, thus improving the robot‘s climbing efficiency. In the design of the unidirectional friction foot pad, this article combines two mechanisms to improve the friction ratio: adjusting the contact area between the foot pad and the climbing surface in the forward and backward directions through asymmetrical patterns, and adjusting the number of micro-prisms participating in contact in the forward and backward directions through the tilted structure. In the design of asymmetrical patterns, this article uses the adhesion-friction model to approximate the van der Waals force, and qualitatively studies the influence of the micro-prism structure‘s tilt direction and height on the contact area through finite element simulation, and formulates the micro-prism structure based on this. In the adjustment of the number of micro-prisms participating in contact, this article proposes the "load-drop" principle, explaining the reason for the prism contact participation rate change in different loading directions of the tilted structure, and verifying this principle through approximate experiments.Subsequently, this article uses methods such as tilt exposure and soft lithography to produce unidirectional friction robot foot pads. In the tilt exposure process, this article focuses on solving the problem of arrayed processing of small-sized holes (~ 35 μm) in thick ( ~ 200 μm) SU-8 photoresist. Through innovative processes such as spraying development solution for leveling, seamless attachment of mask templates, release and flip transfer of photoresist, high-quality micro-prism one-way friction directional foot pads are prepared.Finally, this article designs and produces a soft piezoelectric climbing robot with insect size (55 mm × 42mm × 7mm). This robot can climb smooth surfaces (Ra = 0.1 μm) and rough (Ra = 3.0 μm) plastic surfaces, plastic building block surfaces at 80°, and surfaces with holes and steel plates at 60°. In addition, the soft robot also has fast cross-climbing ability and can complete cross-surface climbing with the highest angle difference of 60° and the roughness difference greater than 10 μm in 5 seconds without active control strategies.
