Biorobotics is increasingly attracting engineers worldwide, due to the high impact this field can have on the society. Biorobotics aims at imitating or taking inspiration from mechanisms and strategies evolved by animals, including their locomotion abilities in real scenarios, such as swimming, running, crawling, and flying. However, the development of skin-mimicking structures, allowing protection without hindering artifacts' movements, has been rarely addressed. Skin-mimicking structures play a key role for biomimetic robots that have to move in unstructured environments. Currently most of the skin used for robots in engineering adopts soft materials or bellow structures to enable both structural deformation and protection. However, the elastic nature of the former can produce support failure and increasing strain with deformation, while the humpy surface of the latter reduces the interactive performance with the environment. Herein, we designed a novel compliant structure for biorobots' skin, fabricated through a special configuration of both soft and rigid materials to reproduce attributes provided by natural epithelial structures. The presented skin has a simple fabrication process, as well as it is cost effective. The structure of this skin includes a thin conical shape where rigid iron rings are wrapped by soft polyester fabrics, allowing a theoretically zero elastic modulus when bended and stretched. The dimension of fabrics was specified to allow rigid rings having a certain range of free rotation and translation. The possibility of free bending and stretching of the structure was implemented by overcoming low sliding friction of adjacent rings. To empirically test the effectiveness of the proposed structure, a model, including 20 segments, was also fabricated. Experimental results from the bending tests, both in aerial and underwater environments, as well as from the folding tests, demonstrated the successful performance of the skin prototype in terms of low resistance and energy consumption. Finally, the proposed highly compliant structural skin was mounted and tested on a fish robot previously developed by authors, to further show its effectiveness.

中文翻译：

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一种基于复合材料的新型仿生顺从结构皮肤，用于生物机器人应用

由于该领域对社会的巨大影响，Biorobotics 越来越多地吸引全世界的工程师。Biorobotics旨在模仿或从动物进化的机制和策略中汲取灵感，包括它们在真实场景中的运动能力，如游泳、跑步、爬行和飞行。然而，皮肤模拟结构的发展，在不妨碍人工制品运动的情况下提供保护，很少得到解决。皮肤模拟结构对于必须在非结构化环境中移动的仿生机器人起着关键作用。目前工程机器人的蒙皮大多采用软质材料或波纹管结构，既能实现结构变形又能起到保护作用。然而，前者的弹性特性会产生支撑失效并随着变形而增加应变，而后者的凹凸不平的表面降低了与环境的交互性能。在这里，我们为生物机器人的皮肤设计了一种新型的顺应结构，通过软硬材料的特殊配置制造，以再现天然上皮结构提供的属性。所展示的皮肤具有简单的制造过程，并且具有成本效益。这种蒙皮的结构包括一个薄锥形，其中刚性铁环由柔软的聚酯织物包裹，在弯曲和拉伸时允许理论上为零的弹性模量。指定织物的尺寸以允许刚性环具有一定范围的自由旋转和平移。通过克服相邻环的低滑动摩擦，实现了结构自由弯曲和拉伸的可能性。为了经验性地测试所提出结构的有效性，还制作了一个包括 20 个部分的模型。在空中和水下环境中的弯曲测试以及折叠测试的实验结果证明了蒙皮原型在低阻力和能耗方面的成功性能。最后，将所提出的高度柔顺的结构皮肤安装在作者先前开发的鱼机器人上并进行测试，以进一步显示其有效性。