Lightweight Highly Tunable Jamming-Based Composites
Lightweight Highly Tunable Jamming-Based Composites
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DOI：
10.1089/soro.2019.0053
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发表时间：
2020-04-15
期刊：
影响因子：
7.9
通讯作者：
Howe, Robert D.
中科院分区：
文献类型：
--
作者：
Narang, Yashraj S.;Aktas, Buse;Howe, Robert D.
可调阻抗机制可以提高大量工程系统和软机器人的自适应性、鲁棒性和效率。在这项研究中，我们引入了一种可调刚度机制，称为“三明治干扰结构”，它融合了最先进的层流干扰结构（也称为层干扰结构）的特殊刚度范围与经典夹层复合材料的高刚度质量比。我们实验性地开发了性能质量比远远大于层流干扰结构的夹层干扰结构（例如，刚度-质量比增加550倍），同时实现标准夹层复合材料固有地不能实现的可调行为（例如，硬度快速且可逆地增加1800倍）。通过理论和计算模型，然后，我们表明，这些比率可以进一步增加几个数量级，我们提供了一个优化程序，允许设计师建立最好的三明治干扰结构给定任意的质量，体积和材料的限制。最后，我们通过将三明治干扰结构集成到可穿戴软机器人（即，刚度可调的腕部矫形器），其在关闭状态下对使用者的影响可以忽略不计，但是在打开状态下可以将肌肉激活平均减少41%。通过这些理论和实验研究，我们表明，三明治干扰结构是一种轻量级的高度可调的机制，可以显着扩展现有的结构和设备的性能限制。
Tunable-impedance mechanisms can improve the adaptivity, robustness, and efficiency of a vast array of engineering systems and soft robots. In this study, we introduce a tunable-stiffness mechanism called a "sandwich jamming structure," which fuses the exceptional stiffness range of state-of-the-art laminar jamming structures (also known as layer jamming structures) with the high stiffness-to-mass ratios of classical sandwich composites. We experimentally develop sandwich jamming structures with performance-to-mass ratios that are far greater than laminar jamming structures (e.g., a 550-fold increase in stiffness-to-mass ratio), while simultaneously achieving tunable behavior that standard sandwich composites inherently cannot achieve (e.g., a rapid and reversible 1800-fold increase in stiffness). Through theoretical and computational models, we then show that these ratios can be augmented by several orders of magnitude further, and we provide an optimization routine that allows designers to build the best possible sandwich jamming structures given arbitrary mass, volume, and material constraints. Finally, we demonstrate the utility of sandwich jamming structures by integrating them into a wearable soft robot (i.e., a tunable-stiffness wrist orthosis) that has negligible impact on the user in the off state, but can reduce muscle activation by an average of 41% in the on state. Through these theoretical and experimental investigations, we show that sandwich jamming structures are a lightweight highly tunable mechanism that can markedly extend the performance limits of existing structures and devices.