Compliant, biomimetic actuation technologies that are both efficient and powerful are necessary for robotic systems that may one day interact, augment, and potentially integrate with humans. To this end, we introduce a fluid-driven muscle-like actuator fabricated from inexpensive polymer tubes. The actuation results from a specific processing of the tubes. First, the tubes are drawn, which enhances the anisotropy in their microstructure. Then, the tubes are twisted, and these twisted tubes can be used as a torsional actuator. Last, the twisted tubes are helically coiled into linear actuators. We call these linear actuators cavatappi artificial muscles based on their resemblance to the Italian pasta. After drawing and twisting, hydraulic or pneumatic pressure applied inside the tube results in localized untwisting of the helical microstructure. This untwisting manifests as a contraction of the helical pitch for the coiled configuration. Given the hydraulic or pneumatic activation source, these devices have the potential to substantially outperform similar thermally activated actuation technologies regarding actuation bandwidth, efficiency, modeling and controllability, and practical implementation. In this work, we show that cavatappi contracts more than 50% of its initial length and exhibits mechanical contractile efficiencies near 45%. We also demonstrate that cavatappi artificial muscles can exhibit a maximum specific work and power of 0.38 kilojoules per kilogram and 1.42 kilowatts per kilogram, respectively. Continued development of this technology will likely lead to even higher performance in the future.

对于有朝一日可能与人类进行交互、增强和潜在集成的机器人系统而言，高效且强大的合规仿生驱动技术是必不可少的。为此，我们介绍了一种由廉价的聚合物管制成的流体驱动的肌肉状执行器。驱动由管的特定处理产生。首先，管被拉伸，这增强了其微观结构的各向异性。然后，将管扭曲，这些扭曲的管可以用作扭转致动器。最后，扭曲的管螺旋盘绕成线性致动器。我们称这些线性致动器为 cavatappi 人造肌肉，因为它们与意大利面食相似。在拉伸和扭曲之后，施加在管内的液压或气动压力导致螺旋微观结构的局部解扭曲。这种解捻表现为盘绕结构的螺旋节距的收缩。鉴于液压或气动驱动源，这些设备有可能在驱动带宽、效率、建模和可控性以及实际实施方面大大优于类似的热激活驱动技术。在这项工作中，我们表明 cavatappi 收缩了其初始长度的 50% 以上，并表现出接近 45% 的机械收缩效率。我们还证明了 cavatappi 人造肌肉可以分别表现出 0.38 千焦每公斤和 1.42 千瓦每公斤的最大比功和功率。这项技术的持续发展可能会在未来带来更高的性能。