Research on soft artificial muscles (SAMs) is rapidly growing, both in developing new actuation ideas and improving existing structures with multifunctionality. The human body has more than 600 muscles that drive organs and joints to achieve desired functions. Inspired by the human muscles, this article presents a new type of SAM fiber formed from twisting and braiding soft hydraulic filament artificial muscles with high aspect ratio, high strain, and high energy efficiency. We systematically investigated the relationship between input pressure and output elongation as well as contraction force of the new muscles using different configurations in terms of an array of single and multiple muscles arranged in nontwisting (or straight), twisting, and braiding variants. Experimental results revealed that the twisting and braiding configurations greatly enhanced the muscle elongation and generated force compared with their nontwisting/braiding counterparts. To demonstrate the new muscles' usability, we implemented several muscle variants to bidirectionally manipulate 3D-printed human fingers and elbow, mimicking the human upper limb with a full range of motion. We also created a bioinspired growing soft tubular muscle that could simultaneously exert longitudinal and radial expansion upon pressurization, similar to that of auxetic metamaterial structures. The new growing soft tubular muscles were experimentally validated and the results showed that they could be potentially implemented in several emerging applications, including smart compression garments, stent-like supporting devices, and tubular grippers for medical use.

中文翻译：

---

用于机器人应用的扭曲和编织流体驱动的软人造肌肉纤维

软人工肌肉 (SAM) 的研究正在迅速发展，无论是在开发新的驱动理念还是改进现有的多功能结构方面。人体有 600 多块肌肉，它们驱动器官和关节来实现所需的功能。受人体肌肉的启发，本文提出了一种新型的SAM纤维，由柔软的液压长丝人工肌肉加捻编织而成，具有高纵横比、高应变和高能效。我们系统地研究了输入压力和输出伸长率之间的关系，以及使用不同配置的新肌肉的收缩力之间的关系，这些肌肉采用不同的配置，即以非扭曲（或直）、扭曲和编织变体排列的单块和多块肌肉阵列。实验结果表明，与非扭曲/编织配置相比，扭曲和编织配置大大提高了肌肉伸长率和产生的力。为了展示新肌肉的可用性，我们实施了几种肌肉变体来双向操纵 3D 打印的人类手指和肘部，模拟人类上肢的全方位运动。我们还创造了一种仿生生长的软管状肌肉，它可以在加压时同时施加纵向和径向扩张，类似于拉胀超材料结构。新生长的软管状肌肉经过实验验证，结果表明它们可能在几种新兴应用中实现，包括智能压缩服装、支架状支撑装置、