Soft actuator is the key component for soft robots to realize flexible motion. But the difficulty of sensing and control of soft actuators seriously restricts their application. Twisted artificial muscles (TAMs) made from together self-coiling of nylon 6,6 fiber and heating wire are potential to address this challenge due to their extremely high actuating stress and self-sensing ability. However, the together coiled twisted artificial muscles (TCTAMs) have a large self-sensing hysteresis because of the small heating area and the self-coiling process restricts their deformation stroke. Besides, the lack of accurate physical models also blocks the development of the TCTAMs. This article presents a new type of tightly wrapped twisted artificial muscles (TWTAMs) to improve the stroke and reduce the hysteresis. Compared with TCTAMs, the hysteresis of TWTAMs is reduced by 76% and the stroke is improved by 35%. Besides, a physical analytical model based on the self-sensing temperature is established and verified by experiments. This article not only provides a new type of TAMs with large stroke and low hysteresis, but also offers an accurate theoretical analysis model for the performance prediction of TWTAM.

中文翻译：

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大行程低滞后紧包扭绞人工肌肉的设计与建模

软执行器是软体机器人实现柔性运动的关键部件。但软执行器的传感和控制难度严重限制了其应用。由尼龙 6,6 纤维和电热丝自缠绕制成的扭曲人造肌肉 (TAM) 具有极高的致动应力和自感应能力，有望应对这一挑战。然而，共同盘绕的扭曲人造肌肉（TCTAM）由于受热面积小而具有较大的自感应滞后，并且自盘绕过程限制了它们的变形行程。此外，缺乏准确的物理模型也阻碍了TCTAM的发展。本文介绍了一种新型紧密包裹的扭曲人工肌肉（TWTAM），以改善行程并减少滞后。与 TCTAM 相比，TWTAM 的滞后减少了 76%，行程改善了 35%。此外，还建立了基于自感温度的物理分析模型，并通过实验进行了验证。本文不仅提供了一种新型的大行程、低滞后的TAM，而且为TWTAM的性能预测提供了准确的理论分析模型。