Tensile and torsional elastomer fiber artificial muscle by entropic elasticity with thermo-piezoresistive sensing of strain and rotation by a single electric signal
Tensile and torsional elastomer fiber artificial muscle by entropic elasticity with thermo-piezoresistive sensing of strain and rotation by a single electric signal
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DOI：
10.1039/d0mh01003k
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发表时间：
2020-12-01
影响因子：
13.3
通讯作者：
Liu, Zunfeng
中科院分区：
文献类型：
--
作者：
Wang, Run;Shen, Yanan;Liu, Zunfeng
天然肌肉表现出拉伸驱动，并通过与骨骼结合实现扭转旋转，将传感和信号功能集成在单个元件中，形成反馈回路。目前研制的人工肌肉和传感装置都是在外界刺激下工作，需要单独的控制和信号传输系统，增加了肌肉设计的复杂性。因此，开发柔性、紧凑、大应变的纤维人工肌肉，用于先进的柔性机器人系统是非常必要的。本文利用扭曲的天然橡胶纤维表面包覆一层弯曲的碳纳米管片，研制了具有拉伸和扭转驱动以及单一电信号传感功能的扭曲弹性体纤维人工肌肉。通过熵弹性，电热驱动加捻天然橡胶纤维，使其产生收缩和旋转。弯曲的碳纳米管片可以传输电流，驱动过程中弯曲的碳纳米管片之间的接触面积增加，通过热压阻效应导致电阻减小。设计了一个反馈电路，通过测量电阻的变化来接通或断开电流，形成一个反馈回路来控制肌肉的开/关。目前的研究为软机器人、控制器和人机集成提供了一种新的肌肉设计。
Natural muscles show tensile actuation and realize torsional rotation by combining with the skeleton, which integrate with sensing and signaling function in a single element to form a feedback loop. The currently developed artificial muscle and sensing devices always work upon external stimuli, and a separate controlling and signal transmission system is needed, increasing the complexity of muscle design. Therefore it is highly desired to develop flexible and compact fiber artificial muscles with large strain for advanced soft robotic systems. In this paper, twisted elastomer fiber artificial muscles with tensile and torsional actuations and sensing function by a single electric signal are developed, by using twisted natural rubber fiber coated with a buckled carbon nanotube sheet. The twisted natural rubber fiber can be electrothermally actuated to show contraction and rotation by entropic elasticity. The buckled carbon nanotube sheet can transmit electric current, and the contact area between the buckled carbon nanotube sheets increased during actuation, resulting in resistance decrease by thermo-piezoresistive effect. A feedback circuit was designed to connect or disconnect the electric current by measuring the resistance change to form a feedback loop to control on/off of the muscle. The current study provides a new muscle design for soft robotics, controllers, and human-machine integration.