A Novel Electromechanical Actuation Mechanism of a Carbon Nanotube Fiber

Guo, Wenhan; Liu, Chao; Zhao, Fangyuan; Sun, Xuemei; Yang, Zhibin; Chen, Tao; Chen, Xuli; Qiu, Longbin; Hu, Xinhua; Peng, Huisheng

doi:10.1002/adma.201201845

Cited by 99 publications

(83 citation statements)

References 20 publications

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“…This impressive performance inspires the use of electromagnetism and magnetic materials to make efficient artificial muscles. Peng's group reported twisted CNT yarn actuators that they propose are driven by electromagnetic attraction between CNTs caused by Ampere's force law (37)(38)(39). However, we find this mechanism improbable.…”

Section: Emerging Types Of Twisted Musclesmentioning

confidence: 57%

New twist on artificial muscles

Haines¹,

Spinks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

290

211

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Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy.

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Section: Emerging Types Of Twisted Musclesmentioning

confidence: 57%

New twist on artificial muscles

Haines¹,

Spinks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

290

211

View full text Add to dashboard Cite

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“…Giant torsional actuation from highly twisted fibres and yarns has been recently discovered [1][2][3][4][5][6] with potential applications in microfluidic mixing [1] and digital displays [3]. Volume expansion induced thermally, chemically, photonically or electrochemically causes partial untwist of highly twisted carbon nanotube, graphene or oriented polymer fibres and yarns [1,6].…”

Section: Introductionmentioning

confidence: 99%

“…The second term in equation (5) relates to the free end rotation resulting from a change in sample torsional stiffness from to ˊ in the starting and final states, respectively.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of torsional actuation in highly twisted yarns and fibres

et al. 2015

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Highly twisted oriented polymer fibres and carbon nanotube yarns show large scale torsional actuation from volume expansion that can be induced, for example, thermally or by electrochemical charging. When formed into spring-like coils, the torsional actuation within the fibre or yarn generates powerful tensile actuation per muscle weight. For further development of these coil actuators and for the practical application of torsional actuators, it is important to standardise methods for characterising both the torsional stroke (rotation) and torque generated. By analogy with tensile actuators, we here introduce a method to measure both the free stroke and blocked torque in a one-end-tethered fibre. In addition, the torsional actuation can be measured when operating against an externally applied torque (isotonic) and actuation against a return spring fibre (variable torque). A theoretical treatment of torsional actuation was formulated using torsion mechanics and evaluated using a commercially available highly-oriented polyamide fibre. Good agreement between experimental measurements and calculated values was obtained. The analysis allows the prediction of torsional stroke under any external loading condition based on the fundamental characteristics of the actuator: free stroke and stiffness. AbstractHighly twisted oriented polymer fibres and carbon nanotube yarns show large scale torsional actuation from volume expansion that can be induced, for example, thermally or by electrochemical charging. When formed into spring-like coils, the torsional actuation within the fibre or yarn generates powerful tensile actuation per muscle weight. For further development of these coil actuators and for the practical application of torsional actuators, it is important to standardise methods for characterising both the torsional stroke (rotation) and torque generated. By analogy with tensile actuators, we here introduce a method to measure both the free stroke and blocked torque in a one-end-tethered fibre. In addition, the torsional actuation can be measured when operating against an externally applied torque (isotonic) and actuation against a return spring fibre (variable torque). A theoretical treatment of torsional actuation was formulated using torsion mechanics and evaluated using a commercially available highly-oriented polyamide fibre. Good agreement between experimental measurements and calculated values was obtained. The analysis allows the prediction of torsional stroke under any external loading condition based on the fundamental characteristics of the actuator: free stroke and stiffness.

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“…Later, carbon nanotube (CNT), an electrical conductor and mechanically strong material, attracted a lot of attention from scientists and engineers. [7][8][9]18,19 Twisted and coiled CNT yarns have been processed into articial muscles. However, the low translation or tension actuation strain (1.3%) is their major limitation.…”

Section: Introductionmentioning

confidence: 99%

High performance and tunable artificial muscle based on two-way shape memory polymer

Fan

2017

RSC Adv.

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Artificial muscles, a class of bio-inspired actuators, have been investigated for decades. Recently, a remarkable breakthrough in artificial muscles was achieved by twisting then coiling polymeric fishing lines or sewing threads. Driven by the negative coefficient of thermal expansion (NCTE), the tensile actuation strain, which was about 4% in the precursor nylon 6,6 fiber, was magnified to about 34% in the muscle. However, the muscle is limited by its higher actuation temperature (up to 160 C). Also, some applications such as soft robots require even larger actuation strain to maintain locomotion. In this study, chemically cross-linked poly(ethylene-co-vinyl acetate) (cPEVA) two-way shape memory polymer (2W-SMP) was synthesized, characterized, and processed into precursor fibers based on a solid solution approach. Artificial muscles were manufactured through twist insertion in the precursor fibers. It was found that the 2W-SMP fibers contract upon heating and expand upon cooling, similar to polymeric fibers with NCTE, but with lower actuation temperature and higher actuation strain. The cPEVA fiber, which has about 18% contraction when the temperature is increased from 20 C to 67 C, exhibits an actuation strain up to 68% in the muscle. It was also found that the muscle actuation is tunable, i.e., independent of its actuation history.

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A Novel Electromechanical Actuation Mechanism of a Carbon Nanotube Fiber

Cited by 99 publications

References 20 publications

New twist on artificial muscles

New twist on artificial muscles

Characterisation of torsional actuation in highly twisted yarns and fibres

High performance and tunable artificial muscle based on two-way shape memory polymer

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