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Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation

Performance of the shape memory alloy (SMA) coil spring actuator in cyclic actuation as an artificial muscle is strongly related to the mechanical design of the coil geometry. This paper proposes a practical design method for improving the frequency and efficiency of the SMA coil spring actuator; by...

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Autor principal: Koh, Je-sung
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6267590/
https://www.ncbi.nlm.nih.gov/pubmed/30463218
http://dx.doi.org/10.3390/ma11112324
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author Koh, Je-sung
author_facet Koh, Je-sung
author_sort Koh, Je-sung
collection PubMed
description Performance of the shape memory alloy (SMA) coil spring actuator in cyclic actuation as an artificial muscle is strongly related to the mechanical design of the coil geometry. This paper proposes a practical design method for improving the frequency and efficiency of the SMA coil spring actuator; by designing the SMA coil spring to have large index (coil diameter/wire diameter) and pitch angle (LIP), cooling characteristics can be improved (increasing the actuation frequency) and large deformation can be obtained. The LIP design process is based on the two-state static model that describes the displacement-force relationship of the SMA coil spring in two states—a fully austenite phase and a fully martensite phase. The design process gives accurate design parameters of the SMA coil spring actuator that satisfy the required stroke and force. The model of the fully martensite phase of the SMA coil that includes the stress-induced detwinning enables the use of maximum shear strain of the SMA. The design method reduces the mass of an SMA without changing the stroke and increase the power density and efficiency. The cyclic actuation experiments demonstrate that the LIP design doubles the maximum frequency of SMA coil actuator with one-sixth the mass of the non-LIP design.
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spelling pubmed-62675902018-12-17 Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation Koh, Je-sung Materials (Basel) Article Performance of the shape memory alloy (SMA) coil spring actuator in cyclic actuation as an artificial muscle is strongly related to the mechanical design of the coil geometry. This paper proposes a practical design method for improving the frequency and efficiency of the SMA coil spring actuator; by designing the SMA coil spring to have large index (coil diameter/wire diameter) and pitch angle (LIP), cooling characteristics can be improved (increasing the actuation frequency) and large deformation can be obtained. The LIP design process is based on the two-state static model that describes the displacement-force relationship of the SMA coil spring in two states—a fully austenite phase and a fully martensite phase. The design process gives accurate design parameters of the SMA coil spring actuator that satisfy the required stroke and force. The model of the fully martensite phase of the SMA coil that includes the stress-induced detwinning enables the use of maximum shear strain of the SMA. The design method reduces the mass of an SMA without changing the stroke and increase the power density and efficiency. The cyclic actuation experiments demonstrate that the LIP design doubles the maximum frequency of SMA coil actuator with one-sixth the mass of the non-LIP design. MDPI 2018-11-19 /pmc/articles/PMC6267590/ /pubmed/30463218 http://dx.doi.org/10.3390/ma11112324 Text en © 2018 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Koh, Je-sung
Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title_full Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title_fullStr Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title_full_unstemmed Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title_short Design of Shape Memory Alloy Coil Spring Actuator for Improving Performance in Cyclic Actuation
title_sort design of shape memory alloy coil spring actuator for improving performance in cyclic actuation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6267590/
https://www.ncbi.nlm.nih.gov/pubmed/30463218
http://dx.doi.org/10.3390/ma11112324
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