A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface

Variable stiffness actuators (VSAs) have attracted considerable attention in wearable robotics and soft exoskeletons due to their ability to adapt to various load conditions. This study presents a modular design for VSAs that incorporates a chain mail structure with various link topologies, allowing...

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Main Authors: John E. Bermeo, Eduardo Castillo-Castañeda, Med Amine Laribi
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Actuators
Subjects:
Online Access:https://www.mdpi.com/2076-0825/14/5/247
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author John E. Bermeo
Eduardo Castillo-Castañeda
Med Amine Laribi
author_facet John E. Bermeo
Eduardo Castillo-Castañeda
Med Amine Laribi
author_sort John E. Bermeo
collection DOAJ
description Variable stiffness actuators (VSAs) have attracted considerable attention in wearable robotics and soft exoskeletons due to their ability to adapt to various load conditions. This study presents a modular design for VSAs that incorporates a chain mail structure with various link topologies, allowing for a reconfiguration of stiffness. The proposed VSA consists of three main parts: the vacuum chamber, the VSA actuator, and the chain mail structure. The VSA fabrication process was carried out in five stages: (1) mold fabrication by 3D FDM printing, incorporating a film of oil to facilitate easy demolding; (2) mold preparation using silicone, with a precise ratio of 1:1 weight-based mixture to optimize material utilization; (3) silicone pouring into molds while applying vibration to eliminate air bubbles; (4) curing for four hours to achieve optimal mechanical properties; and (5) careful demolding to prevent damage. Experimental tests were conducted to characterize the stiffness of actuators with different chain mail fabric configurations, using an experimental setup designed to securely fix the actuator and accurately measure the pneumatic pressure and the angle of deformation after applying weights at its end. The European 6-in-1 and rounded square configurations were shown to be the most effective, increasing stiffness up to 382% compared to the chain mail-free configuration, highlighting the positive impact of these structural designs.
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spelling doaj-art-9fb33a5f27d04102a38ab19daad390652025-08-20T03:14:39ZengMDPI AGActuators2076-08252025-05-0114524710.3390/act14050247A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming InterfaceJohn E. Bermeo0Eduardo Castillo-Castañeda1Med Amine Laribi2Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Querétaro, Querétaro 76090, MexicoInstituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Querétaro, Querétaro 76090, MexicoDepartment of GMSC, Pprime Institute CNRS, École Nationale Supérieure de Mécanique et d’Aérotechnique, University of Poitiers, 86000 Poitiers, FranceVariable stiffness actuators (VSAs) have attracted considerable attention in wearable robotics and soft exoskeletons due to their ability to adapt to various load conditions. This study presents a modular design for VSAs that incorporates a chain mail structure with various link topologies, allowing for a reconfiguration of stiffness. The proposed VSA consists of three main parts: the vacuum chamber, the VSA actuator, and the chain mail structure. The VSA fabrication process was carried out in five stages: (1) mold fabrication by 3D FDM printing, incorporating a film of oil to facilitate easy demolding; (2) mold preparation using silicone, with a precise ratio of 1:1 weight-based mixture to optimize material utilization; (3) silicone pouring into molds while applying vibration to eliminate air bubbles; (4) curing for four hours to achieve optimal mechanical properties; and (5) careful demolding to prevent damage. Experimental tests were conducted to characterize the stiffness of actuators with different chain mail fabric configurations, using an experimental setup designed to securely fix the actuator and accurately measure the pneumatic pressure and the angle of deformation after applying weights at its end. The European 6-in-1 and rounded square configurations were shown to be the most effective, increasing stiffness up to 382% compared to the chain mail-free configuration, highlighting the positive impact of these structural designs.https://www.mdpi.com/2076-0825/14/5/247variable stiffness actuatorVSAflexible actuatorparticle jammingsoft robotics
spellingShingle John E. Bermeo
Eduardo Castillo-Castañeda
Med Amine Laribi
A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
Actuators
variable stiffness actuator
VSA
flexible actuator
particle jamming
soft robotics
title A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
title_full A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
title_fullStr A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
title_full_unstemmed A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
title_short A Soft Variable Stiffness Actuator with a Chain Mail Structure as a Particle Jamming Interface
title_sort soft variable stiffness actuator with a chain mail structure as a particle jamming interface
topic variable stiffness actuator
VSA
flexible actuator
particle jamming
soft robotics
url https://www.mdpi.com/2076-0825/14/5/247
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