Artificial muscles for wearable assistance and rehabilitation

Dong, Tianyun; Zhang, Xiangliang; Liu, Tao

doi:10.1631/fitee.1800618

Cited by 23 publications

(15 citation statements)

References 75 publications

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“…Other artificial muscles based on smart materials which are lightweight, soft, and quiet, could also be viable solutions (Lee et al, 2017;Mirvakili and Hunter, 2018). The artificial muscles could actuate based on thermally responsive methods [e.g., Shape Memory Alloys (SMAs)], electrically responsive methods (e.g, dielectric elastomers, electroactive polymers), and chemically responsive methods (e.g., hydrogels) (Bar- Cohen et al, 2017;Dong et al, 2018). Swallow and Siores (2009) introduced a conceptual design using Piezoelectric Fiber Composites (PFCs) to create a mechanically soft, lightweight glove that could be worn for tremor-suppression.…”

Section: The Need For Lightweight Soft Structure Tremor-suppression Orthosesmentioning

confidence: 99%

Tremor-Suppression Orthoses for the Upper Limb: Current Developments and Future Challenges

Nguyễn

Luu

2021

Front. Hum. Neurosci.

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Introduction: Pathological tremor is the most common motor disorder in adults and characterized by involuntary, rhythmic muscular contraction leading to shaking movements in one or more parts of the body. Functional Electrical Stimulation (FES) and biomechanical loading using wearable orthoses have emerged as effective and non-invasive methods for tremor suppression. A variety of upper-limb orthoses for tremor suppression have been introduced; however, a systematic review of the mechanical design, algorithms for tremor extraction, and the experimental design is still missing.Methods: To address this gap, we applied a standard systematic review methodology to conduct a literature search in the PubMed and PMC databases. Inclusion criteria and full-text access eligibility were used to filter the studies from the search results. Subsequently, we extracted relevant information, such as suppression mechanism, system weights, degrees of freedom (DOF), algorithms for tremor estimation, experimental settings, and the efficacy.Results: The results show that the majority of tremor-suppression orthoses are active with 47% prevalence. Active orthoses are also the heaviest with an average weight of 561 ± 467 g, followed by semi-active 486 ± 395 g, and passive orthoses 191 ± 137 g. Most of the orthoses only support one DOF (54.5%). Two-DOF and three-DOF orthoses account for 33 and 18%, respectively. The average efficacy of tremor suppression using wearable orthoses is 83 ± 13%. Active orthoses are the most efficient with an average efficacy of 83 ± 8%, following by the semi-active 77 ± 19%, and passive orthoses 75 ± 12%. Among different experimental setups, bench testing shows the highest efficacy at 95 ± 5%, this value dropped to 86 ± 8% when evaluating with tremor-affected subjects. The majority of the orthoses (92%) measured voluntary and/or tremorous motions using biomechanical sensors (e.g., IMU, force sensor). Only one system was found to utilize EMG for tremor extraction.Conclusions: Our review showed an improvement in efficacy of using robotic orthoses in tremor suppression. However, significant challenges for the translations of these systems into clinical or home use remain unsolved. Future challenges include improving the wearability of the orthoses (e.g., lightweight, aesthetic, and soft structure), and user control interfaces (i.e., neural machine interface). We also suggest addressing non-technical challenges (e.g., regulatory compliance, insurance reimbursement) to make the technology more accessible.

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Section: The Need For Lightweight Soft Structure Tremor-suppression Orthosesmentioning

confidence: 99%

Tremor-Suppression Orthoses for the Upper Limb: Current Developments and Future Challenges

Nguyễn

Luu

2021

Front. Hum. Neurosci.

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“…4D printing aims at exploiting advanced materials responding to external stimuli to program the actions of the printed objects . Several stimuli‐responsive materials—e.g., electroactive polymers, hydrogels, and nanocomposites—have been investigated for a broad variety of applications, from micro‐ and soft‐robotics to biomedicine . Among the different strategies, an accessible pathway to fabricate stimuli‐responsive (4D) printed objects consists in magnetizing a soft‐polymer by loading the polymeric matrix with magnetic fillers, such as particles of magnetite (Fe 3 O 4 ) or neodymium–iron–boron (NdFeB) .…”

Section: Introductionmentioning

confidence: 99%

3D Printing of Magnetoresponsive Polymeric Materials with Tunable Mechanical and Magnetic Properties by Digital Light Processing

Lantean

Barrera

Pirri

et al. 2019

Adv Materials Technologies

103

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nanocomposites [12][13][14][15] -have been investigated for a broad variety of applications, from micro-and soft-robotics [10,[16][17][18] to biomedicine. [19][20][21][22][23][24] Among the different strategies, an accessible pathway to fabricate stimuli-responsive (4D) printed objects consists in magnetizing a soft-polymer by loading the polymeric matrix with magnetic fillers, such as particles of magnetite (Fe 3 O 4 ) or neodymium-iron-boron (NdFeB). [25][26][27][28][29][30][31] Direct ink writing (DIW) and fused filament fabrication (FFF) have been used to fabricate fast responding actuators, [32][33][34][35][36][37][38][39][40] inks containing high loads of magnetic fillers [41] and 2D planar structures that exploit folding and unfolding processes. [42] Additionally, 3D printed permanent magnets were developed. [43][44][45][46][47][48] However, both DIW and FFF present some drawbacks: first in terms of resolution; second in terms of the dispersion of the fillers, that may lead to nonhomogeneous magnetic response; and third in terms of temperature of processing, which could be not compatible with the fillers. [48,49] For the last one, the temperature can be decreased using some additives, however this approach may affect the mechanical performances of devices. [41] An alternative to DIW and FFF is digital light processing (DLP). This vat polymerization 3D printing technology involves the use of photosensitive (liquid) resins which are able to cure (i.e., to solidify) upon irradiation with a suitable light source. In DLP, a digital light projector (digital micromirror device) illuminates a photocurable resin with a 2D pixel pattern allowing the curing of single slices of the 3D object. [50][51][52] The aforementioned drawbacks associated to DIW and FFF can be overcome by the use of DLP. Indeed: (i) the printing resolution in DLP belongs to the pixel dimensions and it is generally higher than DIW and FFF, [53,54] (ii) in DLP the dispersion of the fillers is easier to control since liquid formulations are used; and (iii) the fabrication process generally occurs at room temperature. Nevertheless, two precautions must be taken into account: first, the increase of the content of nanoparticles may affect the photopolymerization process since they compete with the photoinitiator in absorbing the incident radiation; and second, the dispersion of the fillers must be stable for the whole printing procedure in order to print an object whose response is homogeneous to an external input. For the latter, macroscopic sedimentation, segregation, and spatial inhomogeneity must be avoided.Digital light processing is used for printing magnetoresponsive polymeric materials with tunable mechanical and magnetic properties. Mechanical properties are tailored, from stiff to soft, by combining urethane-acrylate resins with butyl acrylate as the reactive diluent. The magnetic response of the printed samples is tuned by changing the Fe 3 O 4 nanoparticle loading up to 6 wt%. Following this strategy, magnetoresponsive active components ar...

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“…[31,32] DEAs are now widely used for robotics and medical applications, including bioinspired robots, [33][34][35][36][37][38][39][40] grippers, manipulators, [4,41,42] and rehabilitation devices. [43] In terms of fabrication approaches, DEAs are regularly manufactured by planar techniques: applicator coating, [4] spin coating, [44] and serial mechanical assembly. [45] LMPA is a phase-change material that has found application in wearables, [46] medical applications, [47] stretchable antennas, [24] variable stiffness pneumatic actuators, [19] and DEAs.…”

Section: Introductionmentioning

confidence: 99%

“…[ 31,32 ] DEAs are now widely used for robotics and medical applications, including bioinspired robots, [ 33–40 ] grippers, manipulators, [ 4,41,42 ] and rehabilitation devices. [ 43 ] In terms of fabrication approaches, DEAs are regularly manufactured by planar techniques: applicator coating, [ 4 ] spin coating, [ 44 ] and serial mechanical assembly. [ 45 ]…”

Section: Introductionmentioning

confidence: 99%

Lighter and Stronger: Cofabricated Electrodes and Variable Stiffness Elements in Dielectric Actuators

Piskarev

Shintake

Ramachandran

et al. 2020

Advanced Intelligent Systems

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The inherent compliance of soft robots often makes it difficult for them to exert forces on surrounding surfaces or withstand mechanical loading. Controlled stiffness is a solution to empower soft robots with the ability to apply large forces on their environments and sustain external loads without deformations. Herein, a compact, soft actuator composed of a shared electrode used for both electrostatic actuation and variable stiffness is described. The device operates as a dielectric elastomer actuator, while variable stiffness is provided by a shared electrode made of gallium. The fabricated actuator, namely variable stiffness dielectric elastomer actuator (VSDEA), has a compact and lightweight structure with a thickness of 930 μm and a mass of 0.7 g. It exhibits a stiffness change of 183×, a bending angle of 31°, and a blocked force of 0.65 mN. Thanks to the lightweight feature, the stiffness change per mass of the actuator (261× g−1) is 2.6 times higher than that of the other type of VSDEA that has no shared electrode.

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Artificial muscles for wearable assistance and rehabilitation

Cited by 23 publications

References 75 publications

Tremor-Suppression Orthoses for the Upper Limb: Current Developments and Future Challenges

Tremor-Suppression Orthoses for the Upper Limb: Current Developments and Future Challenges

3D Printing of Magnetoresponsive Polymeric Materials with Tunable Mechanical and Magnetic Properties by Digital Light Processing

Lighter and Stronger: Cofabricated Electrodes and Variable Stiffness Elements in Dielectric Actuators

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