Carbon Fiber Based Twisted and Coiled Artificial Muscles (TCAMs) for Powered Ankle-Foot Orthoses (AFO)

2021 ◽  
Author(s):  
Parth Kotak ◽  
Jason Wilken ◽  
Kirsten Anderson ◽  
Caterina Lamuta
Keyword(s):  
Carbon Fiber ◽  
Low Cost ◽  
Input Voltage ◽  
Input Power ◽  
Artificial Muscles ◽  
Specific Work ◽  
Foot Orthoses ◽  
Ankle Foot Orthoses ◽  
Low Cost Manufacturing

Abstract Ankle foot orthoses (AFOs) control the position and motion of the ankle, compensate for weakness, and correct deformities. AFOs can be classified as passive or powered. Powered AFOs overcome the limitations of passive AFOs by adapting their performance to meet a variety of requirements. However, the actuators currently used to power AFOs are typically heavy, bulky, expensive, or limited to laboratory settings. Thus, there is a strong need for lightweight, inexpensive, and flexible actuators for powering AFOs. In this technical brief, Carbon Fiber/Silicone Rubber (CF/SR) Twisted and Coiled Artificial Muscles (TCAMs) are proposed as novel actuators for powered AFOs. CF/SR TCAMs can lift up to 12,600 times their weight with an input power of only 0.025 W cm-1 and are fabricated from inexpensive materials through a low-cost manufacturing process. Additionally, they can provide a specific work of 758 J kg-1 when an input voltage of 1.64 V cm-1 is applied. A mechanical characterization of CF/SR TCAMs in terms of length/tension, tension/velocity, and active-passive length/tension is presented, and results are compared with the performance of skeletal muscles. A gait analysis demonstrates that CF/SR TCAMs can provide the performance required to supplement lower limb musculature and replicate the gait cycle of a healthy subject. Therefore, the preliminary results provided in this brief are a stepping stone for a dynamic AFO powered by CF/SR TCAMs.

scholarly journals Studies Examining the Efficacy of Ankle Foot Orthoses should Report Activity Level and Mechanical Evidence

2010 ◽  
Vol 34 (3) ◽  
pp. 327-335 ◽  
Author(s):  
Jaap Harlaar ◽  
Merel Brehm ◽  
Jules G. Becher ◽  
Daan J. J. Bregman ◽  
Jaap Buurke ◽  
...  
Keyword(s):  
Treatment Algorithm ◽  
Relevant Information ◽  
Current Treatment ◽  
Activity Level ◽  
Walking Ability ◽  
Foot Orthoses ◽  
Level Of Evidence ◽  
Levels Of Evidence ◽  
Ankle Foot Orthoses

Ankle Foot Orthoses (AFOs) to promote walking ability are a common treatment in patients with neurological or muscular diseases. However, guidelines on the prescription of AFOs are currently based on a low level of evidence regarding their efficacy. Recent studies aiming to demonstrate the efficacy of wearing an AFO in respect to walking ability are not always conclusive. In this paper it is argued to recognize two levels of evidence related to the ICF levels. Activity level evidence expresses the gain in walking ability for the patient, while mechanical evidence expresses the correct functioning of the AFO. Used in combination for the purpose of evaluating the efficacy of orthotic treatment, a conjunct improvement at both levels reinforces the treatment algorithm that is used. Conversely, conflicting outcomes will challenge current treatment algorithms and the supposed working mechanism of the AFO. A treatment algorithm must use relevant information as an input, derived from measurements with a high precision. Its result will be a specific AFO that matches the patient's needs, specified by the mechanical characterization of the AFO footwear combination. It is concluded that research on the efficacy of AFOs should use parameters from two levels of evidence, to prove the efficacy of a treatment algorithm, i.e., how to prescribe a well-matched AFO.

scholarly journals Manufacturing and analysis of carbon fiber knee ankle foot orthosis

2018 ◽  
Vol 7 (4) ◽  
pp. 2236 ◽  
Author(s):  
Ayad M. Takhakh ◽  
Saif M. Abbas
Keyword(s):  
Mechanical Properties ◽  
Spinal Cord ◽  
Carbon Fiber ◽  
Tensile Tests ◽  
Foot Orthoses ◽  
Well Control ◽  
Ankle Foot Orthosis ◽  
Cord Injury ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

Knee ankle foot orthoses (KAFOs) are used by paraplegia patients with low level spinal cord injury and having well control of the stem muscles. Four layers of carbon fiber with C- orthocryl lamination resin are used for manufacturing the knee ankle foot orthoses in this work. The mechanical properties of most of the components materials were estimated with the aid of fatigue and tensile test machines. Results of the tensile tests showed that the mechanical properties: yield stress, ultimate strength and modulus of elasticity were 92MPa, 105.7MPa and 2GPa respectively. The value of amidst pressure between the patient limb and the manufactured KAFO was measured using (F-socket) Mat scan sensor and these values of pressure were (663kPa) and (316kPa) for the thigh and calf regions respectively. 

Synthesis and Characterization of the Sizing Agents on the Carbon Fibers

2011 ◽  
Vol 233-235 ◽  
pp. 70-73
Author(s):  
Hong Bo Zhang ◽  
Chun Hui Su ◽  
Xiao Wei Zhu
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Low Cost ◽  
Process Condition ◽  
Decomposition Temperature ◽  
Synthesis Process ◽  
Optimum Process ◽  
Octyl Phenol ◽  
Sizing Agents

The recent development of carbon fiber sizing agent was introduced in this article. The sizing agent used in carbon fiber was synthesized at a temperature range of 55-60°C using epoxy resin and vinyl acetate as a monomer together, octyl phenol ethoxylated(OP-10) as the emulsion agent, ammonium peroxydisulfate as the solicitation agent and water as the dispersant. At the same time, the optimum composition, the optimum process condition and the effects affecting the emulsion stability were discussed. The characterizations were measured by Scanning Electron Microscopy and TG. The results show that the synthesis process is simple, low cost, less polution and remarkbably stable. The diameter of the particle is 1.8μm and the decomposition temperature is 260°C.

Selective Laser Sintered Versus Carbon Fiber Passive-Dynamic Ankle-Foot Orthoses: A Comparison of Patient Walking Performance

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Nicole G. Harper ◽  
Elizabeth M. Russell ◽  
Jason M. Wilken ◽  
Richard R. Neptune
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Lower Limb ◽  
Selective Laser Sintering ◽  
Foot Orthoses ◽  
Gait Performance ◽  
Ankle Foot Orthoses ◽  
Subject Specific ◽  
Walking Performance ◽  
Design Characteristics

Selective laser sintering (SLS) is a well-suited additive manufacturing technique for generating subject-specific passive-dynamic ankle-foot orthoses (PD-AFOs). However, the mechanical properties of SLS PD-AFOs may differ from those of commonly prescribed carbon fiber (CF) PD-AFOs. Therefore, the goal of this study was to determine if biomechanical measures during gait differ between CF and stiffness-matched SLS PD-AFOs. Subject-specific SLS PD-AFOs were manufactured for ten subjects with unilateral lower-limb impairments. Minimal differences in gait performance occurred when subjects used the SLS versus CF PD-AFOs. These results support the use of SLS PD-AFOs to study the effects of altering design characteristics on gait performance.

scholarly journals Characterization of textile-grade carbon fiber polypropylene composites

2020 ◽  
pp. 096739112093010 ◽  
Author(s):  
Pritesh Yeole ◽  
Shailesh Alwekar ◽  
N Krishnan P Veluswamy ◽  
Surbhi Kore ◽  
Nitilaksha Hiremath ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Low Cost ◽  
Length Distribution ◽  
Thermal Characterization ◽  
Polypropylene Composites ◽  
Fiber Length Distribution ◽  
Twin Screw ◽  
Good Potential ◽  
The Impact

In this work, we consider low-cost carbon fiber produced with a textile-grade precursor. The objective of the study is to investigate textile-grade carbon-fiber-reinforced-polypropylene composites (TCF-PP) from compounded pellets for mechanical and thermal characterization. Four sets of pellets with 1%, 5%, 10%, and 15% reinforcement were manufactured using textile-grade carbon fiber (TCF) and polypropylene (PP) by twin-screw compounding. The addition of TCFs through gravimetric feeder directly in the extruder resulted in lower fiber content; however, side feeder has shown good potential. The pellets were further processed in extrusion compression molding to manufacture plaques. An increase in fiber loading has a negligible effect on fiber attrition as fiber length distribution variation between 1% and 15% reinforced pellets was very small. The addition of TCFs in PP showed a significant improvement in mechanical properties. The tensile strength and modulus of the composite were 26% and 161%, respectively, improved by the addition of 10 wt% TCF. Similar results were observed in the flexure test. However, the impact properties were reduced by 25.54% by the addition of 15% TCF.

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