On the applicability of fluidic flexible matrix composite variable impedance materials for prosthetic and orthotic devices

Philen, Michael

doi:10.1088/0964-1726/18/10/104023

Cited by 10 publications

(6 citation statements)

References 26 publications

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“…One possibility that shows great promise is pneumatic artificial muscles (PAMs). These actuators have been in use for many years in prosthetics (Philen, 2009), rehabilitation (Bharadwaj et al, 2004), and robotic devices (Caldwell et al, 1997;Daerden and Lefeber, 2002;Lightner and Lincoln, 2002;Tondu and Lopez, 1997). Because they are artificial muscles, PAMs have been suggested for actuating motion in artificial fish (Zhang et al, 2010) and for driving soft robotic manipulator arms inspired by octopus arms and elephant trunks (Trivedi et al, 2008a(Trivedi et al, , 2008bWalker et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Fatigue life testing of swaged pneumatic artificial muscles as actuators for aerospace applications

Woods

Gentry

Kothera

et al. 2012

Journal of Intelligent Material Systems and Structures

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Pneumatic artificial muscles are a class of pneumatically driven actuators that are remarkable for their simplicity, lightweight, and excellent performance. These actuators are essentially a tubular bladder surrounded by a braided sleeve and sealed at both ends. Pressurization of the actuators generates contraction and tensile forces. Pneumatic artificial muscles have traditionally been used for robotics applications, but there has been recent interest in adapting them to a variety of aerospace actuation applications where their large stroke and force, which are realized at minimal weight penalty, create potential performance improvements over traditional technologies. However, an impediment to wide-spread acceptance of pneumatic artificial muscles is the relatively short fatigue lives of the actuators reported in the literature (typically, less than 18,000 actuation cycles before damage occurs). The purpose of this study is to develop a new construction method designed to greatly increase the number of fatigue cycles before damage occurs. The fabrication methodology employs a swaging process to provide smooth and distributed clamping of the bladder and braided sleeve components onto the end fittings. This approach minimizes stress concentrations and provides high mechanical strength, which can be experimentally validated via testing for the ultimate tensile failure load. Finite element analysis was used to refine the design of the swaged end fittings before extensive fatigue testing began. Long-term fatigue testing of the actuators under realistic operating conditions showed a substantial increase in actuator life, from a maximum of less than 18,000 cycles in previous research studies to more than 120,000,000 cycles in this study.

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Section: Introductionmentioning

confidence: 99%

Fatigue life testing of swaged pneumatic artificial muscles as actuators for aerospace applications

Woods

Gentry

Kothera

et al. 2012

Journal of Intelligent Material Systems and Structures

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“…Variable stiffness is a natural companion of actuation/morphing, for the structure can switch to low stiffness to reduce the power requirements for shape change, once the desired shape is achieved it can switch back to high stiffness to withstand external loads. By exploiting these two functions, F 2 MC were applied to various applications including prosthetic and orthopedic device [59], artificial fish robot [60], morphing aircraft wing [61], force tracking control device [62], switch stiffness vibration controller [63], and earthworm-like robot [64]. It is worth noting that with appropriate design and fluidic control, the aforementioned cellular structure concept could achieve variable stiffness as well.…”

Section: Synthesized Polygonmentioning

confidence: 99%

Plant-inspired adaptive structures and materials for morphing and actuation: a review

Wang

2016

Bioinspir. Biomim.

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Plants exhibit a variety of reversible motions, from the slow opening of pine cones to the impulsive closing of Venus flytrap leaves. These motions are achieved without muscles and they have inspired a wide spectrum of engineered materials and structures. This review summarizes the recent developments of plant-inspired adaptive structures and materials for morphing and actuation. We begin with a brief overview of the actuation strategies and physiological features associated to these plant movements, showing that different combinations of these strategies and features can lead to motions with different deformation characteristics and response speeds. Then we offer a comprehensive survey of the plant-inspired morphing and actuation systems, including pressurized cellular structures, osmotic actuation, anisotropic hygroscopic materials, and bistable systems for rapid movements. Although these engineered systems are vastly different in terms of their size scales and intended applications, their working principles are all related to the actuation strategies and physiological features in plants. This review is to promote future cross-disciplinary studies between plant biology and engineering, which can foster new solutions for many applications such as morphing airframes, soft robotics and kinetic architectures.

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“…The unique adaptations in shape and mechanical properties observed from the case studies of the previous sections illustrate that the metastructures may provide high potential for engineering applications in which such versatility is advantageous, including morphing aircraft (Barbarino et al, 2011), energy absorption (Tolman et al, 2014), and load impedance control (Philen, 2009), to name a few. To develop an understanding of how to take the greatest advantage of these features, the sensitivities of metastructure properties are evaluated as key design parameters are changed.…”

Section: Parametric Study For a Dual-module Metastructurementioning

confidence: 99%

Exploring a modular adaptive metastructure concept inspired by muscle’s cross-bridge

Harne

Wang

2015

Journal of Intelligent Material Systems and Structures

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The multifunctionality and versatility of skeletal muscle is a worthy inspiration towards the development of engineered adaptive structures and material systems. Recent mechanical modeling of muscle suggests that some of muscle's intriguing macroscale, passive adaptivity results from the assembly of nanoscale, cross-bridge constituents that maintain multiple metastable configurations. Inspired by the new observations, this research explores a concept of creating modular, engineered structures from the assembly of mechanical, metastable modules, defined as modules that exhibit coexistent metastable states. The proposed integrated systems are termed metastructures: modular, engineered structures exhibiting unprecedented characteristics resulting from a synergy of the constituents. Analytical and experimental results demonstrate that when modular metastructures are prescribed a global shape/topology, the systems may yield significant and valuable properties adaptivity including variation in reaction force magnitude and direction, numerous globally stable topologies, and orders of magnitude change in stiffness. The influences of important parameters on tailoring the displacement range of coexistent metastable states are investigated to provide insight of how the assembly strategy governs the intriguing versatility and functionality which may be harnessed.

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On the applicability of fluidic flexible matrix composite variable impedance materials for prosthetic and orthotic devices

Cited by 10 publications

References 26 publications

Fatigue life testing of swaged pneumatic artificial muscles as actuators for aerospace applications

Fatigue life testing of swaged pneumatic artificial muscles as actuators for aerospace applications

Plant-inspired adaptive structures and materials for morphing and actuation: a review

Exploring a modular adaptive metastructure concept inspired by muscle’s cross-bridge

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