Mimicking Human-Like Leg Function in Prosthetic Limbs

Grimmer, Martin; Seyfarth, André

doi:10.1007/978-94-017-8932-5_5

Cited by 78 publications

(54 citation statements)

References 135 publications

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“…To extend the concept to walking it is necessary to disable the anti-gravity control during swing phase. First tests used the shank angle and a fixed timing based on a knee extensor moment from literature (Grimmer and Seyfarth, 2014 ), to enable and disable the anti-gravity control during gait. It is planned to further generalize this concept by using a phase plane controller of the shank (Holgate et al, 2009 ) or a virtual leg (Villarreal and Gregg, 2014 ).…”

Section: Discussionmentioning

confidence: 99%

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers

et al. 2017

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Muscle weakness-which can result from neurological injuries, genetic disorders, or typical aging-can affect a person's mobility and quality of life. For many people with muscle weakness, assistive devices provide the means to regain mobility and independence. These devices range from well-established technology, such as wheelchairs, to newer technologies, such as exoskeletons and exosuits. For assistive devices to be used in everyday life, they must provide assistance across activities of daily living (ADLs) in an unobtrusive manner. This article introduces the Myosuit, a soft, wearable device designed to provide continuous assistance at the hip and knee joint when working with and against gravity in ADLs. This robotic device combines active and passive elements with a closed-loop force controller designed to behave like an external muscle (exomuscle) and deliver gravity compensation to the user. At 4.1 kg (4.6 kg with batteries), the Myosuit is one of the lightest untethered devices capable of delivering gravity support to the user's knee and hip joints. This article presents the design and control principles of the Myosuit. It describes the textile interface, tendon actuators, and a bi-articular, synergy-based approach for continuous assistance. The assistive controller, based on bi-articular force assistance, was tested with a single subject who performed sitting transfers, one of the most gravity-intensive ADLs. The results show that the control concept can successfully identify changes in the posture and assist hip and knee extension with up to 26% of the natural knee moment and up to 35% of the knee power. We conclude that the Myosuit's novel approach to assistance using a bi-articular architecture, in combination with the posture-based force controller, can effectively assist its users in gravity-intensive ADLs, such as sitting transfers.

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Section: Discussionmentioning

confidence: 99%

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers

et al. 2017

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“…With the objective to compare the push-off power of three different kinds of prosthetic ankle-foot units (SACH, ESAR, and PWR) it was demonstrated that their push-off power performance progresses differently at different walking speeds. In able-bodied individuals positive peak ankle push-off power increases with walking speed [21]. To mimic human gait, PWR ankle-foot units adjust push-off power based on walking speed, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…In healthy non-amputee subjects, the level of ankle push-off power increases with walking speed [21]. Similar to non-amputee control subjects, unilateral lower-limb amputees exhibit increased push-off ankle power with increasing walking speed [22–24].…”

Section: Introductionmentioning

confidence: 99%

Prosthetic push-off power in trans-tibial amputee level ground walking: A systematic review

et al. 2019

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ObjectiveUnilateral trans-tibial amputation signifies a challenge to locomotion. Prosthetic ankle-foot units are developed to mimic the missing biological system which adapts push-off power to walking speed in some new prosthetic ankle-foot designs. The first systematic review including the two factors aims to investigate push-off power differences among Solid Ankle Cushion Heel (SACH), Energy Storage And Return (ESAR) and Powered ankle-foot units (PWR) and their relation to walking speed. Data sourcesA literature search was undertaken in the Web of Science, PubMed, IEEE xplore, and Google Scholar databases. The search term included: ampu* AND prosth* AND ankle-power AND push-off AND walking. Study appraisal and synthesis methodsStudies were included if they met the following criteria: unilateral trans-tibial amputees, lower limb prosthesis, reported analysis of ankle power during walking. Data extracted from the included studies were clinical population, type of the prosthetic ankle-foot units (SACH, ESAR, PWR), walking speed, and peak ankle power. Linear regression was used to determine whether the push-off power of different prosthetic ankle-foot units varied regarding walking speed. Push-off power of the different prosthetic ankle-foot units were compared using one-way between subjects' ANOVAs with post hoc analysis, separately for slower and faster walking speeds. Results474 publications were retrieved, 28 of which were eligible for inclusion. Correlations between walking speed and peak push-off power were found for ESAR (r = 0.568, p = 0.006) and PWR (r = 0.820, p = 0.000) but not for SACH (r = 0.267, p = 0.522). ESAR and PLOS ONE | https://doi.org/10.1371/journal.pone. Funding:The funders, Klinikum Bayreuth GmbH (https://klinikum-bayreuth.de/) and Ossur hf. (https://www.ossur.com/?select-default-destination=1), provided support in the form of salaries for authors R.M., L.M., R.A. and K.L., but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of PWR demonstrated significant differences in push-off power for slower and faster walking speeds (ESAR (p = 0.01) and PWR (p = 0.02)). ConclusionPush-off power can be used as a selection criterion to differentiate ankle-foot units for prosthetic users and their bandwidth of walking speeds.Prosthetic push-off power in trans-tibial amputee walking PLOS ONE | https://doi.org/10.

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“…Despite our understanding of how muscle function can vary with mechanical demand and anatomical 60 location, there is yet to be a quantitative approach capable of comparing the function of different 61 muscles and how function varies across locomotor demands. Addressing these limitations can assist in 62 tuning the design and control strategies of physiological-inspired robotics and assistive devices that can 63 mimic the diversity of human movement (Grimmer and Seyfarth, 2014). A promising index-based 64 approach was introduced by Qiao and Jindrich (2016) that characterised joint function during 65 locomotion.…”

Section: Introduction 43mentioning

confidence: 99%

Muscle-specific indices to characterise the functional behaviour of human lower-limb muscles during locomotion

Lai

Biewener

Wakeling

2019

Journal of Biomechanics

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27The mechanical output of a muscle may be characterised by having distinct functional behaviours, 28 which can shift to satisfy the varying demands of movement, and may vary relative to a proximo-distal 29 gradient in the muscle-tendon architecture (MTU) among lower-limb muscles in humans and other 30 terrestrial vertebrates. We adapted a previous joint-level approach to develop a muscle-specific index-31 based approach to characterise the functional behaviours of human lower-limb muscles during 32 movement tasks. Using muscle mechanical power and work outputs derived from experimental data 33 and computational simulations of human walking and running, our index-based approach differentiated 34 known distinct functional behaviours with varying mechanical demands, such as greater spring-like 35 function during running compared with walking; with anatomical location, such as greater motor-like 36 function in proximal compared with the distal lower-limb muscles; and with MTU architecture, such as 37 greater strut-like muscles fibre function compared with the MTU in the ankle plantarflexors. The 38 functional indices developed in this study provide distinct quantitative measures of muscle function in 39 the human lower-limb muscles during dynamic movement tasks, which may be beneficial towards 40 tuning the design and control strategies of physiologically-inspired robotic and assistive devices. 41 42 Lai et al. 3

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Mimicking Human-Like Leg Function in Prosthetic Limbs

Cited by 78 publications

References 135 publications

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers

Prosthetic push-off power in trans-tibial amputee level ground walking: A systematic review

Muscle-specific indices to characterise the functional behaviour of human lower-limb muscles during locomotion

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