Development and testing of a passive ankle exoskeleton

Pardoel, Scott; Doumit, Marc

doi:10.1016/j.bbe.2019.08.007

Cited by 23 publications

(22 citation statements)

References 50 publications

(70 reference statements)

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“…Regardless of the exact reasons, it is currently unclear to what extent the cost of increased TA activation may offset reductions in cost from reduced plantarflexion work. Nevertheless, our findings are consistent with exoskeletons that stiffen the ankle, which tend to reduce MG and SOL activity at the expense of increased TA activity 34 , 53 , 54 .…”

Section: Discussionsupporting

confidence: 88%

Stiffening the human foot with a biomimetic exotendon

Riddick

Farris

Brown

et al. 2021

Sci Rep

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Shoes are generally designed protect the feet against repetitive collisions with the ground, often using thick viscoelastic midsoles to add in-series compliance under the human. Recent footwear design developments have shown that this approach may also produce metabolic energy savings. Here we test an alternative approach to modify the foot–ground interface by adding additional stiffness in parallel to the plantar aponeurosis, targeting the windlass mechanism. Stiffening the windlass mechanism by about 9% led to decreases in peak activation of the ankle plantarflexors soleus (~ 5%, p < 0.001) and medial gastrocnemius (~ 4%, p < 0.001), as well as a ~ 6% decrease in positive ankle work (p < 0.001) during fixed-frequency bilateral hopping (2.33 Hz). These results suggest that stiffening the foot may reduce cost in dynamic tasks primarily by reducing the effort required to plantarflex the ankle, since peak activation of the intrinsic foot muscle abductor hallucis was unchanged (p = 0.31). Because the novel exotendon design does not operate via the compression or bending of a bulky midsole, the device is light (55 g) and its profile is low enough that it can be worn within an existing shoe.

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Section: Discussionsupporting

confidence: 88%

Stiffening the human foot with a biomimetic exotendon

Riddick

Farris

Brown

et al. 2021

Sci Rep

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“…The powered exoskeleton directly provides external energy to human motion, in which the actuators are used to convert hydraulic energy, electrical energy, or pneumatic energy into mechanical energy required by the human body ( Stauffer et al, 2009 ; Talaty et al, 2013 ; Tsukahara et al, 2015 ; Lovrenovic and Doumit, 2016 ; Li et al, 2017 ; Munera et al, 2017 ; Ding et al, 2018 ; Niu et al, 2018 ; Pan et al, 2018 ; Zhang et al, 2018 ; Chen et al, 2019 ; Schick et al, 2020 ). The powered exoskeleton has made remarkable achievements in human walking assistance ( Pardoel and Doumit, 2019 ). However, the ambiguity and complexity during the intention recognition for human motion is a dangerous potential factor for the elderly with poor balance.…”

Section: Introductionmentioning

confidence: 99%

Hip–Knee Coupling Exoskeleton With Offset Theory for Walking Assistance

Sun

Chen³

2022

Front. Bioeng. Biotechnol.

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To alleviate the influence of aging on the elderly, a hip–knee coupling exoskeleton with offset theory is designed in this article to improve people’s athletic ability. With the novel design, the unique application strategy of the offset principle for hip and knee joints is developed, and a hip–knee coupling mechanism is proposed to solve the discrete power assistance problem for the knee joint. To acquire the success of the design, the mathematical model of the coupling mechanism is established to optimize the load environment of the exoskeleton system, and furthermore, an algorithm adapted to human movement is proposed to determine the monotonicity of the cam profiles. For the selection of the elastic parameters in the coupling mechanism, the sensitivity condition is proposed, and the human–machine interaction model of the KESM is further established. A man–machine coupling model was used to verify the scientificity of the exoskeleton design, and the comparison between the joint powers with or without exoskeleton indicated that the exoskeleton theoretically saved at least 20% of the human body’s energy.

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“…Walsh et al [14] presented a quasi-passive exoskeletal for load carrying that achieves an improved walking metabolic performance as compared to a standard loaded backpack; it transfers on average 80% of the load to the ground during the single support phase of walking. Scott and Marc [15] presented a passive ankle exoskeleton; it used a pneumatic artificial muscle (PAM) as a non-linear elastic element to store and release energy during walking. Dijk et al [16] developed a passive lower limb exoskeleton that used artifiial tendons to minimize the joint work during walking; it reduces human energy expenditure obviously.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of unpowered lower limb exoskeleton during sit down and stand up

et al. 2021

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Conventional unpowered lower limb exoskeleton paid little attention to the metabolic cost of body during sit down (SD)/stand up (SU). The SD motion model and the motion characteristics of lower extremity are analyzed; then, a novel unpowered lower limb exoskeleton is proposed, and the contribution degree of muscles and stiffness of joints are used for determining the location and stiffness of energy storage element. The metabolic cost of relevant muscles in joints of the left leg is obtained based on Opensim software. The results show that metabolic cost of the gracilis, rectus femoris (RF), and long head of the biceps femoris decreased about 13%, 9%, and 68%, respectively. The total metabolic cost of body decreased about 14% during SD. However, the metabolic cost of the gracilis, RF, and long/short head of the biceps femoris increased about 22%, 33%, 208%, and 46%, respectively. And the metabolic cost of sartorius reduces about 39%, the total metabolic cost of body increased about 25.6% during SU, under the exoskeleton conditions. The results of this study can provide a theoretical basis for the optimal design of unpowered lower limb exoskeleton.

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Development and testing of a passive ankle exoskeleton

Cited by 23 publications

References 50 publications

Stiffening the human foot with a biomimetic exotendon

Stiffening the human foot with a biomimetic exotendon

Hip–Knee Coupling Exoskeleton With Offset Theory for Walking Assistance

Performance analysis of unpowered lower limb exoskeleton during sit down and stand up

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