A Novel Method and Exoskeletons for Whole-Arm Gravity Compensation

Hull, Joshua; Turner, Ranger; Simon, Athulya A.; Asbeck, Alan T.

doi:10.1109/access.2020.3014285

Cited by 22 publications

(15 citation statements)

References 33 publications

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“…Considering passive orthoses that provide dynamic shoulder support, five potentially fully wearable devices designated for assisting ADLs exist to our knowledge. The A-Gear [8], Panto-Arm Exo [9] and Springwear [10] are academic research prototypes, while the EksoUE [11] and Wilmington Robotic Exoskeleton (WREX) [12], [13] are commercially available devices. On the other hand, in recent years several companies have entered the market with wearable work assist exoskeletons.…”

Section: Introductionmentioning

confidence: 99%

Gravity Balancing Flexure Spring Mechanisms for Shoulder Support in Assistive Orthoses

Tschiersky¹,

Hekman²,

Herder³

et al. 2021

Preprint

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Passive shoulder supports show large potential for a wide range of applications, such as assisting activities of daily living and supporting work-related tasks. The rigid architectures of currently available devices, however, may pose an obstacle to finding designs that offer low protrusion and close-to-the-body alignment. This study explores the use of mechanisms that employ a flexible element which connects the supported arm to an attachment at the back and acts as energy storage, transmission and part of the load bearing structure. Based on the synthesis method explained in this paper, we conducted a large scope investigation into possible flexure-based mechanism topologies. Many potential designs were discovered and are presented, categorized and compared. Two promising designs were developed into prototypes that were built and tested on a dedicated test bench. These mechanisms reduce the necessary moment to lift the arm by more than 80 % throughout 85 % of the range of motion, while staying within 18 cm and 10 cm distance from the body, respectively. Our study indicates that, due to its lower protrusion and interface loads, a design with a tapered flexure connecting the upper arm via a hinge to a spring loaded slider at the back offers the most promising solution.

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Section: Introductionmentioning

confidence: 99%

Gravity Balancing Flexure Spring Mechanisms for Shoulder Support in Assistive Orthoses

Tschiersky¹,

Hekman²,

Herder³

et al. 2021

Preprint

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show abstract

“…As previously introduced, WS is a necessary step in many functional rehabilitation processes ( Prange et al, 2006 ; Frisoli et al, 2007 ; Frisoli et al, 2012 ). Therefore, its effect have been studied on disabled patients and healthy participants often using passive systems ( Prange et al, 2009b ; Perry et al, 2017 ; Puchinger et al, 2018 ; Hull et al, 2020 ; Perry et al, 2021 ). These investigations were oriented towards the analysis of muscle activities and workspace in different configurations.…”

Section: Introductionmentioning

confidence: 99%

“…These investigations were oriented towards the analysis of muscle activities and workspace in different configurations. In the horizontal plane (F. Beer et al, 2007 ), in the sagittal plane ( Prange et al, 2009a ; Prange et al, 2009b ; Perry et al, 2021 ) and during three-dimensional movements ( Coscia et al, 2014 ; Puchinger et al, 2018 ; Runnalls et al, 2019 ; Hull et al, 2020 ), a global decrease of electromyographic (EMG) activities and an increase in the number of muscular synergies were observed. Moreover, an increase in the workspace of disabled patient was also reported.…”

Section: Introductionmentioning

confidence: 99%

Human Weight Compensation With a Backdrivable Upper-Limb Exoskeleton: Identification and Control

Verdel

Bastide

Vignais

et al. 2022

Front. Bioeng. Biotechnol.

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Active exoskeletons are promising devices for improving rehabilitation procedures in patients and preventing musculoskeletal disorders in workers. In particular, exoskeletons implementing human limb’s weight support are interesting to restore some mobility in patients with muscle weakness and help in occupational load carrying tasks. The present study aims at improving weight support of the upper limb by providing a weight model considering joint misalignments and a control law including feedforward terms learned from a prior population-based analysis. Three experiments, for design and validation purposes, are conducted on a total of 65 participants who performed posture maintenance and elbow flexion/extension movements. The introduction of joint misalignments in the weight support model significantly reduced the model errors, in terms of weight estimation, and enhanced the estimation reliability. The introduced control architecture reduced model tracking errors regardless of the condition. Weight support significantly decreased the activity of antigravity muscles, as expected, but increased the activity of elbow extensors because gravity is usually exploited by humans to accelerate a limb downwards. These findings suggest that an adaptive weight support controller could be envisioned to further minimize human effort in certain applications.

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“…Considering passive orthoses that provide dynamic shoulder support, ve potentially fully wearable devices designated for assisting ADLs exist to the author's knowledge. The A-Gear [35], Panto-Arm Exo [25] and SpringWear [8] are academic research prototypes, while the EksoUE [16] and Wilmington Robotic Exoskeleton (WREX) [23,73] are commercially available devices. On the other hand, in recent years several companies have entered the market with wearable work-assist exoskeletons.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the amount of force the user has to exert in order to lift the arms is reduced. To this end, these exoskeletons employ rigid-link mechanisms that contain energy storing elements like tension and compression springs [3,41,60], gas springs [16,25], rubber bands [8,35,51,73] and leaf spring exures [61] in combination with transmission elements like rigid linkages [8,25,35,51,61,73], cable-pulley con gurations [3,60], gears [41] and cams [16] which together create the desired mechanical behavior. These types of mechanisms, however, imply an exoskeleton design in which a rigid frame and rigid links are used to interface with the wearer's body.…”

Section: Introductionmentioning

confidence: 99%

Flexure mechanisms for upper-limb support: towards compliant wearable assistive devices

Tschiersky¹

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A Novel Method and Exoskeletons for Whole-Arm Gravity Compensation

Cited by 22 publications

References 33 publications

Gravity Balancing Flexure Spring Mechanisms for Shoulder Support in Assistive Orthoses

Gravity Balancing Flexure Spring Mechanisms for Shoulder Support in Assistive Orthoses

Human Weight Compensation With a Backdrivable Upper-Limb Exoskeleton: Identification and Control

Flexure mechanisms for upper-limb support: towards compliant wearable assistive devices

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