Design and Analysis of a Compliant Shoulder Mechanism for Assistive Exoskeletons
Authors
Desai, Rohan Sameer ; Balser, Felix ; Ekizoglou, Alexandros Marios
Term
4. term
Education
Publication year
2021
Submitted on
2021-06-03
Pages
139
Abstract
I dette speciale designes og analyseres et passivt exoskelet (en bærbar mekanisk støtte uden motorer) til at hjælpe ældre og arbejdere med opgaver over hovedhøjde. Formålet er at modvirke tyngdekraftens påvirkning af armen og dermed mindske anstrengelsen ved at holde armen oppe. Enheden kombinerer en sfærisk skuldermekanisme, som tillader skulderen at rotere i flere retninger, med en passiv mekanisme med variabel stivhed, der kan justere, hvor meget støtte den giver uden ekstern energi. Begge mekanismer beskrives, og yderligere ideer præsenteres. Den variable stivhedsmekanisme vurderes og sammenlignes ved hjælp af numeriske beregninger, analytiske modeller og eksperimenter. For at reducere vægten anvendes topologioptimering. Exoskelettet fokuserer på assistance i sagittalplanet (løft og sænkning af armen foran kroppen), men modulets egenskaber muliggør også bevægelse i andre planer. Det endelige design kompenserer for 50% af armens tyngdemoment (det drejemoment, som armens vægt skaber) med strakt albue.
This thesis designs and analyzes a passive exoskeleton (a wearable mechanical support that works without motors) to help older adults and workers perform tasks above shoulder height. The goal is to counteract gravity on the arm, reducing the effort needed to hold the arm up. The device combines a spherical shoulder mechanism, which allows shoulder rotations in multiple directions, with a passive variable-stiffness mechanism that can adjust how much support it provides without external power. Both mechanisms are described, and further ideas are outlined. The variable-stiffness mechanism is evaluated and compared using numerical calculations, analytical models, and experiments. To reduce weight, topology optimization is applied. The exoskeleton primarily assists movement in the sagittal plane (lifting and lowering the arm in front of the body), but the properties of the modules also enable motion in other planes. The final design compensates for 50% of the arm’s gravitational torque (the turning effect from the arm’s weight) when the elbow is fully extended.
[This summary has been rewritten with the help of AI based on the project's original abstract]
Keywords
SSM ; VSM ; shoulder exoskeleton ; passive
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