Document Detail


Inertia Compensation Control of a One-Degree-of-Freedom Exoskeleton for Lower-Limb Assistance: Initial Experiments.
MedLine Citation:
PMID:  22271684     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
A new method of lower-limb exoskeleton control aimed at improving the agility of leg-swing motion is presented. In the absence of control, an exoskeleton's mechanism usually hinders agility by adding mechanical impedance to the legs. The uncompensated inertia of the exoskeleton will reduce the natural frequency of leg swing, probably leading to lower step frequency during walking as well as increased metabolic energy consumption. The proposed controller emulates inertia compensation by adding a feedback loop consisting of low-pass filtered angular acceleration multiplied by a negative gain. This gain simulates negative inertia in the low-frequency range. The resulting controller combines two assistive effects: increasing the natural frequency of the lower limbs and performing net work per swing cycle. The controller was tested on a statically mounted exoskeleton that assists knee flexion and extension. Subjects performed movement sequences, first unassisted and then using the exoskeleton, in the context of a computer-based task resembling a race. In the exoskeleton's baseline state, the frequency of leg swing and the mean angular velocity were consistently reduced. The addition of inertia compensation enabled subjects to recover their normal frequency and increase their selected angular velocity. The work performed by the exoskeleton was evidenced by catch trials in the protocol.
Authors:
Gabriel Aguirre-Ollinger; J Edward Colgate; Michael A Peshkin; Ambarish Goswami
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society     Volume:  20     ISSN:  1558-0210     ISO Abbreviation:  IEEE Trans Neural Syst Rehabil Eng     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2012-01-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101097023     Medline TA:  IEEE Trans Neural Syst Rehabil Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  68-77     Citation Subset:  IM    
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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