Title: Improvement and analysis of a mechanically adapted Lofstrand Crutch model through bond graph modelling

Authors: Rebeca Hannah De M. Oliveira; Danilo Dos S. Oliveira; Andrey N. Pimenta; Ludmila Evangelista Dos Santos; Giselle De O. Lima; Emerson Fachin-Martins; Danielle Brasil B. Da Silva; Jackson Paz B. De Souza; José Henrique De Oliveira; Suélia De Siqueira Rodrigues Fleury Rosa

Addresses: Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Graduate Program in Energy Management for Buildings and Infrastructures, Polytechnic University of Milan -POLiMI, Milan, 72.444-240, Italy ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Graduate Program in Health Sciences and Technologies, University of Brasília at Ceilândia, Brasília-DF, 72220-275, Brazil ' Graduate Program in Health Sciences and Technologies, University of Brasília at Ceilândia, Brasília-DF, 72220-275, Brazil ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil ' Postgraduate Program in Biomedical Engineering, University of Brasília at Gama- FGA, Brasília-DF, 72.444-240, Brazil

Abstract: Lofstrand Crutches represent a mobility device applied temporarily during the rehabilitation process or permanently as an assistive device. As a permanent device, they have a deep impact on the body due to the reactive force redistributed on the upper limbs. We present a review on the development and implementation of an innovative cushioning crutch-mounting device as well as a sensorial system for gathering feedback data. Following, we propose a bond graph mathematical model to compare the traditional Lofstrand Crutches (LC) with modified LC (mLC). Through state-space equations extracted from our model, we demonstrate a reduction in the resulting force through the introduction of the damping device on the crutch system. The simulation by the mathematical models demonstrated that the cushioning might incur effective minimisations on the upper limbs force redistribution, avoiding further movement disabilities for permanent users.

Keywords: Lofstrand Crutches; adapted Lofstrand Crutches; bond graph modelling; BG model; modelling; control; rehabilitation; crutch mounting device; force sensor resistor; mechanical damping device; assisted gait.

DOI: 10.1504/IJMIC.2020.116909

International Journal of Modelling, Identification and Control, 2020 Vol.36 No.3, pp.256 - 270

Received: 26 Mar 2020
Accepted: 12 Sep 2020
Published online: 06 Aug 2021 *

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