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The Scientific World Journal
Volume 2015, Article ID 923286, 13 pages
http://dx.doi.org/10.1155/2015/923286
Research Article

Detection of Prosthetic Knee Movement Phases via In-Socket Sensors: A Feasibility Study

1Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
2Mechatronics Section, Mechanical Engineering Department, Faculty of Engineering, Assiut University, Assiut 71516, Egypt

Received 23 June 2014; Revised 2 September 2014; Accepted 15 October 2014

Academic Editor: Alberto Borboni

Copyright © 2015 Amr M. El-Sayed et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presents an approach of identifying prosthetic knee movements through pattern recognition of mechanical responses at the internal socket’s wall. A quadrilateral double socket was custom made and instrumented with two force sensing resistors (FSR) attached to specific anterior and posterior sites of the socket’s wall. A second setup was established by attaching three piezoelectric sensors at the anterior distal, anterior proximal, and posterior sites. Gait cycle and locomotion movements such as stair ascent and sit to stand were adopted to characterize the validity of the technique. FSR and piezoelectric outputs were measured with reference to the knee angle during each phase. Piezoelectric sensors could identify the movement of midswing and terminal swing, pre-full standing, pull-up at gait, sit to stand, and stair ascent. In contrast, FSR could estimate the gait cycle stance and swing phases and identify the pre-full standing at sit to stand. FSR showed less variation during sit to stand and stair ascent to sensitively represent the different movement states. The study highlighted the capacity of using in-socket sensors for knee movement identification. In addition, it validated the efficacy of the system and warrants further investigation with more amputee subjects and different sockets types.