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Applied Bionics and Biomechanics
Volume 6, Issue 2, Pages 245-256

Analysis of the Human Interaction with a Wearable Lower-Limb Exoskeleton

Juan C. Moreno,1 Fernando Brunetti,1 Enrique Navarro,2 Arturo Forner-Cordero,1 and José L. Pons1

1Grupo de Bioingeniería, IAI, Consejo Superior de Investigaciones Científicas, Arganda del Rey, Madrid, Spain
2Facultad de la Actividad Física y el Deporte (INEF), Universidad Politécnica de Madrid. Martín Fierro s/n, Madrid, Spain

Received 16 February 2009

Copyright © 2009 Hindawi Publishing Corporation. 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.


The design of a wearable robotic exoskeleton needs to consider the interaction, either physical or cognitive, between the human user and the robotic device. This paper presents a method to analyse the interaction between the human user and a unilateral, wearable lower-limb exoskeleton. The lower-limb exoskeleton function was to compensate for muscle weakness around the knee joint. It is shown that the cognitive interaction is bidirectional; on the one hand, the robot gathered information from the sensors in order to detect human actions, such as the gait phases, but the subjects also modified their gait patterns to obtain the desired responses from the exoskeleton. The results of the two-phase evaluation of learning with healthy subjects and experiments with a patient case are presented, regarding the analysis of the interaction, assessed in terms of kinematics, kinetics and/or muscle recruitment. Human-driven response of the exoskeleton after training revealed the improvements in the use of the device, while particular modifications of motion patterns were observed in healthy subjects. Also, endurance (mechanical) tests provided criteria to perform experiments with one post-polio patient. The results with the post-polio patient demonstrate the feasibility of providing gait compensation by means of the presented wearable exoskeleton, designed with a testing procedure that involves the human users to assess the human-robot interaction.