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

Juan C Moreno,José L Pons,Enrique Navarro,Fernando Brunetti,Arturo Forner-Cordero

doi:10.1155/2009/712530

Abstract

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.

Highlights

Biomechatronics is the application of mechatronics to biological motor systems (Carrozza et al 2002; Pons 2008; Pons et al 2008)
Robotic exoskeletons are used in different rehabilitation applications that can be classified under several categories (Harwin et al 2002)
A major challenge in the field of robotic exoskeletons is that the human being is placed at the centre of mechatronic technologies, and they have to interact with the human, leading to a mutual adaptation and functional enhancement

Summary

Introduction

Biomechatronics is the application of mechatronics (study, analysis, design and implementation of hybrid systems comprising mechanical, electrical and control components or subsystems) to biological motor systems (Carrozza et al 2002; Pons 2008; Pons et al 2008). Robotic exoskeletons are used in different rehabilitation applications that can be classified under several categories (Harwin et al 2002) They can be applied as rehabilitation therapy and diagnosis mechanisms that emulate the movements performed by a patient with a therapist during the treatment, while the sensors placed on the exoskeleton measure the performance of the patient. This provides quantitative information about the recovery process of the patient, allowing the optimisation of the therapeutic treatment. In this type of robotic exoskeletons the main requirement is to apply and measure forces and positions precisely (Scott 1999)

Methods

Results

Conclusion