Human-Robot Interaction during Walking with a Powered Compliant Knee Exoskeleton

^(*) Advanced Rehabilitation Technology and Science Research Group
^(†) Department of Human Physiology & Sports Medicine
^(‡) Robotics & Multibody Mechanics Research Group, Department of Mechanical Engineering
^(¥) Department of Experimental Anatomy
^(£) Department of Biometrics and Biomechanics Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
E-mail: kknaepen@vub.ac.be, pbeyl@vub.ac.be, sduerinc@vub.ac.be, fhagman@vub.ac.be, rmeeusen@vub.ac.be

Abstract

Determinants of locomotor training involve taskspecificity, repeatability, variability, intensity and self-initiative. KNEXO, a unilateral knee exoskeleton has been developed to study the effects of compliant assistance during treadmill gait. Overall, walking within KNEXO, leads to asymmetric kinematics (Figure 1) and changes in naturally occurring muscle activity. Walking without KNEXO and with KNEXO in unassisted mode is difficult to compare as the device is unilateral and the pneumatic muscles give, although weight-compensated, a certain amount of inertia to the movement. Walking with KNEXO in high compliance resembles walking with KNEXO in unassisted mode. Overall, kinematic and EMG data show that the device has its shortcomings (unilateral, 1 DoF, 1 joint) when assisting healthy gait, yet it gives opportunities to study the effects of assistanceas-needed on gait biomechanics.