External dynamics dependent human gait adaptation using a cable-driven exoskeleton

Abstract

The emergence of exoskeleton technology has enabled new opportunities for gait rehabilitation, but effective methods to restore healthy gait patterns with exoskeletons are not yet clearly understood. Early research in robot-based gait rehabilitation offered little improvement over current standards of physical care and emphasized the need for a deeper understanding of the complex interaction between humans and the robot, i.e., physical human-robot interaction (pHRI). Studies reported varied lower limb responses for a similar intervention with different exoskeletons, implying that the exoskeleton's external dynamics affect musculoskeletal adaptation outcomes. Accordingly, the current study aims at showcasing the external dynamics dependent gait adaptation using a Cable-Driven Leg Exoskeleton (CDLE). A swing phase gait intervention using three different CDLE cable-routing configurations that impose varied dynamics at human anatomical joints is studied. Twenty-four healthy participants, eight for each CDLE configuration, were tested. Results showed varied gait adaptation among the three groups such that the subjects used either predominantly their hip joint, knee joint, or a combination of both joints implying selective joint strategy adaptations for different external dynamics conditions for the same intervention. The results of this study can provide insights into the optimal design of leg exoskeleton-based rehabilitation paradigms for effective gait rehabilitation.