Influence of the Physical Interface on the Quality of Human–Exoskeleton Interaction

Despite exoskeletons becoming widespread tools in industrial applications, the impact of the design of human–exoskeleton physical interfaces has received little attention. This study aims at thoroughly quantifying the influence of different physical human–exoskeleton interfaces on subjective and objective biomechanical parameters. To this aim, 18 participants performed elbow flexion/extension movements while wearing an active exoskeleton with three different physical interfaces: a strap without any degree of freedom, a thermoformed orthosis with one (translation) and three degrees of freedom (translation and rotations). Interaction efforts, kinematic parameters, electromyographic activities, and subjective feelings were collected and examined during the experiment. Results showed that increasing the interaction area is necessary to improve the interaction quality at a subjective level. The addition of passive degrees of freedom allows significant improvements on both subjective and objective measurements. Outcomes of this study may provide fundamental insights to select physical interfaces when designing future exoskeletons.