Ankle-Exoskeleton Control for Assisting in Balance Recovery After Unexpected Disturbances During Walking

Abstract

In the last two decades, lower-limb exoskeletons have been developed to assist human standing and locomotion. One of the ongoing challenges is still balance support. Here we present a control strategy for an ankle-exoskeleton to assist balance recovery after unexpected disturbances during walking. We evaluated the controller in two healthy participants wearing the ankles of the Symbitron exoskeleton while receiving forward pushes at the pelvis during walking. Providing low and medium assistance resulted in improvement of balance recovery (decreased center of mass movement in the direction of the perturbation) and reduction of muscle activity, respect to trials with no assistance. These effects saturated with high levels of assistance. The results are promising, but the controller should be improved to use human’s real-time response as a feedback to trigger the support.