A novel active balance assistive control strategy based on virtual stiffness model of XCoM

Purpose This paper aims to propose a novel balance-assistive control strategy for hip exoskeleton robot. Design/methodology/approach A hierarchical balance assistive controller based on the virtual stiffness model of extrapolated center of mass (XCoM) is proposed and tested by exoskeleton balance assistive control experiments. Findings Experiment results show that the proposed controller can accelerate the swing foot chasing XCoM and enlarge the margin of stability. Originality/value As a proof of concept, this paper shows the potential for exoskeleton to actively assist human regain balance in sagittal plane when human suffers from a forward or backward disturbing force.