Passive Mechanical Walkers are a Proxy for Studying Dynamic Balance in Human Gait.pdf Public

Passive mechanical walkers have been shown to be proxies for the study of human gait. Both humans and walkers can be modeled as inverted pendulums wherein the center of mass pivots passively over the foot. Previous studies have largely examined similarities in energy efficiency and stability based on Lyapunov exponents computed on various gait parameters. This study examines the similarities between human and passive-dynamic walkers using the duPont balance index (DN). DN measures the excursion of the COM in a coordinate system defined by the line joining the feet (IFL). Furthermore, since balance loss via tripping or slipping induces a rotation of the subject, moment of inertia (MOI) considerations also play a role. It is seen that for both walkers and humans, the IFL coordinate system tracks with the principle MOI and that the MOI about the IFL is less than that about either foot axis indicating that the IFL is a preferred axis of rotation for potential falls. Such rotation is noted during actual falls of passive dynamic walkers.