Walking dynamics from walking steady state

1. Motivation. How do humans walk and run stably without falling down? How do humans walk without deviating too much from a roughly periodic steady motion, say, when walking on a treadmill? There are many hundred articles with mechanicsbased mathematical models of bipedal walking and running, that demonstrate stable periodic motion, either due to passive dynamics or due to active control. Such theoretical work provide insight into how one might stabilize locomotion. However, it is not yet settled which among this zoo of stabilizing control schemes yield dynamics most similar to that of humans during locomotion. Our goal is characterize, using appropriate human walking experiments, the dynamics near steady state walking motions. We seek a model of the dynamics that will be able to predict the transients back to steady state, not just reproduce the steady state motion. Aside being of general scientific interest, a characterization of walking dynamics might enable us to design prosthetic devices with human-like dynamics, or exoskeletons that do not fight these natural dynamics.