Balance stability characteristics of human walking with preferred, fast, and slow speeds

This work presents a model-based method of evaluating and quantifying stability characteristics of human walking in the sagittal plane. The stability criteria used for this analysis are boundaries in the state space of the center of mass (COM), which represent the maximum capability of a human to maintain balance in single support (SS) and double support (DS) phases or to make a desired step without falling. Complete models of the system dynamics, biomechanical characteristics, its contact interaction with the ground, and gait parameters, are considered. Experimental human COM trajectories during walking are analyzed against computed stability boundaries to quantify the nature of human gait across walking speeds. Stability comparisons with other robotic platforms, an exoskeleton and a humanoid robot, are also provided.