Rate-dependent gait dynamic stability analysis for motor control estimation

This work presents the gait dynamic stability study for different walking speeds adopted by user intentions. Experimental data were collected from four healthy subjects while walking on a force platform at slow, normal and fast speed. The rate-dependent variations in the center of pressure (COP) and ground reaction forces (GRF) were modelled as motor output and input responses. Finite difference and non-linear regression algorithms were implemented to model gait transitions. Dynamic stability estimation for level ground walking was performed by analysis in time and frequency domains. Study of the COP velocity in loading phase showed that, the overdamped motor output response acts as a compensator for instabilities and oscillations in unloading phase and initial contact. Normal walking was predicted, from gait analysis in frequency domain, as the most stable gait for healthy subjects.