Hybrid zero dynamics of human biped walking with foot slip

Abstract

Most existing bipedal dynamics models are built on an assumption of no foot slip. We relax such assumption and present hybrid zero dynamics model and properties for bipedal walking with foot slip. When foot slips, the biped hybrid zero dynamics (HZD) preserve rich features such as high dimensionality and transitions between slip and non-slip dynamics. We present the closed-form of the HZD for human walking and discuss the transition between non-slip and slip states through slip recovery design. We illustrate the analysis and design through human walking experiments. The proposed HZD models and analysis can be further used to design control systems for robotic rehabilitation and assistive devices.