Shape-centric modeling of lateral undulation and sidewinding gaits for Snake Robots

Abstract

Planar equations of motion for lateral undulation and sidewinding by snake robots are derived within a common framework. The equations use a continuous model of the snake shape kinematics. The shape curve is defined as time and arc length parametrized deviations from a fixed curve. Viscous anisotropic friction models the snake-ground interaction. Vertical lifting of the body off of the ground plane defines time and spatially varying contact profiles in the planar model, which influence the external forcing applied to the system. We demonstrate this framework facilitates intuitive and convenient formulation of traveling wave gaits, in the form of cyclically-varying backbone curves and ground contact patterns. Simulation results illustrate that both lateral undulation and sidewinding gaits are indeed modeled by this single formulation.