Dynamic Analysis of Three Snake Robot Gaits

In the present paper, a dynamic analysis is presented, comparing three snake-like robot gaits: lateral undulation, sidewinding locomotion, and sinus-lifting motion. To simplify calculations, sidewinding locomotion and sinus-lifting motion are considered planar movements. Vertical movements are assumed to be small but play a critical role in change where contacts are made. Thus, the normal forces acting on grounded links and the torques applied to pitch joints can be calculated by solving equilibrium equations. The tradeoff between locomotion speed and energy efficiency is studied for all three gaits, at eight different environmental settings distinguished by friction coefficients. Simulation results reveal that sinus-lifting motion and sidewinding locomotion are generally more energy-efficient gaits than is lateral undulation. More specifically, if the anisotropy in friction is large enough, sinus-lifting motion is the most energy-efficient gait; otherwise, sidewinding locomotion is more efficient. However, there are some critical speeds at which the most efficient gait changes, in some environmental settings.