Tensegrity-Based Legged Robot Generates Passive Walking, Skipping, and Crawling Gaits in Accordance With Environment

Legged locomotion animals produce various gaits, e.g., skipping, walking, running, and crawling, depending upon the environmental situation. Such an autonomous selection of distinct gait patterns is highly advantageous for energy efficiency, stress minimization, and postural stability. It should be of interest to introduce such a remarkably flexible mechanism to robotics research. This study addresses the mechanism of generating various gait patterns in a passive legged locomotion system by introducing a tensegrity structure. Building upon the classical model of the rimless wheel, we propose a novel model, called rimless wheel-like tensegrity walker (RTW). Numerical simulations show that the RTW system can generate skipping, walking, and crawling gaits depending upon the strength of the body-leg coupling, which controls independence level of the leg movements. Smooth gait transition can also be realized by a change in the body-leg coupling or the environmental parameter. An experimental study using physical models of the RTW confirmed the validity of the numerical results. The RTW may provide a minimal locomotion model to generate various gaits and to induce their transitions.