Physical synchronization of soft self-oscillating limbs for fast and autonomous locomotion

Abstract

Animals achieve robust locomotion by offloading regulation from the brain to physical couplings within the body. In contrast, locomotion in artificial systems often depends on centralized processors. Here, we introduce a rapid and autonomous locomotion strategy with synchronized gaits emerging through physical interactions between self-oscillating limbs and the environment, without control signals. Each limb is a single soft tube that only requires a constant flow of air to perform cyclic stepping motions at frequencies reaching 300 hertz. Physical synchronization of several of these self-oscillating limbs enables locomotion speeds that are orders of magnitude faster than those of comparable state-of-the-art robots. Through body-environment dynamics, these seemingly simple devices exhibit autonomy, including obstacle avoidance, amphibious gait transitions, and phototaxis.