Pedundulatory robotic locomotion: Centipede and polychaete modes in unstructured substrates

The present paper considers a novel class of robotic systems, termed pedundulatory locomotors, which can be thought of as undulatory robots augmented by multiple pairs of lateral paddle-like appendages (“parapodia”). Bio-inspired strategies for synchronizing the movement of the parapodia with the body undulations, emulating organisms like the centipedes and the polychaete worms, are presented, giving rise to distinct pedundulatory modes. These modes are investigated and comparatively assessed, both in simulation and via experiments with the Nereisbot prototype locomoting on sand and on several other unstructured substrates. Our studies demonstrate the rich gait repertoire and enhanced performance of pedundulatory systems, compared to purely undulatory ones.