Polychaete-like Undulatory Robotic Locomotion

Polychaete annelid worms provide a biological paradigm of versatile locomotion and effective motion control, adaptable to a large variety of unstructured environmental conditions (water, sand, mud, sediment, etc.). The undulatory locomotion of their segmented body is characterized by the combination of a unique form of tail-to-head body undulations, with the rowing-like action of numerous lateral appendages distributed along their body. Computational models of polychaete-like crawling and swimming have been developed, based on the Lagrangian dynamics of the system and on resistive models of its interaction with the environment, and used for simulation studies demonstrating the generation of undulatory gaits. Several lightweight robotic prototypes have been developed, whose undulatory actuation achieves propulsion on sand. Extensive experiments demonstrate that the propulsion of these robots is characterized by essential features of polychaete locomotion, in agreement with the corresponding simulations.