From Coils to Crawls: A Snake-Inspired Soft Robot for Multimodal Locomotion and Grasping

Abstract Currently, numerous biomimetic robots inspired by natural biological systems have been developed. However, creating soft robots with versatile locomotion modes remains a significant challenge. Snakes, as invertebrate reptiles, exhibit diverse and powerful locomotion abilities, including prey constriction, sidewinding, accordion locomotion, and winding climbing, making them a focus of robotics research. In this study, we present a snake-inspired soft robot with an initial coiling structure, fabricated using MXene-cellulose nanofiber ink printed on pre-expanded polyethylene film through direct ink writing technology. The controllable fabrication of initial coiling structure soft robot (ICSBot) has been achieved through theoretical calculations and finite element analysis to predict and analyze the initial structure of ICSBot, and programmable ICSBot has been designed and fabricated. This robot functions as a coiling gripper capable of grasping objects with complex shapes under near infrared light stimulation. Additionally, it demonstrates multi-modal crawling locomotion in various environments, including confined spaces, unstructured terrains, and both inside and outside tubes. These results offer a novel strategy for designing and fabricating coiling-structured soft robots and highlight their potential applications in smart and multifunctional robotics.