Multimodal Limbless Crawling Soft Robot with a Kirigami Skin

For limbless locomotion on flat surfaces, the absence of push points over the surface requires the coordination of body deformation and static friction to generate propulsive forces. The rhythmic contraction of earthworms' muscles produces p e ristaltic waves along their slender bodies [1] while friction - enhancing bristles on their skin, called setae, ensure a firm grip on the ground with each stride [2, 3] . The setae generate a directionally asymmetric friction that is easy to overcome in the direction of movement but strong enough to prevent sliding back . Thus, three fundamental elements of limbless locomotion on terrains with uniform roughness are large deformability, rhythmic contractions, and asymmetric friction . The limbless locomotion of earthworms has inspired the development of several crawling soft robots that replicate some of the ir morphological features, enabling them to crawl on uniform terrains [ 4, 5, 6 ], inside pipes [ 7, 8, 9 ], and through granular media [ 10, 11 ] . However, unifying all of these in a crawling robot remains unexplored. Additionally, many earthworm - inspired soft robots can only move in a straight line and do not possess steering capabilities, which limit s their applicability to unstructured real - world terrains. To replicat e body deformation, several researchers have developed worm - inspired soft robots powered by various actuation mechanisms.