Scissor mechanisms enabled compliant modular earthworm-like robot: Segmental muscle-mimetic design, prototyping and locomotion performance validation

Earthworms are the soft, tube-shaped, segmented worms who move with waves of muscular contractions. This paper presents our recently developed compliant modular earthworm-like robot with the novel segmental muscle-mimetic design unit that efficiently mimics earthworm's segmental muscle contractions. The new class of segmental muscle-mimetic design unit relies on curvature of scissor mechanisms that can be extended and contracted smoothly through controlled servo motors. Connected numbers of the design units with the transmission mechanism, a multi-segment earthworm-like robot can be prototyped and it produces the peristaltic locomotion by controlling motors in each segment with different phase shift angles. In this paper, we detail the bioinspired concept and design of segmental muscle-mimetic unit, and demonstrate extensive simulation and experimental results on the design and the prototyped multi-segment robot. All results prove that both the design and the prototyped earthworm-like robot have excellent locomotion performance.