Dead Matter, Living Machines: Repurposing Crustaceans' Abdomen Exoskeleton for Bio-Hybrid Robots.

Bio-hybrid robots utilize living organisms for robot design, however, their use of living bodies makes maintenance, control, and fabrication of robot challenging. As an alternative, exoskeletons stand out for retaining mobility after the organism's death, making them an accessible candidate. In particular, crustacean exoskeletons, often discarded as food waste, provide both structural strength and flexibility from their segmented rigid shell. By repurposing dead animals' part from bio-waste, a sustainable cyclic design process is proposed in which materials can be recycled and adapted for new tasks after a robot's lifespan. In this paper, a bio-hybrid robot design using the langoustine abdominal exoskeleton as a bending actuator is introduced. Through integration with synthetic components, augmented exoskeletons can generate diverse, fast, and robust motions with extended operational lifetimes. Three robotic applications are demonstrated using a 3 g exoskeleton capable of supporting a 680 g payload: a manipulator handling objects up to 500 g, fingers that grasp various objects and bend at speeds up to 8 Hz, and a swimming robot at speeds up to 11 cm s-1. The method offers a sustainable robot design scheme and can be extended to diverse scales and functionalities by exploring a wide range of repurposable exoskeletons from bio-waste.