Autonomous decentralized control for soft-bodied caterpillar-like modular robot exploiting large and continuum deformation

Building robots from soft materials provides opportunities to create more robust and adaptive designs: soft bodies can conform to complex shapes in the environment and they are able to cushion shocks and store elastic energy. The challenge, however, remains to control highly deformable moveable structures effectively. We have proposed that one useful approach is through an autonomous decentralized control using physically coupled mechano-sensory oscillators. We have developed a highly deformable 3-D printed soft robot (PS robot) as a platform to explore the validity of the control strategy. Based on this platform we introduce a caterpillar-like soft-bodied modular-robot that is controlled in a fully decentralized manner. This paper focuses on one of the advantageous characteristics of autonomous decentralized control, i.e., the extensibility/contractibility of the modularity structures. The numerical and experimental results demonstrate that simple oscillators (controllers) can interact with each other by deforming the soft-bodied structure leading to a phase gradient that propagates crawling locomotion. The PS robots provide a powerful platform for exploring this strategy and they can be generalized for use with different robot shapes and material properties.