Multi-arm robotic swimming with octopus-inspired compliant web

This paper presents an 8-arm compliant robot, able to propel itself underwater by movements of its arms, either alone or interconnected via a passively-compliant web. The robot is inspired by the morphology and outstanding locomotor capabilities of the octopus, and is fabricated primarily from compliant materials. This robotic swimmer is first investigated computationally via dynamical models capturing the arm and web compliance, and indicating the effect of various kinematic parameters of the system on its motion. The performance of the robotic prototype is, then, tested experimentally, to demonstrate this novel mode of underwater propulsion by combining various patterns of sculling movements of the arms and web. Speeds of 0.5 body lengths per second and propulsive forces of up to 10.5 N were achieved, with a cost of transport as low as 0.62.