Octopus-inspired Eight-arm Robotic Swimming by Sculling Movements
ABSTRACT Inspired by the octopus arm morphology and exploiting recordings of swimming octopus, we investigate the propulsive capabilities of an 8-arm robotic system under various swimming gaits, including arm sculling and arm undulations, for the generation of forward propulsion. A dynamical model of the robotic system, that considers fluid drag contributions accurately evaluated by CFD methods, was used to study the effects of various kinematic parameters on propulsion. Exper- iments inside a water tank with an 8-arm robotic prototype successfully demonstrated the sculling-only gaits, attaining a maximum speed of approximately 0.2 body lengths per second. Similar trends were observed, as in the simulation studies, with respect to the effect of the kinematic parameters on propulsion.
- SourceAvailable from: Helmut Hauser
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- "In particular, for the closed-loop control task, our results suggest that soft body dynamics can be sufficient to perform the task to control the body without the need of an external controller for additional memory capacity. This can be, for example, directly applied to the recently proposed octopus-inspired swimming robot  to generate the arm motion in a closed-loop manner exploiting the body dynamics itself, which largely outsources the computational load required to generate the motor command to the body. The technique presented here can be potentially applied to a wide class of soft robots because the main component required is the soft body itself. "
ABSTRACT: Soft materials are not only highly deformable but they also possess rich and diverse body dynamics. Soft body dynamics exhibit a variety of properties, including nonlinearity, elasticity, and potentially infinitely many degrees of freedom. Here we demonstrate that such soft body dynamics can be employed to conduct certain types of computation. Using body dynamics generated from a soft silicone arm, we show that they can be exploited to emulate functions that require memory and to embed robust closed-loop control into the arm. Our results suggest that soft body dynamics have a short-term memory and can serve as a computational resource. This finding paves the way toward exploiting passive body dynamics for control of a large class of underactuated systems.Journal of The Royal Society Interface 06/2014; 11(100). DOI:10.1098/rsif.2014.0437 · 3.92 Impact Factor
Bioinspired Robotics, Frascati, Italy; 06/2014
- "Cephalopods, such as squids and octopuses, often propel themselves in water by resorting to a sequence of cyclic contractions and expansions of a soft cavity of their body, commonly referred to as the mantle . While squids may rely on fin-assisted swimming  and octopi are observed to use arm sculling , here we will be dealing with the pulsed-jet mode of propulsion exclusively. "
Conference Paper: Turning Maneuvers of an Octopus-inspired Multi-arm Robotic Swimmer[Show abstract] [Hide abstract]
ABSTRACT: Inspired by the agile underwater maneuvering of the octopus, an eight-arm robotic swimmer was developed. Associated dynamical models are used here to design turning maneuvers, an important ability for underwater navigation. The performance of several turning gaits, based on sculling arm movements, of this robotic system was investigated in simulation, with respect to their various kinematic parameters. Experiments with a prototype robotic swimmer confirmed the computational results and verified the multi-arm maneuverability of such systems.21st Mediterranean Conference on Control and Automation (MED'13); 06/2013