受動的な尾びれと調整可能な剛性を備えた魚型ロボットの実験的研究
Experimental study of fish-like bodies with passive tail and tunable stiffness
尾柄部にねじりばねを入れて尾の柔軟性を調整できる体長30cmの魚型ロボットを試作し、周波数と剛性を変えて推進力・速度・パワーを計測、実魚に近い進行波的な変形と最適ストローハル数での自走を確認した。
著者: L. Padovani, G. Manduca, D. Paniccia, G. Graziani, R. Piva, C. Lugni
分類: physics.flu-dyn, cs.RO
原文アブストラクト
Scombrid fishes and tuna are efficient swimmers capable of maximizing performance to escape predators and save energy during long journeys. A key aspect in achieving these goals is the flexibility of the tail, which the fish optimizes during swimming. Though, the robotic counterparts, although highly efficient, have partially investigated the importance of flexibility. We have designed and tested a fish-like robotic platform (of 30 cm in length) to quantify performance with a tail made flexible through a torsional spring placed at the peduncle. Body kinematics, forces, and power have been measured and compared with real fish. The platform can vary its frequency between 1 and 3 Hz, reaching self-propulsion conditions with speed over 1 BL/s and Strouhal number in the optimal range. We show that changing the frequency of the robot can influence the thrust and power achieved by the fish-like robot. Furthermore, by using appropriately tuned stiffness, the robot deforms in accordance with the travelling wave mechanism, which has been revealed to be the actual motion of real fish. These findings demonstrate the potential of tuning the stiffness in fish swimming and offer a basis for investigating fish-like flexibility in bio-inspired underwater vehicles.