Design, Fabrication and Morphing Mechanism of Soft Fins and Arms of a Squidlike Aquaticaerial Vehicle with Morphology Tradeoff Some animals have the ability to shuttle freely between water and air. These creatures have evolved special body structures to accommodate both underwater and airborne environments. Natural creatures have given us great inspiration to the variable structure design for aquaticaerial multimodal vehicle. In this paper, we propose a new squidlike soft morphing fins according to the flying squid. This squidlike soft morphing fins can spread and fold for the adaptation of the aquaticaerial multimodal locomotion. When the fin is spread, it can generate lift force for the aquaticaerial vehicle. When the soft fin is folded, it can reduce the drag force during the underwater movement. An unique air cavity inside the fin was designed as actuator to bend the soft fin. The fabrication method of the soft fin was introduced. The bending performance of the soft fin was analyzed by FEA simulation and tested by several experiments. Then, morphology tradeoff strategy of aquaticaerial vehicle with soft morphing fins was investigated by the wind and water tunnel. The results demonstrate the soft morphing fins have fast actuating response and good deformability, which verifies the soft fin can help the aquaticaerial vehicle to realize multimodal locomotion.

Design of a Robotic Fish Based on a Passive Flexible Mechanism In recent years, along with the rapid development of manufacturing, control, sensing and other technologies, biomimetic robotic fish has played an increasingly important role in marine exploration, underwater rescue, water quality monitoring and other fields. This paper designed a robotic fish based on a passive flexible mechanism to realize the fishlike propulsion function. The motion simulation of the designed transmission mechanism was carried out to get the actual curve of the structure. Through the analysis of the force of the fishtail, the preliminary selection scheme of the elastic joints based on the passive flexible mechanism was obtained. Finally, this paper built a robotic fish based on a passive flexible mechanism, which could achieve the motion frequency adjustable from 0.5 to 9 Hz, and the maximum swimming speed reaching 1.05 BLs (BL, body length). This design scheme provided a new reference for the design of the biomimetic robotic fish and had certain practical significance.