A bionic adhesive disc for torrent immune locomotion inspired by the Guizhou Gastromyzontidae The Guizhou Gastromyzontidae showed extraordinary normal adhesion and anisotropic friction on wet and slippery surfaces in the torrential stream. In this study, the surface microstructures of adhesive disc of the Guizhou Gastromyzontidae were characterized firstly by using the Scanning Electron Microscopy (SEM). It had been found that the fin rays of the fish were composed of the hexagonal padlike unculi, setae arrays and micropores. Then, inspired by the surface structures of the adhesive disc of Guizhou Gastromyzontidae, the artificial adhesive discs with surface microstructures were designed and fabricated by using the 3D printing and molding technology. The regular disc with no surface microstructures was also fabricated for comparison study. The adhesion properties of two different disc samples were investigated in water condition on substrates with various roughnesses. The results show that the bionic adhesive discs with composite microstructures have good adhesion properties in water condition. The proposed adhesive disc could have potential applications for underwater robotics.

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.