Abstract: Stingrays can undulate their wide pectoral fins to thrust themselves and swim freely underwater. Many researchers have used bionics to directly imitate their undulating mechanism and manufacture undulatory underwater robots. Based on the limitations of the existing undulatory underwater robots, this paper proposes a novel undulatory propulsion strategy, which aims to use the stingray undulating mechanism more thoroughly. First, the mathematical models of both traditional and novel structures are established to accurately describe their undulating mechanism. Then, based on the dynamic mesh technology, the flow field vortex structure they generated is analyzed through fluid-structure interaction simulation, and the thrust force and lateral force generated by them are calculated, which verified that this novel propulsion strategy is indeed more effective. Finally, a prototype robot based on the improved propulsion strategy is manufactured. Compared with the existing stingray robots, the prototype has obvious advantages, thus verifying the accuracy of the simulation results. 

Key words: bionic underwater robot, stingray, undulatory propulsion mechanism;fluid-structure interaction