Design and Simulation Analysis of Lower Limit Follow-up Mechanism of Submerged Glider Based on the Parallel Four-bar Linkage

The wave glider is a new type of unmanned observation platform on water surface, which can generate forward thrust by obtaining wave energy through the swing of submerged glider's hydrofoils. By analyzing the wave energy loss caused by the umbilical cable inclination angle of the submerged glider of the conventional wave glider, a hydrofoil swing mechanism that can change the lower limit of hydrofoil swing with the change of the umbilical cable inclination angle is designed. Firstly, the adjustment ability of the lower limit follow-up mechanism to the hydrofoil swing angle is simulated and analyzed by the computational fluid dynamics software Fluent; secondly, the prototype of the lower limit follow-up mechanism is designed by adding a set of parallelogram transmission mechanism in the conventional submerged glider. A large wave simulation test platform is setup and the propulsion performance of the prototype is verified by pool tests. The research shows that the new hydrofoil swing mechanism can improve the propulsion performance of the submerged glider.