Motion Analysis and Experimental Study of a Bionic Hybrid-Driven Underwater Glider With a Movable Bow

It remains a great challenge for hybrid-driven underwater glider (HUG) to carry out fine-scale ocean observations by limitations of mobility and flexibility. Inspired by the neck motion of underwater creatures, such as penguins and dolphins, this article proposed an HUG with a movable bow (HUGMB), which was designed to have high maneuverability for oceanographic exploration. The detailed design of HUGMB was given, and its dynamic model was established by considering the correlation between hydrodynamic coefficients and the attitude parameters of the movable bow. Based on the dynamic model, the motion performance of HUGMB was simulated, mainly involving gliding performance, steering capability, spiraling motion, and depth-fixed performance. The minimum spiraling radius was reduced to 1.83 m with an angular velocity of 12.3°/s, the maximum pitch angle reached 64.7°, and the variation in depth can be reduced to nearly 0 m during depth-fixed navigation, which is almost impossible for traditional HUGs. Finally, a prototype of HUGMB was created, and a tank experiment was carried out to verify the simulation results. These proved that the proposed movable bow can effectively improve the maneuverability of HUGs. This study also provides guidance for improving the motion performance of other underwater vehicles.