Design and Motion Performance of a Novel Variable-Area Tail for Underwater Gliders

There is a mutually exclusive relationship between the course stability and heading maneuverability of underwater gliders (UGs), making it challenging to improve the critical motion performance in the design of UGs. An effective measure to solve this issue is to optimize and modify the hydrodynamic shape of UGs. For better motion performance of UGs, this study proposes a novel variable-area tail (VAT) by introducing a multiaxis variable structure, which can adapt to the ocean currents automatically. We optimize the core parameters of the tail by approximate modeling. To evaluate the motion performance of the UG with the proposed tail, a dynamic model is established, which is verified by sea trial data. With fixed initial parameters, the novel tail improves the stability criterion of the UGs by about 6.88% in terms of course stability and reduces the turning radius by about 75.61% regarding heading maneuverability. Our design concept and performance verification have excellent scalability, and the proposed VAT provides a valuable reference for the shape design of other underwater vehicles.