Lifting‐principle‐based design and implementation of fixed‐wing unmanned aerial–underwater vehicle

Abstract This paper presents the implementation of a novel proof‐of‐concept design of a fixed‐wing unmanned aerial–underwater vehicle (UAUV). The UAUV is designed on the basis of the lifting principle and has an overall density between those of water and air. During air flight, fixed‐wings are deployed to create lift to overcome gravity, similar to ordinary fixed‐wing aircraft. Moreover, the fixed‐wings generate sufficient downward lift to overcome the large net buoyancy ( F B ), allowing the vehicle to dive during underwater cruising. Owing to the lack of buoyancy regulation and emergency load rejection systems, the proposed UAUV is relatively simpler than those of ordinary autonomous underwater vehicles or other UAUVs. Water exit of the proposed UAUV is driven by a combination of inertial and tractor propellers in conjunction with F B , which allows smooth maneuverability during water‐to‐air transition. A series of successful water‐exit tests are used to demonstrate that the proposed UAUV can rapidly exit from water with a wide range of pitch angles, indicating strong survival capability in the future bad sea condition. This paper presents the proof‐of‐concept, including the lifting‐based principle, general design, avionics and propulsion systems, and field tests in both air and water. The vehicle performance for endurance, duration, flight speed, attitudes during water‐to‐air transitions, and landing on the water surface are also analyzed and discussed.