A dual-modal unmanned vehicle propelled by marine energy: Design, stability analysis and sea trial

Unmanned vehicles have become indispensable tools for researchers to conduct ocean observation. For atmospheric and ocean observations at large spatial and temporal scales, researchers are turning their attention to novel unmanned vehicles with the ability to work in different domains, instead of adopting the cooperative observation by multiple-type vehicles. This paper proposes a dual-modal unmanned vehicle named Petrel-Dual with the ability to navigate both on surface and underwater, which can get energy supply by harvesting the marine energy. The vehicle is designed to have two operation modes: sailing as a sailboat on surface and traveling as a glider underwater. The static stability analysis in this paper aims to analyze the influence of various design variables of the vehicle on the stability in different navigation modes with a mathematical modeling method, which can guide the selection of various parameters of the prototype design. In surface navigation, through the calculation of sail aerodynamic performance, a simple control system is proposed to control sail and rudder independently. Finally, the prototype of Petrel-Dual is introduced and its performance both on surface and underwater is verified by a series of sea trials.