A marine research ASV utilizing wind and solar power

In this paper, the conceptual design and practical construction of a wind propelled Autonomous Surface Vehicle (ASV), for marine research are described. The ASPire (Autonomous Sailing Platform) will be deployed for collecting marine sensor data (i.e., Conductivity, Temperature and Density (CTD) measurements) and for passive-acoustic monitoring (PAM) of harbor porpoise in the vicinity of the Åland Islands in the Baltic Sea. The construction of hull and rig is presented, along with propulsion methods and energy harvesting strategies. Supplementary electronics, sensors, control systems, communication methods and obstacle avoidance strategies are also described. The ASV design includes several novel features, four are mentioned here. 1) The perhaps most notable feature is the rig with a free rotating rigid wingsail. The rig has two servo wings, one in front of, and one behind the main wing. To our knowledge, this is the first design of a surface vessel that uses such a three-surface configuration for wind propulsion. 2) Another novel feature of the ASPire is the single-axis solar tracker developed for the purpose of increasing the amount of harvested solar energy. The solar panel is angled based on the position and heading of the ASV as well as the time of day. 3) A windvane self steering device is furthermore used to keep the ASV at a straight course relative to the wind in an energy efficient manner. Although the design of the windvane is well known, its use in an autonomous vessel has not been explored. 4) A forward-looking Thermal Imaging Camera (TIC) is utilized for obstacle detection. This approach is currently under-explored for ASV. The ASPire is suited for operation in shallow waters. It is sufficiently large for carrying payload needed for marine sensor measurements and monitoring of high-frequency cetaceans such as harbor porpoise. One further advantage of wind propulsion for audio measurement is the possibility to operate without contributing noise from propulsion engines.