A Dynamic Soaring Algorithm for Powered Fixed-Wing UAVs in Marine Environments

Dynamic soaring is a method used by seabirds or small aircraft to harvest energy from a wind gradient. This work shows an adaptive dynamic soaring controller algorithm, implemented in a software-in-the-loop simulation of a common autopilot flight stack, commanding only the pitch rate, roll rate, and throttle setpoints. The algorithm smoothly transitions from low-wind to high-wind velocity gradients, using the aircraft propulsion system only as necessary, up to the point that the propulsion system is not employed, given sufficient wind. Using this algorithm, a set of four unique fixed-wing UAVs are demonstrated to perform dynamic soaring in an oceanic environment simulation, showing the potential for energy-augmentation and unlimited cross-ocean flight in small fixed-wing UAVs.