Development of an Autonomous Soaring Algorithm for Small Unmanned Aircraft Systems

An autonomous flight control algorithm is proposed for a fixed-wing unmanned aircraft system (UAS) to carry out waypoint navigation tasks while exploiting thermals to cut down on energy consumption. The main components of the flight control algorithm are a waypoint navigation system that is coupled with an altitude controller, a thermaling flight controller, and a gliding flight controller that is combined with a proportional-integral controller to maintain a desired heading angle. The flight control algorithm is tested using a three degrees-of-freedom point mass model for a notional fixed-wing aircraft model. The flight control algorithm is demonstrated to perform satisfactorily. The aircraft reaches all of the desired waypoints and exploits thermals to save energy.