Flight optimization of a solar-powered unmanned aerial vehicle in descent mode

This study investigates the energy consumption of a fixed-wing unmanned aerial vehicle (UAV) during maneuvering. The focus is on a descent mode in which the UAV, powered by solar cells mounted on its wings, decreases altitude–effectively operating in increasingly dense atmospheric conditions. A control function for flight speed as a function of air density along the flight trajectory is introduced. To determine the optimal form of this function, an optimization criterion is formulated as a target functional equal to the average power required to perform the maneuver. Solving the optimization problem yields the optimal functional dependence of speed on air density, 𝑣 = 𝑓(ρ), which minimizes the average integrated power consumption. The results indicate that for a solar-powered UAV performing a descent maneuver, the optimal flight mode corresponds to adjusting the flight speed according to a specific function of air density, which increases as altitude decreases.