Nonconventional angle-of-attack control strategy for reducing the airspeed during the fixed-wing drone landing

In this work, a control strategy for landing a fixed-wing drone with classical configuration and with minimum airspeed on a touchdown point is presented. In this crucial and critic landing phase of this kind of aircrafts the challenge is to absorb the drone's airspeed without loss its controllability. Our strategy proposes a scientific solution for a safe landing by controlling the angle of attack of the drone assuring its stability during all this stage. In our analysis, a flight scheme composed by a cruise flight and a landing scheme is considered. The control strategy obtained from the Lyapunov theory proposes a critic descending angle to obtain a maximum airspeed reduction. In addition, an observer is proposed for estimating external aerodynamics parameters and compensate them in closed-loop system. Numerical validation corroborates the well performance of the proposed control algorithms.