Flight control of hybrid drones towards enabling parcel relay manoeuvres

This work addresses the modeling and controlling process of a hybrid unmanned aerial vehicle (UAV), aimed for parcel delivery with relay maneuvers. Hybrid UAVs bring significant advantages to the drone industry and related applications, such as the capability of flying in two flight modes, rotary and fixed-wing. Nonetheless, this versatility implies the added complexity both in modeling and controlling these vehicles. This work is based on a popular airframe, the Convergence tilt tri-rotor UAV, for which the overall system dynamics for all operation modes are deduced with plausible assumptions. The model is then validated by designing two separate controllers for the main flight modes, rotary and fixed-wing, capable of trajectory tracking in each mode. The control strategy makes use of a custom hybrid control allocation technique that differentiates the control in three parts: vertical, horizontal, and transitional flight modes. Finally, a hybrid controller is proposed, using a finite state machine capable of handling logical events, with the aim to provide control logic to perform autonomous mid flight transitions. The proposed control strategies are validated using Matlab.