Feasibility study for the propulsion system of a tethered UAV

While the UAV market is growing exponentially, new architectures are investigated to overcome limitations of conventional platforms. Tethered UAVs leverage vertical takeoff capabilities and flight control flexibility but at the same time eliminate energy restrictions due to battery lifetime. A cable solution is promising as it allows potentially unlimited flight time: vehicles are able to perform longer mission or carry on heavier payloads. These features make tethered UAVs suitable for applications where endurance is key element, such as permanent surveillance, temporary ad-hoc networks, traffic and crowded management and monitoring. Even though tethered UAV technology is still emerging, some industrial applications are already available in the market. The porpouse of this thesis is to design and simulate the power system of a tethered UAV heavier from the one available on the market. As a matter of fact nowadays are developed only lighter solution than the project's one. The main goal is the design, modeling and simulation the propulsion system of the tethered UAV, which comprises the propeller sizing, the electric motor sizing and the motor control. Secondly, the model of the propulsion system is included in the multicopter dynamic model for a realistic simulation of the UAV behaviour. After that is sized the cable, which has to be able to transmit the power required by the vehicle from the ground to the air module. On this operation plays a crucial role the voltage level of power transmission because it affects the cable's weight and the choice of the power converter aboard and on the ground station. Finally safety system design is considered to improve UAV redundancy and increase the multirotor robustness.