Energy-efficient trajectory control for variable-tilt drones by exploiting the aerodynamic proximity effect close to surfaces

Unmanned aerial vehicles (UAV) have been extensively researched in recent decades, resulting into the development of several types and configurations. In particular, the design of multi rotor aerial vehicles (MRAV) has seen substantial growth due to its agility and manoeuvrability for application in numerous fields. To achieve omnidirectional controllability a new type has been developed called variable tilt MRAV where each propeller group has an additional actuator allowing them to rotate independently during operation. This is beneficial for application in the field of maintenance and inspection where the MRAV must fly and hover in a confined environment. Consequently, the MRAV must operate in proximity of surfaces which influences the free development of the rotorcraft wake due to the obstruction of the airflow and causes a disturbance of the platform. In order to undertake safe operation, the impact of the proximity effect needs to be taken into consideration to avoid destabilization of the platform.

This thesis aims to analyse the effect of surface proximity on variable tilt multi rotor control. First, a variable tilt MRAV is modelled and simulated with the use of a state-of-the-art control. Secondly, the model and simulation are extended to incorporate the proximity effect to analyse the behaviour to the disturbance and to design a strategy to exploit the effect. Lastly, the control approach is extended and compared to the initial design in term of energy efficiency.