PID Controller Applied to Hexacopter Flight

In the last decades, the increasing interest in unmanned aerial vehicles for both military and civil applications made necessary the development of flight control theory and algorithms more and more efficient and fast. In this paper, an original trajectory controller, like a Proportional Integrative Derivative one, is taken into account and the drone structure assumes a hexacopter configuration, i.e. it consists of six rotors, located on the vertices of a regular hexagon with three pairs of counter-rotating fixed pitch blades. The motion of unmanned aerial vehicle is described by means of the Newton-Euler equations in terms of quaternions, in order to improve the numerical efficiency and stability of the controller algorithm, whose novelty lies in the quaternion error definition. Both model and algorithm have been tested and then validated through a wide experimentation, where the drone keeps going to not elementary trajectories.