I. Introduction
In recent years, multirotor (especially quadrotor) unmanned aerial vehicles (UA Vs) have become very popular in the commercial industry [1]–[4] and are currently used in many areas, from the delivery of parcels and aerial photography to the maintenance of power lines and pipelines. This popularity is due to the combination of the advantages of this design:
high maneuverability;
possibility of hovering in the air;
quick pre- flight preparation;
the ability to take off from almost any surface;
compactness and simplicity.