Control techniques to deal with the damage of a quadrotor propeller

Civilians, servicemen, mass media, and researchers paid close attention to unmanned aerial vehicles (UAVs) in the last decade. The growth of applications in which vertical take-off and landing (VToL) UAVs are becoming present in every-day life is incredible. Professional photographers and film-makers are now always accompanied by certified UAV pilots to see the scene from different points of view. One of the most prominent electronic commerce websites around the world is planning to deliver packages to customers hands in thirty minutes, or less, using hexacopters [1]. The White House and the National Science Foundation accelerated the use of UAVs for civilian uses in monitoring and inspection of physical infrastructures, quick response to disasters, agricultural and meteorological domains with a considerable amount of funding [2]. Some companies started to think about a sort of personal UAV equipped with a camera to record self-movies [3], particularly indicated for a sportsman. Oil and gas facilities see the nondestructive measurement tests as a prosperous application for the UAVs in refineries since they are currently performed by human operators climbing huge and costly scaffolding. Several robotic commercial solutions are currently (or are ready-to-be) available like the APPELLIX drone [www.apellix.com], the Texo Drone Survey and Inspection platform [www.texodroneservices.co.uk/blog/ 56], and the Ronik Inspectioneering UT device [www.inspectioneering.eu]. Researchers see in the UAVs an unstable dynamic system that perfectly fits the challenge of implementing safe and robust control and mechatronic designs to accomplish every application mentioned above and go further beyond. As a matter of fact, the UAVs can be both employed for passive tasks like inspection and surveillance, and active tasks like grasping and aerial manipulation. This scenario requires the introduction not only of rules and regulation but also of safe controllers. An overview about control applied to UAVs, and the related applications in aerial ma-