Fault-tolerant systems for unmanned multirotor aerial vehicles

"This chapter presents some recent results on fault-tolerant control systems for unmanned aerial systems, in particular for multirotor-type vehicles, commonly known as drones. Over the last years, these vehicles have become widely popular. Simplicity and cost-effectiveness have turned out to be very appealing and, as a consequence, an increasing number of applications have risen in many fields such as agriculture, surveillance, and photography, among others. As mission requirements become more demanding, the matter of fault tolerance emerges as a key challenge, especially if system certification is sought. Here, the focus is placed particularly on rotor failures in multirotor vehicles, and a specific definition for fault tolerance is considered based on the maneuverability capabilities in case of a failure. A geometric analysis is presented to evaluate the fault tolerant capabilities of a given vehicle, together with an experimental validation. Then, the limitations of this concept are analyzed. Finally, a novel reconfigurable structure is proposed for a fault-tolerant hexarotor, that presents good flight performance in failure cases, together with experimental results."