Fault recoverability for nonlinear systems with application to fault tolerant control of UAVs

Abstract

Unmanned Aerial Vehicles (UAVs) have received numerous attention since they can be used in many applications. Like other systems around us, UAVs are vulnerable to different faults. If a fault appears in UAVs, they should be able to perform their mission within an acceptable level. To ensure successful missions, fault tolerant control (FTC) algorithms need to be used for UAVs. By using FTC algorithms, the system can increase the level of autonomy that allows self-reconfiguration. Having a certain redundancy level in the system, is a prerequisite for the success of FTC techniques. In this paper, the fault recoverability measure for nonlinear systems is presented. The presented measure can be used to ensure that a sufficient redundancy level for the success of FTC exists in the system. It also gives insight into the ways to improve the redundancy level in the systems design process. To extend the notion of fault recoverability to nonlinear systems empirical gramians are used. The proposed method is used to calculate fault recoverability for multirotor UAVs to reveal its relation to redundant actuation possibilities in the model.