Sensor fault diagnosis of singular delayed LPV systems with inexact parameters: an uncertain systemapproach

In this paper, sensor fault diagnosis of a singular delayed linear parameter varying (LPV) systemis considered. In the considered system, the modelmatrices are dependent on some parameters which are real-time measurable. The case of inexact parameter measurements is considered which is close to real situations. Fault diagnosis in this system is achieved via fault estimation. For this purpose, an augmented system is created by including sensor faults as additional system states. Then, an unknown input observer (UIO) is designed which estimates both the systemstates and the faults in the presence of measurement noise, disturbances and uncertainty induced by inexactmeasured parameters. Error dynamics and the original system constitute an uncertain system due to inconsistencies between real andmeasured values of the parameters. Then, the robust estimation of the system states and the faults are achieved with H-infinity performance and formulated with a set of linearmatrix inequalities (LMIs). The designed UIO is also applicable for fault diagnosis of singular delayed LPV systems with unmeasurable scheduling variables. The efficiency of the proposed approach is illustrated with an example.