Nonlinear observer-based fault diagnosis for the control system of the stratospheric airship

This paper is dedicated to investigating an observer-based fault diagnosis (FD) approach for a Lipschitz nonlinear system and applied in a stratospheric airship (SA) flight control system. The system model uncertainties, external disturbances, and sensor noise are considered. Firstly, a detailed model of the SA is obtained by kinematics and dynamics. Then a nonlinear fault detection observer is designed via Linear Matrix Inequation (LMI) in H∞ framework, and a bank of unknown input observers is activated for isolating the faulty component. Moreover, to estimate the size of the fault, an expanded robust estimation observer is designed concerning states and fault estimator error. All of the mentioned observers are designed by a matrix inequation formulation, which reformulated the nonlinear system to a generalized Linear Parameter Varying (LPV) system mathematically. The proposed FD scheme is applied to the control system of a SA and its effectiveness is illustrated. Mathematics Subject Classification (2020) MSC code1 · MSC code2 · more