Interval Observer Based Fault Detection for Lipschitz Nonlinear Systems Under Ellipsoidal Analysis

ABSTRACT This study devotes itself to the issue of fault detection for a class of discrete‐time Lipschitz nonlinear systems by virtue of a set of restricted frequency‐domain specifications. First of all, unlike traditional Luenberger‐like observers, which only contain a unitary parameter matrix, a novel, more design–degree of freedom incorporated fault detection observer (FDO) under linear‐matrix‐inequality (LMI) conditions is innovatively constructed to access a more flexible practical adjustment range. And the evaluations of both fault sensitivity and disturbance robustness were quantified via finite‐frequency and indices, respectively. Besides, the actuator and sensor faults were concurrently addressed in a more wide circumstance, where the reformulated Lipschitz property is utilized to handle what the complex nonlinear term causes. Furthermore, a novel, less computational dynamic threshold based on the ellipsoidal set‐membership technique was creatively synthesized during timely fault detection so as to guarantee a smaller range of residual intervals. Finally, simulation examples were conducted to demonstrate the viability and validity of the proposed strategy.