Fault Diagnosis of a Class of Uncertain Nonlinear Systems with Lipschitz Nonlinearities

This paper presents a fault detection and isolation scheme for a class of Lipschitz nonlinear systems with nonlinear and unstructured modeling uncertainty. This significantly extends previous results by considering a more general class of system nonlinearities which are modeled as functions of the system input and partially measurable state variables. A new fault diagnosis method is developed using adaptive estimation techniques. The fault isolability conditions are rigorously established via the use of the so-called fault mismatch functions, which are defined to characterize the mutual difference between pairs of faults.