Distributed Fault Diagnosis for Input-Output Continuous-Time Nonlinear Systems

In this paper, new results on distributed fault diagnosis of continuous{time nonlinear
systems with partial state measurements are proposed. Following an overlapping decomposition
framework, the dynamics of a nonlinear uncertain large-scale dynamical systems is described as
the interconnection of several subsystems. Each subsystem is monitored by its own Local Fault
Diagnoser, based on a set of local estimators. A consensus-based protocol is used to improve the
detectability and the isolability of faults affecting variables shared among different subsystems
because of the overlapping decomposition. A sufficient condition assuring the convergence of
the estimation errors is derived. Time-varying threshold functions guaranteeing no false-positive
alarms and theoretical results containing detectability and isolability conditions are presented.