Distributed Functional Observer Based Fault Detection for Interconnected Time-Delay Systems

This paper presents a novel distributed functional observer based fault detection (FD) scheme for interconnected time-delay systems with unknown inputs. The scheme employs a set of stand-alone residual generators, one at each subsystem, to detect actuator faults in the system. At each subsystem, depending on the strength of the interactions amongst the subsystems, a residual generator is designed by utilizing either a reduced-order distributed or decentralized functional observer. Our FD scheme offers several advantages in terms of simplicity due to the deployment of stand-alone reduced-order functional observers, and reliability owing to the independence of the operation of each residual generator. Two numerical examples are given to illustrate the effectiveness of our proposed FD scheme.