Output-Feedback Fault Detection and Accommodation of Uncertain Interconnected Systems With Time-Delayed Nonlinear Faults

This paper addresses a distributed fault detection and accommodation (DFDA) problem for uncertain nonlinear interconnected systems with faults in time-delayed nonlinearities. In contrast to existing DFDA works, we consider uncertain time-delayed interactions among subsystems and their faults, and additionally delays are assumed to be unknown. Under these conditions, a distributed memoryless local fault detection scheme consisting of a local detection estimator and its corresponding time-varying detection threshold is presented for each subsystem by using only output measurements. Then, a decentralized output-feedback control scheme for a local fault accommodation is designed based on this detection estimator and the adaptive approximation technique. The fault detectability and the stability of the proposed output-feedback DFDA scheme are thoroughly investigated in the Lyapunov sense. A simulation example is provided to illustrate the effectiveness of the proposed methodology.