Fault diagnosis for non‐linear single output systems based on adaptive high‐gain observer

Abstract

This study deals with the fault diagnosis (FD) problem for affine non‐linear systems with single output. Under a well‐defined persistent excitation condition including m time delays, m parallel coupled adaptive high‐gain FD observers have been designed in some existing literature based on Lyapunov function approach. By employing Lyapunov–Krasovskiii functional approach, this study presents an alternative algorithm to design a simplified FD observer with global exponential convergence, which drastically reduces the complexity of the existing FD systems. A simulation example about a single‐link robot arm is provided to illustrate the proposed theoretical results.