Robust fault detection and isolation for a class of uncertain single output non‐linear systems

The problem of robust fault detection and isolation (FDI) is studied for a class of uncertain single output non‐linear systems with q faults. By designing a switching law, a robust state observer is developed such that its state responses can asymptotically converge to the true system states for both fault‐free and faulty cases. Based on this robust state observer and other q + 1 FDI observers, an efficient scheme is presented such that the FDI can be achieved for the considered single output non‐linear systems. The theoretical results are illustrated through an example of a single‐link flexible joint robot.