Fault Detection, Identification and Accommodation for an Electro-Hydraulic System: An Adaptive Robust Approach

In the present work, we use an adaptive robust approach for fault detection and accommodation in electro-hydraulic systems. It is well known fact that any realistic model of a hydraulic system suffers from significant extent of uncertain nonlinearities and parametric uncertainties. An adaptive robust scheme is robust to such uncertainties and tracks the change in parameters reliably. Consequently, such a scheme becomes a natural choice for designing robust fault detection algorithms for electro-hydraulic systems. In this paper, we present the main results obtained by using adaptive robust state reconstruction and adaptive robust observers for fault detection in electro-hydraulic systems. Furthermore, the useful information about faults contained in the residual is used for designing an active fault-tolerant controller. We give an outline of the stability analysis for the faulty closed loop system, which shows that all states remain bounded and desired performance is restored to acceptable limits after the occurrence of fault. Simulation results show the effectiveness of the proposed scheme.