Robust Fault Detection and Isolation via Unknown Input Observers

Abstract Fault detection filters (a particular class of full order Luenberger observers) are used to generate directional residuals for the purpose of fault isolation. Optimal observers depend on what do we want to achieve in terms of fault isolation and robustness. The paper proposes improved methods for fault isolation and a new unknown input observer with enhanced robustness (in the disturbance decoupling sense). Simulations for various scenarios sustain the conclusions.