Robust fault detection and isolation via a diagnostic observer

We present two methodologies for the design of robust fault isolation obser ver for linear uncertain systems. The proposed fault isolation observer is robust to structural uncertainties by producing disturbance decoupled resid uals. The first method uses a direct eigenstructure assignment scheme to ac complish a diagonal transfer function between the faults and the residuals. The second method is carried out through transformation of the linear syst em under consideration into its special coordinate basis (SCB) form. Once t he system is in SCB form, we propose a disturbance decoupled fault detectio n observer (DDFDO) which is combined either with Beard-Jones detection filt er (BJDF) theory, or input estimation results. This will lead to the final proposed robust fault detection filter. Finally, two numerical examples are given in order to illustrate the validity and effectiveness of the propose d fault detection and isolation (FDI) strategy. Copyright (C) 2000 John Wil ey & Sons, Ltd.