Reduced-order observer-based fault estimation design for multiple input-multiple output discrete-time systems

In this paper, the fault-estimation problem for discrete-time systems is considered. A multiconstrained reduced-order fault estimation observer (RFEO) design is proposed to handle the case of abrupt and time-varying faults, and a comparison with full-order fault estimation observer is discussed in detail. Then, by introducing a slack matrix, a new multiconstrained RFEO result is obtained to reduce conservatism generated by the conventional method. Further, the present authors investigate robust RFEO design to cope with external disturbances. Simulation results of an aircraft example illustrate their contributions.