Design of FDI filter for an aircraft control system

This paper presents a fault detection and isolation (FDI) filter design to linearize longitudinal dynamics of a Boeing 747 series 100/200. The FDI filter design is based on a geometric approach which relies on the use of (C,A) invariant subspaces and provides conditions on separability and mutual detectability of the failures. In our case the fault detection filter is sensitive to elevator faults and pitch rate sensor faults. Typically, the FDI filter design approach is elaborated for an open loop model and applied in the closed loop. The robustness aspect of FDI is considered and the effect of closing the loop is shown in the nominal case as well as in the uncertain case. The FDI filter designed for aircraft control systems is analyzed for a nominal closed loop system in the presence of sensor noise.