Sliding Mode Observer-Based Fault Detection and Isolation in Flight Control Systems

This paper deals with observer-based actuator fault detection, isolation and estimation (FDIE) schemes for a class of linear systems with external disturbances. To isolate and estimate the possible actuator faults, we first relate each possibility to a faulty model, then for each possible faulty model, we design a corresponding sliding mode observer (SMO), the residuals are defined as the norm of the magnitudes of the output estimation errors resulting from all possible faulty models. It is proved that, for the faulty model corresponding to the faulty actuator, the designed SMO can ensure the related output estimation error converges to a sufficiently small neighborhood. It is also shown that, for all other possible faulty models, the related output estimation errors are much larger. Finally, a research civil aircraft model (RCAM) is used to illustrate the design procedures and the effectiveness of the proposed actuator FDIE method.