Observer-based robust fault estimation under non-uniformly sampled measurements

In this paper, we consider the fault estimation problem of non-uniformly sampled system with actuator faults and bounded disturbances. First, after being discretized at sampling instant, the non-uniformly sampled system is modelled as an equivalent polytopic system with norm bounded uncertainties. Then, a full-order discrete-time observer that has the same structure of a Kalman filter is constructed to achieve effective fault estimation. Afterwards, by introducing slack variables, a sufficient condition given in linear matrix inequality (LMI) is provided to obtain the gain parameters and ensure not only the asymptotic stability of fault estimation error but also the robustness of uncertainties and disturbances. Simulation results of an aircraft model is finally presented to illustrate the effectiveness and superiority of the theoretic results obtained.