A hybrid failure detection and isolation structure

Abstract

A hybrid failure detection and isolation (FDI) structure is presented in the paper. In the structure, a bank of auxiliary Kalman filters, each of them processing a subset of the sensor measurements, are applied to provide high accuracy detection references. The failure detection is then undertaken by checking the consistency between the state estimate of the main Kalman filter and the auxiliaries. Two state propagators are also included in the FDI structure to reliably isolate the failed sensor measurement. The two propagators are alternatively reset with the data of the Kalman filter to increase their accuracy and thereby the failure isolation performance. The failure isolation is realized by testing the consistency between the state estimates of the auxiliary Kalman filters and the state propagator.