Fault detection for sector-bounded non-linear systems with servo inputs and sensor stuck faults

Abstract

This paper addresses the fault detection (FD) problem for discrete-time sector-bounded non-linear systems with finite-frequency servo inputs. The non-linear systems are firstly modelled as multi-models. The main contributions are that a novel FD filter which combines the finite-frequency and indices is designed. Different from the existing methods, the proposed FD scheme guarantees that the generated residuals are robust against the servo inputs in fault-free case and sensitive to them in faulty cases. Thus, the small sensor stuck faults including outage faults can be detected. For this class of systems, the existing finite-frequency FD filter design methods are invalid. A new lemma is developed to characterise the system performances in finite-frequency domain. In addition, sufficient conditions for the existence of such a FD filter are derived by introducing slack variable and linear matrix inequalities techniques. Finally, an example is presented to demonstrate the method and its effectiveness.