Reliability assessment method for structural observer based FDI scheme by a graph theoretic approach

The aim of this paper is to assess the reliability of a fault detection and isolation scheme (FDI) and the impact of sensor’s failure probability on such scheme. The proposed method is based on a graph-theoretic approach and assumes only the knowledge of the system’s structure. For a structured linear system (SLS), we first recall the fault diagnosis conditions when using an observer based scheme. Then, we deduce the sets of sensors that ensure the validity of such conditions. Next, we proceed with a reliability analysis of this kind of diagnosability property based on the sensors’ reliability. Through the assessment of an importance factor, we propose a simple maintenance strategy to maintain the level of the property reliability. The contribution concerns the combination of dependability and structural analysis for studying system’s properties.