Structural Analysis

Abstract

Fault Diagnosis (FD) aims at carefully identifying which fault can be hypothesized to be the cause of monitoring events. In general, when addressing the FD problem, two strategies can be found in the literature: hardware redundancy based on the use of physical redundancies, and software or logic redundancies based on the use of software/intelligent sensors or models combining the information provided by sensor measurements, actuator commands, and system knowledge. A powerful instrument for determining the detectability/isolability properties of a system is performing a structural analysis. This technique allows to assess whether the number and place of sensors are adequate to comply with the specifications of diagnosis. Structural analysis is well suited for computer support, and all examples in this chapter have been performed using the freely available MATLAB toolbox (Frisk et al. in IFAC-PapersOnLine 50:3287–3293 (2017) [7]) that can be downloaded from https://faultdiagnosistoolbox.github.io.