Design of Automated Generation of Residual Generators for Diagnosis of Dynamic Systems
Diagnosis and Supervision of technical systems is used to detect faults when they occur. To make a diagnosis, tests based on residuals can be used. Residuals are used to compare observations of the system with a model of the system, to detect inconsistencies.
There are often many different types of faults which affects the state of the system. These states are modeled as fault modes. The difference between fault modes are the presence of faults in the model. For each fault mode a different set of model equations is used to describe the behaviour of the real system. When doing fault diagnosis in real time it is good, and sometimes vital, to be able to change fault mode of the model, when a fault suddenly occurs in the real system. If multiple faults can occur the number of combinations of faults is often so big, even for relatively small systems, that residuals for all fault modes can not be prepared. To handle this problem, the residuals are to be generated when they are needed.
The main task in this thesis has been to investigate how residuals can be automatically generated, given a fault mode with a corresponding model. An algorithm has been developed and to verify the algorithm a model of a satellite power system, called ADAPT-Lite, has been used. The algorithm has been made in two versions. One is focusing on numerical calculations and the other is allowing algebraical calculations. A numerical algorithm is preferred in an automatized process because of generally shorter calculation times and the possibility to apply it to systems which can not be solved algebraically but the algebraical algorithm gives slightly more accurate results in some cases.
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Last updated: 2021-11-10