Robust fault detection observers for nonlinear polynomial systems. (English) Zbl 1038.93510

Summary: This paper proposes a robust fault detection observer (RFDO) for classes of nonlinear models which consists of polynomial nonlinearities up to degree three and are structured in continuous state-space form. The observer and detection signal are designed to be independent of unknown inputs. Sufficient conditions are given, in an efficient compact form, for an RFDO (observer and signal) to exist. Several useable results on detectability conditions are given and a numerical procedure is considered. The modelling of a hydraulic rig system is considered. Design steps are shown in obtaining an RFDO which is sensitive to faults at certain nodal points. This RFDO forms part of a bank of three observers used in a fault isolation procedure which is tested on real input-output data.


93B07 Observability
93E12 Identification in stochastic control theory
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