Optimised active fault detection for an open loop stable system

Busch, Regardt (2016-12)

Thesis (DPhil)--Stellenbosch University, 2016.

Thesis

Active fault detection for a stable open-loop linear time invariant system is considered. The optimal active fault detection setup is developed around an estimator based architecture. The auxiliary signal and estimator are then The effect of the excitation signal frequency on detector performance is investigated, and a minimum targeted detection time parameter is introduced. This set of equations is then used to minimise the fault detection time for fixed performance constraints and minimum targeted detection time. A conceptual Active Fault Tolerant Control Framework is developed for a small unmanned aerial vehicle, emphasising the role of fault detection. The theoretical framework is then applied to this UAV, illustrating the applicability of the proposed AFD framework to more complex practical problems. designed in order to maximize detection performance. Equations are derived which relate the estimator design to the nominal residual signal covariance. The relationship between the auxiliary input and the system performance degradation constraint is considered. The effect of estimator gain and excitation signal frequency on the dual Youla-Jabr-Bongiorno- Kucera parameter is investigated. An LTI input shaping filter is added to allow for added MIMO system complexity. Theory developed for the general output zeroing problem is combined with the extended MIMO architecture in order to arrive at a solution without the nominal performance penalty usually associated with active fault detection. Furthermore, the effect of the control input is considered and formulated as an additional optimisation criterion, resulting in an average-case optimisation scenario.

AFRIKAANSE OPSOMMING: Aktiewe foutdeteksie vir ’n stabiele oop-lus liniere tyd-onafhanklike stelsel word oorweeg. Die optimale aktiewe foutdeteksie stelsel word ontwerp rondom ’n beramer-gebaseerde argitektuur. Die hulpsein en beramer word dan ontwerp om opsporingsvermoe te maksimeer. Vergelykings wat die verband tussen die beramerontwerp en die nominale residuele sein se kovariansie beskryf word afgelei. Die verhouding tussen die hulpsein en die beperking op die stelsel se prestasie agteruitgang word oorweeg. Die effek van beramer aanwins en die hulpsein frekwensie op die dubbel-Youla- Jabr-Bongiorno-Kucera parameter word ondersoek. ’n Liniere tyd-onafhanklike insetvormende filter word bygevoeg om die addisionele multi-inset multi-uitset kompleksietyd te hanteer. Teorie wat ontwikkel is vir die algemene uitset nulstellingsprobleem word gekombineer met die uitgebreide multi-inset multi-uitset argitektuur om ’n oplossing to vind sonder enige van die nominale stelselprestasie agteruitgang wat gewoonlik geassosieer word met aktiewe foutdeteksie. Verder word die effek van die beheerinset oorweeg, en geformuleer as ’n addisionele optimiseringskriterium, wat lei tot gemiddelde-geval optimisering. Die effek van die hulpsein frekwensie op die foutdeteksie prestasie word ondersoek, en ’n minimum teiken opsporingsparameter word ingestel. Hierdie stel vergelykings word dan gebruik om die foutdeteksie tyd vir vaste prestasiebeperkings en minimale geteikende deteksie tyd so laag as moontlik te kry. ’n Konseptuele Aktiewe Foutverdraagsame Beheerraamwerk is ontwikkel vir ’n klein onbemande lugvoertuig, wat die rol van foutdeteksie beklemtoon. Die teoretiese raamwerk word dan tot hierdie onbemande lugvoertuig aangewend, om sodoende die toepaslikheid van die voorgestelde Aktiewe Foutdeteksie raamwerk op meer ingewikkelde praktiese probleme te illustreer.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100083
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