| Summary: | Thesis (MScEng)--University of Stellenbosch, 2004. === ENGLISH ABSTRACT: Improvements in the area of satellite orientation control in the presence of
large actuator gain changes are investigated. Gain changes primarily originate
from actuator failures, but may also result from intermittent sensor
availability and geomagnetic field effects.
The stability and performance of a classic LQR control solution under these
conditions is analyzed through simulation, and two adaptive schemes are
developed to improve the response.
The adaptive schemes mix elements from bang-bang control to increase performance,
and banded control to increase robustness. These control schemes
are thoroughly tested through simulation and the results are compared with
those obtained for the classic solution.
Extensive modelling of the system in the MATLAB™ environment is done
to support the analysis of the controllers, and hardware sensors are built to
provide realistic orientation measurements to the controllers. === AFRIKAANSE OPSOMMING: Verbeterings in die veld van satelliet oriëntasie beheer in die gevalle waar
die aktueerders groot veranderinge in aanwins toon, word ondersoek. Aanwins
veranderinge word primêr veroorsaak deur aktueerder falings, maar kan
ook deur diskontinue sensor metings en magneetveld effekte van die aarde
veroorsaak word.
Die stabiliteit en gehalte van 'n klassieke LQR beheer strategie onder hierdie
omstandighede word ondersoek deur simulasie, en twee aanpasbare beheer
strategieë word ontwikkelom die oordrag te verbeter.
Die aanpasbare beheer strategieë meng elemente van "bang-bang" beheer
om die gehalte te verbeter, en gebande beheer tegnieke om die robuustheid
van die stelsel te verbeter. Hierdie beheer strategieë is deeglik in simulasies
getoets en die resultate is vergelyk met dié van die klassieke beheerder.
Ekstensiewe modelleering van die stelsel is in die MATLAB™ omgewing gedoen
om die beheerders te analiseer, en hardeware sensore is gebou om realistiese
orientasie metings aan die beheerders te verskaf.
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