Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The Attitude Determination and Control System (ADCS) of the Stellenbosch University
Satellite (SUNSAT I) is an integrated system providing some redundancy and the necessary
data management to control the spacecraft. However, the redundancy is not easily
accessible and there is a lack in flexibility when testing individual modules during integration
or when the system needs to be extended. The objective of this thesis was thus
to develop a high reliability, flexible, modular communication system that included some
type of redundancy to manage real-time data and to prevent severe malfunctioning of the
entire system.
The first step in the project's development methodology was to summarise the requirements
and specifications by studying the current ADCS architecture and data management.
An investigation into the Controller Area Network (CAN) protocol showed that
this technology would fit the requirements very well, leading to the design and implementation
of several concept topologies based on CAN. Thereafter, a demonstration model
consisting of three prototype nodes was composed. The performance of the so called
dual CAN node was analysed and an extrapolation was 'made to determine whether the
architecture could support the complete ADCS.
It was demonstrated that the dual CAN node provides enough room to accommodate
all the processors, actuators and sensors of the ADCS. At the same time, it was shown
that reliability and robustness was increased by enhanced redundancy at a node-level as
well as at the greater system-level. A dual CAN bus was provided for redundancy at
a node-level. At the system-level, the command and data-gathering modules (ACP or
OBC's) can now effectively be multiplexed on the network of actuators and sensors. Furthermore,
it was shown that error detection capabilities and diagnostics can be enhanced
and the complexity of the communication architecture and related wiring harnesses can
be reduced. This allows easier access to modules and simplifies development. / AFRIKAANSE OPSOMMING: Die Attitude Determination and Control System (ADCS) van Stellenbosch University
Satellite (SUNSAT I) is 'n geïntegreerde stelsel wat voorsiening maak vir 'n mate van
oortolligheid en 'n vermoeë om stelseldata te bestuur vir goeie satellietbeheer. Nietemin,
hierdie oortolligheid is nie baie toeganklik nie en daar is 'n gebrek aan aanpasbaarheid
tydens die toets en integrasie van individuele modules of moontlike stelseluitbreidings.
Die doelwit van hierdie tesis was dus die ontwikkeling van 'n betroubare, aanpasbare,
modulêre kommunikasie stelsel wat 'n tipe oortolligheid insluit sodat intydse data bestuur
kan word en algehele stelselondergang vermy kan word.
Die eerste stap in die projek se ontwikkelings metodiek was om 'n opsomming te verkry
van die vereistes en spesifikasies deur die huidige ADCS se argitektuur en databestuur
te ondersoek. 'n Ondersoek na die Controller Area Network (CAN) protokol het getoon
dat hierdie tegnologie aan baie van die vereistes voldoen. Dit het aanleiding gegee tot die
ontwerp en implementering van 'n paar konsep ontwerpe gebaseer op CAN. Daarna is 'n
demonstrasie model bestaande uit drie prototipe nodusse gebou. Die werksverrigting van
die sogenoemde dual CAN node, is ondersoek en 'n ekstrapolasie was gemaak om vas te
stelof die argitektuur die volkome ADCS kan huisves.
Deur demonstrasie was daar getoon dat die dual CAN node wel genoeg ruimte verskaf om
al die verwerkers, aktueerders en sensors van die ADCS te akkommodeer. Daar was terselfdertyd
getoon dat betroubaarheid en robuustheid verhoog is deur die verbeterde oortolligheid
op 'n node-vlak sowel as op die groter stelsel-vlak. 'n Dubbele CAN bus is gebruik
vir oortolligheid op 'n node-vlak. Op 'n stelsel-vlak kan die bevel-en-dataversamelings
modules (ACP en aBC's) effektief gemultipleks word op die netwerk van aktueerders
en sensors. Daar was verder getoon dat die foutopspoorings vermoeë en diagnostiese
vermoeë verbeter kan word en die kompleksiteit van die kommunikasie argitektuur en
ooreenkomstige kabelharnasse vereenvoudig kan word. Die gevolg is vereenvoudigde toegang
tot modules en vergemaklikde opgradering.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/51686 |
| Date | 12 1900 |
| Creators | Farr, Xandri C. |
| Contributors | Treurnicht, J., Schoonwinkel, A., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 145 p. : ill. |
| Rights | Stellenbosch University |
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