Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: A new task scheduler for the Attitude Determination and Control System (ADCS) of
the Stellenbosch University Satellite (SUNSAT) has been designed and tested on a
personal computer. This new scheduler is capable of uploading new control tasks, or
changing existing control tasks, on an individual basis. This is an improvement on the
current ADCS task scheduler, where the control tasks are hard-coded in the
scheduler, requiring the entire software image of the scheduler to be uploaded if a
new task is to be added, or an existing task is to be changed.
The new scheduler was developed using the Java programming language. The Java
ClassLoader class is used to dynamically load tasks to a linked list. The scheduler
thread runs through this linked list and schedules all the tasks that have become
schedulable. New tasks can be added to the list without stopping the scheduler.
The new scheduler has been successfully implemented on a personal computer,
laying a good foundation for implementation in an embedded environment based on
processors such as the T800 Transputer of the ADCS or the 80386 processor of the
secondary onboard computer (OBC2). / AFRIKAANSE OPSOMMING: 'n Nuwe taak skeduleerder vir die orientasie beheerstelsel (Engels: Attitude
Determination and Control System, of ADCS) van die Stellenbosch Universiteit
Satelliet (SUNSAT) is ontwerp en getoets op 'n persoonlike rekenaar. Hierdie nuwe
skeduleerder het die verrnoee om ekstra beheertake op te laai, of bestaande
beheertake te wysig, onafhanklik van mekaar. Dit is 'n verbetering op die huidige
ADCS taak skeduleerder waar take hard gekodeer is in die skeduleerder en waar
vereis word dat die volledige sagteware beeld van die skeduleerder opgelaai moet
word indien 'n nuwe taak bygevoeg wil word of 'n bestaande taak gewysig wil word.
Die nuwe skeduleerder is ontwikkel met behulp van die Java programmeringstaal.
Die Java C/assLoader klas is gebruik om take dinamies te laai en te voeg by 'n
skakellys. Die skeduleerder proses stap dan deur hierdie skakellys en skeduleer aile
take wat skeduleerbaar geword het. Nuwe take kan by die skakellys gevoeg word
sonder om die skeduleerder te stop.
Die nuwe skeduleerder is suksesvol ge'lmplementeer op 'n persoonlike rekenaar en Ie
'n goeie grondslag vir implementering in 'n toegewyde stelsel omgewing gebaseer op
byvoorbeeld die T800 Transputer van die ADCS of die 80386 verwerker van die
sekondere aanboord rekenaar (OBC2).
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52487 |
| Date | 12 1900 |
| Creators | Ntsimane, M. H. (Mpho Hendrick) |
| Contributors | Du Plessis, J. J., 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 | 115 leaves |
| Rights | Stellenbosch University |
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