Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This thesis is concerned with the continued development of the Stellenbosch
University joint-type knee wear simulator. Initially, information regarding simulators
from the literature and commercial entities was collected to provide a
knowledge base for current and future work. To further the design of the
simulator itself, electronic hardware and software subsystems was developed
and evaluated during experimental testing procedures. National Instruments’
cDAQ 9174 data acquisition unit was deemed inadequate for real-time inputoutput
control, though proved sufficient for signal capturing purposes in conjunction
with LabView software. Furthermore, the various servo-pneumatic
sub-circuits’ individual ability to conform to the ISO 14243 series standards’
protocol led to the estimation of measurable performance criteria and the application
to a single circuit for illustration. The anterior/posterior actuation
circuit in question demonstrated adequate performance for the cases where the
piston’s rod was respectively fixed and free to move. In-silico modelling and
identification of the relevant servo-pneumatic components then commenced,
with the valve and cylinder chamber models yielding adequate estimates of
the recorded data. The identified quasi-static friction model proved sensitive
to transient effects present within the system, resulting in performance deterioration
of the integrated model. Sufficiently accounting for these effects would
result in the emergence of the sub-circuit’s model as an invaluable tool in
terms of control system development, prediction of the simulator’s behaviour
and subsequent design recommendations. Future work therefore concerns improvement,
identification and integration of the various sub-circuit models to
fully exploit the aforementioned advantages. / AFRIKAANSE OPSOMMING: Hierdie tesis handel oor die voortgesette ontwikkeling van Universiteit Stellenbosch
se gewrigstipe knie-afslytingsimulator. Aanvanklik is inligting versamel
vanaf literatuur en kommersiële entiteite om sodoende ’n kennisbasis te
verskaf vir huidige en toekomstige werk. Elektroniese hardeware en sagteware
stelsels is ontwerp en geëvalueer tydens toetsprosedures om die ontwerp van die
simuleerder self te verbeter. National Instruments se cDAQ 9174 dataversamelaarseenheid
word onvoldoende geag vir intydse inset-uitset beheer, maar wel
vir dataversamelingsdoeleindes tesame met LabView sagteware. Die nodigheid
om die verskeie servo-pneumatiese sub-stroombane se individuele vermoë
om aan te pas by die ISO 14243-reeks se protokol-standaarde te ondersoek,
het gelei tot die beraming van meetbare werkverrigtingskriteria en die toepassing
daarvan ter illustrasie. Die anterior/posterior stroombaan het voldoende
werksverrigting getoon vir studies waar die suier se stang onderskeidelik vas
en los was. In-silico modellering en die identifisering van servo-pneumatiese
komponente het hierna begin. Die klep en silinderkamer modelle het voldoende
skattings gelewer van die gemete data. Die geïdentifiseerde kwasistatiese wrywingsmodel
het sensitiwiteit getoon teenoor die oorgangseffekte teenwoordig in
die stelsel wat gelei het tot verminderde werksverrigting van die geïntegreerde
model. Deur rekening te hou met sulke effekte kan die sub-stelsel se model
waardevol wees sover dit beheerstelsel ontwikkeling aangaan, sowel as die
voorspelling van die simuleerder se optrede en die daaropvolgende ontwerpsvoorstelle.
Toekomstige navorsing kan fokus op die verbetering, identifikasie
en integrasie van die verskeie sub-stroombaan modelle om die voorafgenoemde
potensiaal ten volle ontgin.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/19953 |
| Date | 03 1900 |
| Creators | Van Der Merwe, Johan |
| Contributors | Scheffer, C., Muller, C., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical & Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 129 p. : ill. |
| Rights | Stellenbosch University |
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