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The investigation of an inexpensive infra-red camera based building monitoring system for the aid of efficient building developmentVorajee, Naadir M 25 February 2020 (has links)
As the world is moving toward a greener, more sustainable future, the use of HVAC (Heating, Ventilation and Air-conditioning) systems are detrimental toward providing more efficient structures. Current UAVs (Unmanned Aerial Vehicle) used for surveying purpose are highly priced, with costs ranging upwards of R25 000. In this project, we propose a possible cost effective solution, with a budget of R10 000, that can be used in order to accurately survey a building for cracks and thermal inefficiencies within the envelope of the building. The project proposes a low cost Thermal camera to be used for the surveying as well as a validation of thermal camera for temperature reading. The project also proposes a low cost drone to be used for the possible prototype. The project follows a typical engineering design approach, specifically via the use of a V-model for the thermal camera used for image processing. After the constraints and requirements were defined, the engineering design commenced with a careful selection of both the IR camera and drone to be used for the possible prototype. Thereafter, experiments were set up to validate the use of the drone and IR camera as a viable option as a tool for building envelope surveyance. There were 6 experiments that were recorded during the process of this project. Firstly as statistical validation occurred through four tests whereby the thermal camera was validated with a mercury thermometer for temperature measurement. The second experiment was focused on the capability of the thermal camera to detect anomalies in a structure. This experiment made use of 3 holes of varying size drilled into a ceramic material with a heat source behind. Thermal images were then taken at various distances and then processed accordingly. The third experiment was focused on the ability to detect the area of the anomaly given a known distance from the thermal camera to the anomaly. The experiment followed the same set-up as described in the second experiment, however instead of 3 holes of varying size, only one hole was used. The fourth experiment looked at the building envelope and was focused on developing an algorithm to calculate the weighted average of the temperature of the structure rather than using the given structure temperature at a single point. In addition, the experiment qualitatively showed a difference between new and older insulation types. The fifth experiment focused on the development of an algorithm that would result in automatic image segmentation. The sixth experiment focused on the low cost drone and its ability to be used to survey a building. All experiments were successfully carried out. The thermal camera was validated as a reliable source for temperature measurement and could be used to detect anomalies as small as 3mm in diameter from a distance of 750mm from the target. In addition, an algorithm was developed that could be used to automatically tell the user the area of the anomaly with a 95% accuracy in certain cases. An algorithm was also developed to indicate the weighted mean temperature of an area of a building envelope. Lastly, the drone was successfully used to survey a building via the use of a developed protocol.
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A numerical investigation of the plenum chamber aerodynamic behaviour of mechanical draught air-cooled heat exchangersMeyer, C. J. (Christiaan Johannes) 12 1900 (has links)
Thesis (Ph.D.)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The primary purpose of this dissertation is to further the understanding of the influence of
plenum chamber aerodynamic behaviour on mechanical draught air-cooled heat exchanger
(ACHE) performance. The investigation, which included both forced and induced draught
ACHEs, was conducted through the use of a commercially available computational fluid
dynamics (CFD) code. A numerical axial flow fan and heat exchanger model that simulates
the effect of the axial flow fan and heat exchanger bundle respectively on the flow field
within the ACHE was developed and included in the CFD-code through user-programming.
Where appropriate the numerical investigation was augmented with experimental data. The
plenum chamber aerodynamic behaviour is characterised and included in the draught
equations associated with forced and induced draught ACHEs through the introduction of
dimensionless plenum chamber recovery and plenum chamber loss coefficient respectively.
The influence of changes made to a range of mechanical draught ACHEs on plenum chamber
aerodynamic behaviour was investigated. These changes include:
• Operating conditions of the axial flow fan.
• The height of the plenum chamber in the fan axial direction.
• The heat exchanger bundle isothermal flow resistance.
• The fan to heat exchanger area ratio.
• The axial position of the fan in the fan casing.
From the results of the numerical investigation a set of design guidelines are set for both
forced and induced draught ACHEs. The design guidelines include recommended values for
the dimensionless plenum chamber recovery and plenum chamber loss coefficient to be used
in the respective draught equations enabling a more accurate prediction of the operating point
of a proposed mechanical draught ACHE.
KEYWORDS:
air-cooled heat exchanger
numerical investigation
plenum chamber
aerodynamic behaviour / AFRIKAANSE OPSOMMING: Die primere doel van hierdie proefskrif is om die kennis aangaande die invloed van plenum
ruimte lugdinamiese gedrag op die werking van meganiese-trek lugverkoelde warmteruilers
(LVWRs) te verbreed. Die ondersoek wat geforseerde- asook geinduseerdetrek LVWRs
ingesluit het is uitgevoer deur gebruik te maak van In kornmersiele verkrygbare
berekeningsvloeimeganika-pakket. In Numeriese aksiaalwaaier- en warmteruilermodel wat die
invloed van respektiewelik die aksiaalwaaier en die warmteruiler op die vloeiveld in die
LVWR simuleer is ontwikkel en in die berekeningsvloeimeganika-pakket geinkorporeer
d.m.v gebruikers-roetines. Waar van toepassing is die numeriese ondersoek aangevul met
eksperimentele data. Die plenumruimte lugdinamiese gedrag word gekarakteriseer en
ingesluit in die onderskeie trekvergelykings vir geforseerde- en geiduseerde-trek LVWRs
deur die daarstelling van In dimensielose plenumruimteherwinnings- en plenumruimteverlieskoeffisient.
Die invloed van veranderinge wat aangebring is aan In reeks meganiesetrek
LVWRs op die plenumruimte lugdinamiese gedrag is ondersoek. Hierdie veranderinge
sluit die volgende in:
• Die werking van die aksiaalwaaier.
• Die hoogte van die plenumruimte in die aksiale rigting van die waaier.
• Die isotermiese lugweerstand van die warmteruiler.
• Die waaier-tot-warmteruiler area-verhouding.
• Die aksiale posisie van die aksiaalwaaier in die waaierring.
In Stel ontwerpsriglyne Vir beide geforseerde- en geinduseerde-trek LVWRs word
geformuleer gebaseer op die resultate van die numeriese ondersoek. Die ontwerpsriglyne sluit
aanbevole waardes vir die dimensielose plenumruimte-herwinnings- en plenumruimteverlieskoeffisient
in wat op hulle beurt aangewend kan word om In meer akkurate aanduiding
van die werkspunt van In beplande LVWR te bereken deur gebruik te maak van die toepaslike
trekvergelyking.
SLEUTEL WQORDE:
lugverkoelde warmteruiler
numeriese ondersoek
plenurnruimte, lugdinamiese gedrag
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Research into adventitious lung sound signals originating from pulmonary tuberculosis using electronic auscultationBecker, Konrad Wilhelm 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / Pulmonary tuberculosis is a common and potentially deadly infectious disease, commonly affecting the respiratory area. Over one-third of the world’s population is infected with the tuberculosis bacterium. Since pulmonary tuberculosis damages the respiratory area, the sound properties of infected lungs differ from those of non-infected lungs. However, auscultation is often ruled out as a reliable diagnostic technique due to the random position and severity of damage to the lungs as well as requiring the personal and trained judgment of an experienced medical practitioner. This project investigates a possible improvement in the pulmonary diagnostic and treatment field by applying electronic and computer-aided sound analysis techniques to analyze respiratory actions beyond human audible judgment. Respiratory sounds of both healthy subjects and subjects who were infected with pulmonary tuberculosis were recorded from seven locations per lung on both the posterior and anterior chest walls, using self-designed hardware. Adaptive filtering signal and analysis techniques yielded a wide range of signal features. This included analysis for time, frequency and both wheeze and crackle adventitious respiratory sounds. Following the analysis, statistical methods identified the most attractive signal measurements capable of separating the recordings of healthy and unhealthy respiratory sounds. Selected signal features were used with neural network optimization to obtain a successful implementation for the semi-automated identification of healthy and unhealthy respiratory sounds originating from pulmonary tuberculosis, with a performance of over 80% for sensitivity, specificity and accuracy. The success of categorizing the recordings justifies the capabilities of the digital analysis of respiratory sounds and supports an argument for further research and refinement into the assessment of pulmonary tuberculosis by electronic auscultation. Further research is recommended, with improvements justified and highlighted in this report.
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Nystagmus and eye reflex sensorSwart, Wayne 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Nystagmus is an eye movement pattern that consists of a drifting gaze component, known
as the slow phase, followed by a corrective quick phase component. The presence of
nystagmus or the lack thereof under certain conditions can be used for various diagnostic
purposes including the diagnosis of physiological, pathological and neurological conditions.
The angular velocity of the quick phase can make the detection of nystagmus a challenging
task for the untrained eye, since the quick phases are usually comparable with saccadic eye
motions. The goal is thus to develop a fully automated diagnostic tool that can identify
the presents of nystagmus in a patient’s eye motions.
In this thesis, an appropriate eye tracking method was selected from a number of eye
tracking methods that are commonly implemented in the literature. A video-oculography
goggle concept was chosen based on criteria such as invasiveness, sampling rate, accuracy
and telemedicine capability, amongst other nystagmus related necessities. A binocular
video-oculography concept was chosen that satisfied the technical requirements and
provided a cost-effective design. An automated analysis algorithm was developed for
automatic nystagmus identification from eye motion data. The algorithm was validated
by testing the performance of the algorithm on an optokinetic nystagmus signal. It
proved to provide a reliable automatic identification of nystagmus beats, even in signals
that contained nystagmus as well as random motion components. A statistical analysis
showed that the algorithm provided a sensitivity of 91.8% and a specificity of 96.5% for
pure nystagmus signals, and a sensitivity and specificity of 87.8% and 91.1% respectively
for mixed signals. / AFRIKAANSE OPSOMMING: Nystagmus is ’n oogbewegingspatroon wat bestaan uit ’n dwalende tuurkomponent, wat
die stadige fase genoem word, gevolg deur ’n vinnige korrigereringsbeweging wat bekend
staan as die vinnige fase. Die teenwoordigheid van nystagmus, of afwesigheid daarvan
in sekere gevalle, kan gebruik word in ’n verskeidenheid diagnostiese toepassings, onder
andere die diagnose van fisiologiese-, patalogiese- en neurologiese kwale. Die hoeksnelheid
van die vinnige fase lei daartoe dat nystagmus dikwels moeilik is om te bespeur vir
ongeöefende oë, aangesien dit vergelykbaar is met saccade bewegings. Die doel van hierdie
navorsing is dus die ontwikkeling van ’n stelsel wat ’n volledige automatiese identifisering
van nystagmus kan behartig.
’n Gepaste oogvolgtegniek was gekies vanuit ’n aantal verskillende oogvolgmetodes
wat dikwels in die praktyk gebruik word. Die finale keuse was ’n skermbril, video-oogvolgmetode
wat gekies was op grond van kriteria soos onder andere, invallendheid,
meetfrekwensie, akkuraatheid en geskiktheid vir telemedisyne toepassings. Die ontwikkelde
brilkonsep bied ’n koste-effektiewe oplossing, met die moontlikheid om albei oë
te volg en bevredig al die bogenoemde tegniese spesifikasies. ’n Geoutomatiseerde
nystagmus identifiseringsalgoritme is ontwikkel. Die algoritme se effektiwiteit is getoets
op optokinetiese nystagmusseine. Betroubare resultate is vekry vanaf die algoritme, selfs
in die geval van gemengde seine wat bestaan uit arbritrêre- en nystagmus komponente.
Statistiese analiese het gewys dat die algoritme ’n sensitiwiteit van 91.8% en ’n spesifisiteit
van 96.5% kon behaal vir seine met slegs nystagmus inhoud. Vir gemengde inhoud seine
het die algoritme ’n sensitiwiteit van 87.8% en spesifisiteit van 91.1% behaal.
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Development of a neck palpation device for telemedical environmentsVan den Heever, David Jacobus 12 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / An abnormal sized mass in the neck is a common clinical finding and it can be the result of inflammation caused by bacterial or viral infection or it can be due to more serious diseases and malignant tumours. The most popular method of examining the neck is by manual palpation. Other methods include ultrasound, CT scan, MRI and PET. These methods though are expensive to perform and require specialists to interpret the results. The aim of this thesis was to design and develop a neck palpation device for telemedicine applications.
The device uses an array of Force Sensing Resistors (FSRs) attached to an inflatable bladder. The bladder is mounted to the inside of a neck brace and it is inflated with an air pump controlled by a computer. As the bladder inflates the sensors press against the patient’s neck and the necessary data can be collected. A technique known as image registration is used to improve the resolution of the images sensed with the FSRs.
The device provides a reproducible record of the examination for both the surgeon and the patient’s medical record, and provides the patient information as if the doctor examined the patient with his own hands without physically being there. A prototype of the device was built and used to perform numerous tests. The tests were conducted using different objects which are inserted into a silicone neck to simulate different lymph nodes. The device was used to test for shape, smallest size, different sizes, repeatability and hardness.
The results showed that the device works well for spherical objects of different sizes but gives unsatisfactory results when the objects have sharp edges and complex forms. The image registration algorithm enhanced the images to a good representation of the object. Different sizes could be distinguished as well as hardness to some extend.
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Conceptual design of a fixtureless reconfigurable automated assembly systemDymond, F. S. D. 12 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The conceptual design of a fixtureless reconfigurable automated spot welding
system for manufacturing subassemblies for residential circuit breakers was
investigated. This research was aimed at developing a possible low cost automation
alternative to a South African industrial manufacturer, which is presently heavily
dependent on personnel for manual assembly of their core products.
System reconfiguration allows for the assembly of a range of subassemblies with
geometric component variation on a given system configuration, as well as the
potential for the system to be reconfigured to assemble other ranges of circuit
breaker subassemblies.
The subassembly selected as focus consists of six different components, which vary
geometrically from one product variant to another. A fixtureless approach was
selected, to minimise reconfiguration down time and the need for reconfigurable
fixtures since reconfigurable fixtures have not found significant acceptance in
industry. This varies from a fixture-based approach, which was considered in related
research.
The conceptual assembly system presented here consists of the following modules:
a flexible vision based part feeder, twin 6 DOF robotic manipulators each with a
multipurpose gripper, and a stationary spot welding station. Critical conceptual
design elements were further investigated to refine their selection and confirm
feasibility with respect to the target industry application. This process ended with a
preliminary cost estimate which served as a basis for comparison between the
fixtureless, fixture-based and present manual assembly process. The fixtureless
concept was overall more expensive than the fixture-based concept, primarily
because of the limits to production throughput. The fixtureless concept was
however cheaper than the present manual assembly approach but had a far longer
payback period than desired by the industry. The complexity and possible
uncertainties of the concept combined with the long payback period indicated that
the fixtureless concept is not suitable for the target application. / AFRIKAANSE OPSOMMING: Die konsepsionele ontwerp van 'n setmaatlose herkonfigureerbare outomatiese
puntsweisstelsel vir die vervaardiging van subsamestellings van huishoudelike
stroombrekers is ondersoek. Hierdie navorsing is gemik op die ontwikkeling van 'n
moontlike lae koste outomatiese alternatief vir 'n Suid Afrikaanse industriële
vervaardiger, wat tans sterk afhanklik is van werkers wat die montering van hul kern
produkte met die handsamestelling doen. Stelsel herkonfigurasie laat die
samestelling van 'n reeks subsamestellings, met geometriese komponentvariasies,
op 'n gegewe stelsel toe, asook die potensiaal om die stelsel te herkonfigureer om
ander reekse van stroombreker-subsamestellings te monteer. Die subsamestelling
wat as fokus gekies is, bestaan uit ses verskillende komponente met geometriese
verskille van tussen produkvariante. 'n Setmaatlose benadering is gekies ten einde
aftyd vir herkonfigurasie en die noodsaaklikheid van herkonfigureerbare setmate te
minimeer, omdat laasgenoemde nie noemenswaardig deur die industrie aanvaar
word nie. Hierdie benadering verskil van 'n setmaat-gebaseerde benadering wat in
verwante navorsing ondersoek is.
Die konsepsionele monteringstelsel wat hier aangebied word, bestaan uit die
volgende modules: 'n plooibare, visiegebaseerde voerapparaat; dubbele sesvryheidsgraad
robotiese manipuleerders, elk met 'n veeldoelige gryper; en 'n
statiese puntsweisstasie. Kritiese elemente van die konseptuele ontwerp is verder
ondersoek om hul keuses te verfyn en uitvoerbaarheid in die teiken industriële
toepassing te bevestig. Hierdie proses is afgesluit deur 'n voorlopige kosteraming
wat gedien het as 'n basis vir die vergelyking van setmaatlose, setmaat-gebaseerde
en die huidige handsamestellingstelsels. Die setmaatlose konsep was oorhoofs
duurder as die setmaat-gebaseerde konsep, hoofsaaklik as gevolg van beperkings op
die produksie-deurset. Die setmaatlose konsep was egter goedkoper as die huidige
handmonteringsproses, maar het 'n veel langer terugbetalingstydperk as wat deur
die industrie verlang word. Die kompleksiteit en moontlike onsekerhede van die
konsep, gepaard met die lang terugbetalingstydperk, dui daarop dat die setmaatlose
konsep nie vir die teiken toepassing geskik is nie.
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A hydraulic wave energy converterDu Plessis, Jacques 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: As a renewable energy source, wave energy has the potential to contribute to the increasing
global demand for power. In South Africa specifically, the country’s energy needs may
easily be satisfied by the abundance of wave energy at the South-West coast of the country.
Commercially developing and utilizing wave energy devices is not without its challenges,
however. The ability of these devices to survive extreme weather conditions and the need
to achieve cost-efficacy while achieving high capacity factors are but some of the concerns.
Constant changes in wave heights, lengths and directions as well as high energy levels and
large forces during storm conditions often lead to difficulties in keeping the complexity of
the device down, avoiding over-dimensioning and reaching high capacity factors.
The point absorber device developed as part of this research is based on an innovation
addressing the abovementioned issues. An approach is followed whereby standard "offthe-
shelf" components of a proven hydraulics technology are used. The size of the device
is furthermore adaptable to different wave climates, and the need for a control system is
not necessary if the design parameters are chosen correctly.
These characteristics enable low complexity of the device, excellent survivability and an
exceptionally high capacity factor. This may lead to low capital as well as low operationand
maintenance costs.
In this paper the working principle of this concept is presented to illustrate how it utilises
the available wave energy in oceans. The results obtained from theoretical tests correlate
well with the experimental results, and it is proven that the device has the ability to
achieve high capacity factors. As the device makes use of existing, "off-the-shelf" components,
cost-efficient energy conversion is therefore made feasible through this research. / AFRIKAANSE OPSOMMING: As ’n hernubare/ herwinbare energiebron bied golfenergie die potensiaal om by te dra tot
die bevrediging van die stygende globale energie-navraag. In spesifiek Suid-Afrika kan die
oorvloed van beskikbare golfenergie aan die Suid-Weskus van die land gebruik word om
aan die land se energiebehoeftes te voldoen.
Betroubaarheid en oorlewing in erge weerstoestande, koste-effektiwiteit en die behaal van
hoë kapasiteitsfaktore is beduidende struikelblokke wat oorkom moet word in die poging
om ’n golfenergie-omsetter wat kommersieël vervaardig kan word, te ontwikkel.
Daarby dra voortdurende veranderings in golfhoogtes, -lengtes en -rigtings sowel as hoë
energievlakke en groot kragte tydens storms by to die feit dat dit moeilik is om die
kompleksiteit van die stelsel laag te hou. Dit terwyl daar voorkom moet word dat die
toestel oorontwerp en verhoed word dat hoë kapsiteitsfaktore bereik word.
Die puntabsorbeerder-toestel wat in hierdie navorsing ontwikkel is, bestaan uit ’n ontwerp
wat spesifiek ontwikkel is om die bogenoemde probleme aanspreek. ’n Unieke
benadering is gevolg waardeur standaard, maklik-bekombare komponente gebruik is en
die komponent-groottes ook aangepas kan word volgens golfgroottes. Indien die ontwerpsdimensies
akkuraat gekies word, is die moontlikheid verder goed dat ’n beheerstelsel nie
geïmplementeer hoef te word nie. Hierdie eienskappe verseker lae stelselkompleksiteit,
uitstekende oorlewingsvermoë en ’n uitstaande kapasiteitsfaktor. Lae kapitaal- sowel as
onderhoudskostes is dus moontlik.
Die doel van hierdie dokument is om die werking van die konsep voor te stel en teoreties
sowel as prakties te evalueer. Die resultate van teoretiese toetse stem goed ooreen met
eksperimentele resultate, en dit is duidelik dat die toestel hoë kapasiteitsfaktore kan behaal.
Aangesien die toestel verder gebruik maak van bestaande komponente wat alledaags
beskikbaar is, word die koste-effektiewe omsetting van golfenergie dus moontlik gemaak
deur hierdie navorsing.
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Continued development of a joint-type knee wear simulatorVan Der Merwe, Johan 03 1900 (has links)
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.
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The development of a device for the investigation of dorsiflexion range of the ankle with a capacity to measure pathology, recovery and pharmacological benefitBotha, Jan 12 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / Various ways exist whereby balance abilities of the individual can be assessed.
However, most of these are subjective methods. This thesis strives to demonstrate the
effectiveness of a new device, the Dorsiflexometer that can be used to objectively
assess one’s balance abilities. The Dorsiflexometer was constructed and
mathematically modelled using appropriate simplifying assumptions. After its
construction, the Dorsiflexometer was tested using two experimental set-ups to obtain
raw data. Both these set-ups consisted of the two tiltable platforms equipped with three
load cells each, the bridge amplifiers and the personal computer (PC). The only
difference in the two experimental set-ups is in the type of test that was performed as
well as the bridge amplifiers used. Numerous parameters, such as the radius of
movement and the Lyapunov number can be extracted from the raw data. A computer
program was written to analyse the raw data and present the results in a user-friendly
manner. A new parameter, the Sway Index, was used to obtain a single balance value
for the tested individual. This parameter proved useful in quantifying balance.
An advanced patent search was carried out before the device was constructed. This
was necessary to provisionally patent the device – official application number:
2003/6702.
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Conceptual design of a fixture-based reconfigurable spot welding systemSequeira, Michael Allan 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / This thesis details the conceptual design of a fixture-based, reconfigurable, automated spot welding system aimed at manufacturing various sub-assemblies of circuit breakers. The welding operations are currently done using manual welding equipment, making this stage of the assembly process highly labour intensive. A range of product models and variants are assembled in quantities requiring frequent change-overs. Low-cost automation within a developing country’s manufacturing industry, more specifically within the Republic of South Africa, is the target context. The chosen design restriction, of incorporating a part fixturing design approach, distinguishes this research from F. S. D. Dymond’s work, who addressed the same problem while restricted to a fixtureless assembly approach. A conceptual layout design was developed to address part feeding, manipulation, transportation, fixturing and welding requirements, for an entire breaker model range. A simulation model for three possible layouts of the selected conceptual design provided a means to investigate each layout’s ability to tolerate and balance variation in production requirements, and to establish objective comparative performance data. This showed that the optimal configuration consists of four single loop layout systems. The thesis concludes that the final concept possesses the flexibility to produce the primary product range. Reconfiguration for production beyond this range is assisted by the modular nature of the layout. Ultimately, a reconfigurable design should focus on a properly selected base of core product ranges, providing an expandable and reusable system. The system can be supported by manual assembly stations which handle highly variant, incompatible product ranges.
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