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University of Pretoria
1.
Els, P.S. (Pieter Schalk).
The ride comfort vs. handling compromise for off-road
vehicles
.
Degree: 2011, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-07152008-102911/ 
► This thesis examines the classic ride comfort vs. handling compromise when designing a vehicle suspension system. A controllable suspension system, that can, through the use…
(more)
▼ This thesis examines the classic ride comfort vs.
handling compromise when designing a vehicle suspension system. A
controllable suspension system, that can, through the use of
suitable control algorithms, eliminate this compromise, is proposed
and implemented. It is a well known fact that if a vehicle
suspension system is designed for best ride comfort, then handling
performance will suffer and vice versa. This is especially true for
the class of vehicle that need to perform well both on- and
off-road such as Sports Utility Vehicles (SUV’s) and wheeled
military vehicles. These vehicles form the focus of this
investigation. The ride comfort and handling of a Land Rover
Defender 110 Sports Utility Vehicle is investigated using
mathematical modelling and field tests. The full vehicle,
non-linear mathematical model, built in MSC ADAMS software, is
verified against test data, with favourable correlation between
modelled and measured results. The model is subsequently modified
to incorporate hydropneumatic springs and used to obtain optimised
spring and damper characteristics for ride comfort and handling
respectively. Ride comfort is optimised by minimising vertical
acceleration when driving in a straight line over a rough, off-road
terrain profile. Handling is optimised by minimising the body roll
angle through a double lane change manoeuvre. It is found that
these optimised results are at opposite corners of the design
space, i.e. ride comfort requires a soft suspension while handling
requires a stiff suspension. It is shown that the ride comfort vs.
handling compromise can only be eliminated by having an active
suspension system, or a controllable suspension system that can
switch between a soft and a stiff spring, as well as low and high
damping. This switching must occur rapidly and automatically
without driver intervention. A prototype 4 State Semi-active
Suspension System (4S4) is designed, manufactured, tested and
modelled mathematically. This system enables switching between low
and high damping, as well as between soft and stiff springs in less
than 100 milliseconds. A control strategy to switch the suspension
system between the “ride” mode and the “handling” mode is proposed,
implemented on a test vehicle and evaluated during vehicle tests
over various on- and off-road terrains and for various handling
manoeuvres. The control strategy is found to be simple and cost
effective to implement and works extremely well. Improvements of
the order of 50% can be achieved for both ride comfort and
handling. AFRIKAANS : In hierdie proefskrif word die klassieke
kompromie wat getref moet word tussen ritgemak en hantering, tydens
die ontwerp van ‘n voertuig suspensiestelsel ondersoek. ‘n
Beheerbare suspensiestelsel, wat die kompromie kan elimineer deur
gebruik te maak van toepaslike beheeralgoritmes, word voorgestel en
geïmplementeer. Dit is ‘n bekende feit dat, wanneer die
karakteristieke van ‘n voertuigsuspensiestelsel ontwerp word vir
die beste moontlike ritgemak, die hantering nie na wense is nie, en
ook omgekeerd. Dit…
Advisors/Committee Members: Theron, Nicolaas J (advisor).
Subjects/Keywords: Vehicle suspension system;
Off-road vehicles;
UCTD
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Manager
APA (6th Edition):
Els, P. S. (. S. (2011). The ride comfort vs. handling compromise for off-road
vehicles
. (Doctoral Dissertation). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-07152008-102911/
Chicago Manual of Style (16th Edition):
Els, P S (Pieter Schalk). “The ride comfort vs. handling compromise for off-road
vehicles
.” 2011. Doctoral Dissertation, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-07152008-102911/.
MLA Handbook (7th Edition):
Els, P S (Pieter Schalk). “The ride comfort vs. handling compromise for off-road
vehicles
.” 2011. Web. 24 Jan 2021.
Vancouver:
Els PS(S. The ride comfort vs. handling compromise for off-road
vehicles
. [Internet] [Doctoral dissertation]. University of Pretoria; 2011. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-07152008-102911/.
Council of Science Editors:
Els PS(S. The ride comfort vs. handling compromise for off-road
vehicles
. [Doctoral Dissertation]. University of Pretoria; 2011. Available from: http://upetd.up.ac.za/thesis/available/etd-07152008-102911/
University of Pretoria
2.
[No author].
Longitudinal handling characteristics of a tailless
gull-wing aircraft
.
Degree: 2008, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/
► A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in…
(more)
▼ A handling quality investigation was performed on
the swept gull-wing configuration. The swept gull-wing
configuration is tailless and has a wing with a transition in the
sweep and dihedral angle. An example of this type of aircraft is
the Exulans. This aircraft is currently under development at the
University of
Pretoria. The handling quality study was focussed on
pitch axis dynamics. The Exulans is a research testbed that will be
used to investigate the swept gull-wing configuration and its
special controls by means of full-scale flight testing. Variable
wing sweep, twisting elevons and winglets will be investigated as
means of control. These control devices are configured in such a
way as to have minimum impact on the performance of the aircraft.
The handling qualities of the swept gull-wing configuration have to
be acceptable while using these different control strategies. The
study was launched to investigate whether a gull-wing configuration
aircraft will have satisfactory handling qualities at CG positions
associated with the most favourable aerodynamic performance. There
is an aerodynamic performance gain in designing an aircraft so that
the CG falls on the so-called `E-point'. The E-point is the centre
of pressure for an elliptical circulation distribution. An
elliptical circulation distribution is associated with the highest
Oswald efficiency for an aircraft. Time domain simulation
techniques and frequency domain analysis techniques were used to
analyse the handling qualities of the gull-wing configuration. The
C-star criterion was used to analyse handling qualities with time
domain simulation data as input. Comparative time domain
simulations were performed between the Exulans and other aircraft
to compare handling qualities. Eigenvalue analysis was used
together with the thumbprint criterion to investigate inherent
gull-wing airframe dynamics. The Shomber-Gertsen and Military
Specification 8785 criteria were also used for the same purpose.
The Neal-Smith method was used to investigate the effect of control
authority on handling qualities and the effect of a pilot. The
Monnich and Dalldorff criterion was used to evaluate gust handling
qualities. An analysis chart by Fremaux and Vairo was used to
evaluate the tumbling susceptibility of the gull-wing
configuration. The pitch handling quality investigation shows
sufficient promise that the swept gull-wing configuration will have
acceptable handling qualities with the CG placed at positions
associated with optimised aerodynamic performance. Analysis showed
that the swept gull-wing configuration is potentially prone to
tumbling. With low static margins, the configuration should exhibit
improved handling qualities in gusty conditions when compared to
existing tailless aircraft. It is recommended that a lateral
handling quality study be performed before full scale flight
testing commences on the Exulans. In addition, the possibility of
wingtip stall must be investigated for the case of the swept
gull-wing configuration.
Advisors/Committee Members: Theron, Nicolaas J (advisor).
Subjects/Keywords: Flight simulation;
Tumbling;
Thumbprint criterion;
Neal-smith analysis;
C-star criterion;
Shomber-gertsen analysis;
Pilot induced oscillation;
Oswald efficiency;
Pilot mathematical model;
Variable sweep wing;
Exulans;
Variable static margin;
Swept gull-wing configuration;
O-point;
E-point;
Handling qualities;
Gust handling qualities;
Tailless aircraft;
Pecking;
Monnich and dalldorff criterion;
UCTD
Record Details
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Record Details
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
author], [. (2008). Longitudinal handling characteristics of a tailless
gull-wing aircraft
. (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-09182008-132941/
Chicago Manual of Style (16th Edition):
author], [No. “Longitudinal handling characteristics of a tailless
gull-wing aircraft
.” 2008. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-09182008-132941/.
MLA Handbook (7th Edition):
author], [No. “Longitudinal handling characteristics of a tailless
gull-wing aircraft
.” 2008. Web. 24 Jan 2021.
Vancouver:
author] [. Longitudinal handling characteristics of a tailless
gull-wing aircraft
. [Internet] [Masters thesis]. University of Pretoria; 2008. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/.
Council of Science Editors:
author] [. Longitudinal handling characteristics of a tailless
gull-wing aircraft
. [Masters Thesis]. University of Pretoria; 2008. Available from: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/
University of Pretoria
3.
[No author].
Use of individual wheel steering to improve vehicle
stability and disturbance rejection
.
Degree: 2010, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-09202010-202652/
► The main aim of this research project is to extend theories of four-wheel-steering as developed by J. Ackermann to include an individually steered four-wheel steering…
(more)
▼ The main aim of this research project is to extend
theories of four-wheel-steering as developed by
J. Ackermann to
include an individually steered four-wheel steering system for
passenger vehicles. Ackermann’s theories, including theories
available in this subject area, dwell much on vehicle system
dynamics developed from what is called single track model and some
call it a bicycle model. In the bicycle model, the front two wheels
are bundled together. Similarly, the rear wheels are bundled
together. The problem with this is that it assumes two front wheels
or two rear wheels to be under the same road, vehicle and operating
conditions. The reality on the ground and experiments that are
conducted are to the contrary. Therefore this study discusses
vehicle disturbance rejection through robust decoupling of yaw and
lateral motions of the passenger vehicle. A mathematical model was
developed and simulated using Matlab R2008b. The model was
developed in such a way that conditions can be easily changed and
simulated. The model responded well to variations in road and
vehicle conditions. Focus was in the ability of the vehicle to
reject external disturbances. To generate yaw moment during
braking, the brake on the left front wheel was disconnected. This
was done because lateral wind generators, as used by Ackermann,
were not available. The results from both simulations and
experiments show disturbance rejection in the steady state.
Copyright
Advisors/Committee Members: Theron, Nicolaas J (advisor).
Subjects/Keywords: Robust control;
Iws;
Disturbance rejection;
Yaw rate;
Four wheel steering;
Lateral acceleration;
4ws;
Individual wheel steering;
Robust decoupling;
UCTD
Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
author], [. (2010). Use of individual wheel steering to improve vehicle
stability and disturbance rejection
. (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-09202010-202652/
Chicago Manual of Style (16th Edition):
author], [No. “Use of individual wheel steering to improve vehicle
stability and disturbance rejection
.” 2010. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-09202010-202652/.
MLA Handbook (7th Edition):
author], [No. “Use of individual wheel steering to improve vehicle
stability and disturbance rejection
.” 2010. Web. 24 Jan 2021.
Vancouver:
author] [. Use of individual wheel steering to improve vehicle
stability and disturbance rejection
. [Internet] [Masters thesis]. University of Pretoria; 2010. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-09202010-202652/.
Council of Science Editors:
author] [. Use of individual wheel steering to improve vehicle
stability and disturbance rejection
. [Masters Thesis]. University of Pretoria; 2010. Available from: http://upetd.up.ac.za/thesis/available/etd-09202010-202652/
University of Pretoria
4.
Knijnenburg, Gerard
Franciscus.
Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2017, University of Pretoria
URL: http://hdl.handle.net/2263/62777
► Antiresonance vibration isolation has long been a well known, studied and applied method for alleviating vibrations in stiff structures where small static deflection and a…
(more)
▼ Antiresonance vibration isolation has long been a well
known, studied and applied method for alleviating vibrations in
stiff structures where small static deflection and a low
transmissibility is needed, making it ideal for use in the
rotor-craft industry. Most prior arts focus on passive single
frequency antiresonance vibration isolation, while some, most
notably liquid inertia vibration isolators, are adapted to actively
isolate vibrations at more than one frequency. Very little
literature is found on the adaptation of mechanical pendulum
antiresonance vibration isolators for in-flight tunable multiple
frequency isolation, and although these systems predate the more
modern liquid inertia type isolator, there is merit in their
further development and use as low cost, robust and low maintenance
isolators. A feasibility study on the performance of changing each
fundamental design variable to achieve antiresonance tuning
concludes, that for the antiresonance frequency shift range of
interest in this dissertation, no specific design variable change
quantifiably outperforms another with respect to tuning the
antiresonance. Concept designs are created and investigated,
finding the superior method of tuning the vibration isolator based
on other criteria like overall weight, design simplicity,
practicality, robustness and reliability. Shifting the tuning mass
on the pendulum arm is deemed to be the superior concept, with
respect to the helicopter being developed, and a tunable
multi-frequency pendulum antiresonance vibration isolation system
with a sliding concentrated mass is developed with ADAMS multi-body
dynamics software and SolidWorks. The isolation system along with a
full scale dummy fuselage and transmission-rotor assembly is
manufactured and experimentally tested. Initial experimental
results show antiresonance frequencies 10Hz higher than the design
targets, this phenomenon is later discovered to be related to
friction in the pin joints of the pendulum hinges, increasing the
system overall stiffness. Needle roller bearings are inserted to
eliminate the friction, and experimental and ADAMS model results
are again compared showing good correlation, with experimental
results isolating close to the three target frequencies within 3%
error. An astonishing level of vibration isolation is observed with
the largest transmissibility obtained at the three frequencies
being 0:5%. This dissertation proves the concept of a tunable
mechanical pendulum vibration isolator, and its design methodology,
particularly with respect to shifting the position of the tuning
mass. Suggestions for further work are: to implement this system
with an actuation mechanism, further research on the effects of
friction in isolators and the use of said phenomenon as a tuning
method, development of isolators implementing the other concept of
changing the design variables and a comparison between the effect
of normal damping and friction damping on vibration
isolation.
Advisors/Committee Members: Theron, Nicolaas J. (advisor).
Subjects/Keywords: UCTD
Record Details
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Share »
Record Details
Similar Records
Cite
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Knijnenburg, G. (2017). Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/62777
Chicago Manual of Style (16th Edition):
Knijnenburg, Gerard. “Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle.” 2017. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/62777.
MLA Handbook (7th Edition):
Knijnenburg, Gerard. “Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle.” 2017. Web. 24 Jan 2021.
Vancouver:
Knijnenburg G. Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle. [Internet] [Masters thesis]. University of Pretoria; 2017. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/62777.
Council of Science Editors:
Knijnenburg G. Development
of a vibration isolation system for a rotary wing unmanned aerial
vehicle. [Masters Thesis]. University of Pretoria; 2017. Available from: http://hdl.handle.net/2263/62777
University of Pretoria
5.
Agenbag, Daniel
Sarel.
Longitudinal
handling characteristics of a tailless gull-wing
aircraft.
Degree: Mechanical and Aeronautical
Engineering, 2008, University of Pretoria
URL: http://hdl.handle.net/2263/28011
► A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in…
(more)
▼ A handling quality investigation was performed on the
swept gull-wing configuration. The swept gull-wing configuration is
tailless and has a wing with a transition in the sweep and dihedral
angle. An example of this type of aircraft is the Exulans. This
aircraft is currently under development at the
University of
Pretoria. The handling quality study was focussed on pitch axis
dynamics. The Exulans is a research testbed that will be used to
investigate the swept gull-wing configuration and its special
controls by means of full-scale flight testing. Variable wing
sweep, twisting elevons and winglets will be investigated as means
of control. These control devices are configured in such a way as
to have minimum impact on the performance of the aircraft. The
handling qualities of the swept gull-wing configuration have to be
acceptable while using these different control strategies. The
study was launched to investigate whether a gull-wing configuration
aircraft will have satisfactory handling qualities at CG positions
associated with the most favourable aerodynamic performance. There
is an aerodynamic performance gain in designing an aircraft so that
the CG falls on the so-called `E-point'. The E-point is the centre
of pressure for an elliptical circulation distribution. An
elliptical circulation distribution is associated with the highest
Oswald efficiency for an aircraft. Time domain simulation
techniques and frequency domain analysis techniques were used to
analyse the handling qualities of the gull-wing configuration. The
C-star criterion was used to analyse handling qualities with time
domain simulation data as input. Comparative time domain
simulations were performed between the Exulans and other aircraft
to compare handling qualities. Eigenvalue analysis was used
together with the thumbprint criterion to investigate inherent
gull-wing airframe dynamics. The Shomber-Gertsen and Military
Specification 8785 criteria were also used for the same purpose.
The Neal-Smith method was used to investigate the effect of control
authority on handling qualities and the effect of a pilot. The
Monnich and Dalldorff criterion was used to evaluate gust handling
qualities. An analysis chart by Fremaux and Vairo was used to
evaluate the tumbling susceptibility of the gull-wing
configuration. The pitch handling quality investigation shows
sufficient promise that the swept gull-wing configuration will have
acceptable handling qualities with the CG placed at positions
associated with optimised aerodynamic performance. Analysis showed
that the swept gull-wing configuration is potentially prone to
tumbling. With low static margins, the configuration should exhibit
improved handling qualities in gusty conditions when compared to
existing tailless aircraft. It is recommended that a lateral
handling quality study be performed before full scale flight
testing commences on the Exulans. In addition, the possibility of
wingtip stall must be investigated for the case of the swept
gull-wing configuration.
Advisors/Committee Members: Theron, Nicolaas J. (advisor).
Subjects/Keywords: Flight
simulation;
Tumbling; Thumbprint
criterion; Neal-smith
analysis; C-star
criterion;
Shomber-gertsen analysis; Pilot induced
oscillation; Oswald
efficiency; Pilot
mathematical model; Variable sweep
wing;
Exulans; Variable
static margin; Swept
gull-wing configuration;
O-point;
E-point; Handling
qualities; Gust handling
qualities; Tailless
aircraft;
Pecking; Monnich and
dalldorff criterion;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Agenbag, D. (2008). Longitudinal
handling characteristics of a tailless gull-wing
aircraft. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/28011
Chicago Manual of Style (16th Edition):
Agenbag, Daniel. “Longitudinal
handling characteristics of a tailless gull-wing
aircraft.” 2008. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/28011.
MLA Handbook (7th Edition):
Agenbag, Daniel. “Longitudinal
handling characteristics of a tailless gull-wing
aircraft.” 2008. Web. 24 Jan 2021.
Vancouver:
Agenbag D. Longitudinal
handling characteristics of a tailless gull-wing
aircraft. [Internet] [Masters thesis]. University of Pretoria; 2008. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/28011.
Council of Science Editors:
Agenbag D. Longitudinal
handling characteristics of a tailless gull-wing
aircraft. [Masters Thesis]. University of Pretoria; 2008. Available from: http://hdl.handle.net/2263/28011
University of Pretoria
6.
Kasanalowe Nkhoma, Richard
Chimkonda.
Use of
individual wheel steering to improve vehicle stability and
disturbance rejection.
Degree: Mechanical and Aeronautical
Engineering, 2010, University of Pretoria
URL: http://hdl.handle.net/2263/28064
► The main aim of this research project is to extend theories of four-wheel-steering as developed by J. Ackermann to include an individually steered four-wheel steering…
(more)
▼ The main aim of this research project is to extend
theories of four-wheel-steering as developed by
J. Ackermann to
include an individually steered four-wheel steering system for
passenger vehicles. Ackermann’s theories, including theories
available in this subject area, dwell much on vehicle system
dynamics developed from what is called single track model and some
call it a bicycle model. In the bicycle model, the front two wheels
are bundled together. Similarly, the rear wheels are bundled
together. The problem with this is that it assumes two front wheels
or two rear wheels to be under the same road, vehicle and operating
conditions. The reality on the ground and experiments that are
conducted are to the contrary. Therefore this study discusses
vehicle disturbance rejection through robust decoupling of yaw and
lateral motions of the passenger vehicle. A mathematical model was
developed and simulated using Matlab R2008b. The model was
developed in such a way that conditions can be easily changed and
simulated. The model responded well to variations in road and
vehicle conditions. Focus was in the ability of the vehicle to
reject external disturbances. To generate yaw moment during
braking, the brake on the left front wheel was disconnected. This
was done because lateral wind generators, as used by Ackermann,
were not available. The results from both simulations and
experiments show disturbance rejection in the steady state.
Copyright
Advisors/Committee Members: Theron, Nicolaas J. (advisor).
Subjects/Keywords: Robust
control;
Iws; Disturbance
rejection; Yaw
rate; Four wheel
steering; Lateral
acceleration;
4ws; Individual
wheel steering; Robust
decoupling;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kasanalowe Nkhoma, R. (2010). Use of
individual wheel steering to improve vehicle stability and
disturbance rejection. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/28064
Chicago Manual of Style (16th Edition):
Kasanalowe Nkhoma, Richard. “Use of
individual wheel steering to improve vehicle stability and
disturbance rejection.” 2010. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/28064.
MLA Handbook (7th Edition):
Kasanalowe Nkhoma, Richard. “Use of
individual wheel steering to improve vehicle stability and
disturbance rejection.” 2010. Web. 24 Jan 2021.
Vancouver:
Kasanalowe Nkhoma R. Use of
individual wheel steering to improve vehicle stability and
disturbance rejection. [Internet] [Masters thesis]. University of Pretoria; 2010. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/28064.
Council of Science Editors:
Kasanalowe Nkhoma R. Use of
individual wheel steering to improve vehicle stability and
disturbance rejection. [Masters Thesis]. University of Pretoria; 2010. Available from: http://hdl.handle.net/2263/28064
University of Pretoria
7.
Els,
P.S. (Pieter Schalk).
The ride comfort
vs. handling compromise for off-road vehicles.
Degree: Mechanical and Aeronautical
Engineering, 2011, University of Pretoria
URL: http://hdl.handle.net/2263/26302
► This thesis examines the classic ride comfort vs. handling compromise when designing a vehicle suspension system. A controllable suspension system, that can, through the use…
(more)
▼ This thesis examines the classic ride comfort vs.
handling compromise when designing a vehicle suspension system. A
controllable suspension system, that can, through the use of
suitable control algorithms, eliminate this compromise, is proposed
and implemented. It is a well known fact that if a vehicle
suspension system is designed for best ride comfort, then handling
performance will suffer and vice versa. This is especially true for
the class of vehicle that need to perform well both on- and
off-road such as Sports Utility Vehicles (SUV’s) and wheeled
military vehicles. These vehicles form the focus of this
investigation. The ride comfort and handling of a Land Rover
Defender 110 Sports Utility Vehicle is investigated using
mathematical modelling and field tests. The full vehicle,
non-linear mathematical model, built in MSC ADAMS software, is
verified against test data, with favourable correlation between
modelled and measured results. The model is subsequently modified
to incorporate hydropneumatic springs and used to obtain optimised
spring and damper characteristics for ride comfort and handling
respectively. Ride comfort is optimised by minimising vertical
acceleration when driving in a straight line over a rough, off-road
terrain profile. Handling is optimised by minimising the body roll
angle through a double lane change manoeuvre. It is found that
these optimised results are at opposite corners of the design
space, i.e. ride comfort requires a soft suspension while handling
requires a stiff suspension. It is shown that the ride comfort vs.
handling compromise can only be eliminated by having an active
suspension system, or a controllable suspension system that can
switch between a soft and a stiff spring, as well as low and high
damping. This switching must occur rapidly and automatically
without driver intervention. A prototype 4 State Semi-active
Suspension System (4S4) is designed, manufactured, tested and
modelled mathematically. This system enables switching between low
and high damping, as well as between soft and stiff springs in less
than 100 milliseconds. A control strategy to switch the suspension
system between the “ride” mode and the “handling” mode is proposed,
implemented on a test vehicle and evaluated during vehicle tests
over various on- and off-road terrains and for various handling
manoeuvres. The control strategy is found to be simple and cost
effective to implement and works extremely well. Improvements of
the order of 50% can be achieved for both ride comfort and
handling. AFRIKAANS : In hierdie proefskrif word die klassieke
kompromie wat getref moet word tussen ritgemak en hantering, tydens
die ontwerp van ‘n voertuig suspensiestelsel ondersoek. ‘n
Beheerbare suspensiestelsel, wat die kompromie kan elimineer deur
gebruik te maak van toepaslike beheeralgoritmes, word voorgestel en
geïmplementeer. Dit is ‘n bekende feit dat, wanneer die
karakteristieke van ‘n voertuigsuspensiestelsel ontwerp word vir
die beste moontlike ritgemak, die hantering nie na wense is nie, en
ook omgekeerd. Dit…
Advisors/Committee Members: Theron, Nicolaas J. (advisor).
Subjects/Keywords: Vehicle
suspension system; Off-road
vehicles;
UCTD
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Chicago ·
MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Schalk), E
P.S.. (. (2011). The ride comfort
vs. handling compromise for off-road vehicles. (Doctoral Dissertation). University of Pretoria. Retrieved from http://hdl.handle.net/2263/26302
Chicago Manual of Style (16th Edition):
Schalk), Els,
P.S. (Pieter. “The ride comfort
vs. handling compromise for off-road vehicles.” 2011. Doctoral Dissertation, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/26302.
MLA Handbook (7th Edition):
Schalk), Els,
P.S. (Pieter. “The ride comfort
vs. handling compromise for off-road vehicles.” 2011. Web. 24 Jan 2021.
Vancouver:
Schalk) E
P.S.(. The ride comfort
vs. handling compromise for off-road vehicles. [Internet] [Doctoral dissertation]. University of Pretoria; 2011. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/26302.
Council of Science Editors:
Schalk) E
P.S.(. The ride comfort
vs. handling compromise for off-road vehicles. [Doctoral Dissertation]. University of Pretoria; 2011. Available from: http://hdl.handle.net/2263/26302
University of Pretoria
8.
Theron, Hendrik
Jacobus.
Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2016, University of Pretoria
URL: http://hdl.handle.net/2263/57505
► Optiese loonvragte vir maritieme vaartuie, waarvan die siglyn gestabiliseer word, benodig veranderlike platform toestande tydens ontwikkeling, toets en evaluasie. Een manier om veranderlike dektoestande in…
(more)
▼ Optiese loonvragte vir maritieme vaartuie, waarvan die
siglyn gestabiliseer word, benodig veranderlike platform toestande
tydens ontwikkeling, toets en evaluasie. Een manier om veranderlike
dektoestande in ?n laboratorium te emuleer, is deur ?n
skeepsdeksimulator te gebruik. Hierdie verhandeling beskryf aspekte
van die modelering, stelsel identifikasie en validasie van ?n drie
grade van vryheid skeepsdeksimulator wat gebruik word om ?n
realistiese simulasieomgewing te skep. Die simulator is in die vorm
van ?n gemodifiseerde pneumatiese Gough-Stewart manipulator. ?n
Gesamentlike MSC ADAMS?/Matlab? Simulink? simulasie, wat deur
Matlab? bedryf word, vorm ?n simulasieomgewing waarin ADAMS? die
dinamiese model van die fisiese hardeware huisves, en Simulink? die
pneumatiese model, die wrywingsmodel en die beheerder hanteer. Daar
kan geen soortgelyke simulator gevind word in gepubliseerde
literatuur nie, wat tot gevolg het dat ?n model van eerste
beginsels opgestel is deur die gepubliseerde inligting as fondasie
te gebruik. Die simulasiemodel is opgebreek op substelselvlak wat
die massavloei model van die klep, die silinderkamermodel, sowel as
die kragmodel van die suier, die volledige aktuatormodel en ook,
laastens, die volledige skeepsdeksimulatormodel insluit. Al hierdie
modelle is afgelei, die parameters ge?dentifiseer and gevalideer.
Die behoeftestellings van die simulator, sowel as die
simulasieomgewing, is afgelei uit werklike metings van soortgelyke
seevarende vaartuie. Opsoektabelle, wat bereken is deur met Matlab?
die simulatorplatform binne MSC ADAMS? deur sy volledige
bewegingsberyk te manipuleer, stel die inverse kinematika voor.
Infinietdesimale klein foute is verkry deur die proses in tru aan
te wend en die platform ori?ntasie tydens verskeie
aktuatortposisies te toets. Daar is twee klep massavloeimodelle
beskryf, ?n klassieke model wat van basiese termodinamiese
geginsels afgelei is, en ?n ISO model wat gebaseer is op die
ISO-6358 standaard. Beide hierdie modelle se parameters is deur
eksperimentele stelselidentifikasieprosedures bepaal tydens
opblaas- en afblaastoetse. Hiervoor is ?n konstante volume druktenk
gebruik en beide die tydafhanklike interne druk en lugtemperature
is gemeet. Die massavloei is bepaal deur parameterestimasietegnieke
toe te pas op die voorgestelde modelle, en validering deur die
tydafhanklike druk te vergelyk met die uitsette van die modelle. By
?n werksdruk van 0.4 MPa is die gemiddelde absolute fout van die
ISO model minder as die helfte van die fout van die klassieke model
(MAE < 2 kPa), en die tydafhanklike drukverwantskap in beide die
geslotelus-, sowel as die ooplustoetse toon ?n 93% korrelasie teen
die gemete drukwaardes. Die kombinasie van die afgeleide
silindermodel en die klep massavloeimodel lewer ?n geloofwaardige
wrywingslose aktuatormodel, en deur die dinamiese kragvergelyking
te gebruik, word dit aangevul deur ?n nie-linie?re
wrywingskomponent. ?n Steek-glip wrywingsmodel met ?n
versnellingsafhanklike Stribeckfunksie en ?n eksponeti?le viskeuse
wrywingskomponent stel…
Advisors/Committee Members: Theron, Nicolaas J. (advisor).
Subjects/Keywords: UCTD
Record Details
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Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Theron, H. (2016). Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/57505
Chicago Manual of Style (16th Edition):
Theron, Hendrik. “Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform.” 2016. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/57505.
MLA Handbook (7th Edition):
Theron, Hendrik. “Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform.” 2016. Web. 24 Jan 2021.
Vancouver:
Theron H. Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform. [Internet] [Masters thesis]. University of Pretoria; 2016. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/57505.
Council of Science Editors:
Theron H. Modelling and
characterization of a modified 3-DoF pneumatic Gough-Stewart
platform. [Masters Thesis]. University of Pretoria; 2016. Available from: http://hdl.handle.net/2263/57505
University of Pretoria
9.
Williams, Edward Francis.
Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator.
Degree: Mechanical and Aeronautical
Engineering, 2014, University of Pretoria
URL: http://hdl.handle.net/2263/41015
► The work presented in this dissertation on piezoelectric inchworm motors (IWM) is part of a process to gain an understanding of the design, analysis and…
(more)
▼ The work presented in this dissertation on
piezoelectric inchworm motors (IWM) is part of a process to gain an
understanding of the design, analysis and testing of this smart
actuator technology. This work will form the foundation of what
will hopefully lead to the realisation of a production-ready IWM
design to be used in energy-scarce, battery-operated Unmanned
Aerial Vehicles (UAVs), and forms part of a larger national drive
to expand the UAV industry in South Africa. Although the principles
used in the design of IWMs are well known, a new innovation is
employed. A novel way to increase the force capacity of IWMs
without compromising on the speed or displacement when compared to
conventional methods is shown to be effective, and was used for the
first time on IWMs. The use of a simple design equation is
demonstrated to be useful in predicting the load limits and step
displacements. Challenges of finding a correlation between
predicted and measured performance values are discussed and
solutions are presented. The history of IWMs and some background on
piezoelectricity are given for the reader not familiar with these.
The use of micro ridges on the clamp mechanisms is explored. The
effects of the control signals on the mechanism of the motor are
discussed in detail and some important comments on electrical
controllers are made. The emphasis is on designing a strong motor
that capitalises on the high-force density of piezoelectric
material.
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Loveday, P.W. (coadvisor).
Subjects/Keywords: Piezoelectric inchworm motors (IWM); Smart
actuator technology; Unmanned
Aerial Vehicles (UAVs);
UCTD
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Williams, E. F. (2014). Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/41015
Chicago Manual of Style (16th Edition):
Williams, Edward Francis. “Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator.” 2014. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/41015.
MLA Handbook (7th Edition):
Williams, Edward Francis. “Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator.” 2014. Web. 24 Jan 2021.
Vancouver:
Williams EF. Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator. [Internet] [Masters thesis]. University of Pretoria; 2014. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/41015.
Council of Science Editors:
Williams EF. Design and
analysis of a practical large-force piezoelectric inchworm motor
with a novel force duplicator. [Masters Thesis]. University of Pretoria; 2014. Available from: http://hdl.handle.net/2263/41015
University of Pretoria
10.
Luyt, Ian Christiaan
Berning.
A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2015, University of Pretoria
URL: http://hdl.handle.net/2263/56085
► There is currently a need for large diameter flanges for the supply of water in South Africa. These large diameter pipe flanges are required to…
(more)
▼ There is currently a need for large diameter flanges for
the supply of water in South Africa. These large
diameter pipe
flanges are required to accommodate pipes with nominal bores of up
to 4 m and should
successfully withstand internal pressures of up
to 8 MPa. No current relevant standard / code contains
prescribed
design values for flanges which either operate at such high
pressures or have such large
diameters. Due to this an alternative
method of design, by means of non-linear finite element modelling,
is proposed. Three types of integral flange designs are considered,
namely: flat face, raised face, and
a modified raised face with an
O-ring groove. The effects of creep-relaxation, flange rotation,
and the
bolting sequence are considered.
For each of these
designs a finite element model was created and compared to a small
scale experiment
which included strain and contact pressure
measurements. The proposed non-linear finite element
models were
capable of accurately predicting the strains in the flanges as well
as the contact pressures
between the faces of the flange and the
surfaces of the packing material. Finally, a comparison between
the ASME design method and the proposed non-linear finite element
modelling design method was
done for the large diameter flanges.
It was found that the ASME design code did not have the ability to
accurately predict the stresses in the flanges. It was also found
that by using the maximum equivalent
Von Mises stress as failure
criteria for the flanges and fasteners, and contact pressure for
the sealing
ability, circular bolted flange connections which are
lighter, safer, and leak tight could be designed by
means of the
proposed non-linear finite element models.
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Pietra, F. (coadvisor).
Subjects/Keywords: UCTD
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Luyt, I. C. (2015). A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/56085
Chicago Manual of Style (16th Edition):
Luyt, Ian Christiaan. “A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis.” 2015. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/56085.
MLA Handbook (7th Edition):
Luyt, Ian Christiaan. “A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis.” 2015. Web. 24 Jan 2021.
Vancouver:
Luyt IC. A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis. [Internet] [Masters thesis]. University of Pretoria; 2015. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/56085.
Council of Science Editors:
Luyt IC. A leak tight
design methodology for large diameter flanges based on non-linear
modelling and analysis. [Masters Thesis]. University of Pretoria; 2015. Available from: http://hdl.handle.net/2263/56085
University of Pretoria
11.
Van den Bergh,
Jan-Sjoerd.
Effects of
friction and gas modelling on vehicle dynamics
simulation.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2014, University of Pretoria
URL: http://hdl.handle.net/2263/56116
► Gevalideerde simulasie modelle word al hoe meer belangrik in die huidige tegnologiese en ekonomiese omgewing, waar simulasie as n integrale deel van die ontwerp prosess…
(more)
▼ Gevalideerde simulasie modelle word al hoe meer belangrik
in die huidige tegnologiese en ekonomiese omgewing, waar simulasie
as n integrale deel van die ontwerp prosess is. In die
voertuig-dinamika veld is dit ook die geval, waar vervaardigers en
navorsers meer op simulase staatmaak as ooit tevore. In die
navorsings en ontwikkelings veld met sy strawwe kompetisie, word
die frase so akkuraat moontlik, so kompleks as nodig dikwels ter
harte geneem met die ontwikkeling van voertuig modelle. Die so
kompleks as nodig benadering het die gevolg dat baie verskynsels
soos suspensie kinematika en wrywing nie in ag geneem word nie,
aangesien daar aanvaar word dat die effekte weglaatbaar klein is.
Hierdie oënskynlikke weglaatbare effekte, het n negatiewe impak op
die akkuraatheid en geldigheid van die model waneer daar afgewyk
word van maneuvers waarvoor die model oorspronklik ontwikkel is.
In hierdie studie, waar gefokus word op n voertuig met n
hidro-pneumatiese suspensie stelsel, word die effek van gas
modelering, wrywing, en wrywings modelering strategie op die
geldigheid van die suspensie eenheid karakterestieke, asook die vol
nie-linieêre voertuig model voorgelê. Die benadering tot gas
modelering sluit drie permutasies van die ideale gas wet in,
naamlik isotermies, adiabaties, en die hitte-oordrag afhanklikke
termiese tyd-konstante formulering. Die effekte van wrywing is op
drie maniere in ag geneem, naamklik n opsoek matriks, n LuGre, en n
Aangepaste LuGre wrywings model, terwyl die geval waar wrywing
weggelaat is gebruik word as verwysing.
Die resultate wys dat die
gas modelerings strategie, asook die effek van wrywing elkeen n
waarneembare effek op die model akkuraatheid en geldigheid het
waneer dit vergelyk word met fisiese toets resultate. n Verbetering
is gesien in die enkel suspensie eenheid karakterestiek sowel as
die vol nie-linieêre simulasie model. Dit bewys effektief dat
sekere verskynsels, alhoewel dit klein is in vergelyking met ander
effekte, n groot impak op model geldigheid en akkuraatheid kan
hê.
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Els, P.S. (Pieter.
Subjects/Keywords: UCTD
Record Details
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bergh,
Jan-Sjoerd, V. d. (2014). Effects of
friction and gas modelling on vehicle dynamics
simulation. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/56116
Chicago Manual of Style (16th Edition):
Bergh,
Jan-Sjoerd, Van den. “Effects of
friction and gas modelling on vehicle dynamics
simulation.” 2014. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/56116.
MLA Handbook (7th Edition):
Bergh,
Jan-Sjoerd, Van den. “Effects of
friction and gas modelling on vehicle dynamics
simulation.” 2014. Web. 24 Jan 2021.
Vancouver:
Bergh,
Jan-Sjoerd Vd. Effects of
friction and gas modelling on vehicle dynamics
simulation. [Internet] [Masters thesis]. University of Pretoria; 2014. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/56116.
Council of Science Editors:
Bergh,
Jan-Sjoerd Vd. Effects of
friction and gas modelling on vehicle dynamics
simulation. [Masters Thesis]. University of Pretoria; 2014. Available from: http://hdl.handle.net/2263/56116
University of Pretoria
12.
Tikam, Mayur.
Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2018, University of Pretoria
URL: http://hdl.handle.net/2263/67920
Subjects/Keywords: Unrestricted; UCTD
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tikam, M. (2018). Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/67920
Chicago Manual of Style (16th Edition):
Tikam, Mayur. “Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion.” 2018. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/67920.
MLA Handbook (7th Edition):
Tikam, Mayur. “Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion.” 2018. Web. 24 Jan 2021.
Vancouver:
Tikam M. Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion. [Internet] [Masters thesis]. University of Pretoria; 2018. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/67920.
Council of Science Editors:
Tikam M. Posture control of a
low-cost commercially available hexapod robot for uneven terrain
locomotion. [Masters Thesis]. University of Pretoria; 2018. Available from: http://hdl.handle.net/2263/67920
University of Pretoria
13.
Purkis, Tamsin Leigh.
Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2017, University of Pretoria
URL: http://hdl.handle.net/2263/64317
► Walking is the most common form of human locomotion and the systematic study thereof is known as gait analysis. Measurement and assessment thereof have application…
(more)
▼ Walking is the most common form of human locomotion
and the systematic study thereof is known as gait analysis.
Measurement and assessment thereof have application in many fields
including clinical diagnosis, rehabilitation and biomechanics. The
process of gait evaluation is typically done using an optical
motion analysis system combined with stationary force platforms.
This is considered the gold standard, but unfortunately, has
several drawbacks. It is expensive, requires dedicated laboratories
with spatial restrictions, calls for lengthy set up and
post-processing times and cannot be used in 'real-world'
environments. Alternative systems based on wearable sensors have
been developed to overcome these limitations.
The Council for
Scientific and Industrial Research (CSIR) has therefore developed a
prototype wearable sensor unit consisting of an inertial
measurement unit (IMU). The objective of the current study is,
therefore, to advance the prototype to a wearable multi-sensor
system for quantitative gait analysis. The focus is on the
development of the pre- and post-processing algorithms and methods
used to transform the measurements into interpretable information.
The focus outlined includes establishing techniques for
synchronising the data from the sensors offline, pre-processing the
signals, developing algorithms for stride and gait event detection,
selecting an appropriate gait model and defining methods for
estimating gait parameters. The determined parameters were the
spatio-temporal and joint kinematics (hip, knee and ankle). The
algorithms and new system were validated against the Vicon motion
capture system through gait analyses. The twenty able-bodied
volunteers that took part were required to walk across the
laboratory six times at three self-selected walking speeds (slow,
normal and fast). For the sake of simplicity and due to various
limitations, only data in the sagittal plane of the right lower
limb of each volunteer was used to validate the wearable system and
associated algorithms.
The results obtained were then evaluated
against several validation criteria. The absolute mean difference
between the estimated timing of detected gait events of the two
systems was consistently small (between 0.021 and 7.25% of the gait
cycle overall). The spatially dependent parameters, stride length
and walking speed, had significant maximum mean absolute percentage
errors (31.9 and 34.5% respectively), but with little variation.
Excluding outliers, that of the temporal parameters, stride time
and cadence, was significantly lower (5.7 and 5.6% respectively).
The kinematic results were substantially comparable with a minimum
correlation co-efficient of 0.86 and a maximum RMSE of 7.8 degrees
with little variation implying repeatability.
Although there were
some discrepancies between the outputs, the wearable sensor system
and its corresponding algorithms were considered feasible and
potentially beneficial to developing countries like South Africa.
Recommendations for future work include synchronising data…
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Conning, Mariette (coadvisor).
Subjects/Keywords: Quantitative gait analysis; Wearable
sensors; UCTD
Record Details
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Purkis, T. L. (2017). Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/64317
Chicago Manual of Style (16th Edition):
Purkis, Tamsin Leigh. “Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System.” 2017. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/64317.
MLA Handbook (7th Edition):
Purkis, Tamsin Leigh. “Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System.” 2017. Web. 24 Jan 2021.
Vancouver:
Purkis TL. Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System. [Internet] [Masters thesis]. University of Pretoria; 2017. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/64317.
Council of Science Editors:
Purkis TL. Development
and Validation of the Pre- and Post-Processing Algorithms for
Quantitative Gait Analysis using a Prototype Wearable Sensor
System. [Masters Thesis]. University of Pretoria; 2017. Available from: http://hdl.handle.net/2263/64317
University of Pretoria
14.
Mokobodi, Dineo Stephen.
Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators.
Degree: MEng, Mechanical and Aeronautical
Engineering, 2017, University of Pretoria
URL: http://hdl.handle.net/2263/66225
► A gravimeter is an instrument that measures gravitational force Fg (N) or acceleration g (m/s-2). Absolute gravity measurements are preferred in metrology, due to the…
(more)
▼ A gravimeter is an instrument that measures
gravitational force Fg (N) or acceleration g (m/s-2). Absolute
gravity measurements are preferred in metrology, due to the
shortest traceability links to the SI base units of length and
time, realising acceleration. The investigation on the suitable
method of gravity measurement was performed at the National
Metrology Institute of South Africa (NMISA). The free fall gravity
measuring system was adopted for development. The metrological need
on redefining the kilogramme standard using the watt balance,
supported the decision to mandate this project. Free fall
gravimeters were researched. The new concept of fully pneumatic
controlled vacuum chamber was invented and manufactured. Pneumatic
actuators were used on the vacuum chamber to align, launch, capture
and reposition the falling test mass. Laser interferometer and
high-speed digitiser with embedded accurate clock module, were used
in realising displacement and time, through numerical computations.
Using stabilised He-Ne Laser red with wavelength =633 nm
interferometer, free-falling test mass displacements were traceable
to length standard. Interference intensity signal produced from
experimental free fall drops were converted to A digital voltage
signal enabling processing. Post signal processing algorithms were
applied to the signal to extract the displacement and time
coordinates of the free-falling object, using a zero-crossing
detection method in a LabView environment. The final prototype
setup measured the value 9.786041 m/s2 with uncertainty of
0.0000705 m/s2 at the vacuum pressure of 0.05 Pa. It was validated
and compared with the Council of Geophysics_ measured value of the
site of 9.7860985 m/s2.
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Greeff, Pieter (coadvisor).
Subjects/Keywords: UCTD
Record Details
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Record Details
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Cite
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mokobodi, D. S. (2017). Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/66225
Chicago Manual of Style (16th Edition):
Mokobodi, Dineo Stephen. “Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators.” 2017. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/66225.
MLA Handbook (7th Edition):
Mokobodi, Dineo Stephen. “Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators.” 2017. Web. 24 Jan 2021.
Vancouver:
Mokobodi DS. Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators. [Internet] [Masters thesis]. University of Pretoria; 2017. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/66225.
Council of Science Editors:
Mokobodi DS. Designing and developing a
free fall absolute gravity measuring system using pneumatic
actuators. [Masters Thesis]. University of Pretoria; 2017. Available from: http://hdl.handle.net/2263/66225
University of Pretoria
15.
[No author].
Comparative study into occupant support concepts with
respect to crash response
.
Degree: 2006, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-01112005-124913/
► It is argued that together with improved protection structures and energy dissipation systems, a favourable pilot position with sufficient support and restraint could reduce fatalities…
(more)
▼ It is argued that together with improved protection
structures and energy dissipation systems, a favourable pilot
position with sufficient support and restraint could reduce
fatalities in aviation accidents. In this document the crash
response of three different pilot positions are compared to justify
the proposal of supporting a pilot in the rather unusual prone
position. The normal seated and supine pilot positions have already
been adopted and implemented in various aircraft. The occupant’s
response to specified crash scenarios in these two positions was
compared to that of a pilot in the prone position. To obtain the
best prone pilot support configuration, different concepts were
considered during the analysis. A dynamic event simulation program
called ADAMS was used to perform the analysis and existing injury
criteria and a study of common causes of aviation fatalities and
human body tolerance limits were used to compare the results.
Additionally, methods to improve survivability of a pilot in the
prone position during likely accidents were investigated with
ADAMS. Concepts for the Exulans fuselage layout and energy
absorption systems were proposed and recommendations for the pilot
support system were derived from the results.
Advisors/Committee Members: Theron, Nicolaas J (advisor), Mr R J Huyssen (advisor).
Subjects/Keywords: No key words available;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
author], [. (2006). Comparative study into occupant support concepts with
respect to crash response
. (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-01112005-124913/
Chicago Manual of Style (16th Edition):
author], [No. “Comparative study into occupant support concepts with
respect to crash response
.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-01112005-124913/.
MLA Handbook (7th Edition):
author], [No. “Comparative study into occupant support concepts with
respect to crash response
.” 2006. Web. 24 Jan 2021.
Vancouver:
author] [. Comparative study into occupant support concepts with
respect to crash response
. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-01112005-124913/.
Council of Science Editors:
author] [. Comparative study into occupant support concepts with
respect to crash response
. [Masters Thesis]. University of Pretoria; 2006. Available from: http://upetd.up.ac.za/thesis/available/etd-01112005-124913/
University of Pretoria
16.
[No author].
Verification of hardware-in-the-loop as a valid testing
method for suspension development
.
Degree: 2006, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-07282005-082527/
► A need for a cost effective, versatile and easy to use suspension component testing method has arisen, following the development of a four-state hydro-pneumatic semi-active…
(more)
▼ A need for a cost effective, versatile and easy to
use suspension component testing method has arisen, following the
development of a four-state hydro-pneumatic semi-active
spring-damper system. A method known as hardware-in-the-loop (HiL)
was investigated, in particular its use and compatibility with
tests involving physical systems – previously HiL was used
predominantly for Electronic Control Unit (ECU) testing. The
suitability of HiL in the development of advanced suspension
systems and their control systems, during which various vehicle
models can be used, was determined. A first step in vehicle
suspension design is estimating a desired spring and damper
characteristic, and verifying that characteristic using software
simulation. The models used during this step are usually low-order,
simple models, which hampers quick development progress. To predict
vehicle response before vehicle prototype completion, many
researchers have attempted to use complex and advanced damper
models to simulate the vehicle’s dynamics, but these models all
suffer from some drawback – it is either based on empirical data,
giving no indication of the physical parameters of the design
sought; it may be overly complex, having many parameters and thus
rendering software impractical; or it may be quick but based on the
premise that there is no hysteresis in the damping character. It
can be seen that an obvious answer exists – use a physical
commercially available or prototype damper in the software
simulation instead of the mathematical model. In this way the
suspension deflection, i.e. the true motion of the damper is used
as excitation, and the true damper force is measured using a
hydraulic actuator and load cell. The vehicle mass motions are
simulated in a software environment. This is basically what HiL
simulation does. The HiL method was verified by comparing HiL
simulations and tests to globally accepted testing methods,
employing widely-used vehicle models: linear
single-degree-of-freedom (SDOF) and two-degrees-of-freedom (2DOF)
or quarter-car models were used. The HiL method was also compared
to a non-linear physical system to verify that the method holds for
real vehicle suspension geometries. This meant that HiL had to
perform adequately at both ends of the suspension-testing spectrum
– base software and real system simulation. The comparison of the
HiL and software/real system simulation was done using the “Error
Coefficient of Variance” (ECOV) between the compared signals; this
quantitative measure proved very sensitive and performed dubiously
in the presence of signal offsets, phase lags and scaling errors,
but remains a tangible, measurable parameter with which to compare
signals. Visual confirmation was also obtained to back the ECOV
values. It was found that even using a relatively low-force
actuator, the HiL simulation results followed the software/real
system responses well. Phase lags and DC offsets in the HiL
simulation’s measured signals (as well as the real systems
responses) has an adverse effect on the performance of…
Advisors/Committee Members: Mr. P S Els (advisor), Theron, Nicolaas J (advisor).
Subjects/Keywords: Mass-based suspension testing;
Filters;
Dc offsets;
Phase lags;
Non-linear physical system;
Ecov;
2dof;
Sdof;
Suspension design;
Hardware-in-the-loop;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
author], [. (2006). Verification of hardware-in-the-loop as a valid testing
method for suspension development
. (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-07282005-082527/
Chicago Manual of Style (16th Edition):
author], [No. “Verification of hardware-in-the-loop as a valid testing
method for suspension development
.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-07282005-082527/.
MLA Handbook (7th Edition):
author], [No. “Verification of hardware-in-the-loop as a valid testing
method for suspension development
.” 2006. Web. 24 Jan 2021.
Vancouver:
author] [. Verification of hardware-in-the-loop as a valid testing
method for suspension development
. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-07282005-082527/.
Council of Science Editors:
author] [. Verification of hardware-in-the-loop as a valid testing
method for suspension development
. [Masters Thesis]. University of Pretoria; 2006. Available from: http://upetd.up.ac.za/thesis/available/etd-07282005-082527/
University of Pretoria
17.
[No author].
Development of a methodology for calculating stresses
in track components
.
Degree: 2006, University of Pretoria
URL: http://upetd.up.ac.za/thesis/available/etd-07282005-090746/
► An existing analytical model, in use by Spoornet for the past two decades for calculating rail stresses on railway track, was revisited and improved. The…
(more)
▼ An existing analytical model, in use by Spoornet for
the past two decades for calculating rail stresses on railway
track, was revisited and improved. The model provided engineers
with an easy-to-use program for evaluating track capacity and
authorizing heavier loads on track. The model was modified to
calculate rail and track component stresses more accurately. These
modifications include the incorporation of current best practices
and presentation of guidelines for the engineer on how to determine
some input parameters which are normally difficult to obtain.
Firstly it was determined which input parameters the model was the
most sensitive to. Thereafter it was determined whether or not the
correct information would generally be readily available for those
sensitive parameters. The most sensitive parameters were further
investigated and test results, as well as best practice analytical
methods, were used to establish nominal input values and guidelines
for determining such values. This research was necessary to
establish whether or not the currently used analytical model still
provided railway engineers with a useful tool and whether or not
more modern and popular tools could validate or replace it. After
some modifications to the analytical model, it was proved that it
provides engineers with a suitably accurate tool for calculating
rail and track component stresses, without the need to build
time-consuming models of the track under investigation. It showed
that the model, after some modifications, is current with
calculational methods in recent publications and provides an
immediate answer to "what-if" questions without the need to run
lengthy analyses.
Advisors/Committee Members: Dr R D Fröhling (advisor), Theron, Nicolaas J (advisor).
Subjects/Keywords: Finite element analysis;
Dynamic factor;
Lateral loads;
Eccentricity;
Instrumented wheelset;
Wheelset;
Weigh in motion;
Weighbridges;
Model;
Analytical;
Stresses;
Track;
Rail;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
author], [. (2006). Development of a methodology for calculating stresses
in track components
. (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-07282005-090746/
Chicago Manual of Style (16th Edition):
author], [No. “Development of a methodology for calculating stresses
in track components
.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://upetd.up.ac.za/thesis/available/etd-07282005-090746/.
MLA Handbook (7th Edition):
author], [No. “Development of a methodology for calculating stresses
in track components
.” 2006. Web. 24 Jan 2021.
Vancouver:
author] [. Development of a methodology for calculating stresses
in track components
. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://upetd.up.ac.za/thesis/available/etd-07282005-090746/.
Council of Science Editors:
author] [. Development of a methodology for calculating stresses
in track components
. [Masters Thesis]. University of Pretoria; 2006. Available from: http://upetd.up.ac.za/thesis/available/etd-07282005-090746/
University of Pretoria
18.
Misselhorn, Werner
Ekhard.
Verification of
hardware-in-the-loop as a valid testing method for suspension
development.
Degree: Mechanical and Aeronautical
Engineering, 2006, University of Pretoria
URL: http://hdl.handle.net/2263/26727
► A need for a cost effective, versatile and easy to use suspension component testing method has arisen, following the development of a four-state hydro-pneumatic semi-active…
(more)
▼ A need for a cost effective, versatile and easy to use
suspension component testing method has arisen, following the
development of a four-state hydro-pneumatic semi-active
spring-damper system. A method known as hardware-in-the-loop (HiL)
was investigated, in particular its use and compatibility with
tests involving physical systems – previously HiL was used
predominantly for Electronic Control Unit (ECU) testing. The
suitability of HiL in the development of advanced suspension
systems and their control systems, during which various vehicle
models can be used, was determined. A first step in vehicle
suspension design is estimating a desired spring and damper
characteristic, and verifying that characteristic using software
simulation. The models used during this step are usually low-order,
simple models, which hampers quick development progress. To predict
vehicle response before vehicle prototype completion, many
researchers have attempted to use complex and advanced damper
models to simulate the vehicle’s dynamics, but these models all
suffer from some drawback – it is either based on empirical data,
giving no indication of the physical parameters of the design
sought; it may be overly complex, having many parameters and thus
rendering software impractical; or it may be quick but based on the
premise that there is no hysteresis in the damping character. It
can be seen that an obvious answer exists – use a physical
commercially available or prototype damper in the software
simulation instead of the mathematical model. In this way the
suspension deflection, i.e. the true motion of the damper is used
as excitation, and the true damper force is measured using a
hydraulic actuator and load cell. The vehicle mass motions are
simulated in a software environment. This is basically what HiL
simulation does. The HiL method was verified by comparing HiL
simulations and tests to globally accepted testing methods,
employing widely-used vehicle models: linear
single-degree-of-freedom (SDOF) and two-degrees-of-freedom (2DOF)
or quarter-car models were used. The HiL method was also compared
to a non-linear physical system to verify that the method holds for
real vehicle suspension geometries. This meant that HiL had to
perform adequately at both ends of the suspension-testing spectrum
– base software and real system simulation. The comparison of the
HiL and software/real system simulation was done using the “Error
Coefficient of Variance” (ECOV) between the compared signals; this
quantitative measure proved very sensitive and performed dubiously
in the presence of signal offsets, phase lags and scaling errors,
but remains a tangible, measurable parameter with which to compare
signals. Visual confirmation was also obtained to back the ECOV
values. It was found that even using a relatively low-force
actuator, the HiL simulation results followed the software/real
system responses well. Phase lags and DC offsets in the HiL
simulation’s measured signals (as well as the real systems
responses) has an adverse effect on the performance of…
Advisors/Committee Members: Mr. P S Els (advisor), Theron, Nicolaas J. (advisor).
Subjects/Keywords: Mass-based
suspension testing;
Filters; Dc
offsets; Phase
lags; Non-linear
physical system;
Ecov;
2dof;
Sdof; Suspension
design;
Hardware-in-the-loop;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Misselhorn, W. (2006). Verification of
hardware-in-the-loop as a valid testing method for suspension
development. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/26727
Chicago Manual of Style (16th Edition):
Misselhorn, Werner. “Verification of
hardware-in-the-loop as a valid testing method for suspension
development.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/26727.
MLA Handbook (7th Edition):
Misselhorn, Werner. “Verification of
hardware-in-the-loop as a valid testing method for suspension
development.” 2006. Web. 24 Jan 2021.
Vancouver:
Misselhorn W. Verification of
hardware-in-the-loop as a valid testing method for suspension
development. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/26727.
Council of Science Editors:
Misselhorn W. Verification of
hardware-in-the-loop as a valid testing method for suspension
development. [Masters Thesis]. University of Pretoria; 2006. Available from: http://hdl.handle.net/2263/26727
University of Pretoria
19.
Naude, Francois
Paulus.
Development of a
methodology for calculating stresses in track
components.
Degree: Mechanical and Aeronautical
Engineering, 2006, University of Pretoria
URL: http://hdl.handle.net/2263/26730
► An existing analytical model, in use by Spoornet for the past two decades for calculating rail stresses on railway track, was revisited and improved. The…
(more)
▼ An existing analytical model, in use by Spoornet for the
past two decades for calculating rail stresses on railway track,
was revisited and improved. The model provided engineers with an
easy-to-use program for evaluating track capacity and authorizing
heavier loads on track. The model was modified to calculate rail
and track component stresses more accurately. These modifications
include the incorporation of current best practices and
presentation of guidelines for the engineer on how to determine
some input parameters which are normally difficult to obtain.
Firstly it was determined which input parameters the model was the
most sensitive to. Thereafter it was determined whether or not the
correct information would generally be readily available for those
sensitive parameters. The most sensitive parameters were further
investigated and test results, as well as best practice analytical
methods, were used to establish nominal input values and guidelines
for determining such values. This research was necessary to
establish whether or not the currently used analytical model still
provided railway engineers with a useful tool and whether or not
more modern and popular tools could validate or replace it. After
some modifications to the analytical model, it was proved that it
provides engineers with a suitably accurate tool for calculating
rail and track component stresses, without the need to build
time-consuming models of the track under investigation. It showed
that the model, after some modifications, is current with
calculational methods in recent publications and provides an
immediate answer to "what-if" questions without the need to run
lengthy analyses.
Advisors/Committee Members: Dr R D Fröhling (advisor), Theron, Nicolaas J. (advisor).
Subjects/Keywords: Finite element
analysis; Dynamic
factor; Lateral
loads;
Eccentricity; Instrumented
wheelset;
Wheelset; Weigh in
motion;
Weighbridges;
Model;
Analytical;
Stresses;
Track;
Rail;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Naude, F. (2006). Development of a
methodology for calculating stresses in track
components. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/26730
Chicago Manual of Style (16th Edition):
Naude, Francois. “Development of a
methodology for calculating stresses in track
components.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/26730.
MLA Handbook (7th Edition):
Naude, Francois. “Development of a
methodology for calculating stresses in track
components.” 2006. Web. 24 Jan 2021.
Vancouver:
Naude F. Development of a
methodology for calculating stresses in track
components. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/26730.
Council of Science Editors:
Naude F. Development of a
methodology for calculating stresses in track
components. [Masters Thesis]. University of Pretoria; 2006. Available from: http://hdl.handle.net/2263/26730
University of Pretoria
20.
Meintjes, Schalk Willem van der
Merwe.
Comparative
study into occupant support concepts with respect to crash
response.
Degree: Mechanical and Aeronautical
Engineering, 2006, University of Pretoria
URL: http://hdl.handle.net/2263/30576
► It is argued that together with improved protection structures and energy dissipation systems, a favourable pilot position with sufficient support and restraint could reduce fatalities…
(more)
▼ It is argued that together with improved protection
structures and energy dissipation systems, a favourable pilot
position with sufficient support and restraint could reduce
fatalities in aviation accidents. In this document the crash
response of three different pilot positions are compared to justify
the proposal of supporting a pilot in the rather unusual prone
position. The normal seated and supine pilot positions have already
been adopted and implemented in various aircraft. The occupant’s
response to specified crash scenarios in these two positions was
compared to that of a pilot in the prone position. To obtain the
best prone pilot support configuration, different concepts were
considered during the analysis. A dynamic event simulation program
called ADAMS was used to perform the analysis and existing injury
criteria and a study of common causes of aviation fatalities and
human body tolerance limits were used to compare the results.
Additionally, methods to improve survivability of a pilot in the
prone position during likely accidents were investigated with
ADAMS. Concepts for the Exulans fuselage layout and energy
absorption systems were proposed and recommendations for the pilot
support system were derived from the results.
Advisors/Committee Members: Theron, Nicolaas J. (advisor), Mr R J Huyssen (advisor).
Subjects/Keywords: No key words
available;
UCTD
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Meintjes, S. W. v. d. (2006). Comparative
study into occupant support concepts with respect to crash
response. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/30576
Chicago Manual of Style (16th Edition):
Meintjes, Schalk Willem van der. “Comparative
study into occupant support concepts with respect to crash
response.” 2006. Masters Thesis, University of Pretoria. Accessed January 24, 2021.
http://hdl.handle.net/2263/30576.
MLA Handbook (7th Edition):
Meintjes, Schalk Willem van der. “Comparative
study into occupant support concepts with respect to crash
response.” 2006. Web. 24 Jan 2021.
Vancouver:
Meintjes SWvd. Comparative
study into occupant support concepts with respect to crash
response. [Internet] [Masters thesis]. University of Pretoria; 2006. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2263/30576.
Council of Science Editors:
Meintjes SWvd. Comparative
study into occupant support concepts with respect to crash
response. [Masters Thesis]. University of Pretoria; 2006. Available from: http://hdl.handle.net/2263/30576
. 
Open Access Theses and Dissertations