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The concept of a robotic manipulator is widely used throughout many industries. In this project, a manipulator of the type SCARA, selective compliance articulated robot arm, is constructed. The aim was to examine how such a robot could be constructed using 3D-printing and how accurate it would be. Other than 3D-printing, parts in the form of guiding rods, lead screw, bearings, pulleys and timing belts were used. Together with a microcontroller, the robot operates using three stepper motors. In the end it resulted in a SCARA with reasonable accuracy considering the methods used, more specifically the largest average error was 3.6cm in the X direction and 2.3 cm in the Y direction. The largest drawback of the final construction was the negative balance between tightening the belts and friction in the inner joint. Tightening the belts meant larger friction and thereby undesired movement properties. Doing the opposite meant that the belts could start slipping and enabled backlash. / Konceptet av en robotarm används brett inom många industrier. Detta projekt syftar till att konstruera en robot avtypen SCARA, selective compliance articulated robot arm. Målet var att undersöka hur en sådan robot kan 3D-printas och dess precision. Förutom 3D-printade delar användes även guidestänger, kullager, kamremmar och remskivor. Robotens rörelser styrs tillsammans med en mikrokontroller och tre stegmotorer. Med tillvägagångssätten i åtanke resulterade projektet in en SCARA med rimlig precision. Mer specifikt var medelfelet 3.6 cm i X-led och 2.3 cm i Y-led. Den största nackdelen med den slutgiltiga konstruktionenvar den negativa jämvikten mellan att spänna kamremmarna och friktionen i den inre armleden. Att spänna kamremmarna innebar en ökning i friktion och därmed oönskade rörelseegenskaper. Att göra tvärtom innebar att bältena löpte större risk att glida ur och möjliggjorde dödgång.

As falls and fall-related injuries are a major cause of injuries, the purpose of this study was to investigate whether, and to what extent, the stage combat fall technique training could reduce the impact forces of falls from standing. Twenty-six healthy young adults (14 males and 12 females) participated in our study, and were randomly assigned to either a training group or non-training (control) group. Both groups completed a pre-intervention and a post-intervention fall testing session, separated by two weeks, in which they performed naturalistic falls. The training group performed identical pre-intervention fall testing as the control group, and was then required to receive four 1-hour training sessions in the course of two weeks, led by a certified stage combat fall technique training instructor. The training group then completed a post-intervention fall testing session where they performed naturalistic falls and also falls using the fall technique they learned. Falls were induced in both forward and backward directions using a tether-release protocol. Differences between control and training groups at pre-training, and group differences in the change in dependent measures with training, were examined using Mann-Whitney U tests. The results showed that, following stage-combat fall training, the training group exhibited 32% and 35% reduction in median impact forces for forward and backward falls respectively, while the control group exhibited 5% and 2% reductions (p = 0.002 and <0.001). In addition, the training group showed shorter backward fall duration as well as longer impact time, larger impulse, and longer or larger center-of-pressure based measures for both directions of falling than the control group. However, training was not associated with reduced impact force during the naturalistic falls of the training group. To our knowledge, this was the first study to investigate the stage combat fall technique training and demonstrate its effectiveness as an intervention to reduce impact forces of falls, thereby exploring the potential to reduce the number of fall-related injuries. While these falls were induced from standing, whether these results would transfer to an unanticipated fall while walking due to a slip/trip remain to be explored. / Master of Science / As falls and fall-related injuries are a major cause of injuries, the purpose of this study was to investigate whether, and to what extent, the stage combat fall technique training could reduce the impact forces of falls from standing. Twenty-six healthy young adults (14 males and 12 females) participated in our study, and were randomly assigned to either a training group or non-training (control) group. Both groups completed a pre-intervention and a post-intervention fall testing session, separated by two weeks, in which they performed naturalistic falls. The training group was required to receive four 1-hour training sessions in the two-week intervention period, led by a certified stage combat fall technique training instructor. The training group then completed a post-intervention fall testing session where they performed naturalistic falls and also falls using the fall technique they learned. The results showed that, following stage-combat fall training, the training group exhibited nearly a 1/3rd reduction in impact forces for both forward and backward falls, while the control group only exhibited 5% and 2% reductions respectively. Our analysis also showed that the training group achieved this reduction in impact force by increasing the impact time and spreading out their bodies more, to distribute the impact over a larger area. To our knowledge, this was the first study to investigate the stage combat fall technique training and demonstrate its effectiveness as an intervention to reduce impact forces of falls, thereby exploring the potential to reduce the number of fall-related injuries.

The intense electromagnetic fields surrounding highly charged, ultra-relativistic ions at the LHC provide an intense flux of quasi-real photons. This high-energy photon flux provides a precise probe of the structure of the nucleus in photonuclear interactions and a tool to precisely study the properties of photoproduction in two-photon interactions. This thesis presents recent results from studies of photoproduction processes in √𝒔_𝐍𝐍 = 5.02 TeV Pb+Pb collisions at the LHC, using data collected in 2015 and 2018. A measurement of the differential cross-section for photonuclear jet production is performed with an integrated luminosity of 1.72 nb⁻¹. This measurement is triple-differential in two different sets of kinematic variables ([𝐻_𝐓, 𝒙_𝐀, 𝒛_𝛾] and [𝐻_𝐓, 𝒚_jets, 𝒎_jets) which allow for a direct measurement of the kinematics of struck partons in the nuclear target, and it is fully unfolded in three dimensions. After performing detailed studies of the rate for nuclear breakup in these collisions, the photonuclear jet cross-sections agree with leading-order predictions at the level of 10%. The uncertainty on this measurement and full treatment of its correlated uncertainties will allow for it to significantly constrain the nuclear parton distributions over a wide region of parton kinematics. A measurement was also performed of dimuon production via two-photon fusion in Pb+Pb collisions with nuclear overlap. This measurement studied the relative deflection of muons in each pair, and its results indicated that these distributions are substantially modified as a function of collision centrality. This modification is mostly well-described by initial-state models, which improve the modelling of the photon flux by incorporating correlations between the collision impact parameter and photon 𝒑_𝐓. Additional studies were performed to constrain the potential impact of any deflections due to the presence of strong magnetic fields in the hot, dense medium produced in heavy ion collisions.

In this research, the use of the SteamVR tracking system as a teaching method forindustrial robots was investigated, in particular, how it can make the setup of weldingapplications more intuitive. Therefore, an application was developed, that handles therecording of the teaching data and the control of the robot, which allow fast setup timesof a few minutes only. Tests were conducted and a static accuracy of 10 mm determinedat the TCP. This is not sufficient for welding. Further investigation of the tracking systemshowed directional dependencies, a slow dynamic response of the tracking, which can addanother 10 mm of error, and deviations at the pose determination between 3 and 20 mm,making this tracking setup only usable for applications, where no precision is needed.

Stroke is a leading cause of long-term disability, affecting thousands of individuals annually and significantly impairing their mobility, independence, and quality of life. Traditional methods for assessing motor impairments are often costly and invasive, creating substantial barriers to effective rehabilitation. This thesis explores the use of DeepLabCut (DLC), a deep-learning-based pose estimation tool, to extract clinically meaningful kinematic features from video data of stroke survivors with upper-extremity (UE) impairments. To conduct this investigation, a specialized protocol was developed to tailor DLC for analyzing movements characteristic of UE impairments in stroke survivors. This protocol was validated through comparative analysis using peak acceleration (PA), mean squared jerk (MSJ), and area under the curve (AUC) as kinematic features. These features were extracted from the DLC output and compared to those derived from the assumed ground-truth data from IMU sensors worn by the participants. The accuracy of this analysis was quantified using percent mean squared error (PMSE) between each IMU sensor and DLC. PMSE analysis indicates that DLC-based kinematic features capture aspects of both accelerometer and gyroscope for the control participant. PA (8.78%) and AUC (3.28%) align more closely with the gyroscope, while MSJ (5.20%) demonstrates greater agreement with the accelerometer. On the other hand, for the stroke participant, DLC estimations for all kinematic features predominantly reflect data from the accelerometer. Across all datasets, AUC has the smallest PMSE values, suggesting that, based on our data, motor effort and energy expenditure in the tasks are best represented by DLC. Additionally, PMSE values for the stroke dataset are higher than those for the control, highlighting DLC's limitations in accurately detecting finer details of motion data in individuals with UE impairments. The results indicate that DLC reasonably estimates kinematic data for both participants, although further refinement of the methods is necessary to enhance the analysis of stroke data.

Various researchers have indicated the importance of graphs in physical sciences and the difficulties that learners may experience with graphs. More specifically, learners’ problems with motion graphs have been reported in literature. Learners’ difficulty in the application of basic concepts in graphs to solve kinematics graphs problems leads to underperformance in physical sciences. Their ability to handle problems in kinematics graphs is enhanced if they have an effective knowledge base or conceptual resources on graphs. In South Africa there seems to be a gap between the GET [General Education and Training] and FET [Further Education and Training] band’s requirements on graphs. A smooth learning progression is needed. For this reason this study selected to investigate the conceptual resources acquired by grade 10 learners from grade 9 that can be used productively for the learning of kinematics graphs in grade 10. The primary aim of the study was to determine and analyse grade 10 learners’ conceptual resources for learning kinematics graphs in physical sciences. The use of a mixed method approach was considered appropriate for this study. The mixed method depended on the quantitative method to produce precise and measurable data, while a qualitative method was to enhance the understanding of the data produced by the quantitative method. Data obtained by quantitative methods was drawn into tables and graphs, and the consistency in responses determined. Patterns and trends in learners’ reasoning were probed with the aid of qualitative method. In the study it was reported that the quantitative data in the form of a questionnaire was completed by 201 learners. Qualitative data was also obtained by interviewing three learners with varying abilities. The results showed that many learners could answer mathematics questions, but struggled with similar questions in kinematics. The results further showed that the learners did not answer the questionnaire consistently, but their responses depended on the context of the questions. In the interviews learners used everyday applications to explain scientific concepts, instead of using scientific principles. Still, some of the everyday applications may be used as resources for teaching the science concepts. From the results it can be deduced that learners’ conceptual resources can influence their understanding of kinematics graphs in physics. These resources are gained from everyday experiences and previous learning in mathematics and the natural sciences. A constraint is that many learners do not efficiently integrate their mathematics and physics knowledge. iv In the study some learners did not transfer their mathematics knowledge to physics, while others could not transfer their physics knowledge to mathematics. From the results recommendations can be made for the teaching of graphs in the GET band for easier progress into the FET band. The strategy to improve understanding of kinematics graphs is to progressively integrate mathematics and physics from grade nine. Line graphs should be treated in more detail in grade 9 to form proper conceptual resources for kinematics graphs in grade ten. / MEd (Natural Sciences Education), North-West University, Potchefstroom Campus, 2014

Various researchers have indicated the importance of graphs in physical sciences and the difficulties that learners may experience with graphs. More specifically, learners’ problems with motion graphs have been reported in literature. Learners’ difficulty in the application of basic concepts in graphs to solve kinematics graphs problems leads to underperformance in physical sciences. Their ability to handle problems in kinematics graphs is enhanced if they have an effective knowledge base or conceptual resources on graphs. In South Africa there seems to be a gap between the GET [General Education and Training] and FET [Further Education and Training] band’s requirements on graphs. A smooth learning progression is needed. For this reason this study selected to investigate the conceptual resources acquired by grade 10 learners from grade 9 that can be used productively for the learning of kinematics graphs in grade 10. The primary aim of the study was to determine and analyse grade 10 learners’ conceptual resources for learning kinematics graphs in physical sciences. The use of a mixed method approach was considered appropriate for this study. The mixed method depended on the quantitative method to produce precise and measurable data, while a qualitative method was to enhance the understanding of the data produced by the quantitative method. Data obtained by quantitative methods was drawn into tables and graphs, and the consistency in responses determined. Patterns and trends in learners’ reasoning were probed with the aid of qualitative method. In the study it was reported that the quantitative data in the form of a questionnaire was completed by 201 learners. Qualitative data was also obtained by interviewing three learners with varying abilities. The results showed that many learners could answer mathematics questions, but struggled with similar questions in kinematics. The results further showed that the learners did not answer the questionnaire consistently, but their responses depended on the context of the questions. In the interviews learners used everyday applications to explain scientific concepts, instead of using scientific principles. Still, some of the everyday applications may be used as resources for teaching the science concepts. From the results it can be deduced that learners’ conceptual resources can influence their understanding of kinematics graphs in physics. These resources are gained from everyday experiences and previous learning in mathematics and the natural sciences. A constraint is that many learners do not efficiently integrate their mathematics and physics knowledge. iv In the study some learners did not transfer their mathematics knowledge to physics, while others could not transfer their physics knowledge to mathematics. From the results recommendations can be made for the teaching of graphs in the GET band for easier progress into the FET band. The strategy to improve understanding of kinematics graphs is to progressively integrate mathematics and physics from grade nine. Line graphs should be treated in more detail in grade 9 to form proper conceptual resources for kinematics graphs in grade ten. / MEd (Natural Sciences Education), North-West University, Potchefstroom Campus, 2014

Als elastische Koppelglieder üben Elastomere im Fahrwerk maßgeblichen Einfluss auf die Elastokinematik der Radaufhängung und damit auf die Radstellgrößen aus. Bereits einfache zylindrische Probekörper zeigten in der Vergangenheit Veränderlichkeit der Federsteifigkeiten bei mehrachsiger Belastung auf. Daraus ließ sich ableiten, dass das Bauteilverhalten von zylindrischen Elastomerkörpern, bzw. Fahrwerklagern, schwer vorhersagbar ist und dieser Effekt durch die Verwendung komplexer Geometrien zusätzlich beeinflusst wird. Eigens im Rahmen dieser Arbeit entwickelte Prüfstände ermöglichten die Untersuchung von statischen, mehrachsigen Belastungen sowie zyklischen, einachsigen Belastungen zweier Fahrwerklager einer typischen Vorderradaufhängung, dem Mc-Pherson-Federbein. Für beide Lagertypen wurden derart signifikante Federsteifigkeitsänderungen unter mehrachsiger Belastung beobachtet, dass ein Einfluss auf die Elastokinematik sicher schien. Unter einachsiger, zyklischer Belastung bestätige sich, dass einfache rheologische Ersatzmodelle, wie der Ansatz nach Kelvin-Voigt für eine Modellierung des viskoelastischen Materialverhaltens weiterhin Gültigkeit besitzen. Ein in einem Mehrkörpersimulationsprogramm erstelltes Gesamtfahrzeugmodell zeigte zunächst für die Auslegung der Prüfstände relevante Beanspruchungen in den Fahrwerklagern auf und diente weiterhin als Grundlage für die Untersuchung des Einflusses von Wechselwirkungen auf die Radstellgrößen. Dazu behandelt die Arbeit die Modellierung eines neuen Fahrwerklagermodells innerhalb dieser MKS-Umgebung. Dieses Modell bietet dem Nutzer die Möglichkeit für eine Abbildung von Wechselwirkungen an zylindrischen, zyklisch beanspruchten Bauteilen. Ein spezielles Fahrmanöver zeigte den Einfluss der Wechselwirkungen auf die Radstellgrößen auf und zeigte, dass die Berücksichtigung von Wechselwirkungen für eine Fahrwerkauslegung relevant ist. Darüber hinaus wurde mit kommerziell verfügbaren Materialmodellen für die Beschreibung es Materialverhaltens von Elastomeren innerhalb der Finite-Elemente-Methode aufgezeigt, dass bei einachsiger Belastung die Federsteifigkeiten der Fahrwerklager auf Grundlage der in der Literatur üblichen Auslegungsgleichungen näherungsweise abgebildet werden können, jedoch für mehrachsige Spannungszustände keine hinreichende Aussage über das Bauteilverhalten getroffen werden kann. Hier wurde weiterer Forschung- bzw. Erweiterungsbedarf an den FE-Programmen aufgezeigt.