Thesis (M. Tech.) - Central University of Technology, Free State, 2011 / The objectives of this research were to investigate and establish a procedure to determine the self-damping characteristics of transmission line conductors subjected to free and forced vibrations. The TERN and Aero-Z IEC62219-REV240609 conductor cables were the transmission line conductors that were readily available at the Vibration Research and Testing Centre (VTRC) of the University of KwaZulu-Natal (UKZN). The question to be answered was whether the self-damping characteristics of the TERN and Aero-Z IEC62219-REV240609 conductors were adequate to suppress Aeolian or wake-induced vibrations. In other words, is it necessary for external damping mechanisms to be used with these conductors? This study confirmed that the self-damping characteristics of conductors are not adequate to suppress Aeolian or wake-induced vibrations. Governing partial differential equations describing the characteristics of the catenary and parabolic cable conductors were developed to validate the experimental results. The experimental tests involved both conductors being subjected to an impulse function (a free vibration method) and also to a harmonic function (a forced vibration method). Measurements were carried out using accelerometers, and the recording equipment consisted of oscilloscopes and the PUMA system. With both the free and forced vibration methods, the damping factor of the TERN conductor was confirmed to be ζ ≤ 0.05, whereas the damping factor of the Aero-Z IEC62219-REV240609 was confirmed to be ζ ≤ 0.2. A procedure for determining the self-damping characteristics of the TERN and Aero-Z IEC62219-REV240609 conductors was developed, with the damping factor found to be ζ ≤ 0.2 for both conductors. These methods can assist in the implementation of procedural analysis of the self-damping behaviour of different types of transmission conductors and in finding the most suitable mass absorber (damper) to use in reducing the rate of failure of transmission line conductors. The results of this study can be used to improve the mathematical modelling of Aeolian and wind-induced vibrations where both self-damping properties and a mass absorber are incorporated.

Thesis (M. Tech. Electrical engineering) -- Central University of technology, Free State, 2012 / Infrared thermography is a non-contact method of identifying the thermal behaviour of various plant equipment and machines, including their components, qualitatively via pattern recognition and quantitatively via statistical analysis. This allows for the development of condition monitoring and predictive failure analysis. It is well established that optimized maintenance planning can be more effective when a problem is detected in the early stages of failure. For example, in electrical systems an elevated electrical resistance caused by loose or corroded connections, broken conductor strands and dirty contact surfaces, results in localized heating, and a unique infrared pattern when analysed leads to the location of the problem and an indication of its severity. In recent years industrial thermography has used infrared detectors in the long wave portion of the electromagnetic spectrum normally between 8μm and 15μm, due partly to the fact that these wavelengths are not susceptible to solar radiation and/or solar glint. A number of scientific experiments were carried out on test apparatus to improve the understanding of the impact of convection, ambient air temperature and relative humidity on resultant infrared thermal images. Two similar heat sources, simulating a hotspot, at different temperature settings were used to determine whether the hotspot temperature should also be considered in conjunction with the atmospheric elements. The need for these experiments has also been identified by EPRI (Electrical Power Research Institute) in the USA as necessary to develop international severity criteria, and it is hoped that this study will contribute to this goal.

Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2011 / Traditional designs for component-handling platforms are rigidly linked to the product being produced. Control and monitoring methods for these platforms consist of various proprietary hardware controllers containing the control logic for the production process. Should the configuration of the component handling platform change, the controllers need to be taken offline and reprogrammed to take the changes into account. The current thinking in component-handling system design is the notion of re-configurability. Reconfigurability means that with minimum or no downtime the system can be adapted to produce another product type or overcome a device failure. The re-configurable component handling platform is built-up from groups of independent devices. These groups or cells are each responsible for some aspect of the overall production process. By moving or swopping different versions of these cells within the component-handling platform, re-configurability is achieved. Such a dynamic system requires a flexible communications platform and high-level software control architecture to accommodate the reconfigurable nature of the system. This work represents the design and testing of the core of a re-configurable production control software platform. Multiple software components work together to control and monitor a re-configurable component handling platform. The design and implementation of a production database, production ontology, communications architecture and the core multi-agent control application linking all these components together is presented.

Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013 / Automatic Guided Vehicles (AGVs) are being used more frequently in a manufacturing environment. These AGVs are navigated in many different ways, utilising multiple types of sensors for detecting the environment like distance, obstacles, and a set route. Different algorithms or methods are then used to utilise this environmental information for navigation purposes applied onto the AGV for control purposes. Developing a platform that could be easily reconfigured in alternative route applications utilising vision was one of the aims of the research. In this research such sensors detecting the environment was replaced and/or minimised by the use of a single, omnidirectional Webcam picture stream utilising an own developed mirror and Perspex tube setup. The area of interest in each frame was extracted saving on computational recourses and time. By utilising image processing, the vehicle was navigated on a predetermined route. Different edge detection methods and segmentation methods were investigated on this vision signal for route and sign navigation. Prewitt edge detection was eventually implemented, Hough transfers used for border detection and Kalman filtering for minimising border detected noise for staying on the navigated route. Reconfigurability was added to the route layout by coloured signs incorporated in the navigation process. The result was the manipulation of a number of AGV’s, each on its own designated coloured signed route. This route could be reconfigured by the operator with no programming alteration or intervention. The YCbCr colour space signal was implemented in detecting specific control signs for alternative colour route navigation. The result was used generating commands to control the AGV through serial commands sent on a laptop’s Universal Serial Bus (USB) port with a PIC microcontroller interface board controlling the motors by means of pulse width modulation (PWM). A total MATLAB® software development platform was utilised by implementing written M-files, Simulink® models, masked function blocks and .mat files for sourcing the workspace variables and generating executable files. This continuous development system lends itself to speedy evaluation and implementation of image processing options on the AGV. All the work done in the thesis was validated by simulations using actual data and by physical experimentation.

Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013 / This study compared the usability of three Information and Communication Technology (ICT) network programs in a learning environment. The researcher wanted to establish which program was most adequate from a usability perspective among second-year Information Technology (IT) students at the Central University of Technology (CUT), Free State. The Software Usability Measurement Inventory (SUMI) testing technique can measure software quality from a user perspective. The technique is supported by an extensive reference database to measure a software product’s quality in use and is embedded in an effective analysis and reporting tool called SUMI scorer (SUMISCO). SUMI was applied in a controlled laboratory environment where second-year IT students of the CUT, utilized SUMI as part of their networking subject, System Software 1 (SPG1), to evaluate each of the three ICT network programs. The results, strengths and weaknesses, as well as usability improvements, as identified by SUMISCO, are discussed to determine the best ICT network program from a usability perspective according to SPG1 students.

Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013 / The aim of this study was to create a dynamic software system that captures all information related to a student and delivers it to the educators, principal, higher authorities and parents. In order to achieve this aim, an investigation was launched as to the development of a cost-effective school management system for disadvantaged schools in the Free State Province using the Software as a Service (SaaS) delivery model. Although a variety of other school management systems exist in the market, they are often expensive and difficult to maintain. Details such as previous academic performances, disciplinary actions taken against a student in the current school, ailments the student suffers from and parental details are some of the information that will help an educator to better understand a student. The software that is currently in use fails to deliver this information. Designing the software as a multitenant system, helps accommodate different schools under the same database, while the shared database, shared schema reduces back-end costs. Database design was carried out in such a way that tenant data is logically isolated and that data integrity is maintained throughout. What makes the software explained in this study cost effective is the method of delivery that was employed, which is SaaS. Here, software is not purchased, there is no upfront capital and the yearly license fee is eliminated, as schools need only pay a monthly rental fee for the services they use. Since all services are provided through the Internet, there is no need for system space; the only requirement is a high-speed Internet network.

Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, [2014] / The project is aimed at exploring the application of Machine Vision in a Reconfigurable Manufacturing System (RMS) Environment. The Machine Vision System interfaces with the RMS to verify the reconfiguration and positioning of devices within the assembly system, and inspects the product for defects that infringe on the quality of that product. The vision system interfaces to the Multi-agent System (MAS), which is in charge of scheduling and allocating resources of the RMS, in order to communicate and exchange data regarding the quality of the product. The vision system is comprised of a Compact Vision System (CVS) device with fire-wire cameras to aid in the image acquisition, inspection and verification process. Various hardware and software manufacturers offer a platform to implement this with a multiple array of vision equipment and software packages. The most appropriate devices and software platform were identified for the implementation of the project. An investigation into illumination was also undertaken in order to determine whether external lighting sources would be required at the point of inspection. Integration into the assembly system involved the establishment communication between the vision system and assembly system controller.

Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013 / Markets for manufactured products are characterized by a fragmentation of the market (with regards to size and time), and by shorter product cycles. This is due to the occurrence of mass customization and globalization. In mass customization, the same basic products are manufactured for a broad market, but then consumers are given the liberty to choose the “finishing touches” that go with the product. The areas that manufacturers now compete for are higher quality products, low cost and timely response to market changes. Appropriate business strategies and manufacturing technologies must thus be used to implement these strategic dimensions. The paradigm of Reconfigurable Manufacturing System (RMS) has been introduced to respond to this new market oriented manufacturing environment. The design of RMS allows ease of reconfiguration as it has a modular structure in terms of software and hardware. This allows ease of reconfiguration as a strategy to adapt to changing market demands. Modularity will allow the ability to integrate/remove software/hardware modules without affecting the rest of the system. RMS can therefore be quickly reconfigured according to the production requirements of new models, it can be quickly adjusted to exact capacity requirements as the market grows and products change, and it is able to integrate new technology. In this research project, real-time, open controller is designed and developed for Reconfigurable Manufacturing Tools (RMTs). RMTs are the basic building blocks for RMS. Real time and openness of the controllers for RMT would allow firstly, for the modular design of RMTs (so that RMTs can be adapted easily for changing product demands) and secondly, prompt control of RMT for diagnosability.

Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013 / In the industry, automation is used to optimize production, improve product quality and increase profitability. By properly implementing automation systems, the risk of injury to workers can be minimized. Robots are used in many low-level tasks to perform repetitive, undesirable or dangerous work. Robots can perform a task with higher precision and accuracy to lower errors and waste of material. Machine Vision makes use of cameras, lighting and software to do visual inspections that a human would normally do. Machine Vision is useful in application where repeatability, high speed and accuracy are important. This study concentrates on the development of a dedicated robot vision system to automatically place components exiting from a conveyor system onto Automatic Guided Vehicles (AGV). A personal computer (PC) controls the automated system. Software modules were developed to do image processing for the Machine Vision system as well as software to control a Cartesian robot. These modules were integrated to work in a real-time system. The vision system is used to determine the parts‟ position and orientation. The orientation data are used to rotate a gripper and the position data are used by the Cartesian robot to position the gripper over the part. Hardware for the control of the gripper, pneumatics and safety systems were developed. The automated system‟s hardware was integrated by the use of the different communication protocols, namely DeviceNet (Cartesian robot), RS-232 (gripper) and Firewire (camera).

Thesis (M. Tech. (Engineering: Mechanical)) -- Central University of Technology, Free State, 2013 / This research examines the suitability of Additive Manufacturing (AM) for manufacturing dies used in aluminium high pressure die casting. The study was guided by the following objectives: • The reviews of applicable literature sources that outline technical and application aspects of AM in plastic injection moulds and the possibilities of applying it to high pressure casting die. • To introduce AM grown die components in die manufacture. Further, to develop a methodology that will allow industry to apply AM technology to die manufacture. • Revolutionise the way die manufacture is done. The potential for AM technologies is to deliver faster die manufacture turnaround time by requiring a drastically reduced amount of high level machining accuracy. It also reduces the number of complex mechanical material removal operations. Fewer critical steps required by suitable AM technology platforms able to grow fully dense metal components on die casting tools able to produce production runs. • Furthermore, promising competitive advantages are anticipated on savings to be attained on the casting processing side. AM technology allows incorporation of features in a die cavity not possible to machine with current machining approaches and technology. One such example is conformal cooling or heating of die cavities. This approach was successfully used in plastic injection mould cavities resulting in savings on both the part quality as well as the reduction on cycle time required to produce it (LaserCUSING®, 2007). AM technology has evolved to a point where as a medium for fast creation of an object, it has surpassed traditional manufacturing processes allowing for rapidly bridging the gap between ideas to part in hand. The suitability of the AM approach in accelerating the die manufacturing process sometime in the near future cannot be dismissed or ignored. The research showed that there is promise for application of the technology in the not too distant future. In the South African context, the current number and affordability of suitable AM platforms is one of the main stumbling blocks in effecting more widespread applied research aimed at introduction of the technology to die manufacture.