The work presented in this thesis attempts to improve the performance of industrial robot systems in a flexible manufacturing environment by addressing a number of issues related to external sensory feedback and sensor integration, robot kinematic positioning accuracy, and robot dynamic control performance. To provide a powerful control algorithm environment and the support for external sensor integration, a transputer based open architecture robot controller is developed. It features high computational power, user accessibility at various robot control levels and external sensor integration capability. Additionally, an on-line trajectory adaptation scheme is devised and implemented in the open architecture robot controller, enabling a real-time trajectory alteration of robot motion to be achieved in response to external sensory feedback. An in depth discussion is presented on integrating a stereo vision sensor with the robot controller to perform external sensor guided robot operations. Key issues for such a vision based robot system are precise synchronisation between the vision system and the robot controller, and correct target position prediction to counteract the inherent time delay in image processing. These were successfully addressed in a demonstrator system based on a Puma robot. Efforts have also been made to improve the Puma robot kinematic and dynamic performance. A simple, effective, on-line algorithm is developed for solving the inverse kinematics problem of a calibrated industrial robot to improve robot positioning accuracy. On the dynamic control aspect, a robust adaptive robot tracking control algorithm is derived that has an improved performance compared to a conventional PID controller as well as exhibiting relatively modest computational complexity. Experiments have been carried out to validate the open architecture robot controller and demonstrate the performance of the inverse kinematics algorithm, the adaptive servo control algorithm, and the on-line trajectory generation. By integrating the open architecture robot controller with a stereo vision sensor system, robot visual guidance has been achieved with experimental results showing that the integrated system is capable of detecting, tracking and intercepting random objects moving in 3D trajectory at a velocity up to 40mm/s.

Submitted in partial fulfilment of the academic requirements for the Degree of Doctoral of Technology in Mechanical Engineering, Durban Institute of Technology, 2005. / Increased global competition is challenging manufacturing industries to bring competitively priced, well-designed and well-manufactured products into the marketplace as quickly as possible. Manufacturing companies are responding to these challenges in their industry by extending current internet trends to create virtual marketplaces where factories, suppliers, and customers are part of the solution. Pressing demands to reduce lead-time by providing a suitable manufacturing price for a product has become an important step in the current competition age. This thesis presents an approach for providing a quotation for a product via the web, automatically and autonomously. / D

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This thesis describes the procedures developed to control the quality of centred boiled sweet production at the TREBOR factory at Chesterfield. The current Quality Control theory and documentation of existing sweet process lines is examined and used as a basis to assess the problems and possibilities of implementing techniques in this application. Initial statistical analyses of the range of centres produced and common defects are shown. From these analyses came a confirmation that the Quality Control organisation was essentially limited by the low level of process knowledge and technology and the high level of skill required to operate the current process. Based on this analysis of the problem areas the major necessary improvements were then investigated and corrections implemented. These were the design of the rope sizing equipment, and the establishing of control and monitoring functions within the process. A mechanism for rope sizing was then built, a larger and improved centre pipe was designed and installed, and these together with a photodiode camera system to monitor rope size and reject waste has resolved the problems not resolved by the original quality control system. The results have been, a greater understanding of the way in which Quality Control organisations work in practice, and ways in which a high speed continuous and multivariable process can be altered to facilitate more effective control to enhance the product. TREBOR have gained a manufacturing process line which is improved because of a clear increase in the understanding of the old process, and the modifications necessary to include features for the maintenance of better quality during production. Some of the operators' high skill requirement has been replaced with better designed equipment and in-process monitoring.

This study was carried out in order to investigate the effect of cutting parameters on the conventional hobbing process in which the response is analysed and practically tested. The investigation is n six sections: (i) Assessment of cutting torques and power consumed during hobbing. (ii) The study of the variation of gear teeth surface roughness (iii) Investigation of generated vibrations during hobbing (iv) Analysis of the mechanics of uncut-chip (v) The study of tool wear and tool life (vi) A general viewpoint of the economic problem in hobbing. In section (i) tests were conducted in order to assess readily a method of determining cutting torque encountered by hob shaft. Power consumed during hobbing was also measured by changing various cutting parameters. Observations were taken when hobbing spur and helical gears. Unlike others, the effect of cutting speed was shown to have a significant effect both upon cutting torques and power consumed. In section (ii) the nature of gear teeth surface was discussed. Axial feed, hob speed and hob D.P. were seen to have a highly significant influence on surface roughness. In section (iii) investigation was carried out into the effect of cutting parameters upon the machine tool vibration. Stability was shown to depend strongly upon speed, feed and hob D.P. In section (iv) a practical method to calculate volume of metal removed during hobbing is presented and a theoretical analysis of uncut-chip thickness and width is attempted. In section (v) the wear mechanism in hobbing is discussed, "rake face" wear proved to oe a suitable tool-life criterion when cutting materials less than (20 HB) under normal cutting consitions. Cutting speed was seen to have the highest significant influence on tool life, while axial feed was not significant. Section (vi) combines all the previous effects of cutting parameters to give a general viewpoint of the economic problem in hobbing, where power, surface roughness and tangential cutting force were the only constraints restricting the operability region for the given machining conditions.

South Africa is experiencing a shortage of skills in key industries and many organisations have listed the retention of staff as a key objective in their annual sustainability reports. The factors that affect an employee’s intent to turnover have received greater attention as a study field of late but the literature is not all in agreement on the principal factors that influence an employee’s decision to leave an organisation. Many authors suggested that more empirical evidence are necessary to validate the significance of the identified precursors of employee turnover. Prince (2001) and other contributing authors postulated a causal model that tries to explain the complex interactions between the principal constructs that influence the job satisfaction and organisational commitment of an employee, ultimately leading to the employee’s decision to stay at the organisation or turnover. A Structural Equation Modelling technique was applied to the survey data gathered from a South African organisation to validate its fit to the postulated causal relationships defined in Prince’s (2001) model. Many of causal relationships could be validated for the company under study but this study had to conclude as so many other authors has done before that more empirical research is necessary to test the principal constructs of labour turnover as this research could not confirm all the factors postulated by Prince (2001). Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

The research project measured the influence of lean culture elements as well as power distance elements on the success of lean manufacturing implementations. The literature review revealed that lean transformations are not always successful and sustainable since organisation see these as quick win opportunities to improve short term profits. Lean, however, is a long term philosophy that entails not just quick changes but a fundamental change in the way that business is done. The elements that were measured in the study were organisational awareness, employee engagement, managerial consistency, accountability, mutual respect and autocratic behaviour. The study revealed a strong relationship between these factors and the success of lean implementations. The results indicated that there is a positive relationship between lean culture and the other lean elements. The study also indicated that autocratic behaviour has a positive relationship to lean implementation. The study showed that tools that were developed in the past are valid across various industries and that power distance does play a role in lean implementations.

With global advances in technology, many organizations are finding it difficult and quite challenging to do business as usual. Japanese companies are on top of the world economy, while many Western companies are struggling to find ways to compete with them (Womack, et al., 1990). The Japanese secret weapon “Lean Production” is no longer a secret; more and more western companies are now learning and adopting Lean techniques to remain relevant and competitive. Lean management is a consistent philosophy and a set of practices that must be maintained over time in order to see the gains (Losonci & Demeter, 2013). Lean is not a quick fix to reduce costs, but a continuous improvement journey that will transform an organization into a cost efficient value-driven system. Lean is still a fairly new phenomenon in South Africa, particularly in the Eastern Cape. The road towards the lean implementation is viewed by many as a challenging and yet rewarding journey. South African organizations are following the trend of implementing lean in order to eliminate waste, improve quality, speed, customer satisfaction and thereby increasing profits. It is however still a long journey towards achieving total perfection. The main challenge facing South African organizations is the ability to sustain the lean improvements over a longer period. This study will focus on identifying and analyzing the main barriers that inhibit many successful organizations from sustaining lean improvement efforts.

The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.

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