Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This thesis is concerned with the continued development of the Stellenbosch University joint-type knee wear simulator. Initially, information regarding simulators from the literature and commercial entities was collected to provide a knowledge base for current and future work. To further the design of the simulator itself, electronic hardware and software subsystems was developed and evaluated during experimental testing procedures. National Instruments’ cDAQ 9174 data acquisition unit was deemed inadequate for real-time inputoutput control, though proved sufficient for signal capturing purposes in conjunction with LabView software. Furthermore, the various servo-pneumatic sub-circuits’ individual ability to conform to the ISO 14243 series standards’ protocol led to the estimation of measurable performance criteria and the application to a single circuit for illustration. The anterior/posterior actuation circuit in question demonstrated adequate performance for the cases where the piston’s rod was respectively fixed and free to move. In-silico modelling and identification of the relevant servo-pneumatic components then commenced, with the valve and cylinder chamber models yielding adequate estimates of the recorded data. The identified quasi-static friction model proved sensitive to transient effects present within the system, resulting in performance deterioration of the integrated model. Sufficiently accounting for these effects would result in the emergence of the sub-circuit’s model as an invaluable tool in terms of control system development, prediction of the simulator’s behaviour and subsequent design recommendations. Future work therefore concerns improvement, identification and integration of the various sub-circuit models to fully exploit the aforementioned advantages. / AFRIKAANSE OPSOMMING: Hierdie tesis handel oor die voortgesette ontwikkeling van Universiteit Stellenbosch se gewrigstipe knie-afslytingsimulator. Aanvanklik is inligting versamel vanaf literatuur en kommersiële entiteite om sodoende ’n kennisbasis te verskaf vir huidige en toekomstige werk. Elektroniese hardeware en sagteware stelsels is ontwerp en geëvalueer tydens toetsprosedures om die ontwerp van die simuleerder self te verbeter. National Instruments se cDAQ 9174 dataversamelaarseenheid word onvoldoende geag vir intydse inset-uitset beheer, maar wel vir dataversamelingsdoeleindes tesame met LabView sagteware. Die nodigheid om die verskeie servo-pneumatiese sub-stroombane se individuele vermoë om aan te pas by die ISO 14243-reeks se protokol-standaarde te ondersoek, het gelei tot die beraming van meetbare werkverrigtingskriteria en die toepassing daarvan ter illustrasie. Die anterior/posterior stroombaan het voldoende werksverrigting getoon vir studies waar die suier se stang onderskeidelik vas en los was. In-silico modellering en die identifisering van servo-pneumatiese komponente het hierna begin. Die klep en silinderkamer modelle het voldoende skattings gelewer van die gemete data. Die geïdentifiseerde kwasistatiese wrywingsmodel het sensitiwiteit getoon teenoor die oorgangseffekte teenwoordig in die stelsel wat gelei het tot verminderde werksverrigting van die geïntegreerde model. Deur rekening te hou met sulke effekte kan die sub-stelsel se model waardevol wees sover dit beheerstelsel ontwikkeling aangaan, sowel as die voorspelling van die simuleerder se optrede en die daaropvolgende ontwerpsvoorstelle. Toekomstige navorsing kan fokus op die verbetering, identifikasie en integrasie van die verskeie sub-stroombaan modelle om die voorafgenoemde potensiaal ten volle ontgin.

Uma câmera pan-tilt é capaz de se movimentar em torno de dois eixos de rotação (pan e tilt), permitindo que sua lente possa ser apontada para um ponto qualquer no espaço. Uma aplicação possível dessa câmera é mantê-la apontada para um determinado alvo em movimento, através de posicionamentos angulares pan e tilt adequados. Este trabalho apresenta uma técnica de controle servo visual, em que, inicialmente, as imagens capturadas pela câmera são utilizadas para determinar a posição do alvo. Em seguida, calculam-se as rotações necessárias para manter a projeção do alvo no centro da imagem, em um sistema em tempo real e malha fechada. A técnica de rastreamento visual desenvolvida se baseia em comparação de uma região de referência, utilizando a soma dos quadrados das diferenças (SSD) como critério de correspondência. Sobre essa técnica, é adicionada uma extensão baseada no princípio de estimação incremental e, em seguida, o algoritmo é mais uma vez modificado através do princípio de estimação em multiresolução. Para cada uma das três configurações, são realizados testes para comparar suas performances. O sistema é modelado através do princípio de fluxo óptico e dois controladores são apresentados para realimentar o sistema: um proporcional integral (PI) e um proporcional com estimação de perturbações externas através de um filtro de Kalman (LQG). Ambos são calculados utilizando um critério linear quadrático e os desempenhos deles também são analisados comparativamente. / A pan-tilt camera can move around two rotational axes (pan and tilt), allowing its lens to be pointed to any point in space. A possible application of the camera is to keep it pointed to a certain moving target, through appropriate angular pan-tilt positioning. This work presents a visual servoing technique, which uses first the images captured by the camera to determinate the target position. Then the method calculates the proper rotations to keep the target position in image center, establishing a real-time and closed-loop system. The developed visual tracking technique is based on template region matching, and makes use of the sum of squared differences (SSD) as similarity criterion. An extension based on incremental estimation principle is added to the technique, and then the algorithm is modified again by multiresolution estimation method. Experimental results allow a performance comparison between the three configurations. The system is modeled through optical flow principle and this work presents two controllers to accomplish the system feedback: a proportional integral (PI) and a proportional with external disturbances estimation by a Kalman filter (LQG). Both are determined using a linear quadratic method and their performances are also analyzed comparatively.

Made available in DSpace on 2016-07-27T13:46:29Z (GMT). No. of bitstreams: 1 ROSEMARY FRANCISCA NEVES SILVA.pdf: 1742800 bytes, checksum: 180594893eef6da5b49506d72a814399 (MD5) Previous issue date: 2014-02-28 / The solidary Servant of YHWH with the slave people of Babylon has as purpose to analyze the four songs of the servant of YHWH, as memory of slavery in the Babylonic exile. It emphasizes the concept of slavery, the serch history, the figure of the Servant/slave and the conception of society, from the social context lived by the Servant/slave in the Babylonic exile. By means at analysis of the slavery category, it s possible to affirm that the exiled of the Babylonic exile were slaves because they were living in other nation, far from their temple, and from their roots. The search shows the Servant/slave figure that is presented in four servant songs of YHWH using as reference theoric to prove the hypothesis, the search history of the four Songs of the Servant of YHWH the historic critical and the controversial Reading that eneables a better comprehention of the proposal perícope (Is 42,1-4; Is 49,1-6; Is 50,4-9 and Is 52,13-53,12). In the first chapter it is presented the history of the search of the four songs, that are inserted in Deutero-Isaiah, accoveling to the hypotesis of the three Isaiah. In the second chapter are presented the songs and the exegetic analysis of every one, as well as the thems that permeate them. On the other hand, the third chapter speeaks about the Servant/slave of four songs of the Servant of YHWH in the view of the conflited Reading to evidence the quotidian of the exiled that was marked by the slavery. It shows yet the political questions, economic and socials, as well as the ethnic identity of the group of the exiled and the religious experience of them in the exile of Babylon. The fourth chapter is an hermeneutic approximation between the servant figure of the four songs and the black woman in the Brazilian colonial period, evidenced the approximations of slavey, solidarity and liberty as much the exiled from the Babylonic period as the ensloved black woman in the colonial Brazil. It is hoped that, the results of this search can be very important for future reflections and the teaching of the servant songs of YHWH, as well for its contribution in searches about slavery in exile from the four servant songs of YHWH. / O Servo de YHWH solidário com o povo escravo da Babilônia tem como intuito analisar os quatro Cantos do Servo de YHWH como memória de escravidão no exílio babilônico. Enfatiza o conceito de escravidão, a história da pesquisa, a figura do Servo/escravo e a concepção de sociedade, a partir do contexto social vivido pelo Servo/escravo no exílio babilônico. Por meio da análise da categoria escravidão, é possível afirmar que os exilados do exílio da Babilônia eram escravos porque estavam vivendo em outra nação, longe de seu templo e de suas raízes. A pesquisa mostra a figura do Servo/escravo que é apresentado nos quatro Cantos do Servo de YHWH tendo como referencial teórico, para comprovar a hipótese, a história da pesquisa dos quatro Cantos do Servo de YHWH, o método histórico-crítico e a leitura conflitual que possibilita uma melhor compreensão das perícopes propostas (Is 42,1-4; Is 49,1-6; Is 50,4-9 e Is 52,13-53,12). No primeiro capítulo apresenta-se a História da Pesquisa dos quatro Cantos, que estão inseridos no Dêutero-Isaías, segundo a hipótese dos três Isaías. No segundo capítulo são apresentados os Cantos e a análise exegética de cada um, bem como os temas que os permeiam. Já o terceiro capítulo aborda o Servo/escravo dos quatro Cantos do Servo de YHWH na ótica da leitura conflitual para evidenciar o cotidiano dos exilados que foi marcado pela escravidão. Mostra ainda as questões políticas, econômicas e sociais, bem como a identidade étnica do grupo dos exilados e a experiência religiosa destes no exílio da Babilônia. O quarto capítulo faz uma aproximação hermenêutica entre a figura do servo dos quatro Cantos e a mulher negra no período colonial brasileiro, evidenciando as aproximações de escravidão, solidariedade e libertação tanto dos exilados do período babilônico, como das mulheres negras escravizadas no Brasil colonial. Espera-se que os resultados desta pesquisa sejam relevantes para futuras reflexões e ensino dos Cantos do Servo de YHWH, bem como que deem sua contribuição nas pesquisas sobre a escravidão no exílio a partir dos quatro Cantos do Servo de YHWH.

Orientador: Luis Alberto Martinez Riascos / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-graduação em Energia.

<p>This master thesis holds a modelling in Simulink for a physical model of a main battletank tower, a three-phase induction motor and some mechanics. The aim of this work is to connect an earlier project at AerotechTelub, named StabSim to another called Eldris. In StabSim it has been made a Simulink model of the align and stabilisation system in a main battle tank 122 and in Eldris it has been build a physical model of a main battle tank tower. </p><p>In this thesis the models that differs between Eldris and a real tower is changed in StabSim, and the parts that only exist in Eldris is added, for example a torque generating system which purpose is to make the model to behave like a real tower in control application, although it only has half the inertia as a real tower. </p><p>The thesis even includes proposing a calculation of the torque that the torque generating system will actuate at the model.</p>

Recently, active suspension has been applied to many commercial automobiles. To develop the control algorithm for active suspension, a quarter-car test bed was built by using a direct-drive tubular linear brushless permanent-magnet motor (LBPMM) as a force-generating component. Two accelerometers and a linear variable differential transformer (LVDT) are used in this quarter-car test bed. Three pulse-width-modulation (PWM) amplifiers supply the currents in three phases. Simulated road disturbance is generated by a rotating cam. Modified lead-lag control, linear-quadratic (LQ) servo control with a Kalman filter, and the fuzzy control methodologies were implemented for active-suspension control. In the case of fuzzy control, asymmetric membership functions were introduced. This controller could attenuate road disturbance by up to 78%. Additionally, a sliding-mode controller (SMC) is developed with a different approach from the other three control methodologies. While SMC is developed for the position control, the other three controllers are developed for the velocity control. SMC showed inferior performance due to the drawback of the implemented chattering-proof method. Both simulation and experimental results are presented to demonstrate the effectiveness of these four control methodologies.

Single cell manipulation techniques have important applications in laboratory and clinical procedures such as intracytoplasmic sperm injection (ICSI) and polar body biopsy for preimplantation genetic diagnosis (PGD). Conventionally, manipulation of cells conducted in these procedures have been performed manually, which entails long training hours and stringent skills. Conventional single cell manipulation also has the limitation of low success rates and poor reproducibility due to human fatigue and skill variations across operators. This research focuses on the integration of computer vision microscopy and control algorithms into a system for the automation of the following single cell manipulation techniques: (1) sperm immobilization, (2) cell aspiration into a micropipette, and cell positioning inside a micropipette, and (3) rotational control of cells in three dimensions. These automated techniques eliminate the need for significant human involvement and long training. Through experimental trials on live cells, the automated techniques demonstrated high success rates.

<p>Condition Monitoring is an area that has seen substantial growth in the last few decades. The purpose for implementing condition monitoring in industry is to increase productivity, decrease maintenance costs and increase safety. Therefore, condition monitoring can be used not only for planning maintenance but also for allowing the selection of the most efficient equipment to minimize operating costs. </p><p>Hydraulic systems are widely used in industry, aerospace and agriculture and are becoming more complex in construction and in function. Reliability of the systems must be supported by an efficient maintenance scheme. Due to component wear or failure, some system parameters may change causing abnormal behaviour in each component or in the overall circuit. Research in this area has been substantial, and includes specialized studies on artificial fault simulation at the University of Saskatchewan. In this research, an axial pump was the focus of the study. In an axial piston pump, wear between the various faces of components can occur in many parts of the unit. As a consequence, leakage can occur in locations such as between the valve plate and barrel, the drive shaft and oil wiper, the control piston and piston guide, and the swash plate and slippers. In this study, wear (and hence leakage) between the pistons and cylinder bores in the barrel was of interest. Researchers at the University of Saskatchewan, as well as at other research institutions, have been involved in studies to detect wear in pumps using a variety of condition monitoring algorithms. However, to verify the reliability and indeed, limitations of some of the approaches, it is necessary to test the algorithms on systems with real leakage. To introduce actual wear in the piston of pumps can be very difficult and very expensive. Hence, introducing piston wear in an artificial manner would be of great benefit in the evaluation of various condition monitoring techniques.</p><p>Since leakage is a direct consequence of piston wear, it is logical to conclude that varying the leakage in some prescribed manner can be used to artificially simulate wear. A prime concern, therefore, is to be able to precisely understand the dynamic relationships between the wear and leakage and the effect it has on the output flow or pressure waveform from the pump.</p><p>Introducing an artificial leakage to simulate the wear of pistons is a complex task. The creation of an artificial leakage path was not simply a process of providing a resistive short to the tank at the outlet of the pump port as was done in other studies. The objective was to create a leakage environment that would simulate leakage from a single piston (or combination of several pistons thereof). The complexity of the flow and pressure ripple waveforms (which various condition monitoring algorithms did require) was such that a more comprehensive leakage behaviour had to be modeled and experimentally created. A pressure control servo valve with a very high frequency response was employed to divert the flow from the pump outlet with a prescribed waveform directly to the tank to simulate the piston leakage from the high pressure discharge chamber to the pump case drain chamber as the simulated worn piston made contact with the high pressure chamber. The control algorithm could mimic the action of a single worn piston at various degrees of wear. The experimental results indicated that the experimental system could successfully introduce artificial leakage into the pump which was quite consistent with a unit with a real worn piston. Comparisons of the pressure ripples from an actual faulty pump (worn piston) and the artificial faulty pump (artificial leakage) are presented.</p>

This master thesis holds a modelling in Simulink for a physical model of a main battletank tower, a three-phase induction motor and some mechanics. The aim of this work is to connect an earlier project at AerotechTelub, named StabSim to another called Eldris. In StabSim it has been made a Simulink model of the align and stabilisation system in a main battle tank 122 and in Eldris it has been build a physical model of a main battle tank tower. In this thesis the models that differs between Eldris and a real tower is changed in StabSim, and the parts that only exist in Eldris is added, for example a torque generating system which purpose is to make the model to behave like a real tower in control application, although it only has half the inertia as a real tower. The thesis even includes proposing a calculation of the torque that the torque generating system will actuate at the model.

<p>Condition Monitoring is an area that has seen substantial growth in the last few decades. The purpose for implementing condition monitoring in industry is to increase productivity, decrease maintenance costs and increase safety. Therefore, condition monitoring can be used not only for planning maintenance but also for allowing the selection of the most efficient equipment to minimize operating costs. </p><p>Hydraulic systems are widely used in industry, aerospace and agriculture and are becoming more complex in construction and in function. Reliability of the systems must be supported by an efficient maintenance scheme. Due to component wear or failure, some system parameters may change causing abnormal behaviour in each component or in the overall circuit. Research in this area has been substantial, and includes specialized studies on artificial fault simulation at the University of Saskatchewan. In this research, an axial pump was the focus of the study. In an axial piston pump, wear between the various faces of components can occur in many parts of the unit. As a consequence, leakage can occur in locations such as between the valve plate and barrel, the drive shaft and oil wiper, the control piston and piston guide, and the swash plate and slippers. In this study, wear (and hence leakage) between the pistons and cylinder bores in the barrel was of interest. Researchers at the University of Saskatchewan, as well as at other research institutions, have been involved in studies to detect wear in pumps using a variety of condition monitoring algorithms. However, to verify the reliability and indeed, limitations of some of the approaches, it is necessary to test the algorithms on systems with real leakage. To introduce actual wear in the piston of pumps can be very difficult and very expensive. Hence, introducing piston wear in an artificial manner would be of great benefit in the evaluation of various condition monitoring techniques.</p><p>Since leakage is a direct consequence of piston wear, it is logical to conclude that varying the leakage in some prescribed manner can be used to artificially simulate wear. A prime concern, therefore, is to be able to precisely understand the dynamic relationships between the wear and leakage and the effect it has on the output flow or pressure waveform from the pump.</p><p>Introducing an artificial leakage to simulate the wear of pistons is a complex task. The creation of an artificial leakage path was not simply a process of providing a resistive short to the tank at the outlet of the pump port as was done in other studies. The objective was to create a leakage environment that would simulate leakage from a single piston (or combination of several pistons thereof). The complexity of the flow and pressure ripple waveforms (which various condition monitoring algorithms did require) was such that a more comprehensive leakage behaviour had to be modeled and experimentally created. A pressure control servo valve with a very high frequency response was employed to divert the flow from the pump outlet with a prescribed waveform directly to the tank to simulate the piston leakage from the high pressure discharge chamber to the pump case drain chamber as the simulated worn piston made contact with the high pressure chamber. The control algorithm could mimic the action of a single worn piston at various degrees of wear. The experimental results indicated that the experimental system could successfully introduce artificial leakage into the pump which was quite consistent with a unit with a real worn piston. Comparisons of the pressure ripples from an actual faulty pump (worn piston) and the artificial faulty pump (artificial leakage) are presented.</p>