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Valle, Danilo Basseto do [UNESP]. "A influência do controlador gupfc no sistema elétrico de potência visando a estabilidade a pequenas perturbações." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/111129.
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000796071.pdf: 3231946 bytes, checksum: cd5022e624fc51b6b608afccd527ebed (MD5)<br>Neste trabalho é proposto um modelo de injeção de potência para o controlador Generalized Unified Power Flow Controller (GUPFC) que permite representá-lo em programas de fluxo de potência e fluxo de potência ótimo. Também é proposto um modelo para a estrutura do sistema de controle do GUPFC que permite representar sua dinâmica em sistemas elétricos de potência. Todas as análises dinâmicas realizadas neste trabalho visam a estabilidade a pequenas perturbações, porém, o modelo de injeção de potência do GUPFC e o modelo de sua estrutura de controle permitem representálo também em um ambiente não linear. A partir das equações algébricas fornecidas pelo modelo de injeção de potência do GUPFC e das equações dinâmicas obtidas a partir da sua estrutura do sistema de controle, é possível analisar a influência que o controlador GUPFC causa no sistema, realizando-se inicialmente uma abordagem estática (em regime permanente), que foi realizada utilizando-se a ferramenta de fluxo de potência expandido. A ferramenta de fluxo de potência expandido trata as variáveis diferenciais como algébricas, para um dado ponto de equilíbrio, ficando o problema restrito a encontrar os zeros de um conjunto de funções não-lineares, cuja solução pode ser obtida através do método de Newton-Raphson, como em um fluxo de potência convencional. Com a solução desse fluxo de potência, pode-se incluir diretamente as correspondentes submatrizes do GUPFC no Modelo de Sensibilidade de Potência (MSP), já que este foi o modelo escolhido para representação de todos os componentes dinâmicos do sistema. Com todos os componentes modelados no MSP, foi realizada uma análise dinâmica do sistema, visando a estabilidade a pequenas perturbações. Para melhorar o desempenho dinâmico do sistema, foi essencial que controladores ESPs e POD fossem inclusos às malhas de controle dos Reguladores Automáticos ...<br>This thesis proposes a power injection model for the GUPFC (Generalized Power Flow Controller) which is suited for the GUPFC representation in both power flows and optimal power flows analyses. It is also proposed a model for the control system GUPFC that represents its dynamics in electric power systems. This work main aim is the small signal stability analysis. However, the power injection model of the GUPFC and the structure control model could be used in nonlinear environment. The algebraic equations provided by the power injection model of the GUPFC and the dynamical equations obtained from the control model, are used to analyze the influence of the GUPFC on the system, initially executing a static approach (in steady state) using the expanded power flow tools. The expanded power flow considers the differential variables as algebraic, at a given equilibrium point, and the problem is to find the zeros of a nonlinear function set, whose solution can be obtained by a Newton Raphson method as in a conventional power flow. From the solution of the power flow, it is possible to include directly the corresponding sub matrices of the GUPFC in to the Power Sensitive Model (PSM), which is the chosen model to represent all the dynamic components of the system. Once, every component is modeled in the PSM, a small signal stability is performed. The ESP and POD controllers are included in to the control loop of the Automatic Voltage Regulators (AVR) and the GUPFC respectively, to improve the dynamical performance of the system. To provide additional damping to the unstable or little damped modes and increase the stability limits, a Particle Swarm Optimization (PSO) technique is used to provide the parameters of the supplementary damping controller. Two objective functions are proposed to lead the problem solution to good results and then compared to well known classical techniques
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Svensson, Andreas. "Automatic Generation of Control Code for Flexible Automation." Thesis, Linköpings universitet, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-84412.
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In order to quickly adapt the production on a production line to the demand, there is a needfor flexibility. A tool designed for this purpose, p-sop, has been developed at UniversityWest. This thesis deals with implementation of p-sop in a demonstrator, and developmentof a framework for priority policies as well as a graphical user interface to p-sop. The prioritypolicies evaluated in the demonstrator did note give an increased efficiency, and thegraphical user interface is shown to be well suited for the demonstrator and p-sop in general.
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Erikson, Lars. "Automatic Well Control Simulations." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18381.
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Every year kick incidents occur, maybe best remembered by the Macondo blowout in April 2010 resulting in devastating oil spills throughout the Gulf of Mexico. Well control is one of the most important factors in any drilling operation, preventing disastrous blowouts where people and the environment will be affected. The development of new technologies has increased significantly, lowering the risks of blowouts, mostly because of the reliability of blowout preventers. Better hardware systems have been developed and better materials has increased the performance during critical parts of an operation. There are several causes why we encounter kicks; not keeping the hole full, lost circulation, swabbing, underbalanced pressures, trapped fluids/pressures and mechanical failures. Before an actual kick, there are warning signs that might occur and knowing how to interpret positive indicators of kick is very important. Pit gain, increase in return flow rate and abnormalities in drillpipe pressure are all signs that formation fluid has entered the well. When experiencing a kick, procedures to reduce the danger and the non productive time have to be started. Firstly the well has to be shut in by either the hard shut-in method or the soft shut-in method. Then the influx has to be circulated out of the well by the use of either the Driller’s Method or the Wait and Weight Method. To better understand and visualize the behavior of formation fluid entering the well, the simulation program Drillbench Kick has been used. The soft shut-in has been compared against the hard shut-in and the Driller’s Method has been run against the Wait & Weight Method. The simulations have been performed with both oil based mud and water based mud.
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Enoiu, Eduard. "Automatic test generation for industrial control software." Doctoral thesis, Mälardalens högskola, Inbyggda system, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-33364.
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Since the early days of software testing, automatic test generation has been suggested as a way of allowing tests to be created at a lower cost. However, industrially useful and applicable tools for automatic test generation are still scarce. As a consequence, the evidence regarding the applicability or feasibility of automatic test generation in industrial practice is limited. This is especially problematic if we consider the use of automatic test generation for industrial safety-critical control systems, such as are found in power plants, airplanes, or trains. In this thesis, we improve the current state of automatic test generation by developing a technique based on model-checking that works with IEC 61131-3 industrial control software. We show how automatic test generation for IEC 61131-3 programs, containing both functional and timing information, can be solved as a model checking problem for both code and mutation coverage criteria. The developed technique has been implemented in the CompleteTest tool. To evaluate the potential application of our technique, we present several studies where the tool is applied to industrial control software. Results show that CompleteTest is viable for use in industrial practice; it is efficient in terms of the time required to generate tests that satisfy both code and mutation coverage and scales well for most of the industrial programs considered. However, our results also show that there are still challenges associated with the use of automatic test generation. In particular, we found that while automatically generated tests, based on code coverage, can exercise the logic of the software as well as tests written manually, and can do so in a fraction of the time, they do not show better fault detection compared to manually created tests. Specifically, it seems that manually created tests are able to detect more faults of certain types (i.e, logical replacement, negation insertion and timer replacement) than automatically generated tests. To tackle this issue, we propose an approach for improving fault detection by using mutation coverage as a test criterion. We implemented this approach in the CompleteTest tool and used it to evaluate automatic test generation based on mutation testing. While the resulting tests were more effective than automatic tests generated based on code coverage, in terms of fault detection, they still were not better than manually created tests. In summary, our results highlight the need for improving the goals used by automatic test generation tools. Specifically, fault detection scores could be increased by considering some new mutation operators as well as higher-order mutations. Our thesis suggests that automatically generated test suites are significantly less costly in terms of testing time than manually created test suites. One conclusion, strongly supported by the results of this thesis, is that automatic test generation is efficient but currently not quite as effective as manual testing. This is a significant progress that needs to be further studied; we need to consider the implications and the extent to which automatic test generation can be used in the development of reliable safety-critical systems.
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Fernandes, Ueslei Barbosa [UNESP]. "Controle com Estrutura Variável e Modos Deslizantes Aplicado em Sistema de Suspensão Ativa." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87150.
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fernandes_ub_me_ilha.pdf: 637735 bytes, checksum: e0ec28cfe51e61823ad56670d721ba9b (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Utilizando as técnicas de Controle com Estrutura Variável e Modos Deslizantes (CEV/MD) é proposta aqui uma aplicação das mesmas em um sistema que representa 1/4 do modelo de Suspensão Ativa de um veículo. Teoria e projeto de preditores contínuo são apresentados com o intuito de obter bom desempenho na presença de atrasos no controle ou atrasos na aquisição de dados do sistema. Com a finalidade de verificar a robustez do CEV/MD é feita uma comparação com o controle LQR (Linear Quadratic Regulator) apresentando os resultados de simulações e implementações em bancada para algumas condições de operação, levando em consideração a presença de incertezas no sistema<br>Using the techniques of Control with Variable Structure and Sliding Mode (VSC/SM) is proposed here an implementation in a system that represents 1/4 of the model of an Active Suspension of a vehicle. Theory and design of continuous predictors are presented in order to obtain good performance in the presence of control delays or delays in the data acquisition system. In order to verify the robustness of the VSC/SM a comparison with the LQR control (Linear Quadratic Regulator) in presented good results of simulations and implementations for some operating conditions, taking into account the presence of uncertainties in the system, illustrated the proposed method
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Ainscough, D. M. "Automatic control of weld penetration." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234822.
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RINALDI, FILIPPO. "Automatic control of a multirotor." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2539287.
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Objective of this thesis is to describe the design and realisation phases of a multirotor to be used for low risk and cost aerial observation. Starting point of this activity was a wide literature study related to the technological evolution of multirotors design and to the state of the art. Firstly the most common multirotor configurations were defined and, according to a size and performance based evaluation, the most suitable one was chosen. A detailed computer aided design model was drawn as basis for the realisation of two prototypes. The realised multirotors were “X-shaped” octorotors with eight coaxially coupled motors. The mathematical model of the multirotor dynamics was studied. “Proportional Integral Derivative” and “Linear Quadratic” algorithms were chosen as techniques to regulate the attitude dynamics of the multirotor. These methods were tested with a nonlinear model simulation developed in the Matlab Simulink environment. In the meanwhile the Arduino board was selected as the best compromise between costs and performance and the above mentioned algorithms were implemented using this platform thanks to its main characteristic of being completely “open source”. Indeed the multirotor was conceived to be a serviceable tool for the public utility and, at the same time, to be an accessible device for research and studies. The behaviour of the physical multirotor was evaluated with a test bench designed to isolate the rotation about one single body axis at a time. The data of the experimental tests were gathered in real time using a custom Matlab code and several indoor tests allowed the “fine tuning” of the controllers gains.
Afterwards a portable “ground station” was conceived and realised in adherence with the real scenarios users needs. Several outdoor experimental flights were executed with successful results and the data gathered during the outdoor tests were used to evaluate some key performance indicators as the endurance and the maximum allowable payload mass. Then the fault tolerance of the control system was evaluated simulating and experimenting the loss of one motor; even in this critical condition the system exhibited an acceptable behaviour.
The reached project readiness allowed to meet some potential users as the “Turin Fire Department” and to cooperate with them in a simulated emergency. During this event the multirotor was used to gather and transmit real time aerial images for an improved “situation awareness”.
Finally the study was extended to more innovative control techniques like the neural networks based ones. Simulations results demonstrated their effectiveness; nevertheless the inherent complexity and the unreliability outside the training ranges could have a catastrophic impact on the airworthiness. This is a factor that cannot be neglected especially in the applications related to flying platforms.
Summarising, this research work was addressed mainly to the operating procedures for implementing automatic control algorithms to real platforms. All the design aspects, from the preliminary multirotor configuration choice to the tests in possible real scenarios, were covered obtaining performances comparable with other commercial of-the-shelf platforms.
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Almqvist, Håkan. "Automatic bucket fill." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51490.
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<p>This report contains the first step towards a complete, fully autonomous, robust bucket fill regulator for a wheel loader working with gravel materials.</p><p>The bucket fill procedure is the most critical part of the work cycle of a wheel loader. It is a task that has a long learning curve and also is weary, even for experienced drivers. The automation of it could therefore have a big impact on the cost effectiveness for wheel loaders and for the comfort of the drivers.</p><p>In this report, a suggestion for the complete solution of an automatic bucket fill regulator is presented. A regulator prototype is also constructed with a Volvo L120F as the base. The scope for the prototype is limited to one type of gravel material and quite optimal conditions for the wheel loader, but the complete solution is kept in mind throughout the synthesis. The constructed regulator is prepared for expansion, but the implementation and field testing is limited to the scope.</p>
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Erzini, Gabriel de Castro. "Automatic control of an aquaculture system." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16545.
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Mestrado em Engenharia Mecânica<br>This thesis covers the automated aquaculture scenario around the world and
speci cally Portugal. With research done, a case study and laboratory work,
the goal is to create a reliable remote control system capable of not only
controlling the physical variables within an aquaculture system but monitor
and rectify unwanted situations.<br>Esta tese trata-se de aquacultura pelo mundo e Portugal especi camente.
Com uma pesquisa feita, um "case study" e trabalho laboratorial, o objetivo
é criar um sistema de controlo remoto capaz de controlar as variáveis físicas
dentro de um sistema de aquacultura e monitorizar e reti car situações
indesejadas.
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PICCOLI, FLAVIO. "Visual Anomaly Detection For Automatic Quality Control." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241219.
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Il controllo di qualità automatico nei processi di produzione è uno degli elementi chiave della quarta rivoluzione industriale che porterà alla creazione della cosiddetta industria 4.0. In questo contesto, un elemento fondamentale è il rilievo di difetti, anomalie o guasti del prodotto in tempo compatibile con quello di produzione. Questa tesi si focalizza esattamente su questo tema: il rilevamento delle anomalie per il controllo automatico di qualità, attraverso l'analisi di immagini raffiguranti il prodotto sotto ispezione. Questa analisi verrà fatta tramite l'utilizzo di tecniche di machine learning, in particolare tramite l'uso di reti neurali convoluzionali (CNN) che sono uno strumento molto potente utilizzato nell'analisi di immagini. In primo luogo questa tesi esegue uno studio estensivo sull'argomento per introdurre il lettore e propone una una sequenza di elaborazioni per il rilevamento automatico di anomalie. Le elaborazioni sono: 1) il miglioramento delle immagini per evidenziare i difetti; 2) il rilievo delle anomalie.
La prima elaborazione viene risolta utilizzando una trasformazione colore globale in grado di rimuovere effetti di luce indesiderati ed aumentare il contrasto. Questa trasformazione è ottenuta grazie all'utilizzo di SpliNet, un metodo basato su CNN che viene presentato in questa tesi, che è in grado di migliorare le immagini di input inferendo i parametri di un insieme di spline.
La seconda elaborazione, e cioè il rilievo di anomalie, è stata affrontata proponendo due diversi metodi. Il primo ha l'obiettivo di modellare la normalità imparando un dizionario ed utilizzandolo in fase di test per determinare il grado di abnormalità di una immagine incognita. Questo metodo è basato su CNNs, che notoriamente richiedono grandi quantità di dati per essere addestrate. Tuttavia l'algoritmo proposto è in grado di lavorare su un insieme di immagini di addestramento molto piccolo (nell'ordine delle cinque immagini). Il metodo presentato aumenta le performances rispetto allo stato dell'arte relativo al dataset delle nanofibre acquisite con microscopio SEM del 5%, ottenendo un'area sottesa alla curva di 97.4%. Il secondo metodo proposto usa un insieme di trasformazioni locali per restaurare le immagini di input. Specificamente, queste trasformazioni sono un insieme di polinomi di grado due, i cui parametri vengono determinati attraverso l'utilizzo di una rete neurale convoluzionale. Il metodo è progettato in maniera tale che è possibile, attraverso un parametro, modulare l'accuratezza e il tempo di calcolo in maniera tale da soddisfare le esigenze dell'utente finale.
Per affrontare la mancanza di dati che affligge il campo del rilievo automatico di anomalie, è stato presentato un metodo innovativo di aumento dei dati basato su deep learning. Questo metodo è in grado di generare migliaia di nuovi campioni sintetici a partire da pochi dati reali e pertanto è particolarmente adatto per aumentare dataset di tipo long-tail. La qualità dei campioni sintetizzati è stata dimostrata misurando l'accuratezza delle performance di algoritmi di machine learning addestrati sul dataset aumentato. Questo metodo è stato utilizzato per espandere un dataset di immagini raffiguranti asfalti difettosi. In questo contesto, l'utilizzo del dataset aumentato ha portato ad un incremento delle performance medie sulla segmentazione di anomalie fino a 17.5 punti percentuali. Nel caso di classi aventi bassa cardinalità, l'aumento arriva fino a 54.5 punti percentuali. Tutti i metodi presentati sovraperformano lo stato dell'arte.<br>Automatic quality control is one of the key ingredients for the fourth industrial revolution that will lead to the development of the so called industry 4.0. In this context, a crucial element is a production-compatible-time detection of defects, anomalies or product failures. This thesis focuses exactly on this theme: anomaly detection for industrial quality inspection, ensured through the analysis of images depicting the product under inspection. This analysis will be done through the use of machine learning, and especially through the use of convolutional neural networks (CNNs), a powerful instrument used in image analysis. This thesis starts with an extensive study on the subject to introduce the reader and to propose a pipeline for automatic anomaly detection. This pipeline is composed by two steps: 1) the enhancement of the input images for highlighting defects; 2) the detection of the anomalies.
The first step is addressed with the use of a global color transformation able to remove undesired light effects and to enhance the contrast. This transformation is inferred through the use of SpliNet, a new CNN-based method here presented, that is able to enhance the input images by inferring the parameters of a set of splines.
In the context of anomaly detection, two methods are presented. The first one has the aim of modeling normality by learning a dictionary and using it in test time to determine the degree of abnormality of an inquiry image. This method is based on deep learning, which is known to be data-hungry. However, the proposed algorithm is able to work also on very small trainsets (in the order of five images). The presented method boosts the performances of 5% with respect to the state-of-the art for the SEM-acquired nanofibers dataset, achieving an area under curve of 97.4%. The second proposed algorithm is a generative method able to restore the input, creating an anomaly-free version of the inquiry image. This method uses a set of local transforms to restore the input images. Specifically, these transforms are sets of polynomials of degree two, whose parameters are determined through the use of a convolutional neural network. In this context, the method can be tuned with a parameter toward accuracy or speed, for matching the needs of the final user.
To address the lack of data that is suffered in this field, a totally new method for data augmentation based on deep learning is presented. This method is able to generate thousands of new synthesized samples starting from a few and thus is particularly suitable for augmenting long-tail datasets. The quality of the synthesized samples is demonstrated by showing the increase in performance of machine learning algorithms trained on the augmented dataset. This method has been employed to enlarge a dataset of defective asphalts. In this context, the use of the augmented dataset permitted to increase the average performance on anomaly segmentation of up to 17.5 percentage points. In the case of classes having a low cardinality, the improvement is up to 54.5 percentage points. For all the methods here presented I show their effectiveness by analyzing the results with the respective state-of-the-art and show their ability in outperforming the existing methods.
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Mårtensson, Jonas. "Geometric analysis of stochastic model errors in system identification." Doctoral thesis, KTH, Reglerteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4506.
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Models of dynamical systems are important in many disciplines of science, ranging from physics and traditional mechanical and electrical engineering to life sciences, computer science and economics. Engineers, for example, use models for development, analysis and control of complex technical systems. Dynamical models can be derived from physical insights, for example some known laws of nature, (which are models themselves), or, as considered here, by fitting unknown model parameters to measurements from an experiment. The latter approach is what we call system identification. A model is always (at best) an approximation of the true system, and for a model to be useful, we need some characterization of how large the model error is. In this thesis we consider model errors originating from stochastic (random) disturbances that the system was subject to during the experiment. Stochastic model errors, known as variance-errors, are usually analyzed under the assumption of an infinite number of data. In this context the variance-error can be expressed as a (complicated) function of the spectra (and cross-spectra) of the disturbances and the excitation signals, a description of the true system, and the model structure (i.e., the parametrization of the model). The primary contribution of this thesis is an alternative geometric interpretation of this expression. This geometric approach consists in viewing the asymptotic variance as an orthogonal projection on a vector space that to a large extent is defined from the model structure. This approach is useful in several ways. Primarily, it facilitates structural analysis of how, for example, model structure and model order, and possible feedback mechanisms, affect the variance-error. Moreover, simple upper bounds on the variance-error can be obtained, which are independent of the employed model structure. The accuracy of estimated poles and zeros of linear time-invariant systems can also be analyzed using results closely related to the approach described above. One fundamental conclusion is that the accuracy of estimates of unstable poles and zeros is little affected by the model order, while the accuracy deteriorates fast with the model order for stable poles and zeros. The geometric approach has also shown potential in input design, which treats how the excitation signal (input signal) should be chosen to yield informative experiments. For example, we show cases when the input signal can be chosen so that the variance-error does not depend on the model order or the model structure. Perhaps the most important contribution of this thesis, and of the geometric approach, is the analysis method as such. Hopefully the methodology presented in this work will be useful in future research on the accuracy of identified models; in particular non-linear models and models with multiple inputs and outputs, for which there are relatively few results at present.<br>QC 20100810
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Corrado, Joseph R. "Robust fixed-structure controller synthesis." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/12945.
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Haritos, Georgios. "Automatic semi/automatic generation of software to control flexible manufacturing cells." Thesis, Staffordshire University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308911.
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Möller, Niels. "Automatic control in TCP over wireless." Licentiate thesis, KTH, School of Electrical Engineering (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-444.
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<p>Over the last decade, both the Internet and mobile telephony has become parts of daily life, changing the ways we communicate and search for information. These two distinct tools are now slowly merging. The topic of this thesis is TCP over wireless, and the automatic control that is used both within the system, from the link-layer power control to the end-to-end congestion control. It consists of three main contributions.</p><p>The first contribution is a proposed split-connection scheme for downloads to a mobile terminal. A wireless mobile terminal requests a file or a web page from a proxy, which in turn requests the data from a server on the Internet. During the file transfer, the radio network controller (RNC) sends radio network feedback (RNF) messages to the proxy. These messages include information about bandwidth changes over the radio channel, and the current RNC queue length. A novel control mechanism in the proxy uses this information to adjust the sending rate. The stability and convergence speed of the proxy controller is analyzed theoretically. The performance of the proposed controller is compared to end-to-end TCP Reno, using ns-2 simulations of realistic use cases. It is shown that the proxy control is able to reduce the response time experienced by users, and increase the utilization of the radio channel. The changes are loalized to the RNC and the proxy; no changes are required to the TCP implementation in terminal or server.</p><p>The second contribution is the analysis of an uplink channel using power control and link-layer retransmissions. To be able to design the link-layer mechanisms in a systematic way, good models for the link-layer processes, and their interaction with TCP, are essential.The use of link-layer retransmissions transforms a link with constant delay and random losses into a link with random delay and almost no losses. As seen from the TCP end points, the difference between such a link and a wired one is no longer the loss rate, but the packet delay distribution. Models for the power control and link-layer retransmissions on the link are used to derive packet delay distribution, and its impact on TCP performance is investigated.</p><p>The final contribution considers ways to optimize the link-layer processes. The main result is that TCP performance, over a wireless link with random retransmission delays, can be improved by adding carefully chosen artificial delays to certain packets. The artificial delays are optimized off-line and applied on-line. The additional delay that is applied to a packet depends only on the retransmission delay experienced by that same packet, and this information is available locally at the link.</p>
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Frylmark, Daniel, and Stefan Johnsson. "Automatic Slip Control for Railway Vehicles." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1765.
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<p>In the railway industry, slip control has always been essential due to the low friction between the wheels and the rail. In this master’s thesis we have gathered several slip control methods and evaluated them. These evaluations were performed in Matlab-Simulink on a slip process model of a railway vehicle. The objective with these evaluations were to show advantages and disadvantages with the different slip control methods. </p><p>The results clearly show the advantage of using a slip optimizing control method, i.e. a method that finds the optimal slip and thereby maximizes the use of adhesion. We have developed two control strategies that we have found superior in this matter. These methods have a lot in common. For instance they both use an adhesion observer and non-linear gain, which enables fast optimization. The difference lies in how this non-linear gain is formed. One strategy uses an adaptive algorithm to estimate it and the other uses fuzzy logic. </p><p>A problem to overcome in order to have well functioning slip controllers is the formation of vehicle velocity. This is a consequence of the fact that most slip controllers use the velocity as a control signal.</p>
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Owren, Marit. "Automatic Blood Glucose Control in Diabetes." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8974.
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<p>In this thesis, a closed-loop control algorithm for regulating the blood glucose concentration in type 1 diabetic patients is developed. Two control criteria are imposed on the system, namely: -Avoidance of hypoglycemia. (blood glucose concentrations should always be above $3 frac{mmol}{L}$) -Reduction in the average blood glucose concentration compared to what is achieved with manual control. (average blood glucose concentrations should preferably be less than $7.0 frac{mmol}{L}$). The developed control algorithm manages to fulfill both these control criteria. Hypoglycemia is avoided, and average blood glucose concentrations is reduced by $20%$ and $22%$ to a level of $7.0 frac{mmol}{L}$ and $6.9 frac{mmol}{L}$ in the two test subjects. However, further experiments should be carried out to test the robustness of the control algorithm, and a thorough investigation of safety issues for the user needs to performed. As a basis for the implementation of closed-loop blood glucose control, data from three diabetic patients is used to identify the parameters of a proposed mathematical model of the human insulin-glucose regulatory system. The identification process reveals that there is large variations between individual patient's parameter values, and the difference in insulin sensitivity is found to be specially high, both between and within patients.</p>
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Möller, Niels. "Automatic control in TCP over wireless /." Stockholm : School of Electrical Engineering, Royal Institute of Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-444.
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Boyle, Patrick Joseph. "Automatic gain control for cochlear implants." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648151.
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Andzik, Rob, and Charles (Chuck) N. Brans. "AUTOMATIC RANGE EQUIPMENT SETUP AND CONTROL." International Foundation for Telemetering, 2006. http://hdl.handle.net/10150/604137.
Full textAbstract:
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California<br>Today Ranges are faced with the typical dilemma of doing more with less—less money, less
time, and less experienced range personnel. Meanwhile, Ranges are being forced to make their
operations more efficient in use of time, money, and functionality. As a result, Ranges are
looking for automated ways to remotely configure and operate their tracking stations and to
provide interoperability between ranges, sites, and equipment.
RT Logic worked with numerous range operators and equipment vendors to create an open
software architecture that provides rapid device configuration, equipment status at a glance, and
automatic fault detection and isolation. RT Logic’s architecture utilizes the CORBA
specification to achieve extensibility and scalability for future range requirements. Adoption of
this architecture and approach will reduce costs, time, and mistakes.
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Lindhé, Magnus. "On Communication and Flocking in Multi-Robot Systems." Licentiate thesis, KTH, Automatic Control, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4526.
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<p>Coordination of multi-robot systems to improve communication and achieve flocking is the topic of this thesis. Methods are proposed for mobile autonomous robots to follow trajectories in a way that improves communications with a base station. Further, a decentralized algorithm is presented that yields flocking with obstacle avoidance.</p><p>The communication-aware trajectory tracking is adapted to radio communication in indoor environments. Our experimental data show that the effect of multipath fading, well-known in the radio communication literature, causes significant variations in the signal strength between a mobile robot and a base station. A contribution of this thesis is to formulate a tradeoff between tracking a reference trajectory and maintaining communication, first for a stationary reference position and then for a general trajectory. For the general case, the robot and an onboard communication buffer are modelled as a hybrid system, switching between standing still to communicate at positions with good signal strength and driving to catch up with the reference. This problem is solved using relaxed dynamic programming. For the case of a stationary reference position, experimental validation shows that loss of communication is avoided and that the method yields a gain in signal strength.</p><p>The algorithm for flocking is based on Voronoi partitions. They can be approximated using only local information and allow the agents to avoid collisions. Our contribution is to add obstacle avoidance and movement towards a goal by using a navigation function - a scalar potential field with exactly one local minimum at the goal. To bound the inter-agent distances and thus avoid flock dispersion, any agent on the boundary of the flock uses a mirroring mechanism to create virtual neighbors that drive it inwards. We can prove collision safety and bounded group dispersion, and simulations show reliable goal convergence even in the presence of non-convex obstacles. A version of the algorithm with lower computational complexity is also presented. It can be used for formation control and it is proven to be locally asymptotically stable for a particular case. A hierarchical control structure is proposed for implementing the flocking on non-holonomic vehicles. It has been tested on a realistic car-like robot model in a flight dynamics simulator and the results confirm that the results on safety, group dispersion and goal convergence apply also in this case.</p>
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Hu, Wenshan. "Design of networked control systems and global Web-based control laboratory." Thesis, University of South Wales, 2008. https://pure.southwales.ac.uk/en/studentthesis/design-of-networked-control-systems-and-global-webbased-control-laboratory(0c8a2649-120a-494f-a887-defcaceed570).html.
Full textAbstract:
This thesis mainly focuses on two Internet based control applications. One is a networked control system (NCS) where the control loop is closed through the network. The other is the Networked Control System Laboratory (NCSLab) which is a global web based remote experimentation platform. The contribution in the first part of the thesis relates to the networked predictive control (NPC) which was first introduced by Liu et al. (2004). In this method, the controller uses the model predictive approach to predict a future control sequence and send it to the plant in a network packet. The plant side receives this packet and then determine the appropriate control signal to apply to the actuator according to the time delay measurement. This method is innovative and works well in theory, but it has two deficiencies in practical applications. The first deficiency is that it needs synchronization between the controller and plant side to measure the individual forward and feedback channel time delays and this is very hard to achieve on the Internet. In this thesis, a round-trip NPC is proposed in which the predictive calculations and signal selections are based on the round-trip delay. The measurement of the round-tip delay is achieved using the plant side clock only, so that the need for synchronization is avoided. The second deficiency is that the mathematical model has to be accurately known. Otherwise the accuracy of the predictive calculation is affected, which may result in a degraded control performance. An event-driven NPC scheme is introduced to solve this problem. In this scheme, the selection of the appropriate control signal is not based on the time delay measurement but on the previous system output. This method can compensate for the effect of model uncertainty, which has been verified by both simulations and real-time experiments. Some experiments carried out on other NPC schemes are also reported on in this thesis. They are the NPC in state-space form and nonlinear NPC. These methods expand the use of NPC methodology. The second part of the thesis describes the design and implementation of the Networked Control System Laboratory. The NCSLab is based in the University of Glamorgan but its test rigs are diversely located in four Institutions from both the UK and China. In order to manage these test rigs from different places, a four layer structure (Central Server/Regional Server/Sub-Server/Test Rig) is adopted. The four layers are integrated into one system via the Internet. In order to deliver the remote experimentation to the users, a web-based user interface is designed. It provides great flexibility to the users such as remote monitoring, remote tuning and remote control algorithms. The implementation of the user interface (UI) heavily adopts the AJAX technology, so the remote experiments can be conducted inside the web browsers without installing special plug-ins. In order to show how the NCSLab works, two examples are given in the thesis.
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Soto, Pereyra Herbert [UNESP]. "Detecção robusta de falhas através de filtros H ‘infinito': implementação prática em um helicóptero 3-DOF de bancada e em um servosistema." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87076.
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Made available in DSpace on 2014-06-11T19:22:32Z (GMT). No. of bitstreams: 0
Previous issue date: 2013-08-23Bitstream added on 2014-06-13T18:07:12Z : No. of bitstreams: 1
000739809.pdf: 4366704 bytes, checksum: 7b91676847d065a319125291de36dfeb (MD5)<br>Neste trabalho foi aplicado um método para detecção de falhas utilizando-se filtros H'infinito', no helicóptero de bancada 3-DOF e no servomotor Shake table II, equipamentos da Quanser R . Para o helicóptero foram impostos dois tipos de falhas. No primeiro caso, foi projetado um filtro H'infinito' para a detecção de falha no motor traseiro da aeronave. No segundo caso, foi projetado um filtro H'infinito' para a detecção de falhas no sensor do ângulo de viagem, considera-se ainda que o modelo do helicóptero possui uma incerteza do tipo politópica. Nos dois casos, o helicóptero também está sujeito a uma perturbação exógena. Para o servomotor Shake table II foi projetado um filtro H'infinito' para a detecção de falha no atuador. A metodologia se mostra eficiente na prática para os tipos de falhas impostas.<br>In this work, it was implemented a method for fault detection via H'infinit' filters in a 3-DOF helicopter model and a servomotor Shake table II, facilities from Quanser R . For the helicopter were imposed two types of faults. In the first case, an H'infinit' filter was designed for the fault detection in the back motor of the aircraft. In the second case, an H'infinit' filter was designed for the fault detection in the sensor travel angle, also considering that the helicopter model has a polytopic uncertainty. In both cases, the helicopter is also subjected to an exogenous disturbance. For the servomotor Shake table II an H'infinit' filter was designed for the fault detection in the actuator. The methodology was efficient for these faults imposed.
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Al, Seyab Rihab Khalid Shakir. "Nonlinear model predictive control using automatic differentiation." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1491.
Full textAbstract:
Although nonlinear model predictive control (NMPC) might be the best choice for a
nonlinear plant, it is still not widely used. This is mainly due to the computational
burden associated with solving online a set of nonlinear differential equations and a
nonlinear dynamic optimization problem in real time. This thesis is concerned with
strategies aimed at reducing the computational burden involved in different stages
of the NMPC such as optimization problem, state estimation, and nonlinear model
identification.
A major part of the computational burden comes from function and derivative evaluations
required in different parts of the NMPC algorithm. In this work, the problem is
tackled using a recently introduced efficient tool, the automatic differentiation (AD).
Using the AD tool, a function is evaluated together with all its partial derivative from
the code defining the function with machine accuracy.
A new NMPC algorithm based on nonlinear least square optimization is proposed.
In a first–order method, the sensitivity equations are integrated using a linear formula
while the AD tool is applied to get their values accurately. For higher order
approximations, more terms of the Taylor expansion are used in the integration for
which the AD is effectively used. As a result, the gradient of the cost function against
control moves is accurately obtained so that the online nonlinear optimization can be
efficiently solved.
In many real control cases, the states are not measured and have to be estimated for
each instance when a solution of the model equations is needed. A nonlinear extended
version of the Kalman filter (EKF) is added to the NMPC algorithm for this purpose.
The AD tool is used to calculate the required derivatives in the local linearization
step of the filter automatically and accurately.
Offset is another problem faced in NMPC. A new nonlinear integration is devised
for this case to eliminate the offset from the output response. In this method, an integrated disturbance model is added to the process model input or output to correct
the plant/model mismatch. The time response of the controller is also improved as a
by–product.
The proposed NMPC algorithm has been applied to an evaporation process and a
two continuous stirred tank reactor (two–CSTR) process with satisfactory results to
cope with large setpoint changes, unmeasured severe disturbances, and process/model
mismatches.
When the process equations are not known (black–box) or when these are too complicated
to be used in the controller, modelling is needed to create an internal model for
the controller. In this thesis, a continuous time recurrent neural network (CTRNN)
in a state–space form is developed to be used in NMPC context. An efficient training
algorithm for the proposed network is developed using AD tool. By automatically
generating Taylor coefficients, the algorithm not only solves the differentiation equations
of the network but also produces the sensitivity for the training problem. The
same approach is also used to solve online the optimization problem of the NMPC.
The proposed CTRNN and the predictive controller were tested on an evaporator
and two–CSTR case studies. A comparison with other approaches shows that the
new algorithm can considerably reduce network training time and improve solution
accuracy.
For a third case study, the ALSTOM gasifier, a NMPC via linearization algorithm is
implemented to control the system. In this work a nonlinear state–space class Wiener
model is used to identify the black–box model of the gasifier. A linear model of the
plant at zero–load is adopted as a base model for prediction. Then, a feedforward
neural network is created as the static gain for a particular output channel, fuel gas
pressure, to compensate its strong nonlinear behavior observed in open–loop simulations.
By linearizing the neural network at each sampling time, the static nonlinear
gain provides certain adaptation to the linear base model. The AD tool is used here
to linearize the neural network efficiently. Noticeable performance improvement is
observed when compared with pure linear MPC. The controller was able to pass all
tests specified in the benchmark problem at all load conditions.
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Rioual, Jean-Luc. "The automatic control of boundary layer transition." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259625.
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HERMANN, RODRIGO DE PROENCA GOMES. "AUTOMATIC CAMERA CONTROL IN VIRTUAL DYNAMIC ENVIRONMENTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7646@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>Com o avanço do poder de processamento gráfico e a
popularização dos
jogos eletrônicos, começam a surgir novas formas de
entretenimento, entre
elas a de espectadores de jogos. Os requisitos para o
posicionamento de
câmera para os espectadores visualizarem os jogos são
diferentes dos aplicados
aos jogadores. Enquanto a câmera para os jogadores deve
atender
a requisitos de jogabilidade, a câmera para os
espectadores deve explorar
diferentes ângulos de visualização a fim de aumentar a
imersão no ambiente
dos jogos e explorar a emoção das cenas. O cinema já
evoluiu toda uma
linguagem cinematográfica que potencializa a interpretação
de cenas. Pesquisas
recentes procuram usar a cinematografia na visualização de
jogos.
O principal desafio na adaptação da cinematografia para os
jogos reside na
existência de um ambiente dinâmico, onde não se pode
prever o andamento
da história. Podemos identificar três módulos para a
adaptação da cinematografia
em jogos: roteirista, responsável por identificar o que
está ocorrendo
na cena; diretor/editor, responsável por definir as
melhores tomadas para
capturar a cena; cinegrafista, responsável por posicionar
a câmera no ambiente
dinâmico para melhor atender às demandas do módulo
diretor/editor.
Este trabalho propõe a implementação de um módulo
cinegrafista. A partir
de requisitos para o posicionamento da câmera oriundos de
um módulo externo,
propõe-se um modelo de câmera que faz o posicionamento
automático
da câmera. Os requisitos de posicionamento são expressos
em um conjunto
de restrições que devem ser atendidas pelo modelo de
câmera. A câmera
usa um modelo físico baseado em um sistema de partículas
regido pelo
método de Verlet, empregando o método de relaxação para a
convergência
do sistema a fim de atender às restrições impostas.
Experimentos computacionais
demonstram a capacidade do módulo proposto de atender a
sofisticadas
regras de posicionamento de câmera, baseando-se em
composições
de restrições simples. Princípios da cinematografia, como
enquadramento,
posicionamento e movimento de câmeras, e respeito à linha
de ação, são
facilmente respeitados pelo módulo proposto.<br>With the evolution in graphics processing power and the
popularization
of electronic games, new forms of entertainment, such as
being a game
spectator. The requirements for positioning the camera for
the spectators
to view the games are different from those applied to
players. The camera
for the players must fulfill playability requirements,
while the camera for
the spectators must explore different viewing angles in
order to increase
the immersion in the game environment and to explore the
thrill of the
scenes. The cinema has evolved a whole cinematographic
language that
optimizes the scene interpretation. Recent research has
been seeking to
apply cinematography to game visualization. The main
challenge in the
adaptation of the cinematographic language for games lies
in the existence of
a dynamic environment in which the story`s progress cannot
be anticipated.
Three modules can be identified to adopt the
cinematographic language in
games: screenwriter, responsible for identifying what is
happening in the
scene; director/editor, responsible for defining the best
takes to capture the
scene; and cinematographer, responsible for positioning
the camera in the
dynamic environment to better comply with the
director/editor`s demands.
The present work proposes the implementation of a
cinematographer module.
Based on camera position requirements obtained from an
external module,
we propose a camera model that automatically positions the
camera.
The positioning requirements are expressed by a set of
constraints that must
be respected by the camera model. The camera uses a
physical model based
on a particle system oriented by Verlet`s method, and
employs the relaxation
method to obtain the system`s convergence in order to
comply with imposed
constraints. Computational experiments have demonstrated
the capacity of
the proposed module to comply with sophisticated camera
positioning rules
based on compositions of simple constraints.
Cinematography principles
such as framing, camera position and movement, and
respecting the line of
action are easily accomplished by the proposed module.
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Runde, Jeffrey K. "Modelling and control of an automatic transmission." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15030.
Full textAbstract:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING<br>Includes bibliographical references.<br>by Jeffrey K. Runde.<br>M.S.
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Khan, Irshad. "Automatic frequency control of an induction furnace." Thesis, Cape Technikon, 2000. http://hdl.handle.net/20.500.11838/1092.
Full textAbstract:
Thesis (MTech(Electrical engineering))--Cape Technikon, Cape Town, 2000<br>The development of an automatic frequency control system for a miniature high
frequency induction furnace is described.
A background study into the fields of induction-heating, resonance, power electronic
resonant converters and phase locked-loops are performed with relevance to this
research. An analysis of the resonant load circuit is performed by means of a
combination of measurement and numerical simulations. The study of the load
behavior and power source is used as a :001 to aid effective implementation of the
automatic frequency control system. This Jimulation data is used to detenninc the
operating frequency range of the RLL system.
A background study is performed in whieh several frequency-control schemes for
power electronic converters are investigated. A brief summary, in which the basic
requirements for a frequency control system with regards to this research are
presented.
Two revisions of the Automatic Frequency Control system (RLL) were implemented,
on the induction furnace. Experimental results on both systems (Revl and Rev2),
illustrating the necessity for frequency control are also presented.
Future suggestions for optimizing the loop performance are presented. Further steps in
the developmental process of the miniature high frequencj induction furnace are also
discussed.
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Valle, Danilo Basseto do. "A influência do controlador gupfc no sistema elétrico de potência visando a estabilidade a pequenas perturbações /." Ilha Solteira, 2014. http://hdl.handle.net/11449/111129.
Full textAbstract:
Orientador: Percival Bueno de Araujo<br>Banca: Dilson Amancio Alves<br>Banca: Laurence Duarte Colvara<br>Banca: Igor Kopcak<br>Banca: Carlos Roberto Mendonça da Rocha<br>Resumo: NESTE trabalho é proposto um modelo de injeção de potência para o controlador Generalized Unified Power Flow Controller (GUPFC) que permite representá-lo em programas de fluxo de potência e fluxo de potência ótimo. Também é proposto um modelo para a estrutura do sistema de controle do GUPFC que permite representar sua dinâmica em sistemas elétricos de potência. Todas as análises dinâmicas realizadas neste trabalho visam a estabilidade a pequenas perturbações, porém, o modelo de injeção de potência do GUPFC e o modelo de sua estrutura de controle permitem representálo também em um ambiente não linear. A partir das equações algébricas fornecidas pelo modelo de injeção de potência do GUPFC e das equações dinâmicas obtidas a partir da sua estrutura do sistema de controle, é possível analisar a influência que o controlador GUPFC causa no sistema, realizando-se inicialmente uma abordagem estática (em regime permanente), que foi realizada utilizando-se a ferramenta de fluxo de potência expandido. A ferramenta de fluxo de potência expandido trata as variáveis diferenciais como algébricas, para um dado ponto de equilíbrio, ficando o problema restrito a encontrar os zeros de um conjunto de funções não-lineares, cuja solução pode ser obtida através do método de Newton-Raphson, como em um fluxo de potência convencional. Com a solução desse fluxo de potência, pode-se incluir diretamente as correspondentes submatrizes do GUPFC no Modelo de Sensibilidade de Potência (MSP), já que este foi o modelo escolhido para representação de todos os componentes dinâmicos do sistema. Com todos os componentes modelados no MSP, foi realizada uma análise dinâmica do sistema, visando a estabilidade a pequenas perturbações. Para melhorar o desempenho dinâmico do sistema, foi essencial que controladores ESPs e POD fossem inclusos às malhas de controle dos Reguladores Automáticos ...<br>Abstract: THIS thesis proposes a power injection model for the GUPFC (Generalized Power Flow Controller) which is suited for the GUPFC representation in both power flows and optimal power flows analyses. It is also proposed a model for the control system GUPFC that represents its dynamics in electric power systems. This work main aim is the small signal stability analysis. However, the power injection model of the GUPFC and the structure control model could be used in nonlinear environment. The algebraic equations provided by the power injection model of the GUPFC and the dynamical equations obtained from the control model, are used to analyze the influence of the GUPFC on the system, initially executing a static approach (in steady state) using the expanded power flow tools. The expanded power flow considers the differential variables as algebraic, at a given equilibrium point, and the problem is to find the zeros of a nonlinear function set, whose solution can be obtained by a Newton Raphson method as in a conventional power flow. From the solution of the power flow, it is possible to include directly the corresponding sub matrices of the GUPFC in to the Power Sensitive Model (PSM), which is the chosen model to represent all the dynamic components of the system. Once, every component is modeled in the PSM, a small signal stability is performed. The ESP and POD controllers are included in to the control loop of the Automatic Voltage Regulators (AVR) and the GUPFC respectively, to improve the dynamical performance of the system. To provide additional damping to the unstable or little damped modes and increase the stability limits, a Particle Swarm Optimization (PSO) technique is used to provide the parameters of the supplementary damping controller. Two objective functions are proposed to lead the problem solution to good results and then compared to well known classical techniques<br>Doutor
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Kaya, Muammer. "The effect of air flow rate and froth thickness on batch and continuous flotation kinetics /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63358.
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Fitzsimons, Philip Matthew. "Design of a helicopter automatic flight control system using adaptive control." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/16641.
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Saifuddin, Anita B. "Computing environments for control engineering." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/272698.
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Wahlström, Johan. "Control of EGR and VGT for Emission Control and Pumping Work Minimization in Diesel Engines." Doctoral thesis, Linköpings universitet, Fordonssystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18484.
Full textAbstract:
Legislators steadily increase the demands on lowered emissions from heavy duty vehicles. To meet these demands it is necessary to integrate technologies like Exhaust Gas Recirculation (EGR) and Variable Geometry Turbochargers (VGT) together with advanced control systems. Control structures are proposed and investigated for coordinated control of EGR valve and VGT position in heavy duty diesel engines. Main control goals are to fulfill the legislated emission levels, to reduce the fuel consumption, and to fulfill safe operation of the turbocharger. These goals are achieved through regulation of normalized oxygen/fuel ratio and intake manifold EGR-fraction. These are chosen as main performance variables since they are strongly coupled to the emissions. To design successful control structures, a mean value model of a diesel engine is developed and validated. The intended applications of the model are system analysis, simulation, and development of model-based control systems. Dynamic validations show that the proposed model captures the essential system properties, i.e. non-minimum phase behaviors and sign reversals. A first control structure consisting of PID controllers and min/max-selectors is developed based on a system analysis of the model. A key characteristic behind this structure is that oxygen/fuel ratio is controlled by the EGR-valve and EGR-fraction by the VGT-position, in order to handle a sign reversal in the system from VGT to oxygen/fuel ratio. This structure also minimizes the pumping work by opening the EGR-valve and the VGT as much as possible while achieving the control objectives for oxygen/fuel ratio and EGR-fraction. For efficient calibration an automatic controller tuning method is developed. The controller objectives are captured by a cost function, that is evaluated utilizing a method choosing representative transients. Experiments in an engine test cell show that the controller achieves all the control objectives and that the current production controller has at least 26% higher pumping losses compared to the proposed controller. In a second control structure, a non-linear compensator is used in an inner loop for handling non-linear effects. This compensator is a non-linear state dependent input transformation. PID controllers and selectors are used in an outer loop similar to the first control structure. Experimental validations of the second control structure show that it handles nonlinear effects, and that it reduces EGR-errors but increases the pumping losses compared to the first control structure. Substantial experimental evaluations in engine test cells show that both these structures are good controller candidates. In conclusion, validated modeling, system analysis, tuning methodology, experimental evaluation of transient response, and complete ETC-cycles give a firm foundation for deployment of these controllers in the important area of coordinated EGR and VGT control.
33
Neads, Stephen John. "Automatic assembly of versatile fixtures." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373386.
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Fallgren, Henrik, and Viktor Uvesten. "Modeling and Automatic Control of a Seedbed Tine Harrow." Thesis, Linköpings universitet, Reglerteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-179031.
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The agricultural industry is facing a major technological change with autonomousvehicles in focus. This follows the global trend, where the interest lies in increas-ing production, while reducing costs with the help of automation. Consideringthe vast amount of different agricultural machines on the market today, the pro-cess of automating these machines is long and needs to start on one machine.This thesis covers the process of developing an automatic control system for aseedbed tine harrow. The seedbed tine harrow cultivates the soil at a certain depth in preparationfor planting. The different functions on the harrow are today manually controlledfrom the cab of the tractor, which means that the farmer must constantly moni-tor the process. The proposed control system uses radar sensors to measure andhydraulic systems to control the harrowing depth and the crossboards. The de-velopment of the control system consists of modeling the harrow, creating a sim-ulation environment, choosing a filtering strategy, and testing different controlalgorithms. The resulting control algorithm, implemented and tested on the harrow, con-sisted of a Kalman filter with separate PD-controllers for each function, the har-rowing depth, and the angle of the crossboards. The crossboard controllers usean additional feedforward control from measured disturbance. The thesis alsoexplores a set of experimental control algorithms, for instance, cascade control.These are not possible to implement on this generation of the harrow but showpromising potential from simulation.
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饒勇 and Yong Rao. "The astronomical observation system of 12" telescope: its automatic control system and astronomical application." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214587.
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Gunbatar, Yakup Rokhsaz Kamran. "Automatic airspace avoidance using advanced flight control system." Diss., A link to full text of this thesis in SOAR, 2006. http://soar.wichita.edu/dspace/handle/10057/648.
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Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.<br>"December 2006." Title from PDF title page (viewed on Oct 31, 2007). Thesis adviser: Kamran Rokhsaz. Includes bibliographic references (leaves 92-94).
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Wolfe, Douglas E. "Airplane dynamic modeling and automatic flight control design." Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-01202010-020132/.
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Lim, Wang Kyu. "Control algorithms for unit-load automatic guided vehicles." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/25310.
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Pomprapa, Anake [Verfasser]. "Automatic Control of Artificial Ventilation Therapy / Anake Pomprapa." Aachen : Shaker, 2015. http://d-nb.info/1071527940/34.
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Newell, John B. "Automatic control of straightline motions of towed vessels." Thesis, Monterey, California. Naval Postgraduate School, 1990. http://hdl.handle.net/10945/30704.
Full textAbstract:
Approved for public release, distribution is unlimited<br>A classical control system with a full-order observer is designed to stabilize the motions of towed vessels. The control method is transverse movement of the towline attachment point on the towed vessel. The linearized sway and yaw equations of motion are developed, leading to the control system design. The control system is tested using MATRIX. Results for a barge, mariner-class ship and a tanker are presented. Possible benefits of the implementation of such a system include improved fuel economy, a wider range of environmental conditions during which towing operations can be conducted, and improved safety.
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Rostbakken, Olaf. "Automatic frequency tuning control of microstrip patch antennas." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389137.
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Ahmad, Shah Shahrul. "Improved autogyro flying qualities using automatic control methods." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/39052/.
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An autogyro or Autogiro is a unique type of rotary-wing aircraft that was successfully flown in the 1920s, many years before the first helicopter came to service. As far as the rotorcraft technology is concerned, the technical issues addressed by autogyros were eventually rectified and paved the way for the success of helicopter development. When helicopter became more popular and accepted in the civil aviation industry in the 1940s, autogyros were nearly forgotten and the popularity slowly diminished. The re-emergence of autogyros in the last two decades in hobby and sports flight activities, however, coincides with bad safety records due to stability issues. At the time of this writing, there are no specific flying qualities standards to be em- ployed as guidelines to design a light autogyro with good stability attributes. The only requirements available are addressed in the BCAR Section T airworthiness standard for light autogyros which only prescribes some basic dynamic stability requirements for the vehicle. For existing conventional light autogyros which mostly of 'home-built' type, complying with the airworthiness standards would be an issue as most of them were built beforehand. From these concerns, this Thesis aims to improve the flying qualities performance of existing light autogyros through automatic flight control methods, as one of the ways to practically achieve the required performance. Consequently, specific flying qualities requirements for light autogyros must first be proposed as preliminary guidelines for design and flying qualities improvement. A generic mathematical model of light autogyros named ARDiS is developed based on the 'multiblade' simulation ap- proach which is computationally cost-effective. This model was successfully validated against real autogyro flight data and later implemented in the control enhancement of the vehicle. The control enhancement was developed using classical approaches with limitation in size and simplicity of the vehicle as a light aircraft. Proper actuation control hard- ware was separately modelled and deployed into the autogyro to demonstrate a higher dynamics in the control mechanism so that a more realistic attitude behaviour of the vehicle is presented. This control enhancement was successfully evaluated with both, linear and nonlinear simulations according to the proposed autogyro flying qualities attributes. All presented results signify a higher possibility of improving the flying qualities of currently used and future built light autogyros through control enhance- ment.
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Buchner, Denzil. "Automatic control of commercial airliners in formation flight." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96963.
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Thesis (MEng)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: This thesis presents research contributing towards the automatic control of formation
flight for commercial
airliners. The motivation behind this research is to ultimately reduce fuel consumption of the trailing
airliner through the utilisation of the aerodynamic coupling interactions between the trailing airliner and
the wake vortices of the leading airliner.
A traditional model for an airliner in isolated
flight is developed and expanded to include formation
flight interactions as functions of the vertical and lateral separation between the trailing and leading
airliners. A trim analysis is done, and resulting actuator trims are presented over ranges of lateral and
vertical separation. Regions of reduced throttle setting are identified, as well as risks and challenges for
maintaining formation within these regions. These regions comprise of a potentially risky and challenging
region, coined the "sandwich region"; as well as a safer, more practically viable region, coined the "outer
region". The former is a narrow region sandwiched between two regions that are untrimmable with respect
to maximum aileron deflection,
whereas the latter is only constrained by an inboard untrimmable bound,
but has less significant drag reduction.
Subsequently, a state space representation is constructed, and a linear dynamics analysis follows. It is
determined that the trimmed, uncontrolled trailing airliner is naturally unstable; hence a
flight control
system is required for stability. Furthermore, the analysis revealed that the dynamics stay essentially
constant, especially for conventional modes, within the outer region. In the sandwich region however, the
dynamics change much more drastically.
Next, a control system for the conventional airliner is designed based on the available information of
current representative
fly-by-wire systems; and its performance is analysed in formation
flight scenarios
by means of both linear and non-linear simulations. It is found that, given sufficiently high control
law gains, particularly for lateral controllers, the conventional architecture is sufficient for maintaining
formation. Additional structures are suggested, such as saturation elements to limit the lateral separation
rate and acceleration; and a state machine controller, with states for entering and exiting the wake vortices.
Following this, a robustness analysis was done by once again evaluating the linear dynamics over ranges
of lateral and vertical separation; this time with the
flight controllers augmented into the linear models.
The robustness analysis proved that the controllers are robust against lateral and vertical separation
perturbation, at least in the outer region.
Finally, a series of non-linear simulations prove the success of the control system in maintaining formation
in various atmospheric turbulence conditions. Furthermore, the trailing airliner consistently has a reduced
throttle setting, though with greater dynamic throttling compared to the leading airliner. Lastly, it is
determined that the standard deviations of the control surface defection
of the trailing airliner are in
the same order of magnitude as those of the leading airliner in simulations with moderate turbulence.
Interestingly, it is found that the elevator deflection
of the trailing airliner has a lower standard deviation
than that of the leading airliner, possibly due to the leading airliner carrying the burden of regulating the
formation's altitude.<br>AFRIKAANSE OPSOMMING: Hierdie tesis handel oor navorsing wat 'n bydrae maak tot die outomatiese vlugbeheer van kommersiële
passasiersvliegtuie in formasievlug. Die navorsing is gemotiveer deur die potensiële vermindering in die
brandstofverbruik van die volgervliegtuig wat verkry kan word deur voordeel te trek uit die aerodinamiese
koppeling tussen die volgervliegtuig en die nasleurvortekse van die voorste vliegtuig.
'n Tradisionele vlugmeganika model vir 'n passasiersvliegtuig is ontwikkel en uitgebrei om formasievluginteraksies
in te sluit, as funksies van die vertikale en laterale skeidingsafstande tussen die volgervliegtuig
en die voorste vliegtuig. 'n Ewewig-analise is uitgevoer, en die nodige ewewig-instellings is bereken oor
die bereik van moontlike laterale en vertikale skeidingsafstande. Twee gebiede van verminderde enjin-krag
instellings is gedentifiseer, en die risikos en uitdagings verbonde aan formasievlug in hierdie gebiede is
beskou. Twee gebiede is uitgeken: 'n uitdagende, potensieel gevaarlike gebied, genoem die "sandwich" of
"ingeperkte" gebied; en 'n veiliger, meer lewensvatbare gebied, genoem die "outer" of buitenste gebied.
Die "ingeperkte" gebied is 'n baie nou gebied wat ingedruk is tussen twee ewewig-oninstelbare gebiede,
waar aileron de
eksie instellings vereis word wat die maksimum moontlike de
eksies oorskry. Die "buitenste"
gebied is 'n gebied wat net aan die binnekant begrens word deur 'n ewewig-oninstelbare gebied, maar
wat nie so 'n groot besparing in brandstofverbruik bied as die "ingeperkte" gebied nie.
Vervolgens is 'n toestandsveranderlike voorstelling van die vlugdinamika afgelei, en 'n dinamiese analise
is uitgevoer. Die dinamiese analise het gewys dat die ewewig-ingestelde, onbeheerde vliegtuig natuurlik
onstabiel is, en dat 'n vlugbeheerstelsel benodig word om vlugstabiliteit te verseker. Daarby het die
analise ook onthul dat die vlugdinamika baie min verander oor die bereik van die "buitenste" gebied,
maar dat die vlugdinamika baie meer drasties verander oor die bereik van die "ingeperkte" gebied.
'n Konvensionele vlugbeheerstelsel vir die vliegtuig is volgende ontwerp, gebaseer op beskikbare inligting
oor die argitektuur van tipiese
"fly-by-wire" beheerstelsels wat tans op passasiersvliegtuie gebruik word.
Die prestasie van die konvensionele vlugbeheerstelsel in formasievlugtoestande is ontleed deur middel van
beide lineêre en nie-lineêre simulasies. Die simulasies het gewys dat die konvensionele vlugbeheerargitektuur
in staat is om formasievlug te handhaaf, gegee dat voldoende hoë beheeraanwinste gebruik word.
Bykomende strukture is voorgestel, insluitendend versadigingselemente om die koers en versnelling van
die laterale skeidingsafstand te beperk; en 'n toestandsmasjien-beheerder, met toestande om die nasleurvortekse
binne te gaan en te verlaat. 'n Robuustheidsanalise is ook gedoen, deur die geslotelusdinamika
met die beheerders ingesluit te analiseer oor die bereik van laterale en vertikale skeidingsafstande. Die
robuustheidsanalise het gewys dat die beheerders wel robuust is oor die bereik van beide laterale en
vertikale skeidingsafstande, ten minste in die "buitenste" gebied.
Ten slotte is 'n omvattende reeks nie-lineêre simulasies uitgevoer om die vermoë van die vlugbeheerstelsel
om formasievlug te behou te bevestig in 'n verskeidenheid van turbulensietoestande. Die simulasies het
verder gewys dat die volgervliegtuig deurgaans 'n verminderde enjin-krag instelling het, maar met aansienlik
meer dinamiese enjin-krag instelling variasies vergeleke met die voorste vliegtuig. Laastens het
die simulasies gewys dat die standaard afwykings van die volgervliegtuig se beheeroppervlakde
eksies van
dieselfde ordegrootte is as dié van die voorste vliegtuig. Interessant genoeg is bevind dat die elevator defleksies
van die volgervliegtuig 'n laer standaardafwyking het as dié van die voorste vliegtuig, waarskynlik
omdat die voorste vliegtuig die groter las dra om die formasie se hoogte te reguleer.
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Dysenius, Hannah. "Non-Linear Automatic Control of Autonomous Lawn Mower." Thesis, Linköpings universitet, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129116.
Full textAbstract:
This master thesis contains modeling and nonlinear automatic control of an autonomous lawn mower. The vehicle shall be able to follow a magnetic field loop buried in the lawn on an arbitrary distance, including straddling. A unicycle model of the lawn mower has been derived based on previous work. The model holds for the assumption of non slip environment. Two diff erent control strategies have been implemented and evaluated in this thesis. One is based on feedback linearization and with the feedback gain estimated using an LQ-controller. The other strategy is based on linearization at an equilibrium point and also with the use of an LQ-controller. The only state that can be measured is the distance to the magnetic loop. In order to estimate the other states, an observer has been implemented using the linearized in an equilibrium point model and a Kalman filter. The navigation of the autonomous lawn mower is performed using a magnetic loop buried in the lawn. The non-linearity of the magnetic field causes diffi culties when estimating the distance to the loop. One magnetic field strength corresponds to two distances to the magnetic loop. The nature of the magnetic field and the measurement noise causes the precision of the controller to be limited. The conclusion of this master thesis is that it is possible to navigate and follow the magnetic loop at a distance greater than 0.3 [m], but with overshoots during sharp turns. If the reference distance is smaller than that, the behavior of the robot will be oscillating when following the loop. The limitations of the controller performance is due to the lack of information which can be extracted from the measurements of the magnetic field.
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Hart, John K. "Automatic control program creation using concurrent Evolutionary Computing." Thesis, Bournemouth University, 2004. http://eprints.bournemouth.ac.uk/394/.
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Over the past decade, Genetic Programming (GP) has been the subject of a significant amount of research, but this has resulted in the solution of few complex real -world problems. In this work, I propose that, for some relatively simple, non safety -critical embedded control applications, GP can be used as a practical alternative to software developed by humans. Embedded control software has become a branch of software engineering with distinct temporal, interface and resource constraints and requirements. This results in a characteristic software structure, and by examining this, the effective decomposition of an overall problem into a number of smaller, simpler problems is performed. It is this type of problem amelioration that is suggested as a method whereby certain real -world problems may be rendered into a soluble form suitable for GP. In the course of this research, the body of published GP literature was examined and the most important changes to the original GP technique of Koza are noted; particular focus is made upon GP techniques involving an element of concurrency -which is central to this work. This search highlighted few applications of GP for the creation of software for complex, real -world problems -this was especially true in the case of multi thread, multi output solutions. To demonstrate this Idea, a concurrent Linear GP (LGP) system was built that creates a multiple input -multiple output solution using a custom low -level evolutionary language set, combining both continuous and Boolean data types. The system uses a multi -tasking model to evolve and execute the required LGP code for each system output using separate populations: Two example problems -a simple fridge controller and a more complex washing machine controller are described, and the problems encountered and overcome during the successful solution of these problems, are detailed. The operation of the complete, evolved washing machine controller is simulated using a graphical LabVIEWapplication. The aim of this research is to propose a general purpose system for the automatic creation of control software for use in a range of problems from the target problem class -without requiring any system tuning: In order to assess the system search performance sensitivity, experiments were performed using various population and LGP string sizes; the experimental data collected was also used to examine the utility of abandoning stalled searches and restarting. This work is significant because it identifies a realistic application of GP that can ease the burden of finite human software design resources, whilst capitalising on accelerating computing potential.
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Palaniappan, Karthik. "Algorithms for automatic feedback control of aerodynamic flows /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Hussain, Tanvir M. E. "Development and automatic deployment of distributed control applications." Aachen Shaker, 2008. http://d-nb.info/993180647/04.
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Anderson, Philip D. "Automatic plasma processing control." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23666614.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1990.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 76).
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Yu, Chi-Cheng. "Automatic Exposure with Fuzzy Control." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2306200414113400.
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Wu, Guo-Wei, and 吳國維. "10Gbps Automatic Gain Control Circuit." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/19514234037193297734.
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碩士<br>國立交通大學<br>電子工程系所<br>97<br>Recently, with the progress of the semi-conductor technology, and the demand of power efficiency, multi-cores computation becomes one of the mainstreams to realize a high speed processing platform. Due to the slight cross talk and low EMI properties, optical links are believed to be the suitable media for this high speed, high density data transmission. As a result, implementation of optical transceiver in CMOS technology with small form factor and low cost becomes a challenging and practical research topic for the SOC design of the high density communication platform.
To implement an optical receiver front-end which is suitable for PAM (Pulse Amplitude Modulation), a mechanism of gain variation is indispensable for an input dynamic concern. Furthermore, to overcome the problems of conventional analog AGC (Automatic Gain Control) circuit, such as the gain non-linearity or long response time, an inductor-less, 10Gbps, digitally gain-controlled AGC circuit is proposed in this thesis, and prospected to be applied in low voltage design and advanced process.
In order to enhance the bandwidth of the amplifier, nested active feedback architecture is proposed in the VGA (Variable Gain Amplifier) design, and its transfer function is corresponded with a Bessel type filter response, to alleviate group delay variation. For gain variation, the source degeneration resistance of input stage is controlled digitally and hence the equivalent transconductance. Moreover, the gain-controlled circuit with dual mode, binary search and linear search, is implemented by digital circuit for the design consideration of fast locking and being steady in the lone run.
To keep the output swing in the range of requirement, there are peak detector and comparator in this AGC, for utilities of peak amplitude acquisition and comparing to the reference voltage. In the peak detector, switches are adopted to reduce the reset time and settling time with digital control signal; and the comparator with Hysteresis effect can avoid the instability caused by noise and finite resolution of gain control.
The test chip is implemented in standard 0.18μm CMOS technology. Under 1.8V operating voltage, the measured data rate is about 8Gbps; input dynamic range is 22dB, with 170ns binary search settling time. With 24 bits thermometer code, gain-controlled resolution is 0.9dB/bit. Chip size is 620x620μm2, and total power consumption is 86.4mW.