Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on July 8, 2009). Includes bibliographical references.

Mainly based on Li Li's Ph. D. dissertation: University of Arizona, Tucson, 2005. / Includes bibliographical references and index.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 134-142). Also available on the World Wide Web.

Η παρούσα διπλωματική εργασία παρουσιάζει τα Ευφυή Συστήματα ελέγχου και τις εφαρμογές τους στον έλεγχο συστημάτων ηλεκτρικής ενέργειας. Τα διάφορα είδη Σταθεροποιητών Συστημάτων Ισχύος (ΣΣΙ) παρουσιάζονται επίσης. Τα ηλεκτρικά συστήματα είναι δυναμικά συστήματα και υποβάλλονται συνεχώς σε διαταραχές. Είναι σημαντικό οι διαταραχές αυτές να μην οδηγούν το σύστημα σε αστάθεια. Για αυτόν το λόγο, πρόσθετα σήματα που προέρχονται από την απόκλιση ταχύτητας, την απόκλιση διέγερσης και την ροπή επιτάχυνσης εισάγονται στους ρυθμιστές τάσης. Η συσκευή που παρέχει αυτά τα σήματα αναφέρεται ως Σταθεροποιητής Συστημάτων Ισχύος. Η χρήση των Σταθεροποιητών Συστημάτων Ισχύος είναι πολύ συχνή στη λειτουργία των μεγάλων συστημάτων ηλεκτρικής ενέργειας. Οι συμβατικοί Σταθεροποιητές Συστημάτων Ισχύος που χρησιμοποιούν την αντιστάθμιση προήγησης-καθυστέρησης φάσης, όπου οι ρυθμίσεις κέρδους σχεδιάζονται για τις συγκεκριμένες συνθήκες λειτουργίας, δίνουν φτωχές επίδοσεις υπό τις διαφορετικές συνθήκες φόρτισης. Επομένως, είναι πολύ δύσκολο να σχεδιαστεί ένας σταθεροποιητής που θα μπορούσε να επιτύχει καλές επιδόσεις σε διάφορες συνθήκες λειτουργίας των συστημάτων ηλεκτρικής ενέργειας. Σε μία προσπάθεια να καλυφθεί ένα ευρύ φάσμα των συνθηκών λειτουργίας,τα Ευφυή Συστήματα ελέγχου έχουν προταθεί ως πιθανή λύση για να υπερνικηθεί αυτό το πρόβλημα. Σε αυτήν την εργασία, μια συστηματική προσέγγιση στο σχέδιο ελέγχου Ασαφούς λογικής προτείνεται. Παρουσιάζεται η μελέτη του Σταθεροποιητή Συστημάτων Ισχύος Ασαφούς λογικής για την αύξηση της ευστάθειας ενός συστήματος μιας μηχανής συνδεδεμένης σε άπειρο ζυγό. Προκειμένου να ολοκληρωθεί η αύξηση της ευστάθειας, η απόκλιση ταχύτητας και η επιτάχυνση του ρότορα της σύγχρονης γεννήτριας λαμβάνονται ως είσοδοι στον ελεγκτή ασαφούς λογικής. Αυτές οι μεταβλητές έχουν σημαντική επίδραση στην απόσβεση των μηχανικών ταλαντώσεων των αξόνων των γεννητριών. Τα σήματα ευστάθειας υπολογίστηκαν χρησιμοποιώντας την ασαφή συνάρτηση συμμετοχής ανάλογα με αυτές τις μεταβλητές. Το Simulink/Μatlab χρησιμοποιήθηκε στην εφαρμογή της μελέτης. Η απόδοση του συστήματος με το Σταθεροποιητή Συστημάτων Ισχύος Ασαφούς λογικής συγκρίνεται με το σύστημα με το συμβατικό Σταθεροποιητή Συστημάτων Ισχύος καθώς και με το σύστημα χωρίς Σταθεροποιητή Συστημάτων Ισχύος. / In this thesis the different types of intelligent control systems and the various techniques used in power system stabilizers are considered. The power system is a dynamic system and it is constantly being subjected to disturbances. It is important that these disturbances do not drive the system to unstable conditions. For this purpose, additional signals derived from speed deviation, excitation deviation and accelerating power are injected into voltage regulators. The device to provide these signals is referred as power system stabilizer. The use of power system stabilizers has become very common in operation of large electric power systems. The conventional PSS which uses lead-lag compensation, where gain settings designed for specific operating conditions, is giving poor performance under different loading conditions. Therefore, it is very difficult to design a stabilizer that could present good performance in all operating points of electric power systems. In an attempt to cover a wide range of operating conditions, intelligent control systems have been suggested as a possible solution to overcome this problem. Inittialy in this thesis, an introduction of power system control and the different types of stabilizers is briefly described. Afterwards, the system modeling and power system stabilizer model is presented. Finally, a systematic approach to fuzzy logic control design is proposed. The study of fuzzy logic power system stabilizer for stability enhancement of a single machine infinite bus system is presented. In order to accomplish the stability enhancement, speed deviation and acceleration of the rotor synchronous generator are taken as the inputs to the fuzzy logic controller. These variables take significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals were computed using the fuzzy membership function depending on these variables. Simulink Block Design and Matlab is utilized in implementing the study. The performance of the system with fuzzy logic based power system stabilizer is compared with the system having conventional power system stabilizer and system without power system stabilizer.

Οι φωτοβολταϊκές γεννήτριες παρουσιάζουν μια μη γραμμική χαρακτηριστική V-I και ένα σημείο λειτουργίας μέγιστης ισχύος (MPP) τα οποία ποικίλλουν ανάλογα με την ακτινοβολία και τη θερμοκρασία. Αυτή η εργασία παρουσιάζει έναν MPP-tracker βασισμένο στην ασαφή λογική και ένα σχέδιο ενός μονοφασικού inverter συνδεδεμένου στο ηλεκτρικό δίκτυο. Ο ασαφής ελεγκτής (FLC) παρέχει προσαρμοστικότητα στη επίδοση του συστήματος. Λαμβάνει υπόψη του το τρέχον φορτίο, τη θερμοκρασία, την ακτινοβολία, τον άνεμο καθώς και τις πιθανές σκιάσεις που καλύπτουν τα πλαίσια. Παρέχει επίσης άριστα χαρακτηριστικά όπως γρήγορη απόκριση, καλή επίδοση και την δυνατότητα να αλλάζουν οι παράμετροί του προκειμένου να βελτιώνεται ο έλεγχος του συστήματος. Το γεγονός ότι λαμβάνει υπόψη του τις εξωτερικές συνθήκες εξασφαλίζει καλύτερη γνώση της πραγματικής επίδοσης του φωτοβολταϊκού συστήματος και όχι της βέλτιστης επίδοσης που αυτό έχει στις πρότυπες συνθήκες (STC). Τα αποτελέσματα της προσομοίωσης επιβεβαίωσαν την αποτελεσματικότητα του προτεινόμενου συστήματος. / The photovoltaic generators show a non-linear characteristic VI and one maximum power point (MPP) which vary depending on insolation and temperature. This project presents a MPP tracker, based on fuzzy logic, and a plan of an one-phased grid connected inverter. Fuzzy logic controller provides adaptivity at the system’s performance. It takes into consideration current load, temperature, insolation, wind and possible shades covering the panels. It also provides excellent characteristics such as quick response, great performance and the capacity of changing the system parameters in order to improve the system control. The fact that it takes into consideration the external conditions (in vivo as opposed to in vitro-laboratorial conditions) ensures better knowledge of the actual performance of the photovoltaic systems and not the optimum performance the system can score in standard test conditions (STC). The results of this simulation have confirmed the effectiveness of the proposed system.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2008. / Robot control by TCP/IP communication is investigated in this thesis for existing robots used in tertiary education. The request for newer software for robotic computer control came from the University of Stellenbosch Industrial Engineering department where existing software dating back to 1988 is still in use. A thorough investigation into the research and technologies available is followed by a discussion on the proposed software to adhere to the requirement of compatibility with existing languages in use by the department and provide tools to assist in future research in robotic manipulators and control. The proposed software solution uses a client/server model running over an IP-based network providing online and offline programming with visual feedback by means of video streaming and 3D simulations, developed as separate modules combined into an effective tool for future research and development.

Made available in DSpace on 2014-06-11T19:30:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-24Bitstream added on 2014-06-13T18:41:00Z : No. of bitstreams: 1 000751146.pdf: 4139134 bytes, checksum: f3feebece413982481c6daf8b8d857cf (MD5) / A evasão escolar é um dos problemas mais complexos e cruciais no âmbito da educação. Está presente e é motivo de preocupação nos vários níveis e modalidades de ensino, além de ferir o princípio da dignidade humana. No que tange ao ensino superior, internacionalmente, o fenômeno é objeto de atenção e de cuidado, no intuito de aumentar os índices de permanência e conclusão dos estudantes de graduação e minimizar os prejuízos sociais, econômicos, políticos, acadêmicos e financeiros causados a todos os envolvidos no processo educacional. Nesse contexto, é imprescindível o desenvolvimento de métodos e instrumentos eficientes e eficazes para predição, avaliação e acompanhamento de estudantes em risco de evasão, possibilitando o planejamento e a adoção de medidas proativas no intuito de minimizar a situação. Assim sendo, esta pesquisa tem por objetivo apresentar as potencialidades de um sistema inteligente capaz de identificar, de maneira proativa, continuada e acurada, o grupo de risco de evasão discente, da educação clássica-presencial, no ensino de nível superior. No desenvolvimento deste sistema foi utilizada uma das técnicas da inteligência artificial, as Redes Neurais Artificiais, mais especificamente, a Rede Neural ARTMAP-Fuzzy, uma rede neural da família ART (Adaptive Resonance Theory) que possibilita o aprendizado continuado do sistema. Para o treinamento e teste da Rede Neural e, posteriormente, a validação do sistema proposto foram utilizados os dados socioeconômicos e acadêmicos dos estudantes matriculados nos cursos superiores de tecnologia do Instituto Federal de Mato Grosso - IFMT. Os dados que compuseram os vetores de entrada do sistema foram coletados a partir de dois bancos de dados do sistema de informação do IFMT, respectivamente, o Q-seleção e o Q-Acadêmico. Este sistema faz a classificação dos padrões de entrada em propensos... / School dropout is one of the most complex and crucial problems in the field of education. It permeates and afflicts the several levels and teaching modalities, besides hurting the principle of human dignity. In relation to higher education, internationally, the phenomenon is an object of attention and care, aiming to increase the indexes of permanence and completion rate of the undergraduate students and minimize social, economic, political and financial damage caused to all involved in the educational process. In this context, it is fundamental to develop efficient and effective methods and instruments for prediction, assessment and monitoring of the students at risk of dropping out, making the planning and the adoption of proactive actions possible for the improvement of the situation. Thus, this study aims to present the potentialities of an intelligent system able to identify, in a proactive, continued and accurate way, the student dropout risk group in higher education classroom courses. In the development of this system one of the artificial intelligence techniques was used, the Artificial Neural Networks, more specifically, the Fuzzy-ARTMAP Neural network, a neural network of the ART (Adaptive Resonance Theory) family which makes the continued learning of the system possible. For the training and test of the Neural Network and, later, the validation of the system proposed the socio-economic and academic records of the students enrolled in the technology courses of the Federal Institute of Mato Grosso – IFMT were used. The data that constituted the input vectors of the system were extracted from two database of the IFMT information system, respectively, the Q-selection and the Q-Academic. This system classifies the input patterns in school dropout propensity. The consistence of the results, showing a success rate of the dropout group around 95% and 100% and the overall mean accuracy around ...

The design of automatic systems for steering a ship presents difficult challenges because of their dynamic properties which vary considerably within the range of sailing conditions. Automatic steering of ships has its origin at the beginning of the century and was prompted by the introduction of the gyrocompass. Until the earlier 70s almost all autopilots for a ship were based on the proportional-derivative-integral (PID) controller. The main disadvantage with PID controllers is that the optimal parameters setting can be achieved only for a particular sailing condition. This shortcoming was and is still dealt with in the framework of adaptive theory where the controller parameters are adjusted in the attempt to seek the optimum of a pre-set performance function. Despite such a potential advantage, at present adaptive control theory is limited to linear plants and requires a certain amount of a-priori information for a successful application. This thesis is concerned with the applicability of intelligent control techniques to the problem of designing course-keeping and course-changing autopilots for ships. For this reason the framework of intelligent control theory is introduced and a pragmatic definition of intelligent controllers is stated. The learning and adaptive features of neural networks and fuzzy logic systems are exploited and used to solve advantageously the control design problem. Adaptive networks are used as a unifying structure where different kinds of neural networks and fuzzy logic paradigms can be described. In this framework, comparisons between neural networks and fuzzy logic systems are made and results from one field can be easily extended to the other. Although the use of such systems for the design of autopilots is in its early stage, the majority of the contributions which have appeared in literature have focused on the use of feedforward networks trained with the back-propagation algorithm. The main contributions of this thesis are the critical analysis of the feedforward network controller trained with the back-propagation algorithm, the proposition of an alternative controller architecture based on the use of radial basis function networks and to give conditions under which the stability analysis of the intelligent controllers so designed can be evaluated.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Industrial robots today are widely used in industrial processes, whether in assembly processes or product quality verification processes. The task of the robotic manipulator is then seek to position the tool in the desired position with the smallest error as possible, this is done by using control techniques. Despite the existence of modern techniques of control, fixed earnings drivers are still the most industrially used because of its simplicity. Controller with adjustable gains typically require a training period, which makes replacement of this something expensive from the industrial point of view. This paper presents a comparison between classical control techniques, such as proportional integral derivative control, and adjustable gains techniques, set by gain scheduling and fuzzy logic, from the point of they are easy and quick implementation in the field industrial and it is not necessary to adjust the gains to all new desired trajectory. The results show that the adjusted fuzzy controller has a greater ability to adjust to different paths without modification of parameters when compared to other techniques, besides presenting a tolerance to external disturbances and changes in system dynamics. / RobÃs industriais hoje em dia sÃo amplamente utilizados em processos industriais, sejam em processos de montagem ou processos de verificaÃÃo de qualidade de produtos. A tarefa do manipulador robÃtico Ã, entÃo, buscar posicionar a ferramenta na posiÃÃo desejada com o menor erro possÃvel, isto à feito atravÃs do uso de tÃcnicas de controle. Apesar da existÃncia de tÃcnicas modernas de controle, os controladores de ganhos fixos ainda sÃo os mais utilizados industrialmente devido a sua simplicidade. Controladores de ganhos ajustÃveis normalmente necessitam de um perÃodo de treinamento do controlador ou de dados da dinÃmica do sistema para o seu projeto, o que torna a substituiÃÃo de controladores deste tipo algo dispendioso do ponto de vista industrial. Este trabalho apresenta uma comparaÃÃo entre tÃcnicas de controle clÃssicas, tal como o controle proporcional integral derivativo, e tÃcnicas de ganhos ajustÃveis de fÃcil implementaÃÃo, ajuste por escalonamento dos ganhos e por lÃgica fuzzy, partindo do ponto que sejam fÃceis e de rÃpida implementaÃÃo no ramo industrial e que nÃo seja necessÃrio ajustar os ganhos a toda nova trajetÃria desejada. Os resultados mostram que o controlador ajustado por fuzzy tem uma maior capacidade de se ajustar a diferentes trajetÃrias sem necessidade de modificaÃÃes de parÃmetros quando comparado as outras tÃcnicas, alÃm de apresentar uma tolerÃncia a perturbaÃÃes externas e modificaÃÃes na dinÃmica do sistema.

Orientador: Niederauer Mastelari / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T18:11:18Z (GMT). No. of bitstreams: 1 Cardoso_RaulMariano_M.pdf: 9927638 bytes, checksum: f9633c7839661e2f914d88b7d438913e (MD5) Previous issue date: 2014 / Resumo: Os computadores como conhecemos não são mais a maioria de dispositivos que se comunicam utilizando a Internet. Há alguns anos uma tendência pode ser observada neste sentido: "coisas" recebem pequenos computadores, e são representadas virtualmente, gerando informações de valor aos seus usuários. Esta nova fase de desenvolvimento da sociedade da informação é conhecida como "Internet das Coisas" e tem afetado tanto a relação das pessoas com a vida cotidiana, quanto os modelos de negócio correntes. Este trabalho mostra como esta tendência tecnológica, inserida no contexto dos Sistemas de Transportes, pode gerar aplicações de grande relevância. Com este objetivo, metodologias que pudessem embasar o projeto foram buscadas. Um modelo arquitetural de referência foi utilizado para embasar o projeto e design de um sistema distribuído focado em aplicações específicas. A tecnologia RFID foi utilizada, com leitores e etiquetas eletrônicas, para projetar um arranjo de dispositivos que identifique os veículos e detecte sua presença nas entradas e saídas de um local restrito de interesse. Microcontroladores de baixo custo, de código aberto, tanto em hardware quanto em software, e com capacidade de se comunicar através da Internet também foram definidos por este projeto. Localmente, estes dispositivos filtram informações, mantêm bases de dados reduzidas, monitoram sensores e controlam atuadores. Para gerenciar os dispositivos desta rede, é proposta a utilização de serviços na rede, estabelecendo assim a possibilidade de uma arquitetura em nuvem. Este servidor, por sua vez, deve coordenar os dispositivos distribuídos, obtendo informações da rede que devem sincronizar os bancos de dados e também prover informações de estado dos controladores. O foco principal é o estabelecimento de uma arquitetura e infraestrutura que possam suportar as aplicações propostas. Um estudo de caso foi realizado considerando o campus da Universidade Estadual de Campinas. A primeira aplicação viável de um projeto como este é o controle de acesso veicular ao campus universitário, através da implantação de leitores RFID nas portarias, em conjunto com controladores, cancelas automáticas e sensores de presença. Isso motivou o desenvolvimento de uma prova de conceito. A instrumentação das portarias permite que os veículos sejam automaticamente identificados quando adentram o espaço restrito do campus, gerando informações de valor para outras aplicações possíveis. Dentre as aplicações previstas estão: controle de estacionamento privativo automático, sinalização interativa através de placas eletrônicas, informação de horários de transporte coletivo e elaboração de relatórios periódicos sobre o trânsito. Para que todas estas aplicações sejam disponibilizadas a comunidade, serão necessários trabalhos futuros de pesquisa e desenvolvimento / Abstract: Computers as we know are no longer the majority of devices that communicate using the Internet. A few ago years a trend can be observed in this direction: "things" get small computers, and are represented virtually generating information of value to its users. This new phase of development of the information society is known as the "Internet of Things" and has affected both people's relationship with everyday life, as the current business models. This work shows how this technological trend, inside the context of Transportation Systems, can generate highly relevant applications. With this objective, methodologies that could base the project were sought. An architectural reference model was used to support the project and design of a distributed system focused on specific applications. RFID technology was used with electronic tags and readers, to develop a devices arrangement that identifies vehicles and detect their presence in the inputs and outputs of a restricted location of interest. Low cost, open source and Internet ready devices were also described for work¿s interest. Locally, these devices filter information, maintain reduced data bases, monitor sensors and control actuators. To manage the devices was proposed the use of network services, establishing the possibility of cloud architecture. The server must coordinate the distributed devices, getting information from the network that must synchronize the databases and also provide status information of the controllers. The main focus is to establish an architecture and infrastructure that can support the proposed applications. A case study was designed aiming the campus of the State University of Campinas. The first viable implementation of such a project is the control of vehicular access to the campus, through the installation of RFID readers, controllers, automatic barriers and presence sensors. That result in a deployed proof of concept. The instrumentation of the campus access allows vehicles to be automatically identified when they enter the restricted space of the campus, generating valuable information for other possible applications. Among the intended applications include: automatic control of private parking, signaling through interactive electronic boards, information on public transportation schedules and reporting generation about transit. In order to all these applications are available for the community, needed further in research and development / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica