Estudo Comparativo de Controladores Fuzzy Aplicados a um Sistema Solar Fotovoltaico.

Neste trabalho apresenta-se o modelo de um controlador baseado em Lógica Fuzzy para um sistema de energia baseado em fonte renovável solar fotovoltaica (photovoltaic - PV) multi-string em operação isolada, para o aproveitamento da máxima potência desta fonte. O sistema é composto por painéis solares, conversor CC-CC tipo elevador de tensão (boost), armazenamento por banco de baterias, inversor trifásico e carga trifásica variável. O sistema fotovoltaico foi modelado no MATLAB/Simulink de forma a representar a curva característica V-I do módulo PV, e que é baseado nos dados disponíveis em data-sheets de painéis fotovoltaicos comerciais. Outros estudos de natureza elétrica tais como o cálculo dos valores eficazes das correntes no conversor CC-CC, para avaliação das perdas, indispensáveis para o dimensionamento de componentes eletrônicos, foram realizados. O método tradicional Perturb and Observe de rastreamento do ponto de máxima potência (Maximum Power Point Tracking MPPT) de painéis foi testado e comparado com métodos que usam a Lógica Fuzzy. Devido ao seu desempenho, foi adotado o método Fuzzy que realiza o MPPT por inferência do ciclo de trabalho de um modulador por largura de pulso (Pulse Width Modulation - PWM) através da variação da potência pela variação da corrente do painel solar. O modelo Fuzzy adotado neste trabalho foi testado com sucesso. Os resultados mostraram que ele pode ser robusto e atende à aplicação proposta. Segundo alguns testes realizados, este controlador pode realizar o MPPT de um sistema PV na configuração multi-string onde alguns arranjos fotovoltaicos são usados. Inclusive, este controle pode ser facilmente adaptado para realizar o MPPT de outras fontes de energia baseados no mesmo princípio de controle, como é o caso do aerogerador.

Estudo do Controle das Emissões de poluentes em Caldeira Aquatubular de alta pressão com Queimadores Convencionais, Abordagem da Eficiência Versus Custo do Dano.

As emissões atmosféricas têm sido consideradas por especialistas, poder público, iniciativa privada e organizações ambientalistas, um dos maiores impactos ambientais que o planeta vem enfrentando. Neste contexto estão tanto as fontes estacionárias quanto as fontes móveis. Ao mesmo tempo em que se lançam na atmosfera milhões de toneladas de poluentes a cada ano através da indústria, o homem procura soluções alternativas através de fontes de energia limpa. Adicionalmente, procura-se ao diminuir as emissões das fontes fixas exercer melhor controle e tratamento. Apresenta-se nesse trabalho, a possibilidade da implementação de ações que visem minimizar o impacto causado pelas caldeiras geradoras de energia, em especial as que operam com queimadores convencionais. Experimentou-se um procedimento capaz de ser utilizado de imediato pelas indústrias, antes mesmo de se implementar inovações tecnológicas, que demandam tempo e recursos. Desta forma, pode-se reduzir, de maneira imediata, o volume de poluentes lançados diariamente na atmosfera, em especial o monóxido de carbono, CO, os óxidos de nitrogênio, NOx, e o material particulado, MP. Objetivou-se atingir um nível de emissões capaz de minimizar o custo do dano, sem perder a eficiência da combustão. Apresenta-se ainda a base metodológica de um modelo, utilizando-se a lógica difusa, como forma de se obter um controle e confiabilidade na gestão das emissões.

Uma abordagem da lógica fuzzy no ensino médio

O uso cada vez mais intenso de conceitos subjetivos - provenientes da lógica fuzzy - aplicados a problemas reais nos motivou a desenvolver procedimentos para a introdução destas idéias no âmbito do ensino médio. O projeto propõe inicialmente o estudo de conjuntos fuzzy que podem ser entendidos com exemplos - de variação populacional, de controle de pragas e de epidemias. Posteriormente, usar as “operações fuzzy” Sup e Inf em produtos de matrizes para realizar diagnósticos e avaliações subjetivas. As situações abordadas já estão na literatura (Barros e Bassanezi, 2006), entretanto não como fonte para o Ensino Médio. Um dos objetivos principais deste trabalho é contrapor a crença de exatidão da matemática clássica com os resultados provenientes de lógica subjetiva, utilizando conceitos apropriados para os estudantes destas séries: teoria dos conjuntos, relações e funções, matrizes, equações de diferenças e outros.

A genetic algorithm for the design of a fuzzy controller for active queue management

Active queue management (AQM) policies are those policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the hosts on the network borders, and the adoption of a suitable control policy. This paper proposes the adoption of a fuzzy proportional integral (FPI) controller as an active queue manager for Internet routers. The analytical design of the proposed FPI controller is carried out in analogy with a proportional integral (PI) controller, which recently has been proposed for AQM. A genetic algorithm is proposed for tuning of the FPI controller parameters with respect to optimal disturbance rejection. In the paper the FPI controller design metodology is described and the results of the comparison with random early detection (RED), tail drop, and PI controller are presented.

A fuzzy approach for the network congestion problem

In the recent years, the unpredictable growth of the Internet has moreover pointed out the congestion problem, one of the problems that historicallyha ve affected the network. This paper deals with the design and the evaluation of a congestion control algorithm which adopts a FuzzyCon troller. The analogyb etween Proportional Integral (PI) regulators and Fuzzycon trollers is discussed and a method to determine the scaling factors of the Fuzzycon troller is presented. It is shown that the Fuzzycon troller outperforms the PI under traffic conditions which are different from those related to the operating point considered in the design.

Otimização de reator sequencial em batelada para remoção biológica de carbono e nitrogênio com controle difuso

Este trabalho apresenta a estruturação de um controle difuso, para a automação de reatores seqüenciais em batelada (RSB), no processo de remoção biológica de matéria orgânica e nitrogênio em águas residuárias domésticas, utilizando parâmetros inferenciais, pH, ORP e OD, em que as variáveis controladas foram as durações da reação aeróbia e anóxica. O experimento, em escala de bancada, foi composto por dois reatores seqüenciais em batelada, com volume útil de 10 L, no qual 6 L foram alimentados com esgoto sintético, com características de águas residuárias domésticas. O sistema de automação foi composto pela aquisição dos parâmetros eletroquímicos (pH, ORP e OD), pelos dispositivos atuadores (motor-bomba, aerador e misturador) e pelo controle predeterminado ou difuso. O programa computacional CONRSB foi implementado de forma a integrar o sistema de automação. O controle difuso, implementado, foi constituído pelos procedimentos de: normalização, nebulização, inferência, desnebulização e desnormalização. As variáveis de entrada para o controlador difuso, durante o período: aeróbio foram dpH/dt, dpH/d(t-1) e o pH ; anóxico foram dORP/dt, dORP/d(t-1) e o OD. As normalizações das variáveis crisps estiveram no universo de [0,1], utilizando os valores extremos do ciclo 1 ao 70. Nas nebulizações foram aplicadas as funções triangulares, as quais representaram, satisfatoriamente, as indeterminações dos parâmetros. A inferência nebulosa foi por meio da base heurística (regras), com amparo do especialista, em que a implicação de Mamdani foi aplicada Nessas implicações foram utilizadas dezoito expressões simbólicas para cada período, aeróbio e anóxico. O método de desnebulização foi pelo centro de áreas, que se mostrou eficaz em termos de tempo de processamento. Para a sintonia do controlador difuso empregou-se o programa computacional MATLAB, juntamente com as rotinas Fuzzy logic toolbox e o Simulink. O intervalo entre as atuações do controlador difuso, ficou estabelecido em 5,0 minutos, sendo obtido por meio de tentativas. A operação do RSB 1, durante os 85 ciclos, apresentou a relação média DBO/NTK de 4,67 mg DBO/mg N, sendo classificado como processo combinado de oxidação de carbono e nitrificação. A relação média alimento/microrganismo foi de 0,11 kg DBO/kg sólido suspenso volátil no licor misto.dia, enquadrando nos sistemas com aeração prolongada, em que a idade do lodo correspondeu aos 29 dias. O índice volumétrico do lodo médio foi de 117,5 mL/g, indicando uma sedimentação com características médias. As eficiências médias no processo de remoção de carbono e nitrogênio foram de 90,8% (como DQO) e 49,8%, respectivamente. As taxas específicas médias diárias, no processo de nitrificação e desnitrificação, foram de 24,2g N/kg SSVLM.dia e 15,5 g N/kg SSVLM.dia, respectivamente. O monitoramento, em tempo real, do pH, ORP e OD, mostrou ter um grande potencial no controle dos processos biológicos, em que o pH foi mais representativo no período aeróbio, sendo o ORP e o OD mais representativos no período anóxico. A operação do RSB com o controlador difuso, apresentou do ciclo 71 ao 85, as eficiências médias no processo de remoção de carbono e nitrogênio de 96,4% (como DQO) e 76,4%, respectivamente. A duração média do período aeróbio foi de 162,1 minutos, que tomando como referência o período máximo de 200,0 minutos, reduziu em 19,0% esses períodos. A duração média do período anóxico foi de 164,4 minutos, que tomando como referência o período máximo de 290,0 minutos, apresentou uma redução de 43,3%, mostrando a atuação robusta do controlador difuso. O estudo do perfil temporal, no ciclo 85, mostrou a atuação efetiva do controlador difuso, associada aos pontos de controle nos processos biológicos do RSB. Nesse ciclo, as taxas máximas específicas de nitrificação e desnitrificação observadas, foram de 32,7 g NO3 --N/kg sólido suspenso volátil no licor misto.dia e 43,2g NO3 --N/kg sólido suspenso volátil no licor misto.dia, respectivamente.

Metodologia para ordenação de controles internos contábeis com base em critérios estabelecidos pelo SEC Management Guidance e escala baseada em operadores da lógica Fuzzy

Propõe-se com a presente dissertação conduzir estudo exploratório sobre a razoabilidade de um método de apoio à tomada de decisão para ordenar os controles internos contábeis, utilizando critérios estabelecidos pelo regulador do mercado de capitais dos Estados Unidos, quantificados por meio de uma escala baseada em operadores da lógica fuzzy. O método foi elaborado com base em pesquisa bibliográfica sobre o controle interno contábil e sua relação com os controles internos em geral; a exigência de constituição, avaliação e divulgação da avaliação dos controles internos contábeis pela legislação do mercado de capitais americano ao longo das últimas três décadas; o conceito de matriz de risco; os métodos de apoio à decisão; e os fundamentos da lógica fuzzy. A metodologia proposta foi adaptada à realidade da entidade objeto do estudo de caso e aplicada sobre 2,4 mil controles. Uma amostra de aproximadamente 14% desse universo foi analisada e permitiu concluir pela razoabilidade do método proposto, que será utilizado pela entidade estudada como parte de seu processo de avaliação dos controles internos contábeis.

Detecção de interface em tanques de petróleo usando transmissores de nível e controladores Fuzzy

This work presents a proposal to detect interface in atmospheric oil tanks by installing a differential pressure level transmitter to infer the oil-water interface. The main goal of this project is to maximize the quantity of free water that is delivered to the drainage line by controlling the interface. A Fuzzy Controller has been implemented by using the interface transmitter as the Process Variable. Two ladder routine was generated to perform the control. One routine was developed to calculate the error and error variation. The other was generate to develop the fuzzy controller itself. By using rules, the fuzzy controller uses these variables to set the output. The output is the position variation of the drainage valve. Although the ladder routine was implemented into an Allen Bradley PLC, Control Logix family it can be implemented into any brand of PLCs

Ambiente para avaliação de controladores fuzzy aplicados ao método de elevação artificial por bombeio centrífugo submerso

From their early days, Electrical Submergible Pumping (ESP) units have excelled in lifting much greater liquid rates than most of the other types of artificial lift and developed by good performance in wells with high BSW, in onshore and offshore environments. For all artificial lift system, the lifetime and frequency of interventions are of paramount importance, given the high costs of rigs and equipment, plus the losses coming from a halt in production. In search of a better life of the system comes the need to work with the same efficiency and security within the limits of their equipment, this implies the need for periodic adjustments, monitoring and control. How is increasing the prospect of minimizing direct human actions, these adjustments should be made increasingly via automation. The automated system not only provides a longer life, but also greater control over the production of the well. The controller is the brain of most automation systems, it is inserted the logic and strategies in the work process in order to get you to work efficiently. So great is the importance of controlling for any automation system is expected that, with better understanding of ESP system and the development of research, many controllers will be proposed for this method of artificial lift. Once a controller is proposed, it must be tested and validated before they take it as efficient and functional. The use of a producing well or a test well could favor the completion of testing, but with the serious risk that flaws in the design of the controller were to cause damage to oil well equipment, many of them expensive. Given this reality, the main objective of the present work is to present an environment for evaluation of fuzzy controllers for wells equipped with ESP system, using a computer simulator representing a virtual oil well, a software design fuzzy controllers and a PLC. The use of the proposed environment will enable a reduction in time required for testing and adjustments to the controller and evaluated a rapid diagnosis of their efficiency and effectiveness. The control algorithms are implemented in both high-level language, through the controller design software, such as specific language for programming PLCs, Ladder Diagram language.

Controle aplicado a poços com método de elevação e bombeio centrífugo submerso

The Electrical Submersible Pumping is an artificial lift method for oil wells employed in onshore and offshore areas. The economic revenue of the petroleum production in a well depends on the oil flow and the availability of lifting equipment. The fewer the failures, the lower the revenue shortfall and costs to repair it. The frequency with which failures occur depends on the operating conditions to which the pumps are submitted. In high-productivity offshore wells monitoring is done by operators with engineering support 24h/day, which is not economically viable for the land areas. In this context, the automation of onshore wells has clear economic advantages. This work proposes a system capable of automatically control the operation of electrical submersible pumps, installed in oil wells, by an adjustment at the electric motor rotation based on signals provided by sensors installed on the surface and subsurface, keeping the pump operating within the recommended range, closest to the well s potential. Techniques are developed to estimate unmeasured variables, enabling the automation of wells that do not have all the required sensors. The automatic adjustment, according to an algorithm that runs on a programmable logic controller maintains the flow and submergence within acceptable parameters avoiding undesirable operating conditions, as the gas interference and high engine temperature, without need to resort to stopping the engine, which would reduce the its useful life. The control strategy described, based on modeling of physical phenomena and operational experience reported in literature, is materialized in terms of a fuzzy controller based on rules, and all generated information can be accompanied by a supervisory system

A objetivação do controle concreto de constitucionalidade nas decisões do Supremo Tribunal Federal

The independence of the United States and the revolutions that emerged in Europe in the eighteenth century led to the birth of the written constitution, with a mission to limit the power of the State and to ensure fundamental rights to citizens. Thus, the Constitution has become the norm and ultimate founding of the State. Because of this superiority felt the need to protect her, emerging from that constitutional jurisdiction, taking control of constitutionality of provisions his main instrument. In Brazil, the constitutionality control began with the Constitution of 1891, when "imported" the American model, which is named after incidental diffuse model of judicial review. Indeed, allowed that any judge or court could declare the unconstitutionality of the law or normative act in a concrete case. However, the Brazilian Constituent did not bring the U.S. Institute of stare decisis, by which the precedents of higher courts eventually link the below. Because of this lack, each tribunal Brazilian freely decide about the constitutionality of a rule, so that the decision took effect only between the parties to the dispute. This prompted the emergence of conflicting decisions between judicantes organs, which ultimately undermine legal certainty and the image of the judiciary. As a solution to the problem, was incorporated from the 1934 Constitution to rule that the Senate would suspend the law declared unconstitutional by the Supreme Court. With the introduction of abstract control of constitutionality, since 1965, the Supreme Court went on to also have the power to declare the invalidity of the provision unconstitutional, effectively against all without the need for the participation of the Senate. However, it remained the view that in case the Supreme Court declared the unconstitutionality of the fuzzy control law by the Senate would continue with the competence to suspend the law unconstitutional, thus the decision of the Praetorium Exalted restricted parties. The 1988 Constitution strengthened the abstract control expanding legitimized the Declaratory Action of Unconstitutionality and creating new mechanisms of abstract control. Adding to this, the Constitutional Amendment. No. 45/2004 brought the requirement of general repercussion and created the Office of Binding Precedent, both to be applied by the Supreme Court judgments in individual cases, thus causing an approximation between the control abstract and concrete constitutional. Saw themselves so that the Supreme Court, to be the guardian of the Constitution, its action should be directed to the trial of issues of public interest. In this new reality, it becomes more necessary the participation of the Senate to the law declared unconstitutional in fuzzy control by the Supreme Court can reach everyone, because such an interpretation has become obsolete. So, to adapt it to this reality, such a rule must be read in the sense that the Senate give publicity to the law declared unconstitutional by the Supreme Court, since mutated constitutional

O processo avaliativo institucional de desempenho do sistema público municipal de Teresina-PI (2001 a 2005): entre a lógica da excelência e a lógica da aprendizagem

This work focalize the institutional and educational evaluation, aiming to investigate the Municipal System Institutional Evaluation Performance of Teresina City Piauí (2001-2005), and to reflect about Institutional System Performance and its contribution to compose a new learning evaluation practice. In this sense, classifies elements about the evaluation practice in two Elementary Education municipal public schools, involving Education Municipal Bureau technicians as managers, pedagogues, teachers and students. Based on the ethnographic studies principles in the educational area, the work employs investigative procedures like document analysis, interviews with groups and individuals and also participator s comments. Intending to comprehend the complexity produced by the institutional and education evaluation processes, the wok reveals the Institutional Evaluation legal and educational political basis and the several positions assumed by the Learning Evaluation, as a classification tool or as a learning enhancement. This work points, as results, to a evaluation culture bipolarity carried out by the Municipal Education System as a explicit control and regulation toll, related to the classification and learning in a interaction process that operates both in the pressure and the reflection, as a culture practice established between excellence of logic and learning. The evaluation history has been construct on the evaluation actions dialectics, joint simultaneously between the Institutional Evaluation Performance and the learning evaluation. The senses, meanings and actions bipolarity is a interaction process product sustained between the institutional evaluation, under the scholar ranking application, and the learning evaluation. In this relativity, the teacher evaluation practice is found, ruled by interesting, thoughts and actions on the school evaluation, allowing a higher security and support to the learning results. Grounded in the researched reality, its possible to say that the teacher s evaluation practice is diversified, with different characteristics, when it is done in the learning search and in the learning intention. In the first case, reflects, rearranges and constructs new actions that lead the student to produce learning. In the second, shows the will, the wish of learning, but is a weak action, producing a not really significant learning and development; as a result, remains the mark approach as a determinant in the student future. The work s hope is to contribute not just to rethink these two evaluations dimensions the institutional and the learning ones but also to organize the school and to improve the pedagogic process

Arquitetura inteligente fuzzy para monitoramento de sinais vitais de pacientes: um estudo de caso em UTI

The area of the hospital automation has been the subject a lot of research, addressing relevant issues which can be automated, such as: management and control (electronic medical records, scheduling appointments, hospitalization, among others); communication (tracking patients, staff and materials), development of medical, hospital and laboratory equipment; monitoring (patients, staff and materials); and aid to medical diagnosis (according to each speciality). This thesis presents an architecture for a patient monitoring and alert systems. This architecture is based on intelligent systems techniques and is applied in hospital automation, specifically in the Intensive Care Unit (ICU) for the patient monitoring in hospital environment. The main goal of this architecture is to transform the multiparameter monitor data into useful information, through the knowledge of specialists and normal parameters of vital signs based on fuzzy logic that allows to extract information about the clinical condition of ICU patients and give a pre-diagnosis. Finally, alerts are dispatched to medical professionals in case any abnormality is found during monitoring. After the validation of the architecture, the fuzzy logic inferences were applied to the trainning and validation of an Artificial Neural Network for classification of the cases that were validated a priori with the fuzzy system

Estrutura ANFIS modificada para identificação e controle de plantas com ampla faixa de operação e não linearidade acentuada

In this work a modification on ANFIS (Adaptive Network Based Fuzzy Inference System) structure is proposed to find a systematic method for nonlinear plants, with large operational range, identification and control, using linear local systems: models and controllers. This method is based on multiple model approach. This way, linear local models are obtained and then those models are combined by the proposed neurofuzzy structure. A metric that allows a satisfactory combination of those models is obtained after the structure training. It results on plant s global identification. A controller is projected for each local model. The global control is obtained by mixing local controllers signals. This is done by the modified ANFIS. The modification on ANFIS architecture allows the two neurofuzzy structures knowledge sharing. So the same metric obtained to combine models can be used to combine controllers. Two cases study are used to validate the new ANFIS structure. The knowledge sharing is evaluated in the second case study. It shows that just one modified ANFIS structure is necessary to combine linear models to identify, a nonlinear plant, and combine linear controllers to control this plant. The proposed method allows the usage of any identification and control techniques for local models and local controllers obtaining. It also reduces the complexity of ANFIS usage for identification and control. This work has prioritized simpler techniques for the identification and control systems to simplify the use of the method

Ambiente para desenvolvimento de aplicações fuzzy industriais

This paper describes the design, implementation and enforcement of a system for industrial process control based on fuzzy logic and developed using Java, with support for industrial communication protocol through the OPC (Ole for Process Control). Besides the java framework, the software is completely independent from other platforms. It provides friendly and functional tools for modeling, construction and editing of complex fuzzy inference systems, and uses these logical systems in control of a wide variety of industrial processes. The main requirements of the developed system should be flexibility, robustness, reliability and ease of expansion