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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Combustion Control of Refuse Incineration Plant by DA Type Fuzzy PID Controller

Tsai, Cheng-Yu 04 August 2005 (has links)
For the operation of refuse incineration plant, the major difficulties with trash are the unstable nature and the uncertainty. The complexity of trash ingredient causes the traditional control method fail to obtain a stable combustion condition and steam flow rate. It is necessary to seek a new control method to adapt to the volatile combustion features of refuse incinerator. Based on correlation literature research [2], the fuzzy control theory is proposed to provide a good combustion condition to stabilize the steam flow rate for the combustion control of refuse furnace, and effectively reduce the rate of personnel involvement. Different from the rule based fuzzy theory, the Direct Action type Fuzzy Proportion-Integral-Differential control theory (Direct Action type Fuzzy PID) is designed to combine a single input variable and three-rule fuzzy inference system. With a traditional PID controller, the DA type Fuzzy PID controller will have a simple structure as well as the nonlinear output property. Object of control is a reverse-acting grate type incinerator. Establishment of the model is done with estimates of the value of LHV and steam flow rate, coordinating the actual structure of furnace to infer the speed variable feeder model. Establishment and simulation of the control system works under the MATLAB environment. Parameter-tuning of the controller uses the Genetic Algorithm (GA) for optimization. By joining the furnace model and the controller for simulation, it proves that the Direct Action type Fuzzy PID controller has good performance and is feasible to the combustion control for refuse incineration plant.
2

Controle avançado aplicado ao sistema bcs operando com escoamento monofásico

Souza, Leonardo da Fonseca 29 August 2014 (has links)
Submitted by Marcio Filho (marcio.kleber@ufba.br) on 2017-06-06T12:56:59Z No. of bitstreams: 1 DISSERTAÇÃO_LEONARDO_DA_FONSECA_SOUZA_DEFINITIVA_UFBA.pdf: 1789057 bytes, checksum: 4397ec74708eb43987392c3a881e8939 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-06-16T15:02:39Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_LEONARDO_DA_FONSECA_SOUZA_DEFINITIVA_UFBA.pdf: 1789057 bytes, checksum: 4397ec74708eb43987392c3a881e8939 (MD5) / Made available in DSpace on 2017-06-16T15:02:39Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_LEONARDO_DA_FONSECA_SOUZA_DEFINITIVA_UFBA.pdf: 1789057 bytes, checksum: 4397ec74708eb43987392c3a881e8939 (MD5) / Existem diversas técnicas de elevação artificial de petróleo. Este trabalho trata especificamente o método do Bombeio Centrífugo Submerso (BCS). Este método possui a vantagem de elevar altas vazões de fluidos em relação às demais técnicas de elevação, além de poder atuar sob diferentes condições dinâmicas de escoamento. O presente trabalho tem como objetivo o uso da técnica de controle Supervisor Fuzzy-PID e Adaptativo para levar o bombeio centrífugo submerso a operar no head desejado, mesmo na presença de incertezas e dinâmicas não modeladas. O Laboratório de Elevação Artificial (LEA), da Escola Politécnica da Universidade Federal da Bahia, dispõe de uma planta BCS com um poço de 32mde altura completamente instrumentado, num ambiente experimental que favorece o desenvolvimento de estudos e pesquisas, entre outros, na área de controle. Para o presente estudo foram realizados experimentos práticos que possibilitaram o desenvolvimento de modelos a partir de dados medidos. Além disso, os resultados obtidos com o método de controle Supervisor Fuzzy-PID e Adaptativo em ambiente simulado mostram que há estabilidade no sinal de controle e na resposta da planta. Assim espera-se contribuir na formulação de novas estratégias de controle aplicáveis ao método de bombeio centrífugo submerso.
3

Hybrid Fuzzy PID Controller with Adaptive Genetic Algorithms for the Position Control and Improvement of Magnetic Suspension System

Huang, Jiun-kuei 24 June 2004 (has links)
Magnetic suspension systems are highly nonlinear and essentially unstable systems. In this thesis, we utilize a phase-lead controller operating in the inner loop to stabilize the magnetic suspension system at first. Furthermore, we design a fuzzy PID controller operating in the outer loop to overcome the nonlinearity and to improve the system¡¦s performances. Because of setting the parameters in traditional fuzzy PID is a long-winded trial and error, so we adopt non-binary modified adaptive genetic algorithms to help us finding the parameters of fuzzy PID controller. As to the experimental implementation, we set two situations in our experiment test: (1) we utilize fuzzy PID controller with initial voltage to test the positions control, and eliminate the extra disturbance. And, (2) we utilize fuzzy PID controller without initial voltage to control the position of suspension object. For the experimental results, we obtain that the designed fuzzy PID controller not only increases the system¡¦s operating range, but also positions accurately and rapidly, and it meanwhile can eliminate the extra disturbance.
4

Hybrid Fuzzy PID Controller for Tube-Hydroforming Processes via Genetic Algorithms

Li, Ren-Jei 30 July 2003 (has links)
In this study, the non-binary coding, elitist strategy, increasing mutation rate, extinction, and immigration strategy are used to improve the simple genetic algorithms. The improved search technique can reduce the possibility of falling into the local optimum due to the premature convergence in a large searching space, and increase the chance of finding out the near-optimal parameters. The hydraulic forming machine used in this thesis, includes a power source of a hydraulic motor and a actuator of two hydraulic cylinders. Both the internal pressure and axial force are controlled to hydroform the tubes into the shapes we want. The PID fuzzy logic controller is implemented to control the proportional direction valve and pressure reducing valve of this dual-cylinder electro-hydraulic system so that the loading path can follow the optimal forming curve of axial-feeding and pressure prescribed. From the experimental results, it is clear that the near-optimal PIDFLC controller designed via modified genetic algorithms can make the loading path follow the prescribed curve, and effective for reducing system uncertainty caused by the varying loads and system unstability resulting from the nonlinear characteristics of the hydraulic system.
5

Desenvolvimento de um controlador híbrido Fuzzy-PID para estabilização de um VANT do tipo quadrirrotor na realização de um voo autônomo vertical

Morais, Edpo Rodrigues de 17 February 2017 (has links)
Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-06-29T22:59:45Z No. of bitstreams: 1 EdpoRM_DISSERT.pdf: 4900218 bytes, checksum: 0b5f0ce9961abf50eb5fe43f882601c0 (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: Corrigir referência. on 2017-07-03T12:21:49Z (GMT) / Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-07-04T14:22:25Z No. of bitstreams: 1 EdpoRM_DISSERT.pdf: 4900218 bytes, checksum: 0b5f0ce9961abf50eb5fe43f882601c0 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:48:02Z (GMT) No. of bitstreams: 1 EdpoRM_DISSERT.pdf: 4900218 bytes, checksum: 0b5f0ce9961abf50eb5fe43f882601c0 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:58:07Z (GMT) No. of bitstreams: 1 EdpoRM_DISSERT.pdf: 4900218 bytes, checksum: 0b5f0ce9961abf50eb5fe43f882601c0 (MD5) / Made available in DSpace on 2017-07-04T17:03:31Z (GMT). No. of bitstreams: 1 EdpoRM_DISSERT.pdf: 4900218 bytes, checksum: 0b5f0ce9961abf50eb5fe43f882601c0 (MD5) Previous issue date: 2017-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation proposes the development of a Fuzzy-PID hybrid controller for the height stability control of a four-engine type UAV. The work also contemplates the development of a classical PID controller, used to compare with the hybrid one purposed. The AuRoRA platform is used for the realization of tests with both of the control structures, being this one provided with the parameters of the Drone used. With the test results, it was possible to conclude that both of the controllers, the classical PID and the Fuzzy-PID, are able to perform the Drone height control, and the hybrid control obtained some advantages such as the ability of self-adjust with the system variation, that dispenses the manual tuning of the gains, besides presenting an improvement in the Drone height stability / Esta dissertação propõe o desenvolvimento de um controlador híbrido Fuzzy-PID para o controle de estabilidade de altura de um VANT do tipo quadrirrotor. O trabalho ainda contempla o desenvolvimento de um controlador PID clássico, utilizado para fins de comparação com o controlador híbrido proposto. A plataforma AuRoRA é utilizada para a realização dos testes com ambas as estruturas de controle, sendo a mesma munida dos parâmetros do Drone utilizado. Com os resultados dos testes, foi possível verificar que ambos controladores, PID clássico e Fuzzy-PID, são capazes de realizar o controle de altura do Drone, tendo o controle híbrido obtido algumas vantagens como a capacidade de auto ajuste mediante variações no sistema, o que dispensa as sintonias manuais dos ganhos, além de apresentar uma melhoria na estabilidade da altura do Drone / 2017-06-29
6

Hybrid Fuzzy PID Controller with Adaptive Genetic Algorithms for the Position Control of Linear Motors

Chen, Yi-Kuang 01 July 2003 (has links)
Abstract This thesis studies on the design of hybrid fuzzy PID controller via genetic algorithms and the position control of linear DC motors. Due to the high precision and high speed positioning ability, linear DC motors have been widely used in many fields. However, with the higher requirements of positioning accuracy, the effect of nonlinear friction becomes very significant. Because of the large difference between dynamic friction in macrodynamic region and static friction in microdynamic region, we design the two-stage controller for positioning in macrodynamic and microdynamic stage individually. In the macrodynamic stage, we use the hybrid fuzzy PID controller and finding the optimal membership functions and scaling factors of the controller via adaptive genetic algorithms to enhance performance of the system. A novel formula for calculating adaptive crossover and mutation rate is also presented. Since it is not easy to establish a precise static friction model in the microdynamic region, the relay feedback method is adopted to design PID controllers. Finally, through computer simulations and experiments, it is obviously that the performance of the proposed controllers is satisfactor
7

Intelligent Wind Turbine Using Fuzzy PID Control

Hedlund, Richard, Timarson, Niklas January 2017 (has links)
This thesis demonstrates how small wind turbines can contributeto a greener planet by using wind energy to generateelectrical power. It compares the conventional PIDcontroller with the Fuzzy PID controller, implemented ina small wind turbine that was constructed using variousmachines. The concept of changing the gain parameters of the PIDcontroller with fuzzy logic, depending on the wind directionfor greater power generation, is explained and tested. This,with usage of a DC-motor that gets an output signal fromthe system which reads input values from an encoder anda wind vane. The construction included a powertrain inwhich a transmission, roller bearings and shafts were implementedin the yaw mechanism. The tests resulted in showing that the Fuzzy PID controllerperformed better, minimizing the error, when theerror between the wind turbine and the wind itself, wassmall. The power generation was also increased when utilizingthe Fuzzy PID controller. However, the PID controllerperformed similar to the Fuzzy PID controller whenexposed to larger errors. / Det här arbetet visar hur små vindkraftverk kan bidra tillen grönare planet genom att omvandla vindenergi till elektriskenergi. Det beskriver jämförelsen mellan den vanligtförekommande PID regulatorn och den suddiga PID regulatorn,implementerad i ett litet vindkraftverk som konstruerades med hjälp av flertalet maskiner. Konceptet att ändra på parametrarna i PID regulatorn med hjälp av suddig logik, beroende på vindriktningen, förklaras och testas med syfte att generera energi. Dettamed hjälp av en DC-motor som får utsignaler från systemet som läser insignaler från en encoder och en vindflöjt. Konstruktionen av rotatonsmekanismen innehöll implementation av en växel, kullager och axlar. Testresultaten visade att den suddiga PID regleringenvar bättre på att minimera felet, när felet mellan vindkraftverket och vinden var litet. Även vid generering av energi,visade det sig att den suddiga PID regleringen presterade bättre. Likväl presterade PID regulatorn på samma nivå som den suddiga, när felet var större.
8

PROPOSTA DE CONTROLE NEBULOSO BASEADO EM CRITÉRIO DE ESTABILIDADE ROBUSTA NO DOMÍNIO DO TEMPO CONTÍNUO VIA ALGORITMO GENÉTICO MULTIOBJETIVO. / Nebulous control proposal based on stability criterion Robust in the field of continuous time Multiobjective genetic algorithm.

LIMA, Fernanda Maria Maciel de 31 August 2015 (has links)
Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-08-24T11:30:17Z No. of bitstreams: 1 Fernanda Lima.pdf: 9275191 bytes, checksum: 7f56bba066e97503f4da03ab7ab861c9 (MD5) / Made available in DSpace on 2017-08-24T11:30:17Z (GMT). No. of bitstreams: 1 Fernanda Lima.pdf: 9275191 bytes, checksum: 7f56bba066e97503f4da03ab7ab861c9 (MD5) Previous issue date: 2015-08-31 / A fuzzy project Takagi-Sugeno (TS) with robust stability based on the specifications of the gain and phase margins via multi-objective genetic algorithm in continuos time domain is proposed in this master thesis. A Fuzzy C-means (FCM) clustering algorithm is used to estimate the antecedent parameters and rules number of a fuzzy TS model by means of the input and output experimental data of the plant to be controlled, while minimum squares algorithm estimate the consequent parameters. A multi-objective genetic strategy is defined to adjust the parameters of a fuzzy PID controller, so that, the gain and phase margins of the fuzzy control system are close to the specified values. Two theorems are proposed to analyse the necessary and sufficient conditions for the fuzzy PID controller design to ensure the robust stability in the close-loop control. The fuzzy PID controller was simulated in the Simulink environment and compared with lead and delay compensator. Experimental results obtained in a control platform in real time to validation the methodology proposed are presented and compared with fuzzy PID controller obtained by the Ziegler Nichols method. The results demonstrate the effectiveness and practical feasibility of the proposed methodology. / Um projeto de controle nebuloso Takagi-Sugeno(TS) com estabilidade robusta baseado nas especificações das margens de ganho e fase via algoritmo genético multiobjetivo no domínio do tempo contínuo é proposto nesta dissertação. Um algoritmo de agrupamento Fuzzy C-Means (FCM) é usado para estimar os parâmetros do antecedente e o número da regras de um modelo nebuloso TS, por meio dos dados experimentais de entrada e de saída da planta a ser controlada, enquanto que o algoritmo de mínimos quadrados estima os parâmetros do consequente. Uma estratégia genética multiobjetiva é definida para ajustar os parâmetros de um controlador PID nebuloso, de modo que, as margens de ganho e fase do sistema de controle nebuloso estejam próximos dos valores especificados. São propostos dois teoremas que analisam as condições necessárias e suficientes para o projeto do controlador PID nebuloso de modo a garantir a estabilidade robusta na malha de controle. O controlador PID nebuloso foi simulado no ambiente Simulink e comparado com compensadores de avanço e de atraso e os resultados analisados. Resultados experimentais obtidos em uma plataforma de controle, em tempo real, para validação da metodologia proposta são apresentados e comparado com controlador PID nebuloso obtido pelo método de Ziegler Nichols. Os resultados obtidos demonstram a eficácia e viabilidade prática da metodologia proposta.
9

Implementação de sistemas de controle difuso em uma planta didática / Implementation of fuzzy control systems in a didactic plant

Grimaldos, Miguel Angel Ahumedo 29 August 2016 (has links)
The present work aims to expand the possibilities of PD 3 control strategies implementation and to evaluate, in a practical way, different strategies of fuzzy logic application in the control of processes of a didactic plant (PD 3). This was accomplished by adding fuzzy control strategies to the conventional industrial control strategies with which the PD 3 system is factory configured. The conventional strategies use PID controllers and its variations (P, PI and PD) which parameters are preset and "implanted" in the instruments. Three fuzzy control strategies were performed with temperature as the main process variable to be controlled and flow as the secondary variable to be controlled. The first strategy was the fuzzy-PID temperature control; it was used the local PID controller of PD 3 and a strategy was developed in fuzzy logic in an external workstation, for tuning of the PID parameters in real time. The PD 3 controller acts directly on the power of the heating resistances, which is the manipulated variable. This way, the temperature was controlled in the process. The second strategy, called temperature fuzzy-PID + flow, continued using the same fuzzy-PID temperature controller but was added a fuzzy control to regulate the process flow variable. This fuzzy control was developed at the work station and directly manipulates the actuator of the intelligent water inlet control valve to the heating tank. Finally, a completely fuzzy strategy was developed to control temperature and flow variables of the process. Of the three strategies implemented, completely fuzzy controller presented the best response when observed all metrics and performance indicators. / O presente trabalho tem como objetivos ampliar as possibilidades de implementação de estratégias de controle da PD 3 e avaliar de forma prática diferentes estratégias de aplicação da lógica difusa no controle de processos de uma planta didática (PD 3). Isto foi realizado adicionando estratégias de controle difusas às estratégias convencionais de controle industrial, com as quais o sistema da PD 3 vem configurado de fábrica. As estratégias convencionais utilizam controladores do tipo PID e suas variações (P, PI e PD) cujos parâmetros são pré-ajustados e “implantados” nos instrumentos. Foram realizadas três estratégias de controle difuso com a temperatura como variável principal a controlar e a vazão como variável secundaria a controlar. A primeira estratégia foi o controle de temperatura difuso-PID, na qual foi utilizado o controlador PID local da PD 3 e foi desenvolvida uma estratégia em lógica difusa, em uma estação de trabalho externa, para a sintonia em tempo real dos parâmetros PID. O controlador da PD 3 atua diretamente sobre a potência das resistências de aquecimento, sendo esta a variável manipulada. Desta maneira se realizou o controle da temperatura no processo. A segunda estratégia, denominada temperatura difuso-PID + vazão, continuou usando o mesmo controlador de temperatura difuso-PID, mas foi adicionado um controle difuso para regular a variável vazão do processo. Este controle difuso foi desenvolvido na estação de trabalho e manipula diretamente o atuador da válvula de controle inteligente de entrada de agua ao tanque de aquecimento. Por último, foi desenvolvida uma estratégia totalmente difusa para controlar as variáveis temperatura e vazão do processo. Das três estratégias implementadas, a que apresentou melhor performance foi a do controlador totalmente difuso quando observadas as métricas e índices de desempenho.
10

PROPOSTA DE CONTROLE NEBULOSO BASEADO EM CRITÉRIO DE ESTABILIDADE ROBUSTA NO DOMÍNIO DO TEMPO DISCRETO VIA ALGORITMO GENÉTICO MULTIOBJETIVO / PROPOSAL CLOUDY CONTROL BASED ON ROBUST STABILITY CRITERIA IN DOMAIN OF DISCREET TIME VIA MULTIOBJECTIVE GENETIC ALGORITHM

Pires, Danúbia Soares 30 September 2013 (has links)
Made available in DSpace on 2016-08-17T14:53:25Z (GMT). No. of bitstreams: 1 dissertacao Danubia.pdf: 4153198 bytes, checksum: f8dd2d9ab5e8fbfa00744bcff5dce73b (MD5) Previous issue date: 2013-09-30 / In this master thesis, a robust fuzzy digital PID control methodology based on gain and phase margins specifications, is proposed. A mathematical formulation, based on gain and phase margins specifications, the Takagi-Sugeno fuzzy model of the plant to be controlled, the structure of the digital PID controller and the time delay uncertain system, was developed. From input and output data of the plant, the fuzzy clustering Fuzzy C-Means (FCM) algorithm estimates the antecedent parameters (operation areas ) and the rules number of Takagi-Sugeno fuzzy model. The least squares algorithm provides the consequent parameters linear submodels. A multiobjective genetic strategy is defined to tune the fuzzy digital PID controller parameters, so the gain and phase margins specified to the fuzzy control system are get. An analysis of necessary and sufficient conditions for fuzzy digital PID controller design with robust stability, with the proposal of the two theorems are presented. The digital fuzzy PID controller was implemented on a platform designed for monitoring and control in real time, based on CompactRIO and LabVIEW 9073, National Instruments, of the Laboratory of Computational Intelligence Applied to Technology (ICAT/DEE/IFMA), applying the temperature control of a thermal plant. Experimental results show the efficiency of the proposed methodology, through tracking of the reference and the gain and phase margins keeping closed of the specified ones. / Nesta dissertação é proposta uma metodologia para projeto de controle PID digital nebuloso robusto baseado nas especificações das margens de ganho e fase. É desenvolvida uma formulação matemática, baseada nas especificações das margens de ganho e fase, no modelo nebuloso Takagi-Sugeno da planta a ser controlada, na estrutura do controlador PID digital e o atraso de tempo do sistema incerto. A partir dos dados de entrada e saída da planta, o algoritmo de agrupamento nebuloso Fuzzy C-Means (FCM), estima os parâmetros do antecedente (regiões de operação) e o número de regras do modelo nebuloso Takagi-Sugeno. O algoritmo de mínimos quadrados fornece os parâmetros dos submodelos lineares do consequente. Uma estratégia genética multiobjetiva é utilizada para encontrar os parâmetros do controlador PID digital nebuloso, de modo que as margens de ganho e fase especificadas para o sistema de controle nebuloso sejam alcançadas. Uma análise das condições necessárias e suficientes para o projeto do controlador PID digital nebuloso com estabilidade robusta, a partir da proposta de dois teoremas, é apresentada. O controlador PID digital nebuloso projetado foi implementado numa plataforma para supervisão e controle em tempo real, baseada no CompactRIO 9073 e no software LabVIEW, da National Instruments, do Laboratório de Inteligência Computacional Aplicada à Tecnologia (ICAT/DEE/IFMA), com aplicação ao controle de temperatura de uma planta térmica. Resultados experimentais mostram a eficiência da metodologia proposta, uma vez que a trajetória de referência é seguida e as margens de ganho e fase permanecem próximas às especificadas.

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