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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.
71

Constru??o e controle inteligente de um manipulador rob?tico com dois graus de liberdade

Silva, Jobson Francisco da 08 June 2012 (has links)
Made available in DSpace on 2014-12-17T14:56:03Z (GMT). No. of bitstreams: 1 JobsonFS_DISSERT.pdf: 3147277 bytes, checksum: 9416518f7f32bb71bac0fdf3eb8002f3 (MD5) Previous issue date: 2012-06-08 / The present work shows the development and construction of a robot manipulator with two rotary joints and two degrees of freedom, driven by three-phase induction motors. The positions of the arm and base are made, for comparison, by a fuzzy controller and a PID controller implemented in LabVIEW? programming environment. The robot manipulator moves in an area equivalent to a quarter of a sphere. Experimental results have shown that the fuzzy controller has superior performance to PID controller when tracking single and multiple step trajectories, for the cases of load and no load / O presente trabalho mostra o desenvolvimento e constru??o de um manipulador rob?tico de juntas rotativas com dois graus de liberdade, acionado por motores de indu??o trif?sicos. Os posicionamentos do bra?o e da base s?o realizados, para efeito de compara??o, por um controlador fuzzy e por um controlador PID, implementados no ambiente de programa??o LabVIEW?. O rob? desenvolvido permite movimenta??o numa ?rea espacial equivalente a um quarto de esfera. Resultados experimentais demonstraram que o controlador fuzzy apresenta desempenho superior ao do controlador PID quando o manipulador rob?tico executa trajet?rias dos tipos degrau vari?vel e degrau unit?rio com carga e sem carga
72

Proposta de um controlador difuso Takagi-Sugeno com desempenho H \'INFINITO\' para regulagem da marcha lenta em motores de ciclo Otto / Otto cicle engine idle speed H \'INFINITE\' Takagi-Sugeno fuzzy control

Carlos Eduardo Milhor 22 February 2008 (has links)
Propõe-se um controlador difuso Takagi-Sugeno com índice de desempenho H \'INFINITO\' para regulagem da marcha lenta em motores de ciclo Otto. Obtém-se uma representação difusa do motor de ciclo Otto operando em marcha lenta. Esse modelo é utilizado para a síntese do controlador. O controlador difuso com desempenho H \'INFINITO\' é projetado para rejeitar o efeito de distúrbios de cargas externas sobre a rotação do motor em regime de marcha lenta. As ações de controle, posição da borboleta de aceleração e ponto de ignição, são limitadas a uma faixa de operação específica para a marcha lenta. O controlador projetado apresenta ação de controle por realimentação de estados. Os ganhos de realimentação para cada regra do controlador difuso são obtidos a partir de um problema de otimização formulado através de LMIs. / It is proposed an Otto cicle engine idle speed H \'INFINITE\' Takagi-Sugeno fuzzy control. It is presented an Otto cicle engine idle speed fuzzy model. This model is then used to control design. The H \'INFINITE\' fuzzy control is designed to reject external load disturbance effect at idle speed engine rotation. A specifc idle speed operation range is defined to both actions control, throttle plate position and spark advance. A state feedback control is designed. A LMI optmization problem is used to find the state feedback gains at each fuzzy control rule.
73

Controle difuso em transportadores pneumáticos de sólidos: redução do consumo de potência / Improving the power consumption in pneumatic conveying systems by fuzzy control strategy

Paulo Roberto Barbosa 27 June 2005 (has links)
O transporte pneumático de sólidos constitui uma aplicação comum em processos industriais petroquímicos, de mineração, de alimentos e agrícola. Entretanto, devido a limitações de ordem prática, a maioria das aplicações existente envolve o transporte de 1 a 400 toneladas por hora, através de distâncias de até 1000 m. Entre estas limitações, o consumo de potência provavelmente é a mais severa. Um sistema de transporte seguro e que apresente uma redução no consumo de potência pode ser implementado com técnicas não convencionais de controle. Este trabalho descreve a implementação de um controlador difuso em um circuito experimental de 45 mm de diâmetro interno utilizado para transportar sementes de Setaria Itálica ao longo de 21 metros. Informações obtidas com um estudo prévio de identificação de regimes gás - sólido através de redes neurais auto-organizáveis foram utilizadas no projeto do controlador. Os resultados mostraram uma redução significativa de 41%, em média, no consumo de potência requerida para o transporte de uma mesma carga de sólido. / The pneumatic conveying of solids in a gas stream is a recurrent process in petrochemical industries as well as in agricultural, food and mining. However, due to practical limitations the majority of existing systems have capacities ranging from 1 to 400 tones per hour over distances less than 1000 m, mainly because of a high power consumption per transported unit mass. A safe circuit with reduced power consumption can be designed using non-conventional control techniques. This work describes a fuzzy controller implementation for a 45 mm i.d. pneumatic conveying system used to transport Setaria Italica seeds over a distance of 21 m. Data obtained in a previous study about gas-solid flow regime identification through a self-organizing neural network were used in the controller design. The results show that reduction in power consumption can reach 41% when compared with classical non controller transport.
74

Controlador nebuloso para estabilidade de quadrotores

Sales, Diego Câmara 26 July 2014 (has links)
Submitted by Adriely Bruce (adriely_bruce@hotmail.com) on 2016-12-16T13:13:00Z No. of bitstreams: 1 Dissertação - Diego Câmara Sales.pdf: 3202633 bytes, checksum: b132b1fefafdda85faf38c42f7092ae2 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-12-22T15:15:35Z (GMT) No. of bitstreams: 1 Dissertação - Diego Câmara Sales.pdf: 3202633 bytes, checksum: b132b1fefafdda85faf38c42f7092ae2 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-12-22T15:16:44Z (GMT) No. of bitstreams: 1 Dissertação - Diego Câmara Sales.pdf: 3202633 bytes, checksum: b132b1fefafdda85faf38c42f7092ae2 (MD5) / Made available in DSpace on 2016-12-22T15:16:44Z (GMT). No. of bitstreams: 1 Dissertação - Diego Câmara Sales.pdf: 3202633 bytes, checksum: b132b1fefafdda85faf38c42f7092ae2 (MD5) Previous issue date: 2014-07-26 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / Nowadays kind quadrotor helicopters are becoming popular in developing research in unmanned aerial vehicles UAV, for its ability to planar and vertical landing in hard to reach places. The control of most of these vehicles is based on physical or experimental dynamic models, and may have a high cost due to the time of project development. In this work is presented the stability control using fuzzy logic, which eliminates the need for a dynamic model for the controller design. Using the least amount of linguistic rules in order to enable the implementation of the controller in embedded systems with low computational capacity. / Hoje em dia os helicópteros do tipo quadrotor estão se tornando populares no desenvolvimento de pesquisas em veículos aéreos não tripulados VANT, pela sua capacidade de pouso vertical e de planar em locais de difícil acesso. O controle da maioria destes veículos é baseado em modelos dinâmicos físicos ou experimentais, podendo apresentar um alto custo devido ao tempo de desenvolvimento do projeto. Neste trabalho é apresentado o controle de estabilidade de um quadrotor utilizando lógica fuzzy, que dispensa a necessidade de um modelo dinâmico para o projeto do controlador. Utilizando a menor quantidade de regras linguísticas com o intuito de viabilizar a implementação do controlador em sistemas embarcados de baixa capacidade computacional simplificando o desenvolvimento do controlador de estabilidade do sistema proposto.
75

Automação de um sistema de pulverização para aplicação de agroquímicos a taxa variada usando injeção direta / Automation of a direct injection sprayer system for variable rate application of agrochemicals

Heitor Vinicius Mercaldi 10 September 2012 (has links)
Neste trabalho, a automação de um sistema de pulverização a taxa variada com injeção direta é apresentado. A automação do sistema de pulverização montado em uma bancada laboratorial estática foi baseado em um controlador programável com capacidade de tempo real. Os sistemas de pulverização com injeção direta possibilitam o uso de diferentes agroquímicos em uma mesma aplicação, e adicionalmente reduzem os impactos toxicológico e ambiental relacionados com o preparo e descarte da mistura de agroquímico e água. A automação deste sistema envolve o desenvolvimento de placas de interface, a modelagem do pulverizador e o controle das vazões. Um ambiente de simulação baseado no LabVIEW permitiu que os códigos fonte e as rotinas desenvolvidas fossem utilizadas diretamente no controlador programável, exigindo pouca ou nenhuma modificação. Para regular a vazão de injeção do agroquímico, que é dada por uma bomba de pistão, é utilizado um controlador proporcional-integral (PI). Já para regular a vazão da mistura de agroquímico e água, que é dada por uma válvula de controle proporcional de três vias, são implementados dois controladores: um controlador proporcional-integral-derivativo (PID) e um controlador adaptativo do tipo PID fuzzy por escalonamento de ganho. O desempenho dos controladores implementados são analisados via os resultados do erro de aplicação e das vazões. / In this work, the automation of a direct injection sprayer system for variable rate application of agrochemicals is presented. The automation of the sprayer system assembled on a laboratory static bench is based on a programmable controller with real time capabilities. Variable rate sprayer with direct injection systems allow multiple agrochemical application and additionally reduces the toxicologic and environmental risks associated with the carrier-agrochemical mix preparation and discard. The automation of this system comprises the development of interface boards, the sprayer modeling and the control of flow rates. Using a simulation environment based on LabVIEW, the developed source code and routines could be implemented directly in the programmable controller, requiring few or no changes. For the injection flow rate, which is set by a piston pump, a proportional-integral (PI) controller is used. And, to regulate the carrier-agrochemical mix flow rate, which is set by a three-way proportional control valve, two controllers are used: a proportional-integral-derivative (PID) controller and a fuzzy gain scheduling of PID controller. The performance of the implemented controllers is analyzed via the flow rates and the application error results.
76

Optimisation de la Cartographie et de la navigation des Robots Mobiles Coopératifs / Cooperative Mobile Robots Optimal Mapping and Navigation

Tian, Daji 18 December 2014 (has links)
Cette thèse présente tout d'abord un méthode d’exploration mono-robot, ensuite une stratégie coopérative décentralisée d'exploration pour un groupe de robots équipés de range finders. Une carte 2-D de la zone explorée est construite sous la forme de figure en pixels et est étendue par les robots en utilisant un planner local qui décide automatiquement entre l'information gagnée et le coût d'exploration. La carte est construite en utilisant la méthode des moindres carrés pour réduire les erreurs des données des capteurs. En divisant la tâche globale en sous-tâches, un contrôleur intelligent permet de réduire la complexité. Cependant, la fusion de différents comportements avec des objectifs différents peut entraîner des contradictions et modifier ainsi la stabilité du système. Par conséquent, la question de mécanisme de coordination de comportements est essentielle pour réaliser un mouvement sécurisé sans collisions. Une méthode intégrée par la coordination des comportements et de commande par fusion est proposée dans le présent travail. Une nouvelle approche basée sur cinq comportements de base pour la navigation de robots mobiles est discutée. Player/Stage est un projet de logiciel open-source pour la recherche sur la robotique. Ses composants comprennent le serveur de réseau et les simulateurs de robot pour plusieurs types de plates-formes de robots. Nous utilisons principalement simulation sous Player/Stage pour tester nos algorithmes en mono-agents/multi-agents , en cartographie et en navigation. Les résultats obtenus montrent que les solutions proposées sont efficaces et peuvent être utilisées dans des robots réels. / In this Ph. D., we will present firstly a single robot exploration method, then a decentralized cooperative exploration strategy for a team of mobile robots equipped with a range finders. A two dimensional map of the explored area is built in the form of a pixel figure. This is expanded by the robots by using a randomized local planner that authomatically realizes a decision between information gain and navigation cost. In our work, the map is reconstructed using a least-mean square method to reduce the errors of the sensor data. In dividing the overall task into subtasks, the intelligent controller allows reducing the robots task complexity. But the fusion of different behaviors with different objectives may cause contradiction in the procedure and alter the stability of the system. Therefore, the issue of behavior coordination mechanisms is crucial in order to realize the non-collision safety-ensured movements. A method integrated by behavior coordination and command fusion is proposed. A new approach with five basic behaviors for mobile robot navigation is discussed.Player/ Stage is an open-source software project for research in robotics and sensor systems. Its components include the Player network server and the Stage robot platform simulators providing a hardware abstraction layer to several popular robot platforms. Player is one of the most popular robot interfaces in research. We mainly use Player/Stage simulation to test our algorithms in mono-agent/multi-agent exploration, map reconstruction and robot navigation. Obtained results show that the proposed approaches are effective and can be applied in real robots.
77

OPTIMALIZACE NÁVRHU FUZZY ŘÍZENÍ VZHLEDEM K ROZSAHU POHYBŮ PARALELNÍHO MECHANISMU / OPTIMIZATION OF A FUZZY CONTROL DESIGN WITH RESPECT TO A PARALLEL MECHANISM WORKSPACE

Andrš, Ondřej January 2012 (has links)
The Ph.D. thesis is focused on using the fuzzy logic for control of a parallel manipulator based on a Stewart platform. The proposed mechanism makes possible to simulate the physiological movements of the human body and observe degradation processes of the cord implants. Parallel manipulators such as a Stewart platform represent a completely parallel kinematic mechanism that has major differences from typical serial link robots. However, they have some drawbacks of relatively small workspace and difficult forward kinematic problems. Generally, forward kinematic of a parallel manipulators is very complicated and difficult to solve. This thesis presents a simple and efficient approach to design simulation model of forward kinematic based on Takagi-Sugeno type fuzzy inference system. The control system of the parallel manipulator id based on state-space and fuzzy logic controllers. The proposed fuzzy controller uses a Sugeno type fuzzy inference system (FIS) which is derived from discrete position state-space controller with an input integrator. The controller design method is based on anfis (adaptive neuro-fuzzy inference system) training routine. It utilizes a combination of the least-squares method and the backpropagation gradient descent method for training FIS membership function parameters to emulate a given training data set. The proposed fuzzy logic controllers are used for the control of a linear actuator. The capabilities of the designed control system are shown on verification experiment.
78

Stable Control of Jumping in a Planar Biped Robot

Hester, Matthew S. 15 July 2009 (has links)
No description available.
79

Energy monitoring and quality control of a single screw extruder

Deng, J., Li, K., Harkin-Jones, E., Price, M., Karnachi, N., Kelly, Adrian L., Vera-Sorroche, Javier, Coates, Philip D., Brown, Elaine C., Fei, M.R. 01 1900 (has links)
Yes / Polymer extrusion, in which a polymer is melted and conveyed to a mould or die, forms the basis of most polymer processing techniques. Extruders frequently run at non-optimised conditions and can account for 15-20% of overall process energy losses. In times of increasing energy efficiency such losses are a major concern for the industry. Product quality, which depends on the homogeneity and stability of the melt flow which in turn depends on melt temperature and screw speed, is also an issue of concern of processors. Gear pumps can be used to improve the stability of the production line, but the cost is usually high. Likewise it is possible to introduce energy meters but they also add to the capital cost of the machine. Advanced control incorporating soft sensing capabilities offers opportunities to this industry to improve both quality and energy efficiency. Due to strong correlations between the critical variables, such as the melt temperature and melt pressure, traditional decentralized PID (Proportional-Integral-Derivative) control is incapable of handling such processes if stricter product specifications are imposed or the material is changed from one batch to another. In this paper, new real-time energy monitoring methods have been introduced without the need to install power meters or develop data-driven models. The effects of process settings on energy efficiency and melt quality are then studied based on developed monitoring methods. Process variables include barrel heating temperature, water cooling temperature, and screw speed. Finally, a fuzzy logic controller is developed for a single screw extruder to achieve high melt quality. The resultant performance of the developed controller has shown it to be a satisfactory alternative to the expensive gear pump. Energy efficiency of the extruder can further be achieved by optimising the temperature settings. Experimental results from open-loop control and fuzzy control on a Killion 25 mm single screw extruder are presented to confirm the efficacy of the proposed approach. (C) 2013 Elsevier Ltd. All rights reserved.
80

Fuzzy Set Theory Applied to Make Medical Prognoses for Cancer Patients

Zettervall, Hang January 2014 (has links)
As we all know the classical set theory has a deep-rooted influence in the traditional mathematics. According to the two-valued logic, an element can belong to a set or cannot. In the former case, the element’s membership degree will be assigned to one, whereas in the latter case it takes the zero value. With other words, a feeling of imprecision or fuzziness in the two-valued logic does not exist. With the rapid development of science and technology, more and more scientists have gradually come to realize the vital importance of the multi-valued logic. Thus, in 1965, Professor Lotfi A. Zadeh from Berkeley University put forward the concept of a fuzzy set. In less than 60 years, people became more and more familiar with fuzzy set theory. The theory of fuzzy sets has been turned to be a favor applied to many fields. The study aims to apply some classical and extensional methods of fuzzy set theory in life expectancy and treatment prognoses for cancer patients. The research is based on real-life problems encountered in clinical works by physicians. From the introductory items of the fuzzy set theory to the medical applications, a collection of detailed analysis of fuzzy set theory and its extensions are presented in the thesis. Concretely speaking, the Mamdani fuzzy control systems and the Sugeno controller have been applied to predict the survival length of gastric cancer patients. In order to keep the gastric cancer patients, already examined, away from the unnecessary suffering from surgical operation, the fuzzy c-means clustering analysis has been adopted to investigate the possibilities for operation contra to nonoperation. Furthermore, the approach of point set approximation has been adopted to estimate the operation possibilities against to nonoperation for an arbitrary gastric cancer patient. In addition, in the domain of multi-expert decision-making, the probabilistic model, the model of 2-tuple linguistic representations and the hesitant fuzzy linguistic term sets (HFLTS) have been utilized to select the most consensual treatment scheme(s) for two separate prostate cancer patients. The obtained results have supplied the physicians with reliable and helpful information. Therefore, the research work can be seen as the mathematical complements to the physicians’ queries.

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