Navegando por Assunto "Controle de processos (Eng. sistemas)"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Aplicação de sensores virtuais na inferência da temperatura de banho no processo de fabricação de alumínio primário
(Universidade Federal do Pará, 2009-12-14) SOARES, Fábio Mendes; OLIVEIRA, Roberto Célio Limão de; http://lattes.cnpq.br/4497607460894318
Nowadays, industries worldwide are looking forward to enlarge their profits and become more competitive. A good management is a key factor to accomplish the company’s target, however all management decisions are supported by tools that provide good and relevant information for the process, which usually influences decision making strategically. Soft Sensors have been applied in industries which are aiming that target and its use has been growing lately. A soft sensor can be adapted to any application regarding variable measurement, therefore reducing operational costs without compromising the current information quality, and in some cases, better results can be obtained. Since they are software based, they are not subjected to physical damages as real sensors are, so they can be adapted virtually to hostile environments. The key of this kind of sensor success is the use of computational intelligence techniques, which has been heavily used in nonlinear and highly complex process modeling. Currently, many industries already use them successfully, and this work exploits its use with Neural Networks in a chemical process in an important Brazilian Aluminum Smelter whose control is very hard to maintain once it is not easy to retrieve information from the plant due to its corrosive nature and whose measurements require some operational resources. The usage of soft sensors within it may reduce costs and delays of measures drastically. A case of use of the soft sensor for temperature measure is presented on this work, since its design through implementation at production, according to a researched methodology.
Acesso aberto (Open Access)
Controle automático de adição de AlF3 em cubas de redução de alumínio, usando lógica fuzzy
(Universidade Federal do Pará, 2005-12-21) PEREIRA, Vanilson Gomes; OLIVEIRA, Roberto Célio Limão de; http://lattes.cnpq.br/4497607460894318
This work describes a data analysis system, which generates an intelligent aluminum fluoride (AlF3) addition strategy for electrolytic cells. The project is based on Fuzzy logic concepts, wherein the knowledge accumulated by the process specialist is translated in a qualitative manner into a set of linguistic rules such as: IF THEN. The use of this fuzzy technique for fluoride addition control seeks to explicitly represent an implicit knowledge, retained by the cell operators of the electrolytic cells. Due the conventional system not to contemplate the variations of the phenomena that they involve the dynamics of the process, a controller fuzzy was implemented in the real system for taking of decisions, using the minimum model of Mandani. Based this model, the process variables to input fuzzy system, such as bath temperature and fluoride of aluminum were manipulated to estimate the tendency up and down, through the Method of Least Squares(MLS). The controller fuzzy is applied to calculate the amount of fluoride of aluminum (AlF3) to be added in the electrolytic cells in an automatic way without the need of the the specialist?s of the process intervention. The use of a fuzzy control system is justified by the fact of not having an available dynamic model for aluminum fluoride addition process in electrolytic cells. This lack of modeling is due to the great complexity of the phenomena involved in a cell, which are thermodynamic and electromagnetic processes linked together.
Acesso aberto (Open Access)
Controle de exaustão de fornos de cozimento de anodos baseado em lógica fuzzy
(Universidade Federal do Pará, 2011-01-14) CARNEIRO, Cleber Miralha; COSTA JÚNIOR, Carlos Tavares da; http://lattes.cnpq.br/6328549183075122
With the ambient legislation becoming more rigorous all the time the industry has forced to invest in innovative solutions of control, searching to diminish the emissions of pollutants gases of the mobile and fixed sources, exerting better control and treatment of the pollutants comply to the limits imposed by law. Presented in this work, the implementation of an improvement in the exhaust control system for the anodes baking ovens used at the ALBRAS-Aluminio Brasileiro S.A. smelter, located in Barcarena in the state of Pará, aiming at to minimize the pollution caused by the fuel burning in the ovens without compromising the efficiency of the process. For this, a fuzzy logic based system was used, exploiting the experience of engineers, technicians and process operators, a way of getting better control and reliability in the emissions management of the pollutant gases.
Acesso aberto (Open Access)
Controle Fuzzy aplicado à melhoria da estabilidade dinâmica em sistemas elétricos de potência
(2005-06) BARRA JUNIOR, Walter; BARREIROS, José Augusto Lima; COSTA JÚNIOR, Carlos Tavares da; FERREIRA, André Maurício Damasceno
This work presents a fuzzy control strategy which can be applied to improve the dynamic stability of electric power systems. The gains of fuzzy controller are smoothly adjusted by using interpolation among the gains of a set of previously designed local controllers, according to the current plant operating condition. In this way, the parameters of the fuzzy controller are automatically adjusted on-line, in order to cope with changes in the power system operating conditions. The performance of the fuzzy strategy was assessed by simulation studies, using a nonlinear machine infinite bus bar dynamic model. The results show that it is possible to improve the power system dynamic performance under time-variable operating conditions.in english. Please notice that the abstract in english comes first.