Sistemas de geração de referências para as malhas de controle de laminadores a frio têm proporcionado elevados níveis de produtividade e de qualidade do material processado. No caso de falha da unidade de processamento responsável pela execução do sistema de geração de referências, a operação do laminador fica comprometida e necessita-se de um modo de operação emergencial. Nesse trabalho é desenvolvido um sistema alternativo para geração de referências que visa substituir o modo de operação de emergência de consulta a tabelas de referências pré-calculadas da planta em questão. O sistema de geração de referências desenvolvido, assim como o sistema usado em condições normais de operação, é composto por uma função custo que avalia o nível de produtividade e de qualidade que um conjunto de referências pode proporcionar. A função custo é minimizada pelo método simplex de Nelder e Mead e as variáveis do processo envolvidas na função custo são avaliadas por um modelo de laminação a frio composto somente por equações algébricas, enquanto que o sistema usado em condições normais de operação usa um modelo clássico, composto por equações algébricas e integrais. A comparação entre o sistema usado em condições normais de operação e o sistema desenvolvido mostrou que apesar desse sistema ser mais simples, menos preciso e robusto, as referências por ele calculadas são aceitáveis e podem proporcionar resultados superiores que o modo de operação de emergência baseado na consulta a tabelas. / Setup generation systems for cold mill control loops have provided rolling mill operation with high levels of quality and productivity. In case of malfunctioning in the process unit responsible to execute the setup generation system, the normal procedure for the operation of the mill is interrupted, being necessary the use of an emergency operation mode. This work develops an alternative system for references generation which aims to replace the current emergency operation mode based on pre-calculated, not continuous, setup tables for the rolling mill. The developed references generation system, like the normal system used during mill operation, is composed by a cost function which evaluated the mill quality and productivity operation level which a set of references may propose. The cost function is minimized using the Nelder and Mead simplex method and the process variables involved in the cost function are evaluated by a cold rolling mill model composed only by algebraic equations, while the normal operation system uses a classical model, made up by integrals and algebraic equations. Comparing the existing main setup system to the developed reference system it was observed that, despite its simplicity, less accuracy and less robustness, references calculated using this system were accurate enough to achieve better results than the one emergency table mode has provided.

Orientadores: Sandra Lucia da Cruz, João Alexandre F. R. Pereira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-07-27T15:50:28Z (GMT). No. of bitstreams: 1 Oisiovici_RoniaMarques_D.pdf: 4098399 bytes, checksum: e53dcc32c80f82bc98dfe9a977ac5466 (MD5) Previous issue date: 2001 / Resumo: Os processos em batelada são largamente empregados nas indústrias de Química Fina, produtos bioquímicos, polímeros e fármacos. As plantas em batelada tendem a crescer, já que esse tipo de configuração apresenta características que são desejáveis nas chamadas "plantas do futuro": flexibilidade operacional, resposta rápida às exigências do mercado, capacidade de processar produtos de alta pureza e alto valor agregado. A destilação em batelada, em particular, é a operação unitária mais freqüentemente utilizada nas plantas em batelada. Algumas dificuldades encontradas na sua automação são: fortes não-linearidades, desvios entre o modelo e o processo, ganhos variáveis no tempo, presença de ruídos nas medidas, analisadores de composição "on-line" complexos ou lentos, estimativa do estado do sistema dificil e cara em termos computacionais. O controle de colunas de destilação contínuas de alta pureza é um tópico bastante abordado na literatura. Porém, trabalhos sobre destilação em batelada de alta pureza são escassos e, normalmente, apenas simulações são apresentadas. Esse trabalho teve como objetivo o desenvolvimento de um sistema de controle por inferência para colunas de destilação em batelada de alta pureza robusto às dificuldades de automação encontradas na prática. O algoritmo de controle foi testado por simulação e, para confirmar a aplicabilidade do controlador desenvolvido, corridas experimentais foram realizadas numa coluna de destilação em batelada em escala piloto. Um Filtro de Kalman Estendido (FKE) para colunas de destilação em batelada foi desenvolvido para fornecer estimativas de composições instantâneas a partir de algumas medidas de temperatura. O FKE foi combinado a uma estratégia de controle baseada na estrutura GLC ("Globa1ly Linearizing Control"), resultando num sistema de controle por inferência que mantém constante a composição do produto de topo de colunas de destilação em batelada de alta pureza. O controlador GLC foi testado numa coluna de destilação em batelada em escala piloto com 29 pratos perfurados. As corridas experimentais foram realizadas com o sistema etanol/l-propanol. A interface entre o computador e o processo foi feita através de uma placa ADIDA. Termopares foram utilizados para medir temperaturas instantâneas em alguns estágios da coluna. A cada período de amostragem, o FKE fornece valores de composição instantâneos, utilizando os dados de temperatura lidos pelo computador. Com o objetivo de manter a pureza do produto de topo no valor especificado, o controlador GLC atualiza a razão de refluxo baseado nas estimativas mais recentes de composição. A razão de refluxo calculada é, então, implementada pelo computador que controla a posição e o tempo de abertura da válvula magnética de refluxo. O número de sensores e o intervalo de integração do modelo da coluna foram variáveis importantes no projeto do FKE. Convergência mais rápida e estimativas mais exatas foram obtidas aumentando-se o número de sensores e/ou reduzindo-se o intervalo de integração. No entanto, acima de um certo número de sensores, as melhorias na exatidão das estimativas são insignificantes. Nas corridas em malha fechada, a variável manipulada (razão de refluxo) apresentou um comportamento do tipo liga/desliga quando os sensores de temperatura foram posicionados nos estágios próximos ao topo da coluna, onde as variações de temperatura são pequenas. Afastando-se os sensores do topo da coluna, perfis mais suaves das variáveis manipulada e controlada foram observados e desvios inferiores a 0,2% entre a composição média do destilado estimada e a composição média do destilado medida foram obtidos. Para o controle da composição do destilado de alta pureza, os sensores devem ficar afastados do topo, mas não tão distantes a ponto de diminuir a exatidão das estimativas de composição. Devido à sua robustez em relação aos desvios entre o modelo e o processo, incerteza nas condições iniciais da coluna e a presença de ruídos nas medidas de temperatura, o controlador por inferência desenvolvido nesse trabalho, além de ser flexível, mostrou-se eficaz em aplicações práticas / Abstract: Batch processing has been widely used in the production of fine chemicaIs, biochemicals, polymers and phannaceuticals. Batch configurations present features which are desirable in the ca1led "future plants": flexibility of operation, rapid response to changing market demands, suitability for manufacturing high-quality and high value-added products. Batch distillation is the most frequent separation method in batch processes. Some ofthe challenges to be faced in the automation ofbatch plants are: pronounced nonHnearities, process/model mismatch, time varying process gains, presence of measurement noise, on-line sensors are unavailable or give delayed results, state estimation is difficult and computationally expensive. While the control of high-purity continuous distillation column is a subject often addressed in literature, there are very few papers regarding the control of high-purity batch distillation units. This work aimed to develop an inferential control system for high-purity batch distillation colurnns, which is able to cape with the automation difficulties common1yencountered in practice. The control algorithm was first tested by simulation and then experimental runs were carried out in a pilot-scale batch distillation column to confirm the practical appHcability ofthe designed inferential control system. An Extended Kalman Filter (EKF) for batch distillation columns was developed to provide fast and reHable instantaneous composition values from few temperature measurements. The EKF was then combined with a control strategy based on the Globally Linearizing Control (GLC) structure, resulting in an inferential control system for constant distillate operation of high-purity batch distillation columns. The GLC controller was tested in a pilot-scale batch distillation column with 29 sieve trays. The separation of ethanol/l-propanol mixtures were considered in the experimental runs. The interface between the computer and the process was achieved by an AD/DA converter. Thennocouples were used to measure instantaneous temperature values at some column stages. At each sampling period, the EKF provides instantaneous composition values from the temperature data the computer acquires. In order to keep the product quality at the set-point, the GLC controller updates the reflux ratio using the composition estimates, and the computer controls the position ofthe reflux magnetic valve to implement the calculated reflux ratio. The number of sensors and the model integration interval showed to be important variables in the design ofthe EKF. Faster convergence and more accurate estimates were obtained by increasing the number of sensors and/or reducing the integration intervalo However, above a certain number of sensors the improvement in the EKF performance may not be significant. Spiky reflux ratio profiles were observed when sensors were placed next to the top stages, where the temperature variations are small. As the sensors were placed further from the top stages, smoother manipulated and controlled variable profiles were obtained and the distillate product met the specified purity. The inferential control system achieved tight composition control. The selection of the sensors locations must be a trade-off between obtaining noise reduction and guaranteeing that the EKF will provide acceptable estimate accuracy. Due to its robustness with regards to plant model mismatch, uncertainty in the initial system state and measurement errors, the proposed inferential control scheme is flexible and demonstrated to be feasible for practical on-line applications / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Orientador: Barbara Janet Teruel Mederos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-15T11:28:18Z (GMT). No. of bitstreams: 1 Silva_JoaoCarlosTelesRibeiroda_M.pdf: 3235097 bytes, checksum: 605bf09061dc2c67806ba4d2281cc770 (MD5) Previous issue date: 2010 / Resumo: Este trabalho consiste no estudo da implementação de um controlador clássico utilizando o método de sintonia denominado por IMC (Controle de Modelo Interno, derivado do termo inglês Internal Model Control), visando à redução do consumo de energia elétrica que decorra na adequada relação entre este consumo e tempo de esfriamento do processo de resfriamento com ar forçado. Para isto, o sistema supervisório instalado é capaz de manipular a variável de freqüência do sinal de alimentação do motor de indução trifásico do exaustor (módulo de ar forçado), para acelerar ou desacelerar a perda de calor do produto a ser resfriado por intermédio da variação da vazão de ar que perpassa a massa deste produto. Obteve-se como resultado uma redução no consumo de energia elétrica de 64% e um acréscimo de apenas 8% no tempo de resfriamento para o sistema utilizando o controlador PI/IMC (Proporcional - Integral, com método de sintonia IMC), quando comparado ao sistema em seu funcionamento nominal. Ou seja, sistema que, nominalmente, consume 2,41 kWh para resfriar o produto em 58 minutos, consume 0,87 kWh para resfriar o produto em 63 minutos quando se emprega o controlador que utiliza o método IMC. Este controlador PI/IMC é passível de ser implementado diretamente em alguns modelos comerciais de inversores de freqüência, sem a necessidade de compra de um computador ou controlador lógico programável (CLP), tornando-o mais viável economicamente / Abstract: This work is a study of a classical controller implementation using tuning method referred to as IMC (Internal Model Control), aimed at reducing electrical energy consumption that proceed the appropriate relation between this consumption and cooling time of the cooling process with forced air. For this, the supervisory system installed is able to manipulate the variable of frequency signal power of the exhaust fan engine (forced air module), to accelerate or decelerate the loss of heat from the product to be cooled through of air flow variation that passes through the mass of this product. The results demonstrated a reduction in energy consumption from 64% and an increase of only 8% in the cooling time to the system using PI/IMC (Proportional - Integral with IMC tuning method) compared with the system in its operating nominal condition. In other words, the system, in nominal condition, consumes 2.41 kWh to cool the product in 58 minutes, but when it employs the controller using the IMC method, the system consumes 0.87 kWh to cool the product in 63 minutes. This PI/IMC controller may be implemented directly in some frequency inverter, without the need to purchase a computer or PLC (programmable logic controller), making it more economically viable / Mestrado / Maquinas Agricolas / Mestre em Engenharia Agrícola

Este trabalho apresenta os resultados obtidos no desenvolvimento de um sistema capaz de estabelecer um controle adequado do fluxo da informação e a supervisão de uma rede de sensores. O sistema se caracteriza pelo alto grau de flexibilidade possuindo uma camada de comunicação de dispositivos, uma camada de gerenciamento de regras de negócio para controlar o fluxo de processos, uma camada de interface homem - máquina e de interface com outros sistemas. A camada de comunicação com os dispositivos é responsável pela interface entre os mesmos e o núcleo do sistema, integrando, de forma transparente, diferentes equipamentos, tecnologias e fabricantes. A interface do usuário foi projetada em um único módulo para facilitar modificações sem comprometer o funcionamento geral do sistema. A interface com outros sistemas é feita por meio de drivers de comunicação, permitindo qualquer tipo de integração. O núcleo do sistema faz todo o controle de eventos, do fluxo do processo e geração alarmes, assim como recebimento e envio das informações da camada de dispositivos e da camada de interface. São descritas as diversas camadas da interface e sua implementação analisando as possíveis aplicações do sistema, juntamente com um estudo de caso do controle do processo de descarga de carga a granel no porto de Santos, usando tecnologia RFID. Os resultados obtidos nessa aplicação são descritos e comprovam a utilidade prática do sistema. Apresentam-se inicialmente alguns conceitos básicos necessários ao entendimento deste projeto como: sistemas distribuídos, estrutura webservice, linguagem XML e de tecnologias passíveis de integração com o sistema. / This paperwork presents the results obtained with the development of a system capable of establishing a proper control of information flow and supervision of a sensors network. The system characterizes itself due to its great flexibility degree by having a devices communication layer, a business management layer to do the process flow control, a man-machine interface and interface with other systems layer. The devices communication layer is responsible for the interface between other devices and the system core, integrating in a transparent way, different equipment, technologies and manufactures. The user\'s interface was designed in a single module to facilitate modifications without compromising the system\'s general functioning. The interface with other systems is made throughout communication drivers, allowing any type of integration. The system core makes a control of all events, process flow and alarm generation, as well as receiving and sending information from the devices layer and interface layer. The several interface layers and its implementation are described analyzing the system\'s possible applications along with a case study of loading discharge in a bulk process control at Santos Port using RFID technology. The results obtained with this application are described and prove the practical utility of the system. Some necessary basic concepts to understand this project are presented initially as: distributed systems, web service structure, XML language and technologies subjected to integration with the system.

Orientador: Ana Maria Frattini Fileti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T11:59:30Z (GMT). No. of bitstreams: 1 Eyng_Eduardo_D.pdf: 1208739 bytes, checksum: c9be67bb6bff66ba4c64a7c49af4fe41 (MD5) Previous issue date: 2008 / Resumo: O etanol perdido por evaporacao durante o processo de producao por fermentação pode ser recuperado por uma coluna de absorcao, a qual requer um sistema de controle robusto de acordo com sua complexidade. Este equipamento tambem e utilizado no tratamento do CO2, um co-produto deste processo. Neste sentido, no presente trabalho foi proposto e testado, o emprego de controladores feedforward-feedback, baseados em modelo inverso de redes neurais, os quais manipulam as vazoes de solvente que sao alimentados as colunas, para controlar a concentracao de etanol na corrente gasosa a saida da primeira coluna, e a concentracao de agua residual no efluente gasoso da segunda. Simulacoes foram feitas, sendo abordado tanto o problema regulatorio quanto o problema servo para as duas colunas de absorcao do processo estudado. O desempenho do controlador neural foi superior ao apresentado por um controlador convencional PID, para ambas as colunas de absorcao estudadas, pois o tempo de resposta, assim como o overshoot foi menor. A superioridade do controlador neural foi comprovada pelos valores obtidos para os parametros ITAE (integral do erro absoluto ponderada pelo tempo), IAE (integral do erro absoluto) e ISE (integral do quadrado do erro). Outro objetivo deste trabalho foi avaliar a influencia das incertezas nos sensores sobre o desempenho do sistema de controle. Foram testados tres niveis: 5, 10 e 15%, sendo as incertezas inseridas nas variaveis de entrada do tipo concentracao de etanol/agua residual na corrente gasosa. Para a coluna de recuperacao de etanol, tanto para o problema regulatorio quanto servo, nenhum controlador conseguiu estabilizar a variavel controlada no set point, no entanto, quando empregado o controlador neural a amplitude da faixa de oscilacao da variavel controlada foi menor para todos os niveis de incerteza testados. Já para a coluna de tratamento de CO2, os controladores encontraram dificuldades em manter a estabilidade do sistema. Neste sentido, o controlador neural apresentou um desempenho satisfatorio para incertezas de 5 e 10%, enquanto que o PID nao conseguiu manter o sistema estavel para incertezas superiores a 5%. Com base nos testes realizados foi constatado que o controlador neural proposto constitui uma opcao atrativa para o controle das colunas de absorcao do processo deproducao de etanol por fermentacao, principalmente quando os niveis de incerteza forem de ate 10%. / Abstract: Some of ethanol lost by evaporation during its fermentation production process may be recovered using an absorption column, which requires a robust control system. This equipment also is used on carbonic gas treatment, a by-product of this process. In the present work, the development of nonlinear feedforward-feedback controllers, based on a neural network inverse model, was proposed and tested to manipulate the absorbent flow rates in order to control the residual ethanol concentration in the effluent gas phase at the first absorption column, and the residual water at the second one. Simulation studies were carried out for the regulator and servo problem, for both absorption columns studied. The neural controller proposed outperformed a conventional PID, because the response time, and also the overshoot were smaller when the neural controller was applied. The results were confirmed by the ITAE (integral of time multiplied by the absolute error), IAE (integral of absolute error) and ISE (integral of square error) parameters. The measurement uncertainties influence on control system performance was tested for three levels: 5, 10 and 15%. The uncertainties were introduced on ethanol/residual water concentration on gas phase. For the ethanol recovery column, neither PID nor the neural controller drove the controlled variable exactly to the set point, however, the neural controller provided a smaller oscillation for all uncertainty levels tested, for regulator and servo problem. The neural controller also outperformed PID in CO2 treatment column. For the regulator and servo problems the neural controller successfully proceeded when the uncertainty level was 5% or 10%, while the PID did not deal adequately with uncertainties above 5%. Therefore, the proposed neural controller proved be an attractive control solution for the absorption columns of ethanol production process by fermentation, especially when the input variables carry small uncertainties ( less than 10%) from the sensors. / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

A number of factors have contributed to increased pressure on plant operating efficiency in the chemical processing industry. These factors include more stringent environmental and safety regulations, global economic pressures and downsizing of many support services in order to save money. Control performance monitoring is a tool that is used to keep control systems performing as optimally as possible. Various performance metrics and methods exist to evaluate plant operation. In essence, however, they all refer to the same principle which is to indicate how far a plant is operating from its inherent optimum and what can be done to ensure that the gap between the optimum and the current operation is as small as possible over the longest possible period. Performance monitoring is, although well researched, not a generic, complete and specific application. Current shortcomings of monitoring applications include the following; they are process or unit operation specific and they provide local indications of performance and do not provide a plant wide evaluation of how close the plant is operating to its inherent optimum. Performance reports are usually in terms of statistical measures and graphics which are usually abstract and vague. For high level decisions making (on operation end economic investment) simple and quantifiable measures are needed that are repeatable and transparent. The focus of this project was to develop and implement a regulatory performance monitoring structure for real-time application on an industrial pilot scale distillation column. The structure was implemented by means of two graphical interfaces. The first interface provides a holistic plantwide indication of performance and indicates sources of poor performance in the regulatory control structure. The plantwide interface includes a proposed plant wide performance index (PWI) that reduces operational efficiency to one specific number. The second interface supplements the plantwide interface by providing statistical information on individual loop performance. The individual loop interface is a tool to locate causes of poor performance in the regulatory control structure to aid controller and plant maintenance. / Dissertation (MEng (Control Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted

Please read the abstract (Summary) in the section, 00front of this document / Dissertation (M Eng (Electronic Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

In today's global economy the need for an efficient and optimised supply chain is increasing. Recent studies showed that supply chain management is one of the areas that have a great impact on the financial well being of an organization as well as customer satisfaction. The recognition of the importance of efficient and optimised supply chains has led to increasing investments in supply chain planning and execution systems. In order to compete in the global market place organizations want to develop systems that enable fast and effective on time delivery of products to customers. Therefore generating the necessary customer satisfaction. Today there are APS (Advanced Planning&Scheduling) systems available to help "manage" the supply chains. These tools were specifically designed to have the ability to rapidly and simultaneously plan and schedule customer demand while considering material and capacity constraints. Not only does these systems provide the ability to increase revenues, but it can also increase the customer service and cut costs by synchronized management of the complete supply chain. Although these systems help to improve the system, it is restricted to the static part and it does not incorporate the dynamic part. The result therefore is that a lot of "noise" still exists within the system once the results are achieved. This opened the way for solutions that can provide insight to the uncertainty and interdependency of processes and customer demand within the supply chain. One way of gaining insight into the system variation and interdependencies is through the use of simulation technology. This type of technology allows organizations to predict future behaviour and test future designs or do redesigns of their current supply chains. The scope of this dissertation is to develop a supply chain planning methodology, which will help to improve the understanding of the uncertainty and interdependency of processes within the supply chain. To design this methodology different steps are taken in order to introduce the final solution. Therefore, four main methods were used; literature research, market research, supply chain planning methodology development and a case study. The literature research brought to light the reasons for the inefficiencies and variations in supply chain planning and why the need for change exists. During the supply chain market research several supply chain planning and execution systems were under study. From this it was quite clear that the only way that organisations can ensure one optimal answer is when the demand is constant and there is a zero percent chance that it could change. In real world systems it is virtually impossible to accurately predict future demand 100 percent of the time, and therefore variability and randomness cannot be excluded from a supply chain solution. This paved the way for the introduction of simulation technology as a possible solution for this variability and randomness. The market research was concluded with the analyses of the current simulation solutions in the market. The next step in the design phase was the introduction of the new supply chain planning methodology. The main purpose of this new methodology is to use the power of modelling and simulation to improve the initial supply chain performance. This methodology focuses on initial supply chain design, analyses and optimisation. By introducing this methodology organisations are now able to compare current supply chains with an unlimited realm of possible future configurations .... and without disrupting the initial day-to-day operations of an actual supply chain. The methodology is also designed to help predict the supply chain performance in terms of throughput, tardiness, utilisation, profitability, and other key performance indicators ... In order to experience real-life supply chain problems a case study has been done. This case study is about the automotive industry, which will include the ordering of parts assembly of vehicles, warehousing and distribution of vehicles. Different problems and difficulties were experienced. In conclusion, this case study provided a better insight into the behaviour of a supply chain. The case study was used to evaluate the use of this new methodology and as a result certain inefficiencies were recognized. As a result of the evaluation certain improvements need to be made to the supply chain methodology in order to make it more suitable for the market. These improvements would focus on inventory planning, supply chain analysis as well as database integration. The result of the case study also showed that the supply chain planning methodology is now set to develop a supply chain solution on the lowest level. There is however a need to be able to grow this supply chain methodology from a low level to a relatively high level. These functions are among others higher-level planning modules, which focus on transportation, production, demand and distribution and performance measurements. The focus will be to introduce these functions as objects. Every object will have the ability to design a supply chain solution on a high level or low level depending on the detail and requirements. ••• I also believe that the one who adapts his policy to the times prospers, and likewise that the one whose policy clashes with the demands of the times does not. 11 Niccolo Machiavelli, 1525 / Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2006. / Industrial and Systems Engineering / unrestricted

Computer graphics is being used more and more to provide operator windows to an industrial process, but the development and interfacing are difficult and tedious. As more dedicated microcomputer based control systems are being used in industry, there is more need for computer process display systems that are in the same cost category as control systems. Presently, there is no microprocessor based system that permits plant personnel to develop and interface a process display graph in a simple parameterized way, without the need of a computer systems specialist. This thesis presents a parameterized graphic development and interface software package (IGDISP) developed in Fortran 77 on a PDP 11/44 driving a RAMTEK 9351 raster graphic terminal. IGDISP allows the plant process engineer to develop his own process graph without having to write any software. As part of the design of IGDISP, a human factors study of man to computer graphics display was conducted, with special emphasis being given to those features involved with industrial graphics systems. Different graphical methods used to best illustrate an industrial process are reviewed. The aim of the human factors study is to assist the IGDISP and other industrial computer graphics user to develop the best process window to his process.

The thesis is divided into three parts. Theoretical part defines particular concepts as process, process control or controlling. Practical part contains a company profile and an analysis of current method of costing. In the third part opportunities for improvement of the method of costing are designed.