— In order to know the behavior of DC-DC converters, which provide regulated dc voltage from an unregulated dc source, the study developed in this paper refers to the experimental development of a buck structure type and application of a control strategy in real time using the Arduino platform with the Simulink interface. The purpose of this paper is experimentally verify the lowering characteristic of the converter and to regulate the output voltage using a PI controller. The controller was implemented within the Simulink's block structure, which sends the control signal to the Arduino's analog output port. The Arduino was used to read the converter's output voltage and apply the control signal received from the controller. The expected results were achieved, and the project proved to be a simple and practical alternative for the learning of control systems.

Resumo— Com o objetivo de se conhecer o comportamento dos conversores cc-cc, que fornecem tensão con-tínua regulada a partir de uma fonte contínua não regulada, o estudo desenvolvido neste trabalho refere-se ao desenvolvimento experimental de uma estrutura do tipo buck e aplicação de uma estratégia de controle em tempo real utilizando a plataforma Arduino em conjunto com a interface Simulink. O trabalho tem como propósito verificar experimentalmente a característica abaixadora do conversor e realizar a regulação da tensão de saída por meio de um controlador PI. O controlador foi implementado dentro da estrutura de blocos do Simulink, que envia o sinal de controle para a porta de saída analógica do Arduino. O Arduino foi utilizado para fazer a leitura da tensão de saída do conversor e aplicar o sinal de controle recebido do controlador. Os resultados esperados foram alcançados, e o projeto se mostrou uma alternativa simples e prática para o aprendizado de sistemas de controle.

— In industrial applications, information of the variables of a given process is a crucial step for supervision and control of it. However, in some applications, limitations such as: cost of the sensors, physical space, operational, technological limitations of the sensors, among others, make the direct measurement impossible thereof being necessary to resort to more sophisticated techniques. An interesting alternative to this type of situation is to use the knowledge about observers to estimate (observe) state variables that are not part of the set of measurements using the mathematical model of the process. The objective of this study was to determine the behavior of an RC circuit state variable, using control theory and observer's project via state space of discrete time. It used the Scilab as simulation environment, and the Arduino MEGA2560 as the data acquisition system. Through simulations it was found that the designed observer has met the specifications satisfactorily, since their results were compared with the actual behavior of the estimated state.

Resumo— Nas aplicações industriais, obter informações das variáveis de um dado processó e uma etapa crucial para supervisionamento e controle do mesmo. Porém, em algumas aplicações, limitações como: custo dos sensores, espaço físico, limitações tecnológicas operacionais dos sensores, entre outros, impossibilitam a medição direta das mesmas sendo necessário recorrerà técnicas mais sofisticadas. Uma alternativa interessante a este tipo de situação consiste em utilizar o conhecimento sobre os observadores de estados para estimar(observar) variáveis de estado que não fazem parte do conjunto de medições usando o modelo matemático do processo. O objetivo deste trabalho consistiu em determinar o comportamento da variável de estado de um circuito RC, utilizando teoria de controle e projeto de observadores via espaço de estados de tempo discreto. Utilizou-se o Scilab como ambiente de simulações, e o Arduino MEGA2560, para aquisição de medidas do sistema. Através das simulações realizadas constatou-se que o observador projetado atendeù as especificações de forma satisfatória, uma vez que seus resultados foram comparados com o comportamento real do estado estimado.

Resumo: Com o objetivo de se conhecer o comportamento de conversores CC-CC, que fornecem tensão contínua regulada a partir de uma fonte CC não regulada, o estudo desenvolvido neste trabalho refere-se ao desenvolvimento de um conversor do tipo buck. Este, que fornece tensão reduzida em relação à tensão de entrada, foi objeto de estudo em que obteve-se a partir de modelagem matemática a estratégia de controle para regulação de tensão. Utilizou-se uma estratégia de controle ótima baseada nos índices de desempenho de erro, visando minimizar o efeito de perturbações na regulação da tensão fornecida à carga. Resultados de simulações são apresentados como estágio inicial do estudo.

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In an integrated petroleum company we have the need of taking important decisions concerning the production planning and program in order to maximize the profits. These tasks, production planning and program, demand mathematics models of the process plants. Using these models and with the support of mathematics programs is possible to choose the optimum production strategy or that one which fits better. In this work computer intelligence techniques (neural networks and fuzzy systems) were used to model one of the REGAP's process unit. To achieve this purpose sample datas from the unit were used to get process models. These models were addressed to provide us with the information concerning the operation quality and efficiency. Models were got and these models estimate products yields with enough accuracy when validated against actual data. The approach to model this process combines neural network with fuzzy system (used to define process variable not easy to measure directly such us quality of feedstocks and operation targets). Some important intermediate products had these qualities modeled too. The results show that the proposed methodology is a suitable alternative to be considered in distillation process modeling. In this article we will show the methodology to identify inference models of product qualities.

After a great advance by the industry on processes automation, an important challenge still remains: the automation under abnormal situations. The first step towards solving this challenge is the Fault Detection and Diagnosis (FDD). This work proposes a batch-incremental adaptive methodology for fault detection and diagnosis based on mixture models trained on a distributed computing

This paper develops a Linear Matrix Inequality (LMI) approach to the robust H∞ control problem of uncertain continuous-and discrete-time linear time-invariant systems with time-delay in the state vector and control input. The main results provide sufficient delay-dependent conditions for the control problem, where the explicit size of the time delay plays a crucial role for the closed-loop stability. The solutions that are found for the H∞ control problem are less conservative, when compared to other approaches.

This paper addresses the problem of the synchronization of a class of chaotic oscillators using techniques borrowed from a recently proposed control design based on Takagi-Sugeno (TS) fuzzy modeling. In order to attain better synchronization, this TS fuzzy modeling is combined with the robust H ∞ observer theory based on linear matrix inequalities. A laboratory setup based on Chua's oscillator circuit is used to demonstrate the main ideas of the paper. Information transmission experiments are performed as an index to measure the effectiveness of the proposed approach.

This paper presents a less conservative approach to compute, with any prescribed accuracy, the H∞ guaranteed cost of time-delay continuous-time linear time-invariant systems subjected to polytopic uncertainties. The proposed analysis approach is based on a branch-and-bound algorithm that incorporates a recent LMI-based analysis formulation and a new polytope partition strategy. In the branch-and-bound algorithm, the upper bound function is defined as the worst case guaranteed H∞ disturbance attenuation level computed for the subpolytopes achieved with successive partitions of the polytope which describes the uncertainty domain. The lower bound function is defined as the worst case H∞ norm computed in the polytope and subpolytope vertices. The difference between the upper and lower bound functions converges to zero as the initial polytope is split into smaller subpolytopes resulting in the H∞ guaranteed cost for the whole initial polytope with the required accuracy. It is also presented an algorithm to implement a d−dimensional simplex subdivision technique to be used in the branch-and-bound algorithm.

This paper investigates the synchronization of coupled chaotic systems using techniques from the theory of robust H ∞ control based on Linear Matrix Inequalities. To deal with the synchronization of a class of Lur'e discrete time systems, a project methodology is proposed. A laboratory setup based on Chua's oscillator circuit is used to demonstrate the main ideas of the paper in the context of the problem of information transmission.