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1

Extended state observer based robust feedback linearization control applied to an industrial CSTR

Medjebouri Ali

Journal of Automation Mobile Robotics and Intelligent Systems

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2023

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Vol. 17, No. 4

68--78

EN

In the chemical and petrochemical industry, the Continuous Stirred Tank Reactors (CSTR) are, without doubt, one of the most popular processes. From a control point of view, the mathematical model describing the temporal evolution of the CSTR has a strongly nonlinear cross-coupled character. Moreover, modeling errors such as external disturbances, neglected dynamics, and parameter variations or uncertainties make its control task a very difficult challenge. Even though this problem has been the subject of a wide number of control strategies, this article attempts to propose a viable, robust, nonlinear decoupling control scheme. The idea behind the proposed approach lies in the design of two nested control loops. The inner loop is responsible for the compensation of the nominal model nonlinear cross-coupled terms via static nonlinear feedback; whereas the outer loop, designed around an Extended State Observer (ESO) of which the additional state gathers the global effect of modeling errors, is charged to instantaneously estimate, and then to compensate the ESO extended state. This way, the CSTR complex dynamics are reduced to a series of decoupled linear subsystems easily controllable using a simple Proportional-Integral (PI) linear control to ensure the robust pursuit of reference signals respecting the desired performance. The presented control validation was performed numerically by an objective comparison to a classical PID controller. The obtained results clearly show the viability and the effectiveness of the proposed control strategy for dealing with such nonlinear, strongly cross-coupled plants subject to a wide range of disturbances despite the precision of their described mathematical model.

2

Control of PID parameters by iterative learning based on neural network

Karkar Nora, Nadjet Zarroug, Yamina Tighilt, Benmhamed Khier

Przegląd Elektrotechniczny

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2021

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R. 97, nr 4

158--161

EN

Iterative learning refers to the development, analysis and implementation of methods that allow a machine to evolve through a learning process, and thus perform tasks that are difficult or impossible to perform by more conventional algorithmic.Learning is a dynamic and iterative process for modifying the parameters of a network in response to the stimuli it receives from its environment. The type of learning is determined by how parameter changes occur. In this article , we contribute to the design and development of an algorithm, that can optimize the parameters of a PID controller for the control of repetitive system, using the iterative learning approach based on neural network. The theoretical are illustrated by simulation. The results of simulations prove clearly the efficiency of the control by iterative learning based on neural network.

PL

Uczenie się iteracyjne odnosi się do rozwoju, analizy i wdrażania metod, które pozwalają maszynie rozwiązywać problem w procesie uczenia się, a tym samym wykonywać zadania, które są trudne lub niemożliwe do wykonania przy użyciu bardziej konwencjonalnego algorytmu. Rodzaj uczenia się zależy od tego, jak zachodzą zmiany parametrów. W tym artykule zaprojektowano i opracowano algorytmu, który może zoptymalizować parametry regulatora PID, wykorzystując podejście iteracyjnego uczenia się w oparciu o sieć neuronową. Wyniki symulacji jednoznacznie dowodzą skuteczności sterowania poprzez iteracyjne uczenie się w oparciu o sieć neuronową.

3

Microwave energy absorption in water.ethanol solutions

Łupiński M., Dmyszewicz A., Kozioł A.

Chemical and Process Engineering

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2008

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Vol. 29, z. 1

257-269

EN

Results of experimental studies of microwave energy (MW) absorption by water.ethanol solutions have been presented such as testing equipment, assumptions and methods of investigation. CSTR energy balance model has been used in mathematical analysis of the process. Equations similar to the Margules and van Laar models have been used to describe dependence of the MW absorption coefficient b on the mixture composition.

PL

Przedstawiono wyniki badań doświadczalnych absorpcji energii mikrofalowej w roztworze woda.etanol w szerokim zakresie stężeń. Opisano aparaturę, założenia i metody badań. Do opisu zjawiska zaproponowano bilans energetyczny reaktora CSTR. Podjęto próbę przybliżenia zależności współczynnika absorpcji energii mikrofalowej od stężenia za pomocą równań nawiązujących do modeli Margulasa i van Laara.