Spelling suggestions: "subject:"closedloop control"" "subject:"closed_loop control""
31 |
Closed-loop control for cardiopulmonary management and intensive care unit sedation using digital imagingGholami, Behnood 29 June 2010 (has links)
This dissertation introduces a new problem in the delivery of healthcare, which could result in
lower cost and a higher quality of medical care as compared to the current healthcare practice. In
particular, a framework is developed for sedation and cardiopulmonary management for patients
in the intensive care unit. A method is introduced to automatically detect pain and agitation
in nonverbal patients, specifically in sedated patients in the intensive care unit, using their facial
expressions. Furthermore, deterministic as well as probabilistic expert systems are developed to
suggest the appropriate drug dose based on patient sedation level. This framework can be used
to automatically control the level of sedation in the intensive care unit patients via a closed-loop
control system. Specifically, video and other physiological variables of a patient can be constantly
monitored by a computer and used as a feedback signal in a closed-loop control architecture. In
addition, the expert system selects the appropriate drug dose based on the patient's sedation level.
In clinical intensive care unit practice sedative/analgesic agents are titrated to achieve a specific
level of sedation. The level of sedation is currently based on clinical scoring systems. In general,
the goal of the clinician is to find the drug dose that maintains the patient at a sedation score
corresponding to a moderately sedated state. This is typically done empirically, administering a
drug dose that usually is in the effective range for most patients, observing the patient's response,
and then adjusting the dose accordingly. However, the response of patients to any drug dose is
a reflection of the pharmacokinetic and pharmacodynamic properties of the drug and the specific
patient. In this research, we use pharmacokinetic and pharmacodynamic modeling to find an
optimal drug dosing control policy to drive the patient to a desired sedation score.
|
32 |
Ανάπτυξη μοντέλου πεπερασμένων στοιχείων και ανάλυση σύγχρονου κινητήρα μόνιμου μαγνήτη οδηγούμενου από ηλεκτρονικό μετατροπέα ισχύος / Finite element analysis of a permanent magnet synchronous motor driven by a three-phase inverterΑλκαλάης, Βίκτωρ 28 January 2015 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη, το σχεδιασμό και την εξομοίωση ενός σύγχρονου κινητήρα μόνιμου μαγνήτη οδηγούμενο από ελεγχόμενο τριφασικό αντιστροφέα. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών.
Σκοπός λοιπόν της παρούσας εργασίας είναι η μελέτη και προσομοίωση ενός σύγχρονου κινητήρα μόνιμου μαγνήτη μέσω της μεθόδου των πεπερασμένων στοιχείων, με τη βοήθεια του λογισμικού Opera σε δύο διαστάσεις (2d). Στο περιβάλλον σχεδίασης κυκλωμάτων του ίδιου προγράμματος, μοντελοποιήθηκε και ο τριφασικός αντιστροφέας ισχύος για την οδήγηση του κινητήρα. Στην συνέχεια, έγινε διασύνδεση του λογισμικού Opera με το πρόγραμμα Simulink του λογισμικού Matlab, με απώτερο σκοπό να επιτευχθεί έλεγχος κλειστού βρόχου της ταχύτητας περιστροφής του κινητήρα
Συγκεκριμένα, έγινε μελέτη και προσομοίωση ενός συγκεκριμένου 8πολικού κινητήρα τύπου Brushless DC, ονομαστικής ισχύος 660 W, ονομαστικής τάσης 48 V, και ονομαστικής ταχύτητας 3000 rpm ο οποίος τροφοδοτήθηκε στην είσοδό του με τριφασικό αντιστροφέα.
Ιδιαίτερη προσοχή δόθηκε, στην εξομοίωση του τρόπου λειτουργίας των αισθητήρων Hall, μέσω των ημιαγωγικών διακοπτικών στοιχείων του αντιστροφέα, τα οποία ρυθμίστηκαν για να λειτουργούν σε κατάλληλες, για την υπό μελέτη μηχανή, χρονικές περιόδους. Κρίσιμη ήταν επίσης, η διαδικασία εύρεσης των κατάλληλων κερδών των ελεγκτών PI, έτσι ώστε να βελτιωθεί η μεταβατική απόκριση του συστήματος κλειστού βρόχου και να μειωθεί το σφάλμα μόνιμης κατάστασης ταχύτητας.
Αναλυτικά, στο κεφάλαιο 1 γίνεται αναφορά στα θεμελιώδη μεγέθη του μαγνητικού πεδίου, καθώς και στις ιδιότητες των μαγνητικών υλικών που χρησιμοποιούνται στην κατασκευή σύγχρονων μηχανών μόνιμου μαγνήτη.
Στο κεφάλαιο 2 αναλύονται οι σύγχρονοι κινητήρες μόνιμου μαγνήτη και γίνεται εκτενής αναφορά στα κατασκευαστικά χαρακτηριστικά, στη βασική αρχή λειτουργίας και στις μαθηματικές εξισώσεις που τους περιγράφουν.
Στο κεφάλαιο 3 περιγράφεται η διάταξη οδήγησης του κινητήρα και αναλύονται λεπτομερώς η λειτουργία και του αντιστροφέα και του κυκλώματος ελέγχου κλειστού βρόχου.
Στο κεφάλαιο 4 περιγράφεται η διαδικασία διεξαγωγής μετρήσεων και σχεδιασμού του μοντέλου πεπερασμένων στοιχείων της μηχανής στο περιβάλλον του υπολογιστικού προγράμματος Opera-2d.
Στο κεφάλαιο 5 περιγράφεται η διαδικασία σχεδιασμού του τριφασικού αντιστροφέα και παρουσιάζονται τα αποτελέσματα εξομοίωσης για το σύστημα ανοικτού βρόχου.
Στο κεφάλαιο 6 εξηγείται η διαδικασία διασύνδεσης των δύο προγραμμάτων (Matlab-Opera) και παρουσιάζονται τα αποτελέσματα της εξομοίωσης για το σύστημα ελέγχου κλειστού βρόχου. / In this dissertation, the design and simulation of a permanent magnet synchronous motor driven by a three-phase inverter, is presented. The work was conducted at the Laboratory of Electromechanical Energy Conversion, Department of Electrical and Computer Engineering, University of Patras. The objective of this dissertation is the study and simulation of a permanent magnet synchronous motor employing the finite element method, with the help of Opera-2d simulation software. In the Circuit Editor environment of the same software, a three-phase inverter for driving the motor was designed, utilizing the PWM method and achieving open loop control of the motor rotation speed under constant loads. In addition, a closed loop control system was designed on Simulink user interface of Matlab software and making use of the interconnection capability of the two programs (Matlab-Opera) closed loop control of the motor rotation speed was achieved.
Specifically, chapter 1 gives reference to fundamentals of the magnetic field and the magnetic properties of materials used in the construction of modern permanent magnet machines.
Chapter 2 analyzes synchronous permanent magnet motors and makes an extensive reference to the constructional features, basic operation principle and the mathematical equations that describe them.
Chapter 3 describes the motor driving converter and analyzes in detail the operation of the inverter and the closed loop control circuit.
Chapter 4 describes the procedure for carrying out measurements and designing the finite element model of the machine in the environment of Opera-2d software.
Chapter 5 describes the three-phase inverter design process and presents the simulation results for the open loop system.
Chapter 6 explains the interconnection process of the two programs (Matlab-Opera) and presents the results of the simulation for the closed loop control system.
|
33 |
Contribution to the implementation of a process control system for continuous powder mixingZhao, Xiaojuan 26 November 2013 (has links) (PDF)
Powder mixing is an essential operation in various industrial fields, such as pharmaceuticals, agro-food, cements, etc. Continuous powder mixing, as an alternative to conventional batch mixing, has attracted a lot of interest mainly due to its capacity in handling high volume manufacturing. This work aims at the contribution to the implementation of process control applications for powder mixing in a pilot-scale continuous mixer. Prior to developing process control strategies, new developments have been presented for better understanding continuous mixing of two components. Hold-up weight and relative hold-up weight distribution of each component in the whole mixer have been experimentally investigated under different operating conditions. An improved Markov chain model has been finally presented to predict the mean concentration of the mixtures obtained at the mixer's outlet. The implementation of a proportional-integral-derivative (PID) controller has been experimentally performed as an initial attempt to real-time control the homogeneity of the mixture produced. The rotational speed of the stirrer, identified as an important deciding factor towards the mixer's efficiency, has been considered as the manipulated variable. The closed-loop control is based on either the mean concentration or the relative standard deviation. The performances of the proposed closed-loops have been evaluated for continuous mixing subjected to step changes in feed rates of the mixer. Four case studies have been defined and presented. The main challenge in the process control system is the tuning of PID parameters. The performance of closed-loop control of either the mean concentration or the relative standard deviation has been compared to open-loop operation.
|
34 |
Evaluating the functionality of an Industrial Internet of Things system in the FogGranlund, Mathias, Hoppe, Christoffer January 2018 (has links)
The Internet is one of the greatest innovations ever created by mankind, and it is a technical trend that has moved into industries to facilitate automation, supervision and management in the form of IoT devices. These devices are designed to be extremely lightweight and operate in low-power and lossy networks, and therefore run a low duty cycle and CPU-clock frequency to reserve battery life. Fog nodes are located on site to minimize network delay and provide centralized processing to handle data from hundreds of connected devices in wireless sensor networks. This is the future of industrial automation. Our goal is to show the functionality of an industrial IoT network within the scope of Fog computing by implementing a closed-loop control system in Cooja. Performance evaluations considered network reliability in terms of packet delivery ratio and timeliness. We assume that wireless IoT devices are running RPL routing (one of the most common standard routing protocols for IoT applications). We implement a mobility controller at the Fog-server in order to collect measurements made by the Fog nodes and send commands to IoT devices. In this thesis work, we assume that the commands are related to the mobility pattern of mobile node (e.g. AGVs in industrial automation) in order to avoid collision. From the simulation results we can conclude that sampling rates and node density have a greater impact on performance compared to payload size. We cannot be sure that our results reflect what a real-world evaluation would imply as we are running an emulation software, even though it has a very realistic physical layer. We do however believe that with substantial testing and improvements to both Cooja and our implementation, an accurate representation can be accomplished and algorithms in Cooja can be moved to real-world implementations.
|
35 |
Desenvolvimento de um sistema de controle em um robô móvel agrícola em escala reduzida para deslocamento entre fileiras de plantio / Development of a control system to a low scale agricultural mobile robot navigation between crop rowsHenry Borrero Guerrero 02 June 2016 (has links)
O adequado deslocamento autônomo de robôs móveis entre fileiras de cultura agrícola implica a apropriada configuração estrutural do veículo, bem como considerar a detecção das filas de plantas ou árvores, e também o desenvolvimento de um sistema de controle de locomoção. Esta tese apresenta o desenvolvimento de um sistema de controle em malha fechada baseado na técnica de otimização H∞, que é aplicado no deslocamento entre fileiras de plantio de um robô móvel agrícola em escala reduzida. Mais especificamente, o foco deste trabalho é o seguimento de caminhos na cultura através da aplicação de técnicas de controle robusto. Duas questões foram fundamentais na elaboração da tese: 1) \"Quais são os métodos e procedimentos necessários para implementar a navegação autônoma de um protótipo de robô móvel entre fileiras de cultura agrícola?\" e, 2) \"É possível aplicar os conceitos relativos a sistemas de controle em malha fechada para solucionar o problema da navegação autônoma do robôs móveis entre fileiras de cultura agrícola?\". Primeiramente é apresentada uma revisão bibliográfica sobre robôs móveis agrícolas que tem locomoção baseada em rodas. Posteriormente, os conceitos relacionados com o projeto de controle baseado na técnica de otimização H∞ são fundamentados. Em seguida, são descritos os detalhes relacionados com a construção da plataforma robótica proposta, o projeto do controlador de caminho, as respectivas simulações e as especificações para a realização de testes em ambiente agrícola. Finalmente os resultados alcançados são apresentados. Conclui-se que o sistema de controle proposto se mostrou efetivo na realização da navegação autônoma do robô entre as fileiras da cultura previamente configuradas para a avaliação do seu desempenho. / Appropriate autonomous navigation of mobile robots between crop rows implies, besides appropriate structural configuration, considering detection of plants or trees in rows, as well as the development of a locomotion control system. Consequently, this thesis presents the development of a closed loop control system based on H∞ optimization technique, which is applied to control the navigation of a low scale car-like mobile robot between crop rows; more specifically, main focus of this work is tracking paths in the culture, by the application of robust control techniques. Two questions were fundamental in the development of the thesis: 1) which are the methods and procedures to implement the autonomous navigation of a mobile robot prototype between crop rows? And 2) is it possible to apply the concepts of closed-loop control systems to solve the problem of autonomous navigation of mobile robots between crop rows? Firstly, we provide a literature review on agricultural mobile robots whose mobility depends on wheels. Secondly, control systems design fundamentals based on the H∞ optimization technique are addressed. Thirdly, details related to the construction of the proposed robotic platform and also the design of the proposed path controller (including its simulation and specifications for testing within an agricultural environment) are described. Finally, results of our findings are presented. It is concluded that our control system showed to be effective in the realization of autonomous navigation between crop rows in agricultural environment, which was properly configured in order to evaluate the performance of our robot.
|
36 |
Unidade microcontroladora para gerenciamento eletrônico de um motor de combustão interna ciclo Otto. / Microcontroller electronic unit to manage an Otto cycle internal combustion engine.Bruno Martin de Alcantara Dias 26 March 2015 (has links)
Nas últimas décadas, a indústria automobilística mundial vem investindo no desenvolvimento tecnológico dos motores, com o objetivo de alcançar melhor eficiência energética e atender às legislações que limitam a quantidade de resíduos tóxicos nos gases de exaustão e menor consumo de combustível. Isso resultou na implantação dos sistemas de gerenciamento eletrônico do motor, que possibilitam funcionalidades para se controlar diversas variáveis do motor, aumentando consideravelmente o rendimento do motor. Este trabalho tem como objetivos explorar a dinâmica de um motor de combustão interna ciclo Otto, os sinais elétricos associados, e os componentes de seu gerenciamento eletrônico. A partir dessas informações, o trabalho apresenta o processo de analise dos sinais elétricos e as estratégias de controle utilizadas em um sistema de gerenciamento real. Assim, são desenvolvidos o hardware e o firmware de uma unidade microcontroladora para gerenciamento eletrônico do motor. O hardware foi elaborado com uma concepção centralizada, ou seja, foi usado apenas um microcontrolador de 32-bit para gerenciar todas as funções. O firmware de controle foi desenvolvido de forma modular baseado em modelos de malha fechada. O modelo matemático do motor foi identificado utilizando técnicas de controle em um veículo real, e a avalidação do modelo foi obtida através de testes em um dinamômetro inercial. / In the last few decades, the world automotive industry has invested in the technological development of the engines, aiming to get better energetic efficiency and comply with legislations that limit the amount of toxic exhaustion gases. This resulted in electronic management systems for engines, which allowed flexibility to control several engine-related variables, considerably increasing the engine efficiency. This work aims to explore the Otto cycle combustion engine dynamics, its electronic signals, and the elements of its electronic management. Based on that information, this work presents the analysis process of the electronic signals, and the control strategies used in a real management system. Then, the hardware and firmware of a microcontroller unity are developed for the electronic management of the engine. The hardware was elaborated with a centralized concept, i.e., only one 32-bit microcontroller was used to control all functions. The control firmware was developed in a modular scheme, based on the closed loop models. The engine mathematical model was identified using control techniques in a real engine. The results were obtained by tests in an inertial dynamometer.
|
37 |
Commande expérimentale en boucle fermée des systèmes de post-traitement SCR en utilisant des sondes à NOx sensibles au NH3 / Experimental closed-loop control of SCR aftertreatment systems using NOx sensors cross-sensitive to NH3Bonfils, Anthony 11 December 2013 (has links)
Le problème étudié dans cette thèse est la commande en boucle fermée d'un système SCR (Réduction Sélective Catalytique) par l'urée tel qu'utilisé dans les systèmes de dépollution des gaz d'échappement des moteurs diesel automobiles. Une première contribution du manuscrit est en un modèle détaillé de la SCR, soulignant de la nature distribuée (1D) du système considéré, et plusieurs réductions successives de ce modèle de simulation conduisant à un modèle plus simple, utilisable à des fins de synthèse de contrôleur. Une seconde contribution consiste à prendre en compte la sensibilité au NH3 du capteur de NOx utilisé pour la rétroaction lors du développement d'algorithmes de commande (observateur d'état, boucle de rétroaction, séquencement de gain, interprétation du signal capteur). L'observateur-contrôleur présenté possède plusieurs points d'équilibre dues à la sensibilité du capteur de sortie. On montre que seul le point d'intérêt pratique est asymptotiquement stable, les autres étant instables naturellement, rendus instables par une implémentation spécifique ou aisémentdétectés comme indésirables. Ces deux contributions ont été testées expérimentalement et validées. En résumé, la méthode de contrôle proposée dans cette thèse permet, à partir d'un moteur conforme aux exigences Euro 5 et avec une procédure de pré-conditionnement du catalyseur, de satisfaire la norme Euro 6. / The problem studied in this thesis is the closed-loop control of a urea-SCR (urea Selective Catalytic Reduction) as used in aftertreatment systems of diesel vehicles. A first contribution of the thesis is a detailed model for the SCR, highlighting the distributed (1D) nature of the considered system, and several successive reductions of this simulation model leading to a simpler one, better-suited for control design purposes. A second contribution consists in considering the sensitivity to NH3 of the NOx sensor used in a feedback loop, in the development of the control algorithms (state observer, feedback, gain scheduling, measurement interpretation). The ambiguity of the output measurement could be detrimental to the closed loop response, as it generates multiple equilibrium points (artefacts), besides the point of practical interest. A study of the closed-loop dynamics is performed in the vicinity of each point, which shows that the closed loop system naturally converges to the point of interest not to the artefacts. Both contributions have been tested and validated experimentally. In summary, the method proposed in this thesis might allow an engine equipped with Euro 5 hardware to satisfy Euro 6 standard using a preconditioning procedure of the catalyst.
|
38 |
Contribution to the implementation of a process control system for continuous powder mixing / Contribution à l'implémentation d'un système de contrôle-commande pour mélange de poudres en continuZhao, Xiaojuan 26 November 2013 (has links)
Le mélange de poudres est une opération essentielle dans divers domaines industriels, tels que les produits pharmaceutiques, agro-alimentaires, ciments, etc. Le mélange de poudres en continu, comme alternative intéressante au mélange conventionnel en batch, suscite beaucoup d'intérêt surtout en raison de sa capacité à gérer de grands volumes de production. Ce travail vise à contribuer à l'implémentation des applications de contrôle-commande. Avant de développer des stratégies de contrôle-commande, de nouveaux développements ont été présentés pour mieux comprendre le mélange continu de deux composants. La masse retenue et la répartition relative de la masse retenue de chaque composant dans le mélangeur ont été étudiées et prédites sous les différentes conditions opératoires. L'amélioration d'un modèle basé sur les chaînes de Markov a été finalement présentée pour prédire la concentration moyenne des mélanges obtenus à la sortie du mélangeur. L'implémentation d'un contrôleur PID a été expérimentalement réalisée comme une première tentative pour contrôler en temps réel l'homogénéité du mélange produit. La vitesse de rotation du mobile d'agitation, identifiée comme un facteur important influençant l'efficacité du mixer, a été considérée comme la variable manipulée. La commande en boucle fermée est basée, soit sur la concentration moyenne, soit sur le coefficient de variation. Les performances des boucles fermées proposées ont été évaluées pour le mélange continu subi à des changements d'échelon dans les débits d'alimentation du mélangeur. Quatre études de cas ont été définies et présentées. Le défi principal dans le système de contrôle-commande est le réglage des paramètres PID. La performance de commande en boucle fermée soit de la concentration moyenne, soit du coefficient de variation a été comparée à l'opération en boucle ouverte. / Powder mixing is an essential operation in various industrial fields, such as pharmaceuticals, agro-food, cements, etc. Continuous powder mixing, as an alternative to conventional batch mixing, has attracted a lot of interest mainly due to its capacity in handling high volume manufacturing. This work aims at the contribution to the implementation of process control applications for powder mixing in a pilot-scale continuous mixer. Prior to developing process control strategies, new developments have been presented for better understanding continuous mixing of two components. Hold-up weight and relative hold-up weight distribution of each component in the whole mixer have been experimentally investigated under different operating conditions. An improved Markov chain model has been finally presented to predict the mean concentration of the mixtures obtained at the mixer's outlet. The implementation of a proportional-integral-derivative (PID) controller has been experimentally performed as an initial attempt to real-time control the homogeneity of the mixture produced. The rotational speed of the stirrer, identified as an important deciding factor towards the mixer's efficiency, has been considered as the manipulated variable. The closed-loop control is based on either the mean concentration or the relative standard deviation. The performances of the proposed closed-loops have been evaluated for continuous mixing subjected to step changes in feed rates of the mixer. Four case studies have been defined and presented. The main challenge in the process control system is the tuning of PID parameters. The performance of closed-loop control of either the mean concentration or the relative standard deviation has been compared to open-loop operation.
|
39 |
An Experimental Study of Disturbance Compensation and Control for a Fractional-Order SystemTalarcek, Steven C. January 2018 (has links)
No description available.
|
40 |
Periodic Vortical Gust Encounter and Mitigation Using Closed Loop ControlKillian, Andrew Edward 15 May 2023 (has links)
No description available.
|
Page generated in 0.061 seconds