Submitted by Marcos Rogerio Caldieri null (mrcaldieri@gmail.com) on 2016-12-14T23:11:29Z No. of bitstreams: 1 Marcos-Mestrado.pdf: 2168690 bytes, checksum: 11f237fc5587a57486d006c939b576af (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-19T17:40:14Z (GMT) No. of bitstreams: 1 caldieri_mr_me_bauru.pdf: 2168690 bytes, checksum: 11f237fc5587a57486d006c939b576af (MD5) / Made available in DSpace on 2016-12-19T17:40:14Z (GMT). No. of bitstreams: 1 caldieri_mr_me_bauru.pdf: 2168690 bytes, checksum: 11f237fc5587a57486d006c939b576af (MD5) Previous issue date: 2016-10-21 / A recente introdução de transmissores sem fio na indústria provocou um novo interesse em técnicas de medição e controle, porém a maioria das aplicações está restrita a medições de variáveis de processo em malha aberta ou aplicações de monitoramento. O motivo é a falta de confiabilidade devido aos problemas inerentes ao meio de transmissão, que pode ser a perda de pacotes de informação, atrasos de comunicação variantes no tempo, atualização muito lenta e não periódica da medição e vários tipos de interferências. A maior parte dos controladores industriais em controle de processos assumem que o ciclo de controle é executado de forma periódica e que uma nova medição está disponível para ser usada em intervalos de tempo conhecidos. No entanto esta situação não pode ser garantida quando sensores ou transmissores sem fio são usados em aplicações de controle em malha fechada, denominadas de Sistemas de Controle via Redes sem fio (WNCS – Wireless Networked Control Systems). Nesses tipos de aplicações, os transmissores sem fio devem transmitir novas medições de forma não periódica e somente se a medição da variável do processo tiver alterado significativamente. Para tornar esta tecnologia de WNCS mais confiável, muitas técnicas de controle têm sido pesquisadas, entre elas o PIDPlus que representa uma modificação do algoritmo PID para controle via rede sem fio. Este trabalho apresenta a implementação do protocolo Modbus para aplicações de WNCS. O protocolo Modbus TCP foi embarcado em hardware dedicado viabilizando a transmissão de dados via Ethernet TCP/IP e Wi-Fi. Uma comparação e avaliação de controladores PID para aplicação em WNCS sob condições de amostragem e atrasos de comunicações variáveis e de perdas de transmissão de mensagens foi realizada. Os resultados são analisados do ponto de vista de desempenho de controle e robustez. Resultados experimentais numa planta piloto comprovam a eficiência da implementação de uma malha de controle sem fio usando uma rede Wi-Fi com o protocolo Modbus embarcado e um controlador PIDPlus. / The recent introduction of wireless transmitters in the industry has driven a new interest in measuring and control techniques, but most applications are restricted to measurements of process variables in open loop or monitoring applications. The reason is the lack of reliability due to problems inherent to the transmission medium, which may be the packet loss, time varying delay, slow and aperiodic measurement updates and interference. Most industrial process controllers assume that the control cycle is performed periodically and that a new measurement is available to be used at known time intervals. However it cannot be guaranteed when wireless sensors or transmitters are used in closed loop control applications, called Wireless Networked Control Systems (WNCS). In these type of applications, wireless transmitters shall transmit new measurements not periodically and only if the process variable measurement has changed significantly. In order to enable and make this WNCS technology reliable, many control techniques have been researched including the PIDPlus that is a modified PID algorithm for wireless control. This paper presents the implementation of the Modbus protocol for WNCS applications. The Modbus TCP was embedded in dedicated hardware enabling the transmission of data via Ethernet TCP/IP and Wi-Fi. A comparison and evaluation of PID controllers for WNCS were done considering situations of variable sampling and communication delays and packet losses. The results are analyzed from the point of view of control performance and robustness. Experimental results in a pilot plant prove the efficiency of the implementation of a wireless control loop using a Wi-Fi network with embedded Modbus protocol and PIDPlus controller.

Submitted by RAUL KATAYAMA MANSANO null (rkmansano@yahoo.com.br) on 2016-11-04T01:12:57Z No. of bitstreams: 1 Dissertação Raul Katayama Mansano.pdf: 4167710 bytes, checksum: 35cc706c4a721f9334825773f9f2ff77 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-10T13:57:40Z (GMT) No. of bitstreams: 1 mansano_rk_me_bauru.pdf: 4167710 bytes, checksum: 35cc706c4a721f9334825773f9f2ff77 (MD5) / Made available in DSpace on 2016-11-10T13:57:40Z (GMT). No. of bitstreams: 1 mansano_rk_me_bauru.pdf: 4167710 bytes, checksum: 35cc706c4a721f9334825773f9f2ff77 (MD5) Previous issue date: 2016-09-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com os recentes avanços das tecnologias sem fio e a proliferação de sensores sem fio, há um crescente interesse na implementação de Sistemas Controle via Redes Sem Fio (WNCSs), que fornecem vantagens em relação às arquiteturas tradicionais ponto-a-ponto e às arquiteturas de redes cabeadas. Apesar das vantagens, a inserção de redes industriais na malha de controle impõe não-linearidades e restrições que afetam o desempenho e a estabilidade do WNCS. Além disto, uma questão fundamental para aplicações de WNCS é a vida útil da bateria de alimentação dos sensores sem fio, uma vez que é uma fonte limitada de energia. Como a transmissão da informação na rede sem fio requer um alto gasto energético pelo dispositivo, deve-se restringir a quantidade de comunicações para poupar bateria. Esta restrição inviabiliza o uso de sensores sem fio em diversas aplicações de WNCS. Neste contexto, este trabalho apresenta o desenvolvimento de um controlador adaptativo multi-rate para eficiência energética em aplicações industriais de WNCSs, através da diminuição da frequência de transmissão de dados na rede e, portanto, redução do consumo energético dos dispositivos sem fio. Um controlador adaptativo auto-ajustável foi implementado para identificar o modelo do WNCS, simular tal modelo e sintonizar os parâmetros do controlador a cada passo de controle, fornecendo robustez contra distúrbios e não-linearidades inerentes ao WNCS. O diferencial do controlador adaptativo é a incorporação das técnicas de identificação por pacote e de controle multi-rate. A técnica de identificação por pacote consiste em transmitir mensagens com vários dados (não somente o mais atual) coletados durante o período de amostragem do sensor sem fio, melhorando a identificação do modelo do WNCS e, consequentemente, o desempenho do controlador adaptativo. A técnica de controle multi-rate consiste em usar dados virtuais de realimentação, provenientes do modelo simulado do WNCS, para possibilitar uma atuação sobre o processo a uma frequência mais rápida que a amostragem dos sensores sem fio, permitindo a redução das transmissões sem fio do WNCS. Resultados experimentais mostram que o controlador adaptativo multi-rate é robusto e efetivo para aplicações de WNCS, permitindo poupar energia das baterias dos sensores sem fio sem prejudicar significativamente o desempenho de controle do WNCS. As análises do impacto do período de amostragem e do parâmetro Γ do controlador permitiram a obtenção de valores ótimos para a melhoria da eficiência energética do WNCS. / Recent advances in wireless technologies and the proliferation of wireless sensors led to an increasing interest in the implementation of Wireless Networked Control Systems (WNCS), which provide advantages over traditional peer-to-peer and cabled networks architectures. Despite these advantages, inserting a communication network in the control loop impose nonlinearities and constraints which affect stability and performance of the system. Furthermore, a major issue in wireless applications is the lifetime of the sensors batteries, which are a limited source of power. As transmitting data over the network requires high-energy expenditure, it is imperative to reduce the number of communications, in order to save battery. This constraint makes it unfeasible to use wireless sensors in most WNCS applications. In this context, this work aims to develop a multi-rate adaptive controller to enhance energy efficiency in industrial WNCS applications, by reducing frequency of data transmission over the network, thus reducing power expenditure of the wireless devices. A self-tuning adaptive controller is implemented, which can identify the WNCS model, simulate such model and tune the controller parameters at each control step, then providing robustness to disturbance and inherent nonlinearities of the WNCS. The adaptive controller is augmented with a multi-rate control technique and packet-based identification. The packet-based identification consists in transmitting messages with a pack of data (instead of only transmitting the most recent one) sampled during the inter-samples period, thus improving identification of the WNCS model and, consequently, improving control performance. The multi-rate control technique consists in using virtual feedback data, provided by the simulated model of the WNCS, then enabling actuation faster than wireless sampling, allowing the reduction of wireless transmissions in the WNCS. Experimental results show that the implemented multi-rate adaptive controller is robust and effective to WNCS and improve battery lifetime without decreasing control performance of the WNCS significantly. By investigating the impacts of sampling period and of controller parameter Γ determined optimized values to improve energy efficiency of the WNCS.

Submitted by Felipe Fakir null (zafakir@yahoo.com.br) on 2017-06-27T07:01:28Z No. of bitstreams: 1 FFAKIR Dissertação vFinalFichaCataAta.pdf: 2064786 bytes, checksum: 158a935a636b9dbf9e59618a35b4c8ef (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-28T19:39:58Z (GMT) No. of bitstreams: 1 fakir_f_me_bauru.pdf: 2064786 bytes, checksum: 158a935a636b9dbf9e59618a35b4c8ef (MD5) / Made available in DSpace on 2017-06-28T19:39:58Z (GMT). No. of bitstreams: 1 fakir_f_me_bauru.pdf: 2064786 bytes, checksum: 158a935a636b9dbf9e59618a35b4c8ef (MD5) Previous issue date: 2017-06-01 / A tecnologia de comunicação wireless vem se tornando parte fundamental do cotidiano das indústrias de processos, onde o uso de transmissores wireless aplicados à monitoração e controle já é uma realidade. A arquitetura de Sistema de Controle via Rede Sem Fio (WNCS) possui vantagens em relação às arquiteturas tradicionais ponto-a-ponto e às arquiteturas de redes cabeadas devido à facilidade de instalação, configuração e manutenção. No entanto, a evolução desta tecnologia introduziu novos desafios para a implementação da malha de controle fechada por um instrumento wireless como as não linearidades, perda de pacote de dados e restrições da comunicação de dados nas redes sem fio. Outro fator crítico relacionado à implementação de WNCSs é a fonte de energia limitada destes transmissores, que possuem vida útil dependente da quantidade de acessos e dados transmitidos. Este trabalho apresenta o estudo e o desenvolvimento de um controlador preditivo multi-rate como alternativa para melhorar a eficiência energética em aplicações industriais de WNCSs. A estratégia proposta não necessita receber constantemente os valores reais das variáveis do processo transmitidos pelos transmissores wireless, pois o controlador preditivo baseado em modelo (MPC) se utiliza do submodelo interno das variáveis de processo para estimar os valores das variáveis quando estas não são transmitidas. Dessa forma, uma diminuição da frequência de transmissão de dados na rede sem fio pode ser obtida e, consequentemente uma redução do consumo energético dos dispositivos sem fio. Resultados de simulações em diferentes condições de operação de um WNCS multivariável de controle de tanques acoplados demonstram que o MPC multi-rate possui características de robustez e é efetivo para aplicações de WNCS, garantindo requisitos de controle e estabilidade mesmo com a diminuição da frequência de transmissão de dados de realimentação na rede sem fio. Adicionalmente, resultados do consumo energético dos dispositivos do WNCS mostraram que o MPC multi-rate proporciona uma economia de energia de até 20% das baterias dos transmissores wireless. Uma análise da eficiência energética do WNCS é apresentada através do estudo dos limites operacionais do controlador MPC multi-rate considerando a relação de compromisso entre o período de amostragem dos dispositivos sem fio e o desempenho de controle do WNCS. / Wireless communication technology has become a fundamental part of the everyday life of process industries, where the use of wireless transmitters for monitoring and control is already a reality. The architecture of Wireless Networked Control Systems (WNCSs) has advantages over point-to-point and wired networks architectures due to the ease of installation, configuration and maintenance. However, the evolution of this technology has introduced new challenges to the implementation of the closed loop control with a wireless instrument as nonlinearities, packet losses and data communication constraints in the wireless networks. Another critical factor related to implementation of WNCSs is the energy source of these transmitters, which have limited lifetime dependent on the amount of access and data transmitted. This work presents the study and the development of a multi-rate predictive controller as an alternative to improve energy efficiency in industrial applications of WNCSs. The proposed strategy does not need to frequently receive updated process variables transmitted by wireless transmitters, because the model predictive controller (MPC) uses the internal submodel of the process variables to estimate the variables values when they are not transmitted. Thus, a decrease in the frequency of data transmission on the wireless network can be obtained and consequently a reduction of energy consumption of wireless devices. Simulation results for different operating conditions of a multivariable WNCS of coupled tanks shows that the multi-rate MPC provides robustness and it is effective for WNCS applications, ensuring control and stability requirements even with the reduction of the transmission frequency of the feedback data in the wireless network. In addition, energy consumption results from the WNCS devices showed that MPC multi-rate provides 20% of energy economy as it is effective in saving the energy expenditure of the wireless transmitter’s battery. An energy efficiency analysis of the WNCS is presented by studying the operating limits of the multi-rate MPC controller considering the compromise relationship between the sampling period of the wireless devices and the control performance of the WNCS.

Η παρούσα διατριβή κινείται στο χώρο των Ασύρματα Δικτυωμένων Συστημάτων και έχει ως αντικείμενο τη μελέτη και τη σύνθεση μηχανισμών που βελτιώνουν τη λειτουργία τους. Ο όρος Ασύρματα Δικτυωμένα Συστήματα αναφέρεται στα συστήματα των οποίων τα δομικά στοιχεία συνδέονται μέσω ασύρματων δικτύων, με την έμφαση να δίνεται στα αυτό-οργανωμένα δίκτυα και στα δίκτυα αισθητήρων. Η βελτιστοποίηση και ο έλεγχος ενός Ασύρματα Δικτυωμένου Συστήματος γίνεται με γνώμονα την Ποιότητα των παρεχόμενων Υπηρεσιών του δικτύου, η οποία χρησιμοποιείται ως μέτρο αξιολόγησης και επαναπροσδιορισμού των παραμέτρων λειτουργίας αυτού. Προσεγγίζοντας το θέμα από την οπτική γωνία του δικτύου, οι μηχανισμοί που είναι υπεύθυνοι για τη βελτιστοποίηση της λειτουργίας των Ασύρματα Δικτυωμένων Συστημάτων, αποστασιοποιούνται από την ανάπτυξη νέων πρωτοκόλλων για τα διάφορα επίπεδα του μοντέλου αναφοράς Ανοιχτής Διασύνδεσης Συστημάτων. Για τον λόγο αυτό, αναφορικά με το μοντέλο αναφοράς Ανοιχτής Διασύνδεσης Συστημάτων, το ζήτημα της βελτιστοποίησης της λειτουργίας των Ασύρματα Δικτυωμένων Συστημάτων προσεγγίζεται από τα ακραία επίπεδα της στοίβας πρωτοκόλλων, και συγκεκριμένα από την οπτική γωνία του Επιπέδου Εφαρμογής και του Φυσικού Επιπέδου. Στο Επίπεδο Εφαρμογής το ενδιαφέρον επικεντρώνεται στην διασφάλιση των περιθωρίων ευστάθειας για τα Ασύρματα Δικτυωμένα Συστήματα Ελέγχου. Η διασφάλιση της ομαλής λειτουργίας του συστήματος κλειστού βρόχου βασίζεται σε διακοπτικές δομές ελέγχου, των οποίων οι παράμετροι λειτουργίας καθορίζονται από την Ποιότητα Υπηρεσίας του δικτύου, και συγκεκριμένα από το ποσοστό των επιτυχώς ληφθέντων πακέτων. Στο Φυσικό Επίπεδο εξετάζεται αρχικά το πρόβλημα αποκατάστασης της συνδεσιμότητας μεταξύ των μελών ενός Ασύρματα Δικτυωμένου Συστήματος και στην συνέχεια το πρόβλημα επαναπροσδιορισμού της ποιότητας των ασύρματων ζεύξεων. Οι κεντρικοποιημένοι και κατανεμημένοι μηχανισμοί που αναπτύσσονται για τη βελτιστοποίηση των παραμέτρων της Ποιότητας Υπηρεσίας των Ασύρματα Δικτυωμένων Συστημάτων στο Φυσικό Επίπεδο βασίζονται σε εργαλεία της Υπολογιστικής Γεωμετρίας, συνδυάζοντας τα χωρικά χαρακτηριστικά ενός Ασύρματα Δικτυωμένου Συστήματος με δημοφιλή μοντέλα διάδοσης μεγάλης κλίμακας. Τέλος, η αξιολόγηση των μεθόδων ελέγχου και βελτιστοποίησης της λειτουργίας των Ασύρματα Δικτυωμένων Συστημάτων πραγματοποιείται με την εφαρμογή τους σε κατάλληλες πειραματικές διατάξεις και σε ένα καθορισμένο σύνολο σεναρίων εξομοίωσης. / The primary objective of the present PhD thesis is the analysis and the synthesis of mechanisms and algorithms that optimize the operation of Wireless Networked Systems. The term Wireless Networked Systems is used to describe the distributed systems, whose components are interconnected over wireless networks. Referring to wireless networking, the emphasis is given at the self-organized Ad-hoc and Sensor Networks. The effort made is focused on the reconfiguration of the Quality of Service of the underlying network. From such a perspective, the mechanisms responsible for improving the Quality of Service differentiate from the design of novel, specialized communication protocols. More specifically, with respect to the Open Systems Interconnection Reference Model (OSI-RM), the optimization issues of the Wireless Networked Systems’ operation are examined at the Application and Physical Layer. At the Application Layer, problems related to the guarantee of the stability margins for Wireless Networked Controlled Systems are studied. More precisely, the assurance of the desired performance for the closed-loop controlled system is based on switching control techniques. The optimization decision variables are determined by the network’s Quality of Service parameters. At the Physical Layer the objective is twofold: (a) to establish the physical connectivity among the members of the Wireless Networked System and (b) to optimize of the wireless link’s quality. Based on the combination of the spatial characteristics of the Wireless Networked Systems with large-scale radio propagation models, the centralized and distributed mechanisms, synthesized for the optimization of the network’s Quality of Service at the Physical Layer, exploit effectively concepts adopted by the Computational Geometry. Finally, properly developed experimental testbeds and network simulation scenaria are utilized to examine the efficiency of the synthesized mechanisms for the control and optimization of the operation of Wireless Networked Systems at the Application and Physical Layer.

The integration of control systems with wireless communication networks has gainedsignificant popularity, leading to the emergence of wireless networked control systems(WNCS). WNCS comprises wireless devices such as sensors, actuators, andcontrollers that work together to ensure system stabilizability. However, communicationamong these wireless devices often relies on relay nodes, which presents a challengein guaranteeing system stabilizability due to potential failures caused by natural eventsor malicious activities targeting and disabling these nodes. This study proposes an approach to enhance the resilience of wireless sensor networks(WSNs) utilizing the WirelessHART communication protocol. The objective is to designthe WSNs and controller that can ensure stabilizability, even in the specific number ofrelay node failures. The study employs two key methodologies: firstly, the analysis ofconditions such as controllability, observability, solvability of fault detection andisolation, and the associated requirements to guarantee system stabilizability. Secondly,MATLAB simulations are employed to test the proposed system. By combiningtheoretical analysis and practical simulations, the study provides valuable insights anddesign strategies that contribute to the advancement of WNCS, enabling their reliabilityand stability in the face of potential relay node failures. / Integrationen av styrsystem med trådlösa kommunikationsnätverk har blivit mycketpopulär, vilket har lett till framväxten av trådlösa nätverksstyrningssystem (WNCS).WNCS omfattar trådlösa enheter som sensorer, aktuatorer och styrenheter som arbetartillsammans för att säkerställa systemets stabilisering. Kommunikationen mellan dessatrådlösa enheter förlitar sig emellertid ofta på relänoder, vilket utgör en utmaning föratt garantera systemets stabilisering på grund av potentiella fel orsakade av naturligahändelser eller skadliga aktiviteter som riktar sig mot och inaktiverar dessa noder. Denna studie föreslår ett tillvägagångssätt för att förbättra motståndskraften hos trådlösasensornätverk (WSNs) med hjälp av kommunikationsprotokollet WirelessHART. Måletär att utforma WSN och styrenheter som kan säkerställa stabilisering även vid ettspecifikt antal relänodfel. Studien använder sig av två huvudsakliga metoder: för detförsta analys av villkor såsom styrbarket, observerbarheten, lösbarheten hos felupptäcktoch isolering metod och de tillhörande kraven för att garantera systemets stabilisering.För det andra används MATLAB-simuleringar för att testa det föreslagna systemet.Genom att kombinera teoretisk analys och praktiska simuleringar ger studien värdefullainsikter och designstrategier som bidrar till framsteg inom WNCS, vilket möjliggörtillförlitlighet och stabilitet även vid potentiella fel på relänoder.

Networked control over wireless networks is of growing importance in many application domains such as industrial control, building automation and transportation systems. Wide deployment however, requires systematic design tools to enable efficient resource usage while guaranteeing close-loop control performance. The control system may be greatly affected by the inherent imperfections and limitations of the wireless medium and malfunction of system components. In this thesis, we make five important contributions that address these issues.  In the first contribution, we consider event- and self-triggered control and investigate how to efficiently tune and execute these paradigms for appropriate control performance. Communication strategies for aperiodic control are devised, where we jointly address the selection of medium-access control and scheduling policies. Experimental results show that the best trade-off is obtained by a hybrid scheme, combining event- and self-triggered control together with contention-based and contention-free medium access control. The second contribution proposes an event-based method to select between fast and slow periodic sampling rates. The approach is based on linear quadratic control and the event condition is a quadratic function of the system state. Numerical and experimental results show that this hybrid controller is able to reduce the average sampling rate in comparison to a traditional periodic controller, while achieving the same closed-loop control performance. In the third contribution, we develop compensation methods for out-of-order communications and time-varying delays using a game-theoretic minimax control framework. We devise a linear temporal coding strategy where the sensor combines the current and previous measurements into a single packet to be transmitted. An experimental evaluation is performed in a multi-hop networked control scenario with a routing layer vulnerability exploited by a malicious application. The experimental and numerical results show the advantages of the proposed compensation schemes. The fourth contribution proposes a distributed reconfiguration method for sensor and actuator networks. We consider systems where sensors and actuators cooperate to recover from faults. Reconfiguration is performed to achieve model-matching, while minimizing the steady-state estimation error covariance and a linear quadratic control cost. The reconfiguration scheme is implemented in a room heating testbed, and experimental results demonstrate the method's ability to automatically reconfigure the faulty system in a distributed and fast manner. The final contribution is a co-simulator, which combines the control system simulator Simulink with the wireless network simulator COOJA. The co-simulator integrates physical plant dynamics with realistic wireless network models and the actual embedded software running on the networked devices. Hence, it allows for the validation of the complete wireless networked control system, including the study of the interactions between software and hardware components. / <p>QC 20140929</p>