This thesis is an effort to develop closed-loop control strategies on computer networks and study their stability in the presence of network delays and packet losses. An algorithm using predictors was designed to ensure the system stability in presence of network delays and packet losses. A single actuator magnetic ball levitation system was used as a test bed to validate the proposed algorithm. A brief study of real-time requirements of the networked control system is presented and a client-server architecture is developed using real-time operating environment to implement the proposed algorithm. Real-time performance of the communication on Ethernet based on user datagram protocol (UDP) was explored and UDP is presented as a suitable protocol for networked control systems. Predictors were designed based on parametric estimation models. Autoregressive (AR) and autoregressive moving average (ARMA) models of various orders were designed using MATLAB and an eighth order AR model was adopted based on the best-fit criterion. The system output was predicted several steps ahead using these predictors and control output was calculated using the predictions. This control output output was used in the events of excessive network delays to maintain system stability. Experiments employing simulations of consecutive packet losses and network delays were performed to validate the satisfactory performance of the predictor based algorithm. The current system compensates for up to 20 percent data losses in the network without loosing stability.

This thesis is an effort to develop closed-loop control strategies on computer networks and study their stability in the presence of network delays and packet losses. An algorithm using predictors was designed to ensure the system stability in presence of network delays and packet losses. A single actuator magnetic ball levitation system was used as a test bed to validate the proposed algorithm. A brief study of real-time requirements of the networked control system is presented and a client-server architecture is developed using real-time operating environment to implement the proposed algorithm. Real-time performance of the communication on Ethernet based on user datagram protocol (UDP) was explored and UDP is presented as a suitable protocol for networked control systems. Predictors were designed based on parametric estimation models. Autoregressive (AR) and autoregressive moving average (ARMA) models of various orders were designed using MATLAB and an eighth order AR model was adopted based on the best-fit criterion. The system output was predicted several steps ahead using these predictors and control output was calculated using the predictions. This control output output was used in the events of excessive network delays to maintain system stability. Experiments employing simulations of consecutive packet losses and network delays were performed to validate the satisfactory performance of the predictor based algorithm. The current system compensates for up to 20 percent data losses in the network without loosing stability.

Les systèmes multi-agents sont des systèmes dynamiques composés par plusieurs éléments qui interagissent entre eux. Ces éléments sont appelés agents. Un agent est un système dynamique caractérisé par deux propriétés. La première est que les agents sont autonomes— c’est-à-dire qu’ils ne sont pas dirigés par l’environnement extérieur et ils peuvent évoluer selon un comportement auto-organisé. La seconde est que les agents sont capables de communiquer entre eux pour accomplir des tâches complexes, telles que la coopération, la coordination et la résolution de conflits. L’un des problèmes courants concernant les systèmes multi-agents est la synchronisation. Les agents sont synchronisés lorsque leur évolution dans le temps converge vers une trajectoire commune. Plusieurs applications du monde réel peuvent être conceptualisés comme des problèmes de synchronisation des systèmes multi-agents : par exemple, l’alignement en vitesse ( flocking en anglais), et le contrôle de la formation du mouvement de groupes cohérents. La synchronisation des systèmes multi-agents peut être obtenue grâce à différentes techniques de contrôle. Dans cette thèse nous proposons des méthodes de contrôle centralisées et distribuées pour la synchronisation des systèmes multi-agents. Nous développons des conditions nécessaires et suffisantes pour la synchronisation des systèmes multi-agents, composés par des agents identiques et linéaires qui ne changent pas dans le temps, en utilisant une approche Lyapunov. Ces conditions sont utilisées pour la conception de lois de contrôles distribuées. ensuite, nous étendons les résultats aux systèmes multi-agents soumis à des perturbations externes, assurant un niveau de performance désiré grâce à une technique de contrôle de type 퐻 ∞ . enfin, nous étendons l’analyse aux systèmes multi-agents avec contraintes sur les actionneurs, en utilisant des techniques de contrôle anti-windup. Nous évaluons l’efficacité et les performances des stratégies de contrôle proposées dans plusieurs simulations, dont deux d’entre elles sont inspirées par des applications issues du monde réel. La première est le contrôle du vol en formation d’avions, et la seconde est l’analyse de la transmission de contenus vidéo comme un problème de synchronisation. Nous comparons aussi les résultats obtenus avec des techniques de contrôle alternatives. / Multi-agent systems are dynamical systems composed of multiple interacting elements known as agents . Each agent is a dynamical system with two characteristics. First, it is capable of autonomous action—that is, it is able to evolve according to a self-organised behavior, which is not influenced by the external environment. Second, it is able to exchange information with other agents in order to accomplish complex tasks, such as coordination, cooperation, and conflict resolution. One commonly studied problem in multi-agent systems is synchronization. The agents are synchronized when their time evolutions converge to a common trajectory. Many real-world applications, such as flocking and formation control, can be cast as synchronization problems. Agent synchronization can be achieved using different approaches. In this thesis, we propose distributed and centralized control paradigms for the synchronization of multi-agent systems. We develop necessary and sufficient conditions for the synchronization of multi-agent systems, composed by identical linear time-invariant agents, us- ing a Lyapunov-based approach. Then we use these conditions to design distributed synchronization controllers. Then, we extend this result to multi-agent systems subject to external disturbances enforcing disturbance rejection with 퐻 ∞ control techniques. Furthermore, we extend the analysis to multi-agent systems with actuator constraints using LMI-based anti-windup techniques. We test the proposed control design strategies in simulated examples among which two are inspired by real-world applications. In the first, we study airplane formation control as a synchronization problem. In the second, we analyze the delivery of video streams as a synchronization problem and we compare the results to existing controllers.

Standards are, nowadays, a useful and sometimes essential tool, in the world of automated industry. Since the development of the standard IEC 61131-3, automation has made progresses in a consistent manner. This allows an engineer to develop control programs for any type of systems using the language set in the standard. However, this standard was not enough because it did not cover the control over distributed systems. Therefore, it was necessary to establish rules in this field. In order to fill this gap, the new standard IEC 61499 was developed. Its main objective is to describe how to develop, design and implement distributed control systems, using the new concept of function blocks. By the use of the new function blocks, it is possible to control distributed systems in a quick and easy way, adding some advantages such as reusability, portability, and much enhanced maintenance.This project involves the preparation of a manufacturing cell composed of a gantry robot interacting with a CNC machine. The project is developed in two sections; one is focused on the computer programming with function blocks for the gantry robot and HMI, and the other is prepared for the programming of function blocks for the CNC machine and HMI. The communications between PLC, PC, gantry robot and CNC machine are developed using the standard IEC 61499. This document covers the survey and research made for the first section of the project.The new standard IEC 61499 provides the methodologies and the appropriated tools to achieve a good control in distributed systems. The basic tools offered by this standard are the new function blocks which will be the main tool used in this project. Equally important, it is necessary to take into account the different assembly features and the machining features in order to design better function blocks to control the system. An HMI has to be developed in order to obtain a good interface for a worker of this cell.The aim of this project is to investigate how the new standard IEC 61499 works in a real manufacturing cell and how the new function blocks interact in a real distributed system. Moreover, it is important to see how the event flow works, controlling all the sequences required in the manufacturing cell.

In the field of the industrial automatic control, both MCU (Micro Control Unit) and PLC (Programmable Logic Controller) are widely being used in DCS (Distributed Control System). Since MCU can provide complex process scheduling, accurate timing control and PLC has the advantages of easy programming and maintaining. However, the control programs of the MCU are hard to design and maintain. Identically, the poor signal processing ability, high cost and the restrictive functions are the major defects of PLC. In order to solve the drawbacks described above in MCU and PLC, we provide a PLC-like interface for users to access the devices and set the registers of MCU. Likewise, designers can develop the control program via Event-table-driven modules. On the other hand, our main goal of DCS is to quickly construct the distributed N level network topology based on Modbus protocol, which is efficient and reliable. Therefore, we bring up a data collection method and Slave-to-Slave strategy so as to distribute the master loading, reduce the package transmission times and improve the real-time latency. In conclusion, our research results not only congregate the benefits of MCU and PLC but provide an environment to quickly construct and conveniently monitor DCS, which meets the time-to-market demands.

AN ABSTRACT OF THE THESIS OF PRASHANTHI BANALA, for the Master of Science degree in ELECTRICAL AND COMPUTER ENGINEERING, presented on 31 October 2011, at Southern Illinois University Carbondale. TITLE: OUTPUT FEEDBACK H-inf CONTROL DESIGN FOR MULTI-AGENT SYSTEMS MAJOR PROFESSOR: Dr. Farzad Pourboghrat In this thesis, the design of distributed control for identical multi-agent systems is considered based on the optimization of H-inf cost function. Identical dynamically coupled but interacting systems (agents) are considered where control action of each agent is based on relative output measurement of their neighboring agents and a subset of their own output. The agents communicate with each other to achieve a common goal. A distributed dynamic output feedback control strategy that satisfies H-inf performance for multi-agent systems is developed and corresponding H-inf performance region is analyzed. An example illustrates the necessary and sufficient condition for dynamic output feedback controller synthesis to obtain desired H-inf performance.

This thesis describes creation of dynamically evolvable node, which will cooperate with other nodes. Group of these nodes will then create a distributed control system. The MQTT protocol is used for communications purposes between individual nodes. As hardware platform is used ESP32 and ESP8266. Whole operating system is written in MicroPython and supports a live uploading of user applications written in the same language. Later in thesis is decribed creation of monitoring node on Raspberry Pi, which control network. Complete system can be then used to control a intelligent house.

Current global business competition has resulted in significant challenges for manufacturing and production sectors focused on shorter product lifecyc1es, more diverse and customized products as well as cost pressures from competitors and customers. To remain competitive, manufacturers, particularly in automotive industry, require the next generation of manufacturing paradigms supporting flexible and reconfigurable production systems that allow quick system changeovers for various types of products. In addition, closer integration of shop floor and business systems is required as indicated by the research efforts in investigating "Agile and Collaborative Manufacturing Systems" in supporting the production unit throughout the manufacturing lifecycles. The integration of a business enterprise with its shop-floor and lifecycle supply partners is currently only achieved through complex proprietary solutions due to differences in technology, particularly between automation and business systems. The situation is further complicated by the diverse types of automation control devices employed. Recently, the emerging technology of Service Oriented Architecture's (SOA's) and Web Services (WS) has been demonstrated and proved successful in linking business applications. The adoption of this Web Services approach at the automation level, that would enable a seamless integration of business enterprise and a shop-floor system, is an active research topic within the automotive domain. If successful, reconfigurable automation systems formed by a network of collaborative autonomous and open control platform in distributed, loosely coupled manufacturing environment can be realized through a unifying platform of WS interfaces for devices communication. The adoption of SOA- Web Services on embedded automation devices can be achieved employing Device Profile for Web Services (DPWS) protocols which encapsulate device control functionality as provided services (e.g. device I/O operation, device state notification, device discovery) and business application interfaces into physical control components of machining automation. This novel approach supports the possibility of integrating pervasive enterprise applications through unifying Web Services interfaces and neutral Simple Object Access Protocol (SOAP) message communication between control systems and business applications over standard Ethernet-Local Area Networks (LAN's). In addition, the re-configurability of the automation system is enhanced via the utilisation of Web Services throughout an automated control, build, installation, test, maintenance and reuse system lifecycle via device self-discovery provided by the DPWS protocol.

This master's thesis deals with distributed control protocols for industrial applications. It explains term distributed control system, control protocol and it is dealing with properties, frame structures and ways of communication within CAN, Modbus, IEC60870-5-101 and DLMS protocols. This thesis includes informations, which are in most cases difficult to find. Second part of the thesis is dedicated to education system. This part is contained by information about protocols and their layers based on ISO/OSI model, pictures of structure of messages, knowledge test and an application based on JavaScript language. This JavaScript application emulates behavior of workstations, which are using communication based on IEC 60870-5-101 protocol. This application can set various conditions for influence of message transfer. These conditions are setting way of message transfer, data availability, filling of workstation’s buffer or intentional damage of message's content. It also contains a large amount of context help, activated after moving mouse cursor over most of application's elements. Even visitor without great knowledge of distributed control systems should understand how this protocol works, thanks to these context help and messages printed in lower part of the application. The conclusion of this work is aimed to positive and negative features and comparison of mentioned control protocols.

ABB s r.o. is one of the most important companies that are concerned with setting of trends in electro-energetic field. One of these trends is digitalization of medium voltage substations that leads to simplified of internal connection and easier connection of substation to the control system. This thesis deals possibilities of connection of communication, methods of controlling logical operations by centralized or distributed system and compares potential of these systems.