172 research outputs found

    Reconciling a component and process view

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    In many cases we need to represent on the same abstraction level not only system components but also processes within the system, and if for both representation different frameworks are used, the system model becomes hard to read and to understand. We suggest a solution how to cover this gap and to reconcile component and process views on system representation: a formal framework that gives the advantage of solving design problems for large-scale component systems.Comment: Preprint, 7th International Workshop on Modeling in Software Engineering (MiSE) at ICSE 201

    Fully-deterministic execution of IEC-61499 models for Distributed Avionics Applications

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    © 2018 by the authors. The development of time-critical Distributed Avionics Applications (DAAs) pushes beyond the limit of existing modeling methodologies to design dependable systems. Aerospace and industrial automation entail high-integrity applications where execution time is essential for dependability. This tempts us to use modeling technologies from one domain in another. The challenge is to demonstrate that they can be effectively used across domains whilst assuring temporally dependable applications. This paper shows that an IEC61499-modeled DAA can satisfy temporal dependability requirements as to end-to-end flow latency when it is properly scheduled and realized in a fully deterministic avionics platform that entails Integrated Modular Avionics (IMA) computation along with Time-Triggered Protocol (TTP) communication. Outcomes from the execution design of an IEC61499-based DAA model for an IMA-TTP platform are used to check runtime correctness through DAA control stability. IEC 61499 is a modeling standard for industrial automation, and it is meant to facilitate distribution and reconfiguration of applications. The DAA case study is a Distributed Fluid Control System (DFCS) for the Airbus-A380 fuel system. Latency analysis results from timing metrics as well as closed-loop control simulation results are presented. Experimental outcomes suggest that an IEC61499-based DFCS model can achieve desired runtime latency for temporal dependability when executed in an IMA-TTP platform. Concluding remarks and future research direction are also discussed

    Towards a new methodology for design, modelling, and verification of reconfigurable distributed control systems based on a new extension to the IEC 61499 standard

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    In order to meet user requirements and system environment changes, reconfigurable control systems must dynamically adapt their structure and behaviour without disrupting system operation. IEC 61499 standard provides limited support for the design and verification of such systems. In fact, handling different reconfiguration scenarios at runtime is difficult since function blocks in IEC 61499 cannot be changed at run-time. Hence, this thesis promotes an IEC 61499 extension called reconfigurable function block (RFB) that increases design readability and smoothly switches to the most appropriate behaviour when a reconfiguration event occurs. To ensure system feasibility after reconfiguration, in addition to the qualitative verification, quantitative verification based on probabilistic model checking is addressed in a new RFBA approach. The latter aims to transform the designed RFB model automatically into a generalised reconfigurable timed net condition/event system model (GRTNCES) using a newly developed environment called RFBTool. The GR-TNCES fits well with RFB and preserves its semantic. Using the probabilistic model checker PRISM, the generated GR-TNCES model is checked using defined properties specified in computation tree logic. As a result, an evaluation of system performance and an estimation of reconfiguration risks are obtained. The RFBA methodology is applied on a distributed power system case study.Dynamische Anforderungen und Umgebungen erfordern rekonfigurierbare Anlagen und Steuerungssysteme. Rekonfiguration ermöglicht es einem System, seine Struktur und sein Verhalten an interne oder externe Änderungen anzupassen. Die Norm IEC 61499 wurde entwickelt, um (verteilte) Steuerungssysteme auf Basis von Funktionsbausteinen zu entwickeln. Sie bietet jedoch wenig Unterstützung für Entwurf und Verifikation. Die Tatsache, dass eine Rekonfiguration das System-Ausführungsmodell verändert, erschwert die Entwicklung in IEC 61499 zusätzlich. Daher schlägt diese Dissertation rekonfigurierbare Funktionsbausteine (RFBs) als Erweiterung der Norm vor. Ein RFB verarbeitet über einen Master-Slave-Automaten Rekonfigurationsereignisse und löst das entsprechende Verhalten aus. Diese Hierarchie trennt das Rekonfigurationsmodell vom Steuerungsmodell und vereinfacht so den Entwurf. Die Funktionalität des Entwurfs muss verifiziert werden, damit die Ausführbarkeit des Systems nach einer Rekonfiguration gewährleistet ist. Hierzu wird das entworfene RFB-Modell automatisch in ein generalised reconfigurable timed net condition/event system übersetzt. Dieses wird mit dem Model-Checker PRISM auf qualitative und quantitative Eigenschaften überprüft. Somit wird eine Bewertung der Systemperformanz und eine Einschätzung der Rekonfigurationsrisiken erreicht. Die RFB-Methodik wurde in einem Softwarewerkzeug umgesetzt und in einer Fallstudie auf ein dezentrales Stromnetz angewendet

    IEC 61499 REPLICATION FOR FAULT TOLERANT SYSTEM

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    The IEC 61499 was developed thinking about the new generation of distributed control and automation systems. This provides essential resources for the development of distributed systems such as encapsulation, portability and reconfiguration. In this sense, and to ensure confidence in the operation should be implemented fault tolerance techniques dealing with hardware failures and errors off software associated with us where the distributed application runs. In this paper, we propose an approach to deal with failures in distributed systems tolerance problems, based on a replication model based on replication software/hardware as a means to achieve confidence in the operation.info:eu-repo/semantics/publishedVersio

    An architecture to integrate IEC 61131-3 systems in an IEC 61499 distributed solution

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    The IEC 61499 standard has been developed to allow the modeling and design of distributed control systems, providing advanced concepts of software engineering (such as abstraction and encapsulation) to the world of control engineering. The introduction of this standard in already existing control environments poses challenges, since programs written using the widespread IEC 61131-3 programming standard cannot be directly executed in a fully IEC 61499 environment without reengineering effort. In order to solve this problem, this paper presents an architecture to integrate modules of the two standards, allowing the exploitation of the benefits of both. The proposed architecture is based on the coexistence of control software of the two standards. Modules written in one standard interact with some particular interfaces that encapsulate functionalities and information to be exchanged with the other standard. In particular, the architecture permits to utilize available run-times without modification, it allows the reuse of software modules, and it utilizes existing features of the standards. A methodology to integrate IEC 61131-3 modules in an IEC 61499 distributed solution based on such architecture is also developed, and it is described via a case study to prove feasibility and benefits. Experimental results demonstrate that the proposed solution does not add substantial load or delays to the system when compared to an IEC 61131-3 based solution. By acting on task period, it can achieve performances similar to an IEC 61499 solution

    OPTIMIZATION OF PRODUCTION LINES USING ADVANCED CNC INTERPOLATION METHODS AND DISTRIBUTION OF CONTROL LOGIC

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    These days, information technology really makes the difference in manufacturing industry. High performance computers allow to realize control algorithms of increasing complexity and high speed reliable computer networks allows the communication between different devices and realization of advanced distributed control applications. In this thesis, we focus on the optimization of the production lines using two different approaches. First we focus on the improvement of a single workstation of the production line, then we focus on the improvement of the interactions between various stations of the production line.. A typical workstation that can be found in a production line is the machine tool for manufacturing workpieces. Advances in manufacturing technologies allow to increase quality and efficiency in production lines, but also ask for new and increasing requirements on the motion planning and control systems. The increase of CPU processing power has permitted, in traditional CNC systems, the introduction of NURBS interpolation capabilities, thus determining a further increase in machining quality and efficiency. This has posed new and still unsolved issues, such as the need to satisfy multiple opposite constraints like limiting chord error, acceleration and jerk and offering real-time guarantees. In addition, the ability of privileging the production throughput by relaxing one or more of the previous constraints in a simple way has emerged as another requirement of modern manufacturing plants. Nevertheless, none of the existing NURBS interpolators have these characteristics. In this thesis, we propose a NURBS interpolator that is able to satisfy all the manufacturing technology requirements and is able to respect, thanks to its bounded computational complexity, the position control real-time constraints. Such interpolator is easily reconfigurable, i.e. it can relax some of the constraints and can be adapted in order to include constraints that were not originally considered. Performances of the proposed algorithm have been evaluated both by simulations and by real milling experiments. However, improvements in productivity of a the machine tool can be neutralized if the various workstations of the production line are not properly synchronized. Distributed control allows to improve the coordination of different workstations but its design is challenging. The IEC 61499 standard has been developed to ease the modeling and design of distributed control systems, providing advanced concepts of software engineering (such as abstraction, encapsulation, reuse) to the world of control engineering. The introduction of such standard in already existing control environments poses challenges, since the widespread IEC 61131-3 programming standard is not compatible with the new standard. In order to solve this problem, this thesis presents an architecture that permits to integrate modules of the two standards, allowing to exploit the benefits of both. The proposed architecture is based on coexistence of control logic of both standards. Each standard interacts with some particular interfaces that encapsulate information and functionalities to be exchanged with the other standard. A methodology of integration of 61131-3 modules in a 61499 distributed solution based on such architecture is also developed, and it is described via a case study to prove feasibility and benefits

    Software framework for the development of context-aware reconfigurable systems

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    In this project we propose a new software framework for the development of context-aware and secure controlling software of distributed reconfigurable systems. Context-awareness is a key feature allowing the adaptation of systems behaviour according to the changing environment. We introduce a new definition of the term “context” for reconfigurable systems then we define a new context modelling and reasoning approach. Afterwards, we define a meta-model of context-aware reconfigurable applications that paves the way to the proposed framework. The proposed framework has a three-layer architecture: reconfiguration, context control, and services layer, where each layer has its well-defined role. We define also a new secure conversation protocol between distributed trustless parts based on the blockchain technology as well as the elliptic curve cryptography. To get better correctness and deployment guarantees of applications models in early development stages, we propose a new UML profile called GR-UML to add new semantics allowing the modelling of probabilistic scenarios running under memory and energy constraints, then we propose a methodology using transformations between the GR-UML, the GR-TNCES Petri nets formalism, and the IEC 61499 function blocks. A software tool implementing the methodology concepts is developed. To show the suitability of the mentioned contributions two case studies (baggage handling system and microgrids) are considered.In diesem Projekt schlagen wir ein Framework für die Entwicklung von kontextbewussten, sicheren Anwendungen von verteilten rekonfigurierbaren Systemen vor. Kontextbewusstheit ist eine Schlüsseleigenschaft, die die Anpassung des Systemverhaltens an die sich ändernde Umgebung ermöglicht. Wir führen eine Definition des Begriffs ``Kontext" für rekonfigurierbare Systeme ein und definieren dann einen Kontextmodellierungs- und Reasoning-Ansatz. Danach definieren wir ein Metamodell für kontextbewusste rekonfigurierbare Anwendungen, das den Weg zum vorgeschlagenen Framework ebnet. Das Framework hat eine dreischichtige Architektur: Rekonfigurations-, Kontextkontroll- und Dienste-Schicht, wobei jede Schicht ihre wohldefinierte Rolle hat. Wir definieren auch ein sicheres Konversationsprotokoll zwischen verteilten Teilen, das auf der Blockchain-Technologie sowie der elliptischen Kurven-Kryptographie basiert. Um bessere Korrektheits- und Einsatzgarantien für Anwendungsmodelle zu erhalten, schlagen wir ein UML-Profil namens GR-UML vor, um Semantik umzufassen, die die Modellierung probabilistischer Szenarien unter Speicher- und Energiebeschränkungen ermöglicht. Dann schlagen wir eine Methodik vor, die Transformationen zwischen GR-UML, dem GR-TNCES-Petrinetz-Formalismus und den IEC 61499-Funktionsblöcken verwendet. Es wird ein Software entwickelt, das die Konzepte der Methodik implementiert. Um die Eignung der genannten Beiträge zu zeigen, werden zwei Fallstudien betrachtet

    Data Distribution Service for industrial automation

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    Anpassen verteilter eingebetteter Anwendungen im laufenden Betrieb

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    The availability of third-party apps is among the key success factors for software ecosystems: The users benefit from more features and innovation speed, while third-party solution vendors can leverage the platform to create successful offerings. However, this requires a certain decoupling of engineering activities of the different parties not achieved for distributed control systems, yet. While late and dynamic integration of third-party components would be required, resulting control systems must provide high reliability regarding real-time requirements, which leads to integration complexity. Closing this gap would particularly contribute to the vision of software-defined manufacturing, where an ecosystem of modern IT-based control system components could lead to faster innovations due to their higher abstraction and availability of various frameworks. Therefore, this thesis addresses the research question: How we can use modern IT technologies and enable independent evolution and easy third-party integration of software components in distributed control systems, where deterministic end-to-end reactivity is required, and especially, how can we apply distributed changes to such systems consistently and reactively during operation? This thesis describes the challenges and related approaches in detail and points out that existing approaches do not fully address our research question. To tackle this gap, a formal specification of a runtime platform concept is presented in conjunction with a model-based engineering approach. The engineering approach decouples the engineering steps of component definition, integration, and deployment. The runtime platform supports this approach by isolating the components, while still offering predictable end-to-end real-time behavior. Independent evolution of software components is supported through a concept for synchronous reconfiguration during full operation, i.e., dynamic orchestration of components. Time-critical state transfer is supported, too, and can lead to bounded quality degradation, at most. The reconfiguration planning is supported by analysis concepts, including simulation of a formally specified system and reconfiguration, and analyzing potential quality degradation with the evolving dataflow graph (EDFG) method. A platform-specific realization of the concepts, the real-time container architecture, is described as a reference implementation. The model and the prototype are evaluated regarding their feasibility and applicability of the concepts by two case studies. The first case study is a minimalistic distributed control system used in different setups with different component variants and reconfiguration plans to compare the model and the prototype and to gather runtime statistics. The second case study is a smart factory showcase system with more challenging application components and interface technologies. The conclusion is that the concepts are feasible and applicable, even though the concepts and the prototype still need to be worked on in future -- for example, to reach shorter cycle times.Eine große Auswahl von Drittanbieter-Lösungen ist einer der Schlüsselfaktoren für Software Ecosystems: Nutzer profitieren vom breiten Angebot und schnellen Innovationen, während Drittanbieter über die Plattform erfolgreiche Lösungen anbieten können. Das jedoch setzt eine gewisse Entkopplung von Entwicklungsschritten der Beteiligten voraus, welche für verteilte Steuerungssysteme noch nicht erreicht wurde. Während Drittanbieter-Komponenten möglichst spät -- sogar Laufzeit -- integriert werden müssten, müssen Steuerungssysteme jedoch eine hohe Zuverlässigkeit gegenüber Echtzeitanforderungen aufweisen, was zu Integrationskomplexität führt. Dies zu lösen würde insbesondere zur Vision von Software-definierter Produktion beitragen, da ein Ecosystem für moderne IT-basierte Steuerungskomponenten wegen deren höherem Abstraktionsgrad und der Vielzahl verfügbarer Frameworks zu schnellerer Innovation führen würde. Daher behandelt diese Dissertation folgende Forschungsfrage: Wie können wir moderne IT-Technologien verwenden und unabhängige Entwicklung und einfache Integration von Software-Komponenten in verteilten Steuerungssystemen ermöglichen, wo Ende-zu-Ende-Echtzeitverhalten gefordert ist, und wie können wir insbesondere verteilte Änderungen an solchen Systemen konsistent und im Vollbetrieb vornehmen? Diese Dissertation beschreibt Herausforderungen und verwandte Ansätze im Detail und zeigt auf, dass existierende Ansätze diese Frage nicht vollständig behandeln. Um diese Lücke zu schließen, beschreiben wir eine formale Spezifikation einer Laufzeit-Plattform und einen zugehörigen Modell-basierten Engineering-Ansatz. Dieser Ansatz entkoppelt die Design-Schritte der Entwicklung, Integration und des Deployments von Komponenten. Die Laufzeit-Plattform unterstützt den Ansatz durch Isolation von Komponenten und zugleich Zeit-deterministischem Ende-zu-Ende-Verhalten. Unabhängige Entwicklung und Integration werden durch Konzepte für synchrone Rekonfiguration im Vollbetrieb unterstützt, also durch dynamische Orchestrierung. Dies beinhaltet auch Zeit-kritische Zustands-Transfers mit höchstens begrenzter Qualitätsminderung, wenn überhaupt. Rekonfigurationsplanung wird durch Analysekonzepte unterstützt, einschließlich der Simulation formal spezifizierter Systeme und Rekonfigurationen und der Analyse der etwaigen Qualitätsminderung mit dem Evolving Dataflow Graph (EDFG). Die Real-Time Container Architecture wird als Referenzimplementierung und Evaluationsplattform beschrieben. Zwei Fallstudien untersuchen Machbarkeit und Nützlichkeit der Konzepte. Die erste verwendet verschiedene Varianten und Rekonfigurationen eines minimalistischen verteilten Steuerungssystems, um Modell und Prototyp zu vergleichen sowie Laufzeitstatistiken zu erheben. Die zweite Fallstudie ist ein Smart-Factory-Demonstrator, welcher herausforderndere Applikationskomponenten und Schnittstellentechnologien verwendet. Die Konzepte sind den Studien nach machbar und nützlich, auch wenn sowohl die Konzepte als auch der Prototyp noch weitere Arbeit benötigen -- zum Beispiel, um kürzere Zyklen zu erreichen

    A Semantic Interoperability Model Based on the IEEE 1451 Family of Standards Applied to the Industry 4.0

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    The Internet of Things (IoT) has been growing recently. It is a concept for connecting billions of smart devices through the Internet in different scenarios. One area being developed inside the IoT in industrial automation, which covers Machine-to-Machine (M2M) and industrial communications with an automatic process, emerging the Industrial Internet of Things (IIoT) concept. Inside the IIoT is developing the concept of Industry 4.0 (I4.0). That represents the fourth industrial revolution and addresses the use of Internet technologies to improve the production efficiency of intelligent services in smart factories. I4.0 is composed of a combination of objects from the physical world and the digital world that offers dedicated functionality and flexibility inside and outside of an I4.0 network. The I4.0 is composed mainly of Cyber-Physical Systems (CPS). The CPS is the integration of the physical world and its digital world, i.e., the Digital Twin (DT). It is responsible for realising the intelligent cross-link application, which operates in a self-organised and decentralised manner, used by smart factories for value creation. An area where the CPS can be implemented in manufacturing production is developing the Cyber-Physical Production System (CPPS) concept. CPPS is the implementation of Industry 4.0 and CPS in manufacturing and production, crossing all levels of production between the autonomous and cooperative elements and sub-systems. It is responsible for connecting the virtual space with the physical world, allowing the smart factories to be more intelligent, resulting in better and smart production conditions, increasing productivity, production efficiency, and product quality. The big issue is connecting smart devices with different standards and protocols. About 40% of the benefits of the IoT cannot be achieved without interoperability. This thesis is focused on promoting the interoperability of smart devices (sensors and actuators) inside the IIoT under the I4.0 context. The IEEE 1451 is a family of standards developed to manage transducers. This standard reaches the syntactic level of interoperability inside Industry 4.0. However, Industry 4.0 requires a semantic level of communication not to exchange data ambiguously. A new semantic layer is proposed in this thesis allowing the IEEE 1451 standard to be a complete framework for communication inside the Industry 4.0 to provide an interoperable network interface with users and applications to collect and share the data from the industry field.A Internet das Coisas tem vindo a crescer recentemente. É um conceito que permite conectar bilhões de dispositivos inteligentes através da Internet em diferentes cenários. Uma área que está sendo desenvolvida dentro da Internet das Coisas é a automação industrial, que abrange a comunicação máquina com máquina no processo industrial de forma automática. Essa interligação, representa o conceito da Internet das Coisas Industrial. Dentro da Internet das Coisas Industrial está a desenvolver o conceito de Indústria 4.0 (I4.0). Isso representa a quarta revolução industrial que aborda o uso de tecnologias utilizadas na Internet para melhorar a eficiência da produção de serviços em fábricas inteligentes. A Indústria 4.0 é composta por uma combinação de objetos do mundo físico e do mundo da digital que oferece funcionalidade dedicada e flexibilidade dentro e fora de uma rede da Indústria 4.0. O I4.0 é composto principalmente por Sistemas Ciberfísicos. Os Sistemas Ciberfísicos permitem a integração do mundo físico com seu representante no mundo digital, por meio do Gémeo Digital. Sistemas Ciberfísicos são responsáveis por realizar a aplicação inteligente da ligação cruzada, que opera de forma auto-organizada e descentralizada, utilizada por fábricas inteligentes para criação de valor. Uma área em que o Sistema Ciberfísicos pode ser implementado na produção manufatureira, isso representa o desenvolvimento do conceito Sistemas de Produção Ciberfísicos. Esse sistema é a implementação da Indústria 4.0 e Sistema Ciberfísicos na fabricação e produção. A cruzar todos os níveis desde a produção entre os elementos e subsistemas autónomos e cooperativos. Ele é responsável por conectar o espaço virtual com o mundo físico, permitindo que as fábricas inteligentes sejam mais inteligentes, resultando em condições de produção melhores e inteligentes, aumentando a produtividade, a eficiência da produção e a qualidade do produto. A grande questão é como conectar dispositivos inteligentes com diferentes normas e protocolos. Cerca de 40% dos benefícios da Internet das Coisas não podem ser alcançados sem interoperabilidade. Esta tese está focada em promover a interoperabilidade de dispositivos inteligentes (sensores e atuadores) dentro da Internet das Coisas Industrial no contexto da Indústria 4.0. O IEEE 1451 é uma família de normas desenvolvidos para gerenciar transdutores. Esta norma alcança o nível sintático de interoperabilidade dentro de uma indústria 4.0. No entanto, a Indústria 4.0 requer um nível semântico de comunicação para não haver a trocar dados de forma ambígua. Uma nova camada semântica é proposta nesta tese permitindo que a família de normas IEEE 1451 seja um framework completo para comunicação dentro da Indústria 4.0. Permitindo fornecer uma interface de rede interoperável com utilizadores e aplicações para recolher e compartilhar os dados dentro de um ambiente industrial.This thesis was developed at the Measurement and Instrumentation Laboratory (IML) in the University of Beira Interior and supported by the portuguese project INDTECH 4.0 – Novas tecnologias para fabricação, que tem como objetivo geral a conceção e desenvolvimento de tecnologias inovadoras no contexto da Indústria 4.0/Factories of the Future (FoF), under the number POCI-01-0247-FEDER-026653
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