Anpassen verteilter eingebetteter Anwendungen im laufenden Betrieb

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

Evaluation of C# for a station controller in a reconfigurable manufacturing system

Thesis (MEng)--Stellenbosch University, 2016.ENGLISH ABSTRACT: Reconfigurable manufacturing systems (RMSs) are aimed at dynamic situations, such as varying products, variations in production volume requirements and changes in available resources. RMSs distinguish themselves from other types of manufacturing systems in that they can quickly adapt to a new product being introduced without the need for long reconfiguration times, and can therefore cost effectively produce smaller batch sizes. RMSs in research environments in most cases used Agent Based Control (ABC), but the main automation vendors in the industry do not support ABC. This inhibits the acceptance of RMSs by the industry. For this research, C# was investigated as an alternative to ABC, since C# can provide for many of the functionalities of agents, yet is a more widely known language than ABC. Furthermore, C# is an object-oriented programming (OOP) language and thus possesses characteristics aligned with the core characteristics of reconfigurable manufacturing systems. The focus of this thesis is to determine the suitability of C# for the development of the control software for RMSs. This thesis describes the design, implementation, testing and evaluation of a reconfigurable stacking and buffering station. The controller was implemented in C# and made use of the ADACOR architecture. The physical test-setup was built to evaluate the reconfigurability of the controller in a series of reconfiguration experiments. The thesis showed that the controller could handle all the hardware interfaces without problems, since C# generally simplifies the task of hardware interfacing. OOP characteristics helped making developing and maintaining the code an intuitive task. The stacking station handled all communication with the cell controller correctly, which proved that it could easily be integrated into a distributed control architecture.AFRIKAANSE OPSOMMING: "Reconfigurable manufacturing systems" (RMSs) is gemik op dinamiese situasies, soos veranderende produkte, veranderings in produksievolumes en veranderinge in beskikbare hulpbronne. RMSs onderskei hulself van ander tipes vervaardigingstelsels deurdat hulle vinnig kan aanpas by nuwe produkte wat bekendgestel word sonder dat dit nodig is om die stelsel eers lank te herkonfigureer, en kan sodoende kleiner lotgroottes koste-effektief produseer. RMSs maak in navorsingmilieus meestal gebruik van "Agent Based Control" (ABC), maar die hoof outomatisasie-verkopers in die industrie ondersteun nie ABC nie. Dit belemmer die aanvaarding van RMSs in die industrie. Vir hierdie navorsing is C# as 'n alternatief vir ABC ondersoek omdat C# baie van die funksionaliteite kan voorsien wat aangetref word in ABC, maar terselfdertyd 'n meer bekende taal is as ABC. Verder is C# 'n objek-georiënteerde programmerings- (OOP) taal en beskik dus oor karakteristieke wat in lyn is met die kernkarakteristieke van RMSs. Die fokus van hierdie tesis is die geskiktheid van C# vir die ontwikkeling van beheersagteware vir 'n RMS. Hierdie tesis beskryf die ontwerp, implementering, toetsing en evaluering van 'n herkonfigureerbare stapel- en bufferstasie. Die beheerder was in C# geïmplementeer en het van die ADACOR-argitektuur gebruik gemaak. Die fisiese toets-opstelling was gebou om die herkonfigureerbaarheid van die beheerder te kan evalueer aan hand van 'n reeks herkonfigureringseksperimente. Die tesis het gewys dat die beheerder sonder probleme alle hardeware-intervlakke kon hanteer, omdat C# dit oor die algemeen vergemaklik om met hardeware te kommunikeer. OOP karakteristieke was nuttig om die ontwikkeling en instandhouding van die program intuïtief te maak. Die stapelstasie het alle kommunikasie met die selbeheerder korrek hanteer, wat bewys het dat dit probleemloos in 'n verspreide beheerargitektuur opgeneem kon word

Extending the BASE architecture for complex and reconfigurable cyber-physical systems using Holonic principles.

Thesis (MEng)--Stellenbosch University, 2021.ENGLISH ABSTRACT: ndustry 4.0 (I4.0) represents the newest technological revolution aimed at optimising industries using drivers such as Cyber-Physical Systems (CPSs), the Internet of Things (IoT) and many more. In the past two decades, the holonic paradigm has become a major driver of intelligent manufacturing systems, making it ideal to advance I4.0. The objective of this thesis is to extend an existing holonic reference architecture, the Biography-Attributes-Schedule-Execution (BASE) architecture, for complex and reconfigurable CPSs. In the context of this thesis, complex and reconfigurable systems are considered to be systems that are comprised of many diverse, autonomous and interacting entities, and of which the functionality, organization or size is expected to change over time. The thesis applies the principles of holonic systems to manage complexity and enhance reconfigurability of CPS applications. The BASE architecture is extended for two reasons: to enable it to integrate many diverse entities, and to enhance its reconfigurability. With regards to research on holonic systems, this thesis aims to address two important functions for systems implemented using holonic principles, namely cooperation and cyber-physical interfacing The most important extensions made to the architecture were to enable scalability, refine the cooperation between holons, and integrate cyber-physical interfacing services as Interface Holons. These extensions include platform management components (e.g. a service directory) and standardised plugins (e.g. cyber-physical interfacing plugins). The extended architecture was implemented on an educational sheep farm, because of the many heterogeneous resources (sheep, camps, sensors, humans, etc.) on the farm that need to be integrated into a BASE architecture implemented CPS. This case study implementation had to integrate data from different sensors, provide live analysis of observed data and, when required, notify the physical world of any problems in the CPS. At the end of the implementation, an evaluation was done using the requirements of a complex, reconfigurable CPS as evaluation criteria. This evaluation involved setting up quantitative and qualitative evaluation metrics for the evaluation criteria, doing the evaluations, and discussing what the results from the different evaluations indicate about the effectiveness and efficiency of the extensions made to the BASE architecture. The extensions made to the BASE architecture were found to improve robustness and resilience. The use of Erlang was found to play a very important role in the resulting reliability. The extensions also helped to fully address the original BASE architecture’s scalability shortcomings and to increase development productivity. Lastly, the extensions show the benefits of using service orientation to enable cooperation between holons and how extracting all cyber-physical interfacing of a system into dedicated Interface Holons reduces development time, improves reusability and enhances diagnosability of interfacing problems.AFRIKAANSE OPSOMMING: ndustrie 4.0 (I4.0) is die nuutste tegnologiese revolusie en dit is daarop gemik om industrieë te optimiseer deur middel van drywers soos Kuber-Fisiese Stelsels (KFSs), die Internet of Things (IoT) en vele meer. In die afgelope twee dekades het die holoniese paradigma ʼn belangrike drywer van intelligente vervaardigingstelsels geword, wat dit ideaal maak om I4.0 te bevorder. Die doel van hierdie tesis is om ‘n bestaande holoniese verwysings argitektuur, die Biography-Attributes-Schedule-Execution (BASE-) argitektuur, uit te brei vir komplekse, herkonfigureerbare KFSs. In die konteks van hierdie tesis, word komplekse en herkonfigureerbare stelsels gesien as stelsels wat bestaan uit menige diverse, outonome entiteite wat met mekaar interaksie het en waarvan die funksionaliteit, organisasie en grootte verwag is om te verander met verloop van tyd. Hierdie tesis pas die beginsels van holoniese stelsels toe om die kompleksiteit van KFSs te bestuur en om herkonfigureerbaarheid van KFSs te verbeter. Die BASE-argitektuur word uitgebrei om twee redes, naamlik om die integrasie van menige diverse entiteite te ondersteun en om die argitektuur se herkonfigureerbaarheid te verbeter. Die studie sal ‘n navorsingsbydrae lewer oor holoniese stelsels deur twee belangrike funksionaliteite van stelsels wat geïmplementeer is deur middel van holoniese stelsels aan te spreek – samewerking tussen holons en kuber-fisiese koppeling. Die belangrikste uitbreidings wat gemaak is aan die argitektuur was om skaleerbaarheid moontlik te maak, samewerking tussen holons te verfyn en om kuber-fisiese koppelingsdienste te integreer as holons. Hierdie uitbreidings sluit nuwe platformbestuurkomponente en gestandaardiseerde plugins in. Die uitgebreide argitektuur is geïmplementeer op ʼn opvoedkundige skaapplaas, omdat die skaapplaas baie heterogene hulpbronne (skape, kampe, sensors, mense, ens.) insluit wat in die BASE-argitektuur geïmplementeerde KFS geïntegreer kon word. v Hierdie gevallestudie-implementering moes data van verskillende sensors integreer, intydse analises doen van die waargeneemde data en wanneer nodig, ‘n entiteit in die fisiese wêreld inlig van enige probleme in die KFS. Aan die einde van die implementering is ʼn evaluering gedoen deur die vereistes van ʼn komplekse, herkonfigureerbare KFS as evalueringskriteria te gebruik. Die evaluering het bestaan uit die opstel van kwantitatiewe en kwalitatiewe evalueringsmaatreëls, die uitvoer van die evaluerings en ʼn bespreking van wat die evalueringsresultate aandui oor die effektiwiteit en doeltreffendheid van die uitbreidings wat aan die BASE- argitektuur gemaak is. Dit is bevind dat die uitbreidings wat gemaak is aan die BASE-argitektuur robuustheid en veerkragtigheid verbeter het. Die gebruik van Erlang het ʼn groot rol gespeel in die gevolglike betroubaarheid. Die uitbreidings aan die BASE- argitektuur het ook gehelp om die argitektuur volledig skaleerbaar te maak en om ontwikkelingsproduktiwiteit te verbeter. Laastens, bewys die uitbreidings die voordele van diensoriëntasie in die samewerking tussen holons en hoe die gebruik van Koppelings Holons (Interface Holons) ontwikkelingstyd verminder, die herbruikbaarheid van programbronkode verbeter en diagnoseerbaarheid van koppelingsprobleme versterk.Master

Service-based Fault Tolerance for Cyber-Physical Systems: A Systems Engineering Approach

Cyber-physical systems (CPSs) comprise networked computing units that monitor and control physical processes in feedback loops. CPSs have potential to change the ways people and computers interact with the physical world by enabling new ways to control and optimize systems through improved connectivity and computing capabilities. Compared to classical control theory, these systems involve greater unpredictability which may affect the stability and dynamics of the physical subsystems. Further uncertainty is introduced by the dynamic and open computing environments with rapidly changing connections and system configurations. However, due to interactions with the physical world, the dependable operation and tolerance of failures in both cyber and physical components are essential requirements for these systems.The problem of achieving dependable operations for open and networked control systems is approached using a systems engineering process to gain an understanding of the problem domain, since fault tolerance cannot be solved only as a software problem due to the nature of CPSs, which includes close coordination among hardware, software and physical objects. The research methodology consists of developing a concept design, implementing prototypes, and empirically testing the prototypes. Even though modularity has been acknowledged as a key element of fault tolerance, the fault tolerance of highly modular service-oriented architectures (SOAs) has been sparsely researched, especially in distributed real-time systems. This thesis proposes and implements an approach based on using loosely coupled real-time SOA to implement fault tolerance for a teleoperation system.Based on empirical experiments, modularity on a service level can be used to support fault tolerance (i.e., the isolation and recovery of faults). Fault recovery can be achieved for certain categories of faults (i.e., non-deterministic and aging-related) based on loose coupling and diverse operation modes. The proposed architecture also supports the straightforward integration of fault tolerance patterns, such as FAIL-SAFE, HEARTBEAT, ESCALATION and SERVICE MANAGER, which are used in the prototype systems to support dependability requirements. For service failures, systems rely on fail-safe behaviours, diverse modes of operation and fault escalation to backup services. Instead of using time-bounded reconfiguration, services operate in best-effort capabilities, providing resilience for the system. This enables, for example, on-the-fly service changes, smooth recoveries from service failures and adaptations to new computing environments, which are essential requirements for CPSs.The results are combined into a systems engineering approach to dependability, which includes an analysis of the role of safety-critical requirements for control system software architecture design, architectural design, a dependability-case development approach for CPSs and domain-specific fault taxonomies, which support dependability case development and system reliability analyses. Other contributions of this work include three new patterns for fault tolerance in CPSs: DATA-CENTRIC ARCHITECTURE, LET IT CRASH and SERVICE MANAGER. These are presented together with a pattern language that shows how they relate to other patterns available for the domain

Survey of Template-Based Code Generation

L'automatisation de la génération des artefacts textuels à partir des modèles est une étape critique dans l'Ingénierie Dirigée par les Modèles (IDM). C'est une transformation de modèles utile pour générer le code source, sérialiser les modèles dans de stockages persistents, générer les rapports ou encore la documentation. Parmi les différents paradigmes de transformation de modèle-au-texte, la génération de code basée sur les templates (TBCG) est la plus utilisée en IDM. La TBCG est une technique de génération qui produit du code à partir des spécifications de haut niveau appelées templates. Compte tenu de la diversité des outils et des approches, il est nécessaire de classifier et de comparer les techniques de TBCG existantes afin d'apporter un soutien approprié aux développeurs. L'objectif de ce mémoire est de mieux comprendre les caractéristiques des techniques de TBCG, identifier les tendances dans la recherche, et éxaminer l'importance du rôle de l'IDM par rapport à cette approche. J'évalue également l'expressivité, la performance et la mise à l'échelle des outils associés selon une série de modèles. Je propose une étude systématique de cartographie de la littérature qui décrit une intéressante vue d'ensemble de la TBCG et une étude comparitive des outils de la TBCG pour mieux guider les dévloppeurs dans leur choix. Cette étude montre que les outils basés sur les modèles offrent plus d'expressivité tandis que les outils basés sur le code sont les plus performants. Enfin, Xtend2 offre le meilleur compromis entre l'expressivité et la performance.A critical step in model-driven engineering (MDE) is the automatic synthesis of a textual artifact from models. This is a very useful model transformation to generate application code, to serialize the model in persistent storage, generate documentation or reports. Among the various model-to-text transformation paradigms, Template-Based Code Generation (TBCG) is the most popular in MDE. TBCG is a synthesis technique that produces code from high-level specifications, called templates. It is a popular technique in MDE given that they both emphasize abstraction and automation. Given the diversity of tools and approaches, it is necessary to classify and compare existing TBCG techniques to provide appropriate support to developers. The goal of this thesis is to better understand the characteristics of TBCG techniques, identify research trends, and assess the importance of the role of MDE in this code synthesis approach. We also evaluate the expressiveness, performance and scalability of the associated tools based on a range of models that implement critical patterns. To this end, we conduct a systematic mapping study of the literature that paints an interesting overview of TBCG and a comparative study on TBCG tools to better guide developers in their choices. This study shows that model-based tools offer more expressiveness whereas code-based tools performed much faster. Xtend2 offers the best compromise between the expressiveness and the performance

Industry 4.0 for SMEs

This open access book explores the concept of Industry 4.0, which presents a considerable challenge for the production and service sectors. While digitization initiatives are usually integrated into the central corporate strategy of larger companies, smaller firms often have problems putting Industry 4.0 paradigms into practice. Small and medium-sized enterprises (SMEs) possess neither the human nor financial resources to systematically investigate the potential and risks of introducing Industry 4.0. Addressing this obstacle, the international team of authors focuses on the development of smart manufacturing concepts, logistics solutions and managerial models specifically for SMEs. Aiming to provide methodological frameworks and pilot solutions for SMEs during their digital transformation, this innovative and timely book will be of great use to scholars researching technology management, digitization and small business, as well as practitioners within manufacturing companies

Industry 4.0 for SMEs

This open access book explores the concept of Industry 4.0, which presents a considerable challenge for the production and service sectors. While digitization initiatives are usually integrated into the central corporate strategy of larger companies, smaller firms often have problems putting Industry 4.0 paradigms into practice. Small and medium-sized enterprises (SMEs) possess neither the human nor financial resources to systematically investigate the potential and risks of introducing Industry 4.0. Addressing this obstacle, the international team of authors focuses on the development of smart manufacturing concepts, logistics solutions and managerial models specifically for SMEs. Aiming to provide methodological frameworks and pilot solutions for SMEs during their digital transformation, this innovative and timely book will be of great use to scholars researching technology management, digitization and small business, as well as practitioners within manufacturing companies

Control Network Performance Engineering: Qualitätsorientierter Entwurf von CSMA-Netzwerken der Automation

Beim Entwurf großer Netzwerke der Automation ermöglichen Methoden der Leistungsbewertung den Test und die Dimensionierung eines Netzwerkes bereits vor der Inbetriebnahme und erlauben damit einen effizienten, qualitätsorientierten Entwurf. Es ist jedoch sehr wissensintensiv und aufwendig, entsprechende Analyse- oder Simulations-Modelle aufzustellen und die Ergebnisse auszuwerten, weshalb die Methoden in der Praxis der Automation selten verwendet werden. Viel vertrauter sind dem Entwerfer hingegen die speziellen Software-Tools, mit denen in der Automation Netzwerke entworfen werden. Auf Basis der Datenbanken dieser Tools werden in dieser Arbeit verschieden Verfahren zur automatischen Systemmodellierung, Verkehrsmodellierung, Leistungsbewertung und Fehlerdiagnose zu einem Control Network Performance Engineering kombiniert, welches die Qualitätsbewertung und -beratung nahtlos und ohne Mehraufwand in den Netzwerkentwurf integriert. (Die Dissertation wurde veröffentlicht im Jörg Vogt Verlag, Voglerstr. 20, 01277 Dresden, Internet: http://www.vogtverlag.de/, email: [email protected], ISBN 978-3-938860-10-6)During the design of large automation networks, performance analysis methods can be used for testing and dimensioning the network before implementation and are essential for an efficient and reliable design process. However, setting up the necessary analytical or simulative models is time-consuming, requires in-depth knowledge, and is therefore often not applicable in practice. The network designers are much more used to the design tools used to develop automation networks. Based on these tools' databases various methods for automated system and traffic modeling, performance analysis and diagnoses are combined in the control network performance engineering that seamlessly integrates quality analysis and consulting into network design without requiring additional effort. (This manuscript is also available - in the form of a book - from Jörg Vogt Verlag, Voglerstr. 20, 01277 Dresden, Germany world-wide web address: http://www.vogtverlag.de/, electronic-mail address: [email protected], ISBN 978-3-938860-10-6