244 research outputs found

    Medium Voltage Solid-State Transformer:An IEC60076-3 based design

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    QoS-aware architectures, technologies, and middleware for the cloud continuum

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    The recent trend of moving Cloud Computing capabilities to the Edge of the network is reshaping how applications and their middleware supports are designed, deployed, and operated. This new model envisions a continuum of virtual resources between the traditional cloud and the network edge, which is potentially more suitable to meet the heterogeneous Quality of Service (QoS) requirements of diverse application domains and next-generation applications. Several classes of advanced Internet of Things (IoT) applications, e.g., in the industrial manufacturing domain, are expected to serve a wide range of applications with heterogeneous QoS requirements and call for QoS management systems to guarantee/control performance indicators, even in the presence of real-world factors such as limited bandwidth and concurrent virtual resource utilization. The present dissertation proposes a comprehensive QoS-aware architecture that addresses the challenges of integrating cloud infrastructure with edge nodes in IoT applications. The architecture provides end-to-end QoS support by incorporating several components for managing physical and virtual resources. The proposed architecture features: i) a multilevel middleware for resolving the convergence between Operational Technology (OT) and Information Technology (IT), ii) an end-to-end QoS management approach compliant with the Time-Sensitive Networking (TSN) standard, iii) new approaches for virtualized network environments, such as running TSN-based applications under Ultra-low Latency (ULL) constraints in virtual and 5G environments, and iv) an accelerated and deterministic container overlay network architecture. Additionally, the QoS-aware architecture includes two novel middlewares: i) a middleware that transparently integrates multiple acceleration technologies in heterogeneous Edge contexts and ii) a QoS-aware middleware for Serverless platforms that leverages coordination of various QoS mechanisms and virtualized Function-as-a-Service (FaaS) invocation stack to manage end-to-end QoS metrics. Finally, all architecture components were tested and evaluated by leveraging realistic testbeds, demonstrating the efficacy of the proposed solutions

    Time-sensitive autonomous architectures

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    Autonomous and software-defined vehicles (ASDVs) feature highly complex systems, coupling safety-critical and non-critical components such as infotainment. These systems require the highest connectivity, both inside the vehicle and with the outside world. An effective solution for network communication lies in Time-Sensitive Networking (TSN) which enables high-bandwidth and low-latency communications in a mixed-criticality environment. In this work, we present Time-Sensitive Autonomous Architectures (TSAA) to enable TSN in ASDVs. The software architecture is based on a hypervisor providing strong isolation and virtual access to TSN for virtual machines (VMs). TSAA latest iteration includes an autonomous car controlled by two Xilinx accelerators and a multiport TSN switch. We discuss the engineering challenges and the performance evaluation of the project demonstrator. In addition, we propose a Proof-of-Concept design of virtualized TSN to enable multiple VMs executing on a single board taking advantage of the inherent guarantees offered by TSN

    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

    Design of a 350 kW DC/DC Converter in 1200-V SiC Module Technology for Automotive Component Testing

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    In this paper, the design and implementation of a DC/DC converter for automotive component testing with state-of-the art performance is described. The converter is the core of a battery emulator for the characterization and development of automotive batteries, electronic chargers, traction inverters, DC-DC converters, E-motors and E-axles. Cutting edge performance, flexibility and compactness are obtained by exploiting 1200-V SiC modules, high switching frequency, planar transformer technology, suitable topology solutions and fast digital control strategies. The implemented system is a liquid-cooled, bidirectional converter with galvanic isolation capable of 350 kW continuous output power, output voltage range 48-1000 V, continuous output current up to 800 A (1600 A peak), voltage/current ramp-up time below 10/2 ms and 0.1% current/voltage accuracy. The entire instrument is implemented in a standard full-height 19-inch rack cabinet

    Design and Control of a Single-Leg Exoskeleton with Gravity Compensation for Children with Unilateral Cerebral Palsy

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    Children with cerebral palsy (CP) experience reduced quality of life due to limited mobility and independence. Recent studies have shown that lower-limb exoskeletons (LLEs) have significant potential to improve the walking ability of children with CP. However, the number of prototyped LLEs for children with CP is very limited, while no single-leg exoskeleton (SLE) has been developed specifically for children with CP. This study aims to fill this gap by designing the first size-adjustable SLE for children with CP aged 8 to 12, covering Gross Motor Function Classification System (GMFCS) levels I to IV. The exoskeleton incorporates three active joints at the hip, knee, and ankle, actuated by brushless DC motors and harmonic drive gears. Individuals with CP have higher metabolic consumption than their typically developed (TD) peers, with gravity being a significant contributing factor. To address this, the study designed a model-based gravity-compensator impedance controller for the SLE. A dynamic model of user and exoskeleton interaction based on the Euler–Lagrange formulation and following Denavit–Hartenberg rules was derived and validated in Simscape™ and Simulink® with remarkable precision. Additionally, a novel systematic simplification method was developed to facilitate dynamic modelling. The simulation results demonstrate that the controlled SLE can improve the walking functionality of children with CP, enabling them to follow predefined target trajectories with high accuracy

    Quo vadis real time ethernet

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    Real time Ethernet (RTE) protocol suites are commonly operated within an exclusively allocated Ethernet based network that is used to exchange data for a distributed real time application. In practice, RTE protocol stack implementations interlace the maintenance of their data objects on the (standardised and loosely coupled) application layer with the task of traffic fitting. The latter includes the egress and ingress of application data over the underlying layers but also the coordination (scheduling) of the same. The set of time sensitive networking (TSN) IEEE standards is an addendum to common Ethernet (IEEE 802.3*). It has the aim to provide technologies to implement deterministic Ethernet networks. In factory automation RTE, an ongoing establishment of such technologies is observed. They lay the ground for various possibilities to shift the mechanisms for scheduling data transmissions towards networking juncture elements, e.g. Ethernet switch. This work intends to fabricate a stronger separation between the application layer and the tasks concerning traffic fitting. A demonstration setup is developed. It consists of an Ethernet switch (partly TSN capable), two programmable logic controllers (PLCs) and one input/output (I/O) device. Simultaneous operation of two unsimilar RTE protocol suites within the same network is shown. Possible optimisations applied to RTE application components, which target a higher level of determinism, are presented. Measurements underpin the chosen optimisations

    When Operation Technology Meets Information Technology: Challenges and Opportunities

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    Industry 4.0 has revolutionized process innovation while facilitating and encouraging many new possibilities. The objective of Industry 4.0 is the radical enhancement of productivity, a goal that presupposes the integration of Operational Technology (OT) networks with Information Technology (IT) networks, which were hitherto isolated. This disruptive approach is enabled by adopting several emerging technologies in Enterprise processes. In this manuscript, we discuss what we believe to be one of the main challenges preventing the full employment of Industry 4.0, namely, the integration of Operation Technology networking and Information Technology networking. We discuss the technical challenges alongside the potential tools while providing a state-of-the-art use case scenario. We showcase a possible solution based on the Asset Administration Shell approach, referring to the use case of camera synchronization for collaborative tasks

    Ros-based control of a robotic leg for a quadruped robot

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    The sector of Autonomous Mobile Robots (AMR) has grown a lot during the last years. In the literature an AMR is a robot able to move without any human operator control. With the im- provements of the control systems, robots have gained a lot of dexterity and flexibility in the movements, migrating from restrictive mechanical systems like wheeling. AMR with wheels are very efficient on plane grounds, like conventional industrial environ- ments. Nevertheless, they lose efficiency when dealing with rough terrains like the ones you can find on mountain rescue, vineyards or building industry. A good alternative is to use legged robots, which imitate animal walking behaviour, for these types of terrain since they are able to easily overcome these obstacles. The objective of this project is to create a control system for the robotic leg of a quadruped robot. A mechanical leg was developed and implemented at the CDEI for a quadruped robot, aimed for its locomotion in rugged and unknown terrain. This project will create the control system for this leg, so that it can execute the desired motions and it can be later integrated in the com- plete quadruped robot. The system will be designed so that it can be part of the stack of the quadruped robot. In this sense, the control systems software will be developed using the Robot Operating System (ROS) and MATLAB&Simulin
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