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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Radialmåttavvikelser i Transformatorlindningar : Ett examensarbete hos Hitachi ABB Power Grids Ludvika / Radial Dimensional Deviations in Transformer Windings

Strandh, Johan, Ruda, Viktor January 2021 (has links)
This assignment is based on the tolerance problems that occur with the radial dimensions or RR-dimensions for the windings. The purpose is to identify the various parameters that affect said RR-dimensions and where these parameters originate from to be able to assure quality of the winding process. The RR-dimension has a tolerance of + 2,2 and - 1,1 mm, but it is only the positive tolerance that cause problems. The case study is based on a mixture of quantitative and qualitative methods. Quantitative data collections of dimensions for leaders and how the RR-measurement are affected by them, analysis of tolerances and how well they are adapted for their purpose. Qualitative observations, experiments and semi-structured interviews have also been conducted to gain a deeper understanding of the problem. The results show that tolerance problems originate from several different factors. The first factor is the debatable tolerance setting on some conductors, mainly the thin CTC conductors that do not have a high radial dimension. These conductors have tolerances that do not fill a purpose because it does not ensure the quality for the winding. The conductors need a tighter tolerance spectrum for the positive direction to be fully functional. The air gap that can occur between the conductors is also a cause of error. This stems from the fact that it is not possible to achieve a sufficiently high force when tensioning the disc. This can also occur from the uneven surface of the CTC-conductor that can create gaps. Another cause of error that affects the dimension is the number of turns for a disc. When a disc is wound with a high number of turns it will lead tothat the influencing factors have a higher amount of turns to effect on. This means that a small increase of the conductor's nominal dimension or small air gaps has a large impact on the overall RR-dimension. / För att kvalitetssäkra transformator- och reaktorlindningarna hos företaget Hitachi ABB skade utsatta toleranserna för varje lindning uppfyllas för att kunna fortsätta vidare i produktionslinan. Arbetet är grundat utifrån de förekommande variationerna hos lindningarnas mått i radiell riktning (RR-mått. Arbetets syfte är att undersöka Hitachi ABB:s lindningsproduktion för att finna de faktorer som ger upphov till måttvariationer hos RRmåttet. De identifierade faktorerna ska användas för att kvalitetssäkra företagets lindningsprocess. Färdigställt arbete ska användas som grund för företagets fortsatta arbetekring kvalitetssäkring. RR-måttet har en tolerans på + 2,2 och – 1,1 mm, däremot är detendast de variationer i positivt led där problem uppstår. Vid ett för högt mått genomförs enutredning för att se över om lindningen kan brukas ändå eller utifall de för höga måttet i radiell riktning påverkar prestandan samt montering. Arbetet är en fallstudie utfört med en blandning av kvantitativa och kvalitativa metoder. Denkvantitativa datainsamlingens syfte är att undersöka ledares mått i lindningar för att se hur RR-måttet påverkas måttsättning och varvantal. Den kvantitativa datainsamlingen genomför också analyser av toleranser och hur väl anpassade de är för sitt syfte. Kvalitativa observationer, experiment och halvstrukturerade interjuver har genomförts för att skapa en djupare förståelse kring problemet.Resultatet visar att de variationer som uppstår hos RR-måttet påverkas av flera olika faktorer.Variationer hos RR-måttet uppstår främst för lindningar där en CTC-ledare används. En påverkande faktor är toleransvidden för ledarna, främst för de tunna CTC-ledarna. Ledarna lindas runt varandra där ledarens mått staplas på varandra för att bilda ett RR-mått. För de tunna CTC-ledarna bör en mindre toleransvidd användas, mer specifikt en lägre positiv tolerans likt de platta ledarna för att kunna kvalitetssäkra lindningen. En annan påverkandefaktor är de luftspalter som uppstår mellan ledarna. Luftspalter härstammar ifrån att det integår att uppnå tillräckligt hög kraft vid spänning av en skiva alternativt från CTC-ledarens knöliga yta. Utöver dessa två faktorer har antalet lindade varv för en skiva en påverkan förtoleransstapling. Fler varv resulterar i att små måttavvikelser för ledare påverkar det totala måttet, vilket innebär att de luftspalter som kan uppstå blir fler när antalet varv ökar.
242

Ovládání robota s Ackermannovým podvozkem / Controlling of Robot with Ackermann Steering

Fryč, Martin January 2017 (has links)
In this paper is described creation of a robot in Robot Operating system (ROS) withAckermann steering. It contains the principle of Ackermann steering geometry, search ofcontroller boards and basics of ROS structure. A RC car with connected PixHawk controlleris used as a basis of the robot. On the robot is placed an onboard computer Raspberry Pi3 with running ROS. This computer is connected to a laptop through Wi-Fi network. Theprocedure of starting up the robot and ROS is also described in this paper, as well asdesign of the graphical user interface (GUI) that will display sensory data and allow otherfunctionality. Another part of thesis explains principle of an optical encoder and how tocreate your own encoder which can detect rotation of a wheel. This is used to implementrobot odometry. The structure of ROS navigation library is analyzed with regards to itscommissioning. Implementation of the GUI and navigation library will follow in the masterthesis.
243

Bezdrátové zabezpečovací zařízení / Wireless Security and Surveillance System

Výborný, Jiří January 2008 (has links)
This Master’s thesis deals with design and construction of a wireless security and surveillance system in ZigBee wireless networks (IEEE802.15.4). The design consists of creating a star network topology with intended monitoring of home area via end device boards paired with coordinator board, which provides basic networking functionality. End device is used to send data from a temperature sensor DS1631 and magnetic reed switches to coordinator. ZigBee module ZDM-A1281-A2 made by MeshNetics company embedded on each board contains a micro controller ATMega1281 and a transceiver AT86RF230 working in a 2,4GHz frequency band. System is able to notice of any door or window move actions and too high temperature. The non-fully functional ZigBee stack, which is called an Open MAC software, based on MAC (Media Access Control ) layer and PHY (Physical) layer from MeshNetics, has been used to develop the user software. Open MAC consists of three application samples in C code. One of them was modified by the user for an application of communication between the module and sensors. The same design with module RC2204AT made by Radiocrafts company was tested as well, but it couldn’t be executed. All developed boards have been constructed and tested via Terminal PC program.
244

Speciální aplikace VoIP / Special application of VoIP

Lembard, Tomáš January 2011 (has links)
The aim of this master's thesis is suggestion and following realization of voice transmission over the local network equipment and a description of used circuits and solutions in terms of hardware and software. This thesis deals with digitization of low-frequency signals, the structure of IP and UDP protocols, implementation of TCP/IP stack cIPS
245

Modulární RGB LED displej s rozhraním Ethernet / Modular RGB LED display with Ethernet

Zemánek, Petr January 2014 (has links)
This thesis deals with an electronic circuit and a PCB of a modular RGB LED display with the Ehernet interface. Firstly, author describes a RGB colour model, features of RGB LED displays, ways of control them. The next chapter contains a short description of the Ethernet interface, UDP and TCP protocols and a lwIP TCP/IP stack. The last theoretical chapter is an introduction to ARM Cortex-M3 and Cortex-M4 based microcontrollers. The next chaper is deals with a hardware design of the modular RGB LED display. The device is designed to be modular. Individual devices can be combosed together and create a larger display. Data from the Ethernet interface will be displayed on the RGB LED matrix, resolution of the matrix is 32 × 32 (1024 diodes). A refresh frequency is 100 Hz, a color depth is High color (16 bits) and a scanning 1/16 (two rows is driven at the same time). The next chapter describes the firmware for the RGB LED display, all its logical parts including a web page. Author also created the PC application, which sends pictures using UDP protocol to individual modules.
246

Měření veličin ve stavebních konstrukcích / Meassuring system for building constructions

Vladař, Martin January 2015 (has links)
This thesis deals with the measurement of physical quantities in building using decentralized system for data collecting. The system consists of Raspberry Pi as a master device of the system. There are three branches connected to this master device. Each branch consists of up to 32 modules for data-concentration from sensors of physical quantities. The Raspberry Pi has implemented web interface for displaying measured values and system administration.
247

Simulace vlivu teploty a proudění vzduchu v poli rozvaděče s frekvenčním měničem / Simulation of temperature and airflow in a field distributor with frequency converter

Melechovský, Ondřej January 2016 (has links)
Presented work deals with heat transfer and its methods. At the beginning thesis describes the theory and the ways of heat transfer with connected quantities and equations. Then it explains the stack effect and impact of temperature on electro technical device. In work is also described ABB driver ACS line and calculation of heat transfer according to IEC 60890 standard. In the practical part there is the calculation of heat transfer in Flow Simulation simulating CFD program solved and finite element method is mentioned. Important part of work is devoted to setting and optimization of simulation. In conclusion are made some changes of construction of driver, dependence on heat transfer is inspected.
248

Analyses thermomécaniques multi-échelles expérimentale et numérique pour des empilements de couches minces en microélectronique / Multi-scale experimental and numerical thermomechanical analysis of stacked thin films in microelectronics

Yao, Wei-Zhen 20 June 2018 (has links)
Ce travail a pour objectifs de comprendre et de prédire les gauchissements de plaquettes en silicium durant le procédé de fabrication des composants électroniques de type PTIC. Ces gauchissements sont en partie responsables de plusieurs problèmes de productivité. Cette étude repose sur un couplage entre les calculs analytiques, la modélisation par élément finis et l’expérimentation. La caractérisation mécanique des films minces constituant l’empilement a été effectuée par des techniques spécifiques comme la nanoindentation complétée par des modélisations numériques. Les contraintes intrinsèques dans les films minces ont été déterminées en couplant des mesures de gauchissements des plaquettes et des calculs par éléments finis. Les valeurs du module d’Young et des contraintes intrinsèques obtenues constituent des variables d’entrée pour calculer les gauchissements de la plaquette par des approches analytiques et numériques. La complexité des structures (plaquettes avec des milliers de puces) a nécessité l’utilisation des modèles d’homogénéisation pour estimer numériquement les gauchissements. Les résultats obtenus ont permis de prédire les gauchissements à l’échelle des plaquettes dans le but d’optimiser les conditions de fabrication afin de minimiser les risques d’apparition des problèmes mécaniques. / The aim of this work is to understand and predict the warpage of silicon wafers during the fabrication process of PTIC microelectronic components. The warpages are partially responsible for several productivity problems. This study is done by coupling analytical calculation, finite element modeling and experimentation. The mechanical characterization of thin films constituting the multi-layered stack has been carried out by an experimental method nanoindentation with the help of a finite element model. The intrinsic stress in the thin films has been determined by coupling measurements of the wafer warpage and a finite element model. The obtained Young’s modulus and intrinsic stress are used to feed the database for calculating the wafer warpage by analytical and numerical approaches. The complexity of the structures (thousands of components in the wafer) required the use of homogenized models to calculate the wafer warpage. These results obtained allow the prediction of the wafer-level warpage in order to optimize the fabrication process flow and therefore reduce the risk of the mechanical problem.
249

SHAP-Secure Hardware Agent Platform

Zabel, Martin, Preußer, Thomas B., Reichel, Peter, Spallek, Rainer G. 11 June 2007 (has links)
This paper presents a novel implementation of an embedded Java microarchitecture for secure, realtime, and multi-threaded applications. Together with the support of modern features of object-oriented languages, such as exception handling, automatic garbage collection and interface types, a general-purpose platform is established which also fits for the agent concept. Especially, considering real-time issues, new techniques have been implemented in our Java microarchitecture, such as an integrated stack and thread management for fast context switching, concurrent garbage collection for real-time threads and autonomous control flows through preemptive round-robin scheduling.
250

Fit-4-AMandA – Automation of PEMFC-Stack Manufacture

Biak, Martin, von Unwerth, Thomas 25 November 2019 (has links)
An EU-funded project Fit-4-AMandA aims to establish a technological roadmap to scale-up from less than hundred stacks/year (manual assembly) to 50,000 stacks/year (automated assembly) in 2020 and beyond. Existing membrane-electrode assembly (MEA) and stack were redesigned/adapted for manufacturability and automation. The technology and machine system for the automated assembly of polymer-electrolyte-membrane fuel cell (PEMFC) stacks were developed, manufactured and are currently being tested. Fast in-line non-destructive quality-assurance methods for automated production of MEAs and stack assembly are being developed and implemented. For the final period of the project, a validation of the designs, hardware, tools and software for the automated production of MEAs and stack assembly as well as an integration of one of the prototype stacks manufactured by the automated processes into a light-commercial vehicle followed by a field-testing are scheduled. / Die breite Markteinführung von wasserstoffbasierten Antriebssystemen verlangt zunehmend nach einer kosteneffizienten und serientauglichen Produktion von Brennstoffzellenstacks. So sehen die Ziele der Europäischen Union vor, die Herstellung von aktuell unter 100 Stacks pro Jahr auf 50.000 Stacks pro Jahr bis zum Jahr 2020 zu erhöhen. Um dies zu erreichen, sollen im Rahmen des vom Fuel Cell and Hydrogen Joint Undertaking (FCH JU) der europäischen Union geförderten Projektes Fit-4-AMandA automatisierte Anlagen für solche Stückzahlen befähigt werden. Der Beitrag beschreibt, wie die bereits verfügbare Membran-Elektroden-Einheit (MEA) und der Stack bezüglich Herstellbarkeit und Automatisierung konstruktiv umgestaltet und angepasst wurden. Die neu entwickelte Technologie und das Maschinensystem für die automatisierte Montage von PEM-FC-Stacks sowie Verfahren der INLINE-Qualitätssicherung und der zerstörungsfreien Prüfung werden mit ihren Implementierungsmöglichkeiten in die automatisierte Fertigungsstrecke vorgestellt. Ein Ausblick gibt eine Übersicht über die weiteren Entwicklungsschritte wie die Validierung der Entwürfe, der Hard- und Software für die automatisierte Produktion der MEAs und Stacks. Eine vorgesehene spätere Integration der so gefertigten Stacks in ein Fahrzeug und die damit verbundenen Feldtests zur Untersuchung der Reproduzierbarkeit und Zuverlässigkeit der Stacks werden abschließend dargestellt. Die Förderung des Projektes erfolgt im Rahmen der Finanzhilfevereinbarung Nr. 735606 des FCH JU der EU.

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