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Johnson, Kevin, i Daniel Hällström. "Uppbyggnaden av ett orange hjärta : Varumärket IFK Kristianstad". Thesis, Linnéuniversitetet, Institutionen för idrottsvetenskap (ID), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-77321.
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IFK Kristianstad har gått från guldåldern under 1940- och 1950-talen till att vara på gränsen till konkurs men har rest sig och är idag Sveriges rikaste handbollsklubb. 2009 tog föreningen återigen tillbaka sin plats i Elitserien och valde att göra en förändring då ekonomin återigen inte var hållbar. Med ett dåvarande negativt eget kapital på en halv miljon kronor är dem 2018 en toppklubb i Europa med en omsättning på 34 miljoner kronor. Trots att handboll inte är den största idrotten i Sverige har de störst publiksnitt av alla handbollsklubbar i landet, även mer än vissa allsvenska fotbollsklubbar som utövar den mest populära idrotten. I denna fallstudie belyses hur IFK Kristianstad har utvecklat sitt varumärke samt hur dem bibehåller det hållbart. För att skapa en helhetssyn har representanter från föreningen samt samarbetspartners som är delaktiga i arbetet intervjuats vilket ger fler perspektiv över de strategier som har givit dem dagens resultat.
2
Olsson, Jesper. ""Inte fan ska ni väl heta Luleå FF/IFK Luleå?" : Diskussionerna inom IFK Luleå om sammanslagningar inför säsongerna 1986 och 2000". Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66324.
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This qualitative study examines two historical decisions made by the same football club, IFK Luleå, in regards of merging with other local clubs. The purpose with the study is to compare the reasons behind the first decision, prior to the season of 1986, and the second one, prior to the season of 2000. A positive decision is made prior to the season of 1986, while a negative decision is made prior to the season of 2000. The comparison of the decisions, the purpose, is achieved through interviews and deep dives into archived files. The study shows that the first decision is made mostly due to sport related reasons, while the second desicion is rather an economic one.
3
Dresden, Technische Universität. "12th International Fluid Power Conference (12. IFK): October 12-14, 2020 in Dresden". Dresdner Verein zur Förderung der Fluidtechnik e.V. Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A38661.
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The International Fluid Power Conference is one of the world's most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists.
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Per, Staffansson. "Kommunen, idrottsrörelsen och det sociala kapitalet : Östersunds kommuns samröre med IFK Östersund 1965–1978". Thesis, Karlstads universitet, Fakulteten för humaniora och samhällsvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-71023.
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The Swedish model was constructed on the idea of corporatism. In the welfare state that the social democratic government where building, the sport movement played a considerable part. Through sport the citizens, in their leisure, where fostered for their role as good, productive members of the community. This was achieved by teaching them democracy, giving them the right spirit of solidarity and keeping them mentally and physically healthy. Attributes that were determined to social benefit the community. For doing so the government gave financial contribution to the sport movement. By investigating the municipality’s official records and those of the big local athletic club, more specifics about this relationship appeared. This could be connected to thesis about social capital. It becomes clear how high the running authorities treasured the local sport movement, and in which way this was manifested by the especial contribution, above the general contribution. In doing so missing facts in research were filled out.I det välfärdssamhälle som den socialdemokratiska regeringen byggde, spelade idrottsrörelsen en betydande roll. Genom idrotts- och föreningslivet skulle medborgarna på sin fritid, fostras i rollen som goda, produktiva medlemmar av samhället. Det skulle uppnås genom att lära dem demokrati, ge dem rätt känsla av solidaritet och hålla de mentalt och fysiskt friska. Attribut som ansågs vara samhällsnyttiga. Genom att göra det gav de styrande ekonomiska bidrag till idrottsrörelsen. Uppsatsens syfte är att undersöka hur förhållandet mellan Östersunds kommun och idrottsföreningen IFK Östersund såg ut under åren 1965–1978. Syftet ska uppfyllas genom att svara på hur, och med vilka argument, som Östersunds kommun stöttade IFK Östersund ekonomiskt. Källmaterialet hämtades ur Östersunds kommuns arkiv samt föreningsarkivet i Jämtlands län. Med en kvalitativ metod undersöktes materialet, där ord och formuleringar som kunde knytas till IFK Östersunds ekonomi tolkades. Genom att undersöka den kommunala fritidsnämndens styrelseprotokoll och protokollen från den stora lokala idrottsföreningen, framträdde fler detaljer rörande de båda aktörernas förhållande. Resultatet av undersökningen visar att kommunens ekonomiska stöd var vitalt för att idrottsföreningen överhuvudtaget kunde fortsätta med sin verksamhet. Den samhällsnytta som idrottsföreningen bidrog med ansåg kommunen motivera det ekonomiska stödet. Idrottsföreningars samhällsnytta kopplas till teorier om socialt kapital. Det blir uppenbart hur högt kommunen värderade den lokala idrottsrörelsen och varför det ekonomiska stödet delades ut samt hur det stödet såg ut. Speciellt i form av de extra ekonomiska bidragen utöver de generella bidragen. Föreningslivet som idrottsrörelsen består av, i den här uppsatsen exemplifierad i IFK Östersund, är en stark bidragande orsak till ett demokratiskt fungerande samhälle där tillit mellan medborgarna råder enligt Robert D. Putnams teori om socialt kapital. Det är i ljuset av denna teorin som Östersunds kommuns agerande ska förstås i.
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Larsson, Emma, i Hanna Samuelsson. "Den gode supportern : En kvalitativ studie om hur supportrar till IFK Göteborg ser på sin kommunikativa roll". Thesis, Karlstads universitet, Institutionen för geografi, medier och kommunikation (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-71161.
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Supportrar är en stor del av en fotbollsklubb, men de är lite av en gråzon. Även fast det inte finns en ekonomisk vinning i engagemanget finns det fortfarande motivation att vara där för klubben. Supportrar beskrivs ofta som lojala och hängivna, men är detta ord som de skulle använda för att beskriva sig själva och sitt supporterskap? IFK Göteborg har en stor skara av supportrar som de själva beskriver som lojala. Säsongen 2018 skakade om klubben då dåliga resultat ledde till en kris och relationen mellan klubb och supporter sattes på spel. Bra kommunikation är en viktig del för att behålla supportrarna och kunna styra utgången av krisen. Syftet med studien är att undersöka hur supportrar till IFK Göteborg ser på sin kommunikativa roll, både under och utanför en kris. Studien ämnar att undersöka huruvida supportrarna uppfattar om de besitter en roll och om den rollen kommer med ansvar och skyldigheter till IFK Göteborg. Detta är kopplat till IFK Göteborgs kommunikation gentemot supportrarna, därför är det även relevant att undersöka supportrarnas uppfattning av kommunikationen och om de ser förbättringsmöjligheter. Då supportrarna utgör en stor del av klubben kommer studien även att undersöka hur supportrarnas identitet påverkas av den aktuella krisen. De frågeställningar som utformats för att svara på studiens syfte är: - Vad anser supportrar att deras kommunikativa roll är när IFK Göteborg befinner sig i och utanför en kris? - Hur uppfattar supportrarna klubbens kommunikation samt hur vill de att kommunikationen ska se ut? - Hur påverkas supportrarnas identitet när klubben är i en kris? Studien bygger på teorier och tidigare forskning om kriser inom sport, kriskommunikation samt identitet. Det är en kvalitativ studie där intervju har använts som metod för att svara på syfte och frågeställningar. Studiens resultat visar att supportrarna tidigt introduceras till klubben vilket stärker deras identifikation med IFK Göteborg. Det som motiverar supportrarna är gemenskapen och samhörigheten som supporterskapet erbjuder. De centrala delarna av supporterskapet är stöttning , framförande av åsikter och beskyddande av klubben oavsett om klubben befinner sig i en kris eller ej. Resultatet visar även att supportrarna är missnöjda med hur klubben hanterat kommunikationen under säsongen 2018 och de önskar mer tydlighet. Det framgår också att identiteten hos supportrarna påverkas negativt då klubben befinner sig i en kris. Konstaterbart är även att alla supportrarna ser hoppfullt på framtiden.Supporters are a big part of a football club, but they are a bit of a gray area. Even though there is no financial gain in the engagement, there is still motivation to be there for the club. Supporters are often described as loyal and devoted, but are these the words that they would use to describe themselves and their supportership? IFK Gothenburg has a large crowd of supporters who they themselves describe as loyal. The season of 2018 shook the club as bad results led to a crisis and the relationship between club and supporter was at stake. Good communication is an important part of maintaining the supporters and being able to control the outcome of the crisis. The purpose of the study is to examine how supporters of IFK Gothenburg perceive their communicative role, both during and outside a crisis. The study aims to examine whether the supporters perceive whether they have a role and whether that role comes with responsibility and obligations to IFK Gothenburg. This is linked to IFK Gothenburg's communication with the supporters, therefore it is also relevant to examine the supporters' perception of communication and whether they see improvement opportunities. As the supporters make up a large part of the club, the study will also examine how the supporters' identity is affected by the current crisis.The questions designed to answer the purpose of the study are: - What do supporters think their role is when IFK Gothenburg is in and outside a crisis? - How do the supporters perceive the club's communication and how do they want the communication to look like? - How does the identity of the supporters get affected when the club is in a crisis? The study is based on theories and previous research on crises in sports, crisis communication and identity. It is a qualitative study where interview has been used as a method for answering the essay’s purpose and questions. The study results show that the supporters are introduced to the club early, which strengthens their identification with IFK Gothenburg. What motivates the supporters is the community and the affinity that the supportership offers. The key elements of the supportership are support, to speak up about one's opinions and the protection of the club regardless of whether the club is in a crisis or not. The result also shows that the supporters are dissatisfied with how the club handled the communication during the season of 2018 and they want more clarity. It also appears that the identity of the supporters is adversely affected when the club is in a crisis. It is also evident that all the supporters look hopefully for the future.
6
Edh, Fredrik, Marcus Karlsson i Stefan Persson. "Värderingsproblematik kring fotbollsspelare : Fungerar en redovisning till marknadsvärde eller är dagens regelverk den bästa lösningen?" Thesis, Karlstad University, Faculty of Economic Sciences, Communication and IT, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-436.
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Dagens värderings och redovisningssystem av spelare uppvisar brister när det gäller att utläsa en klubbs egentliga värde i en balansräkning. Spelarna får idag redovisas enligt en av de två alternativ som det Svenska Fotbollsförbundet ställt upp. Alternativen går dock främst ut på att periodisera kostnader, inte att spegla ett rättvisande värde av klubben.
Begreppet ”verkligt värde” är aktuellt inom dagens redovisning. IASB arbetar med att harmonisera redovisningen världen över och i deras arbete spelar begreppet en viktig roll. Inom flera olika tillgångsslag ges idag möjligheten till att värdera och redovisa en tillgång till dess verkliga värde, dess marknadsvärde. Skulle inte det på sikt kunna implementeras för fotbollsspelare?
Vårt syfte är att ge svar på om och i så fall hur en värdering till marknadsvärde skulle fungera. Vi ifrågasätter om dagens system kommit till som en tillfällig men fungerande lösning i väntan på något bättre. Vi har ställt upp tre frågor som ständigt fanns med oss under arbetsprocessen:
♦ Skulle en värdering till marknadsvärden kunna fungera som substitut till nu gällande regelverk för att ge en mer rättvisande bild av klubbarnas egna kapital?
♦ Hur bemöts detta av verkligheten, av SvFF samt de allsvenska klubbarna?
♦ Är dagens gällande redovisningsmetoder de bästa möjliga lösningarna?
7
Qin, Daoming. "Role of 16S Ribosomal RNA in Translation Initiation". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299007063.
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Steffen, Haack, i Mark C. Krieg. "Industrial hydraulics: now – next - beyond". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71167.
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Industrial hydraulics is often perceived as an old fashioned technology at the end of its innovation cyle. Despite its indiscussable technical benefits as well as its economical importance it is not seen as a promising future technology so that influencing people like to talk about and to promote. This results in disadvantages when it comes to customer choices comparing solutions, bidding processes, and – maybe most important – in a difficult position concerning the war for talents in the long run [... aus dem Text]
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Marani, Pietro, Massimo Martelli, Cesare Dolcin i Silvia Gessi. "Orifices flow saturation in oil hydraulic applications". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71070.
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Even though the orifice is the simplest and most common control component in fluid power systems and cavitation is an already well-established topic in the scientific literature, the flow choking or saturation effect is largely overlooked in the common engineering practice. Most of the times the phenomenon is completely ignored, unless the peculiar hissing noise is observed at the test rig, giving a hint that something wrong is happening in the hydraulic system. Even then, the focus is just on the possible component damage induced by strong cavitation, while the functional implications – in terms of flow characteristic – are neglected. The objective of the paper is to study the phenomenon of flow saturation in hydraulic orifices to assess the formulation of the different critical cavitation numbers and cavitation indexes available from literature. For this reason, a full factorial design of experiments (DOE) is performed to determine the influence of three factors: orifice size, fluid temperature and upstream pressure. The testing is carried out on 5 orifice sizes at 3 different temperatures and 5 different upstream pressure levels. In each test, the downstream pressure is changed from 0 to the upstream pressure level, to sweep the available Δp range, both ascending and descending. In the results section an analysis of the experimental results is drawn, proposing a correlation between the critical cavitation index and the factors considered in the OE. To the authors’ knowledge, no systematic analysis, as the one here proposed, currently exists in literature for mineral oil applications.
10
Hankel, Martin. "Digitization of the hydraulics - uniform semantics only allows interoperability". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71171.
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Machine builder integrate products from different suppliers in their machines or production lines. Today, most of the information is supplier-specific. The major challenge is to extract the necessary information from all products from different suppliers. [... aus dem Text]
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Tikkanen, Seppo, Mikko Heikkilä, Matti Linjama i Kalevi Huhtala. "Emission reduction by hydraulic hybrids". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71222.
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Emissions of non-road machines are reduced by precise control of combustion process inside the engine and by after-treatment systems. One additional measure is the hybridization of the powertrain, which can be used to stabilize the engine load. This reduces harmful emissions because most nitrogen oxide emissions and particle emissions are related to sudden load and speed changes of the engine. In this study, four different hydraulic hybrid systems and their emission reduction potential are tested in one case study of a forwarder. The comparison study was done using a hardware-in-the-loop system (HIL) that consisted of a real-time simulation model, hydraulic secondary controlled loading system, real diesel engine, and emission measurement systems. The most efficient system (i.e., the system with the lowest fuel consumption) was the Four-pressure system. However, the difference between this system and the second-best system was negligible, and fuel consumption was about 40% less than with the reference system (a load-sensing system). Results showed that absolute emissions can be reduced by hybridization. Nitrogen oxide emissions were 15 25% lower and particulate matter emissions were 60 75% lower. The Four-pressure system had the lowest emissions. All studied hybrid systems resulted in reduction in fuel consumption and harmful emissions in the studied use case.
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Rahmfeld, Robert. "Displacement machines - key elements of future technology". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71184.
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Fluid Power displacement machines are still by far the dominant power transfer principles in mobile machinery. Power density, simple continuous variability for rotary and linear drives as well as straight forward repair and service concepts have enabled this technology a very successful development in the last decades. This general lecture will critically analyze if and how those drive line elements will be Key Elements of Future Technology in this market in the future, especially under the view that battery technologies are facing many challenges for powerful machines with intense duty cycles (see also automotive industry) [... aus dem Text].
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Straub, David. "Behaviour and impact of leakage in vacuum gripping systems". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71214.
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Leakage in a vacuum system causes the pressure to rise if it is not compensated like in case the supply energy carriers fail. This leads to the workpiece to be dropped. So in order to design vacuum gripping systems that can withstand a failure of the supply energy carriers over a predefined amount of time, it is crucial to know the influences and effects of leakage. In previous examinations the behavior of leakage has been examined on the basis of a closed fluidic reservoir with a hole in its wall. But the only impacts taken into account here are the volume of the reservoir, the diameter of the hole and the pressure difference. Whereas when it comes to vacuum gripping systems, the leakage has significantly more influencing factors as it is neither a single component nor a closed system. In vacuum gripping systems leakage mostly occurs at the interface between the suction cups and the workpiece. So in this contribution the focus is on the impact of the properties of those components, and how the variation of these properties affects leakage. To achieve this, a theoretical description is done based on the aforementioned research, which is expanded in order to the relevant characteristics of a vacuum gripping system. After that the description is evaluated on a test bench. The goal is to be able to make a statement about the leakage rate for a vacuum gripping system composed of standard components. This can then be used in the design process of such gripping systems, which have to fulfil the requirement of compensating leakage in case the energy supply fails.
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Araújo, Weslei Silva de. "Das Escolas Técnicas Federais aos Institutos Federais: a licenciatura em Física no campus Goiânia do IFG". Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/5983.
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In this paper we sought to understand how the Degree in Physics in IFG Goiânia campus is structured and what the perspective of teachers in the area, specifically in the implementation of degree in Physics, and forward the changes in the institution. The choice of this theme is due to the requirement stipulated by law 11.892 of December 29, 2008, the Federal Institutes of Education, Science and Technology, in offering undergraduate courses, especially in the areas of Science and Mathematics, despite its recognized expertise in professional education. Some research has dealt with the theme of the presence of the degrees in FIs, discussing the profile, the deployment and the challenges that they are consoli dated. However, here we seek teachers' perception of the process. Characterized as a qualitative study we used bibliographical research to survey the changes via legal documents in the institution, as well as research on the site e -MEC for recognizing the quantity of courses offered in this mode before and after the creation of the IFs. For analysis of the survey responses a nd interviews with teachers of Physical area of Goiânia the IFG campus, we used content analysis, according to Bardin (2002). It was identified as perceived by teachers who: (i) changes in the institution provided an expansion and internalization, even disorderly; (Ii) the change in the teaching profession and school mischaracterization with devaluation of technical education; (Iii) the course designed to meet the law, structure and operation in construction, has a focus on specific knowledge at the expense of teaching; (Iv) teachers work almost exclusively in the classroom, with little or no research and extension activities. These aspects lead to understand that there is still a lack of identity in I Fs after implantation of degrees and forward the changes in this institutions.
Neste trabalho buscou-se compreender de que forma a Licenciatur a em Física no campus Goiânia do IFG se estrutura e qual a perspectiva dos professores da área , especificamente, na implantação da licenciatura em Física , e frente as mudanças ocorridas na instituição. A escolha deste tema se deve pela obrigatoriedade, estipulada pela lei 11.892 de 29 de dezembro de 2008, dos Institutos Federais de Educação, Ciência e Tecnologia, em ofertar cursos de licenciaturas, principalmente nas áreas de Ciências e Matemática, apesar de sua reconhecida competência na área de educação p rofissional. Algumas pesquisas têm tratado da temática sobre a presença das licenciaturas nos IFs, discutindo o perfil, a implantação e os desafios para que os mesmos sejam consolidados. No entanto, aqui buscamos a percepção dos professores sobre todo o pr ocesso. Caracterizado como um trabalho de abordagem qualitativa utilizou-se inicialmente de pesquisa bibliográfica para levantamento das alterações ocorridas via documentos legais na instituição, assim como pesquisa no site e -MEC para o reconhecimento do quantitativo de cursos ofertados nesta modalidade antes e depois da cria ção dos IFs. Para análise das respostas do questionário e das entrevistas realizadas com os professores da área de Física, do campus Goiânia do IFG, utilizou-se a Análise de Conteúdo, segundo Bardin (2002). Identificou-se, segundo a percepção dos professores que: (i) as mudanças na instituição proporciona ram uma expansão e interiorização, mesmo que desordenada ; (ii) a alteração na carreira do professor e a descaracterização da escola com desvalorização do ensino técnico; (iii) o curso criado para atender a lei, com estrutura e funcionamento em construção, possui um enfoque no conhecimento específico em detrimento do pedagógico; (iv) os professores atuam quase que exclusivamente em sala de aula, com poucas ou nenhuma atividade de pesquisa e de extensão. Estes aspectos levam a entender que há ainda uma falta de identidade nos IFs após a implantação das licenciaturas e frente as mudanças ocorridas nesta s instituições.
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Casoli, Paolo, Fabio Scolari, Carlo Rossi i Manuel Rigosi. "A cfd design of engineered surface for tribological performance improvements in hydraulic pumps". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71104.
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In the present paper the preliminary results of the potentialities that surface texturing has in improving the coupling of lubricated surfaces in relative motion is presented. This kind surface engineering requires careful design of the geometry to obtain relevant improvements; therefore, it is useful to study in detail the behavior of the fluid confined between the coupled surfaces by means of CFD analysis. The purpose of this research is to study the effect of dimples created on one of the two coupled surfaces and to observe the variation of tribological properties as their principal design parameters vary, such as dimple shape, size and spatial distribution. Furthermore, simulations have been carried out with different sliding velocities and fluid temperatures to analyze the effects that these variables have on the tribological performance of the textured surface. The simulations also consider the presence of cavitation and the influence of this phenomenon on the overall behavior of the textured surface is evaluated.
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Pasieka, Lucian. "The applicability of the mass-flow-model according to iso 6358 with the parameter critical conductance c and critical pressure ratio b for gases in high-pressure range up to 300 bar". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71162.
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Mass flow models for gaseous media describe the relationship between gas flow through throttle elements depending on pressure, temperature and type of medium. These models are used to calculate pneumatic components, to simulate pneumatic systems or to plan facilities. The known flow models are verified for ideal gases, such those as according to ISO 6358-1 (International Standard ISO 6358- 1: pneumatic fluid power – Determination of flow-rate characteristics of components using compressible fluids: General rules and test methods for steady-state flow, 2013). But they fail with real gases, especially at higher pressures. The objective of this contribution is to recommend a simple-touse model for the mass flow calculation of real gases. The advantage of the C and b model is the use of only two parameters. A testbench for high pressure up to 300 bar was used for model verification with air and hydrogen. The Library for standard dry air and hydrogen up to 1000 bar was used for the state variables of the real gases. The parameters C and b are obtained, applied and verified in the state space of real gas. With the C and b parameter it is possible to simulate not only the single component (valve, throttle, nozzle and so on) but also the whole system with a complete system simulation, like such as hydrogen filling stations.
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Moosavi, Atena, Sven Osterland, Dominik Krahl, Lutz Müller i Jürgen Weber. "Numerical prediction and experimental investigation of cavitation erosion of hydraulic components using hfc". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71096.
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Hydraulic devices play an essential role in mechanical engineering due to their high-power density, good controllability, flexible application and high robustness, which expose innovative methods of energy transmission. However, in applications where there is an increased risk of fire or explosion, the commonly used combustible mineral oils represent an unacceptable safety hazard. In such cases, fireresistant, water-based hydraulic fluids are in demand. A special feature of these liquids is their high cavitation tendency and the associated strong erosion wear. The aim of this research is to predict the cavitation behaviour of HFC and the subsequent erosion phenomena using numerical methods and to validate the results with experiments. Additionally, experimental results for HFC were compared with HLP. The findings help to implement further developments to decrease the erosive effect of cavitation in high-pressure differences in hydraulic components. For this purpose, flow geometries of typical hydraulic components, e.g. valve and pump, are used for experimental and numerical investigation. The large-eddy simulation (LES) turbulent modelling is used with Zwart-Gerber cavitation model. The cavitation aggressiveness is quantified by cavitation erosion indices according to Nohmi.
18
List, Walter. "Efficiency that borders on the impossible electrohydraulic drives". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71234.
Pełny tekst źródłaStreszczenie:
Hydraulic displacement systems are a technology that has been known for many years. Nevertheless, the impression is created that the large fields of application are not only being developed very tentatively, but in many cases are being completely denied. What might be the reason for this? Are the electromechanical solutions better? What is the missing element to build the bridge from the available hydraulic-mechatronic technology to broad customer application? This paper provides an overview of how the targeted use of the latest technologies in the product and in the entire value-added chain has resulted in a complete mechatronic hydraulic system that pushes the limits of feasibility in terms of power, accuracy and efficiency and delivers a clearly calculable benefit for both the plant manufacturer and the end customer. In addition to the great accuracy and high reliability, there are also considerable savings in the total cost of ownership (TCO) due to a previously unattained level of efficiency. The thoughts of health and environmental protection are just as much a part of the considerations as product safety and personal protection. Finally, an outlook on possible expansions is given, and which areas of application are possible for the technologies developed within the project. The aim is not to show how the traditional fields of application of hydraulics are to be defended, but rather to use the strengths of a hydraulic-mechatronic approach in a conscious and clearly structured way to make new applications possible.
19
Minav, Tatiana, Jani Heikkinen, Soumadipta Pyne, Sami Haikio, Juha Nykanen i Matti Pietola. "Analysis of novel zonal two-cylinder actuation system for heavy loads". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71078.
Pełny tekst źródłaStreszczenie:
Climate change and economic opportunities motivate investigating electric distributed power for working hydraulics in non-road mobile machinery (NRMM) instead of conventional hydraulics. This recent method allows significant energy savings in hydraulic systems, which was demonstrated previously by many independent studies. In this study, zonal hydraulics (as electrically distributed) are realized with direct driven hydraulics drive (DDH) units. Unlike conventional hydraulic drives the DDH units are disconnected from the engine (main prime mover) and distributed throughout the system. In a DDH unit, a single fixed displacement pump/motor with a speed-controlled electric servomotor directly controls the flow. The aim of this paper is to determine functionality of this new two-cylinder DDH-system in a lifting work cycle (or a swerve motion of the work machine). For this purpose, a model was created to investigate performance of the new test rig Dolores. The results of the simulation model will be utilized in future research to discover and compare other alternatives for working hydraulics architectures.
20
Lyu, Fei, Junhui Zhang i Bing Xu. "Wear prediction of piston/cylinder pair in axial piston pump". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71106.
Pełny tekst źródłaStreszczenie:
The piston/cylinder pair is the key lubricating interface of axial piston pumps. It suffers from excessive wear due to the huge lateral force, especially under high output pressure. In order to achieve predictive maintenance, it is significant to detect the performance degradation of the piston/cylinder pair. In this paper, a method to predict the wear of the piston/cylinder pair is proposed. The wear regions and corresponding wear depths under different conditions are investigated. The distributive characteristic parameters of the oil film are obtained, which can reflect the load-bearing and lubrication conditions at each region of the friction pair. Based on the oil film characteristic parameters, the most suitable wear model is chosen to calculate the wear depth, and then the entire wear profile of the piston/cylinder pair is obtained. The experimental investigation is carried out, and the results show that the accuracy of the wear regions and corresponding wear depth prediction is high. This method can be used to pump healthy management and choose the suitable working conditions of the axial piston pump.
21
Schweizer, Hartmut, Raphael Alt, Katharina Schmitz i Martin Wollschläger. "B2MML as an exchange format for asset administration shells as part of a plug-and-produce process for a fluid power engineering application". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71180.
Pełny tekst źródłaStreszczenie:
One development in the course of industrial digitalisation, which is being driven forward particularly in the German-speaking countries and will gain in importance in the future, is that of the Asset Administration Shell (AAS) [1]. The present work deals with the distribution, instantiation and use of those AASs for assets within the domain of a fluid power engineering application, which by themselves do not currently have the corresponding hardware and software for harbouring an AAS. The Business to Manufacturing Markup Language (B2MML) is used here for the deployment and instantiation of these AASs. In the present work, B2MML is extended with the concept definitions of AAS using its enhancement mechanisms. The distribution of the AASs to computing resources then takes place using B2MML and its transaction definitions. Furthermore, B2MML is used in a submodel to orchestrate process queues. In the course of the FL4 research project, B2MML is integrated as a partial model into the AAS and is used for orchestrating the Plug-and-Produce processes one the business and on subordinate levels.
22
Achten, P. A. J., R. F. H. Mommers, H. W. Potma i J. J. Achten. "Design and testing of pistons and cups for large hydrostatic pumps and motors". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71187.
Pełny tekst źródłaStreszczenie:
A new transmission is being designed for a next generation of large, offshore wind turbines, based on floating cup pumps and motors. The machines have a fixed displacement of around five liter per revolution. The objective of this study is to design, manufacture and test the pistons and cups of these machines. To this end, a new test bench has been designed and build, to measure the leakage and friction of the pistons up to a pressure level of 350 bar. Several sets of pistons and cups have been tested against a reference set which was proven to have very little friction at rated and peak operating conditions. The leakage between the pistons and cups was measured at different piston positions at stationary conditions. The friction between the piston and the cup has been measured continuously. From the tests it can be concluded that the friction force is below 0,01% of the piston force. The leakage losses are less than 0,5% of the total effective flow output.
23
Gauchel, Wolfgang, Thilo Streichert i Yannick Wilhelm. "Predictive maintenance with a minimum of sensors using pneumatic clamps as an example". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71204.
Pełny tekst źródłaStreszczenie:
In standard pneumatics, the available signals for data analytics are very limited. As a rule, no continuous status information is available. Usually only the reaching of the end position is indicated - by means of a digital signal of a proximity sensor. This paper examines whether these limited data can be used to derive usable and useful information for predictive maintenance. Pneumatic clamps in bodyin- white construction were chosen as application example. The paper describes a continuous run to investigate the basic feasibility of predictibility. In the following chapters, possibilities for error classification are discussed. Finally, the implementation of the findings in a field test is described.
24
Bauer, Wolfgang. "Hydropneumatic all-wheel suspensions: applications, challenges and special solutions". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71226.
Pełny tekst źródłaStreszczenie:
All-wheel suspensions are generally challenging, particularly if they are equipped with an automatic level control. In mobile machines, the special application conditions make their use even more demanding regarding layout and control. A high center of gravity, load variations, off-road-conditions etc. require special measures to reduce roll and pitch movements. Additionally the uneven ground along with the mechanical suspension setup often create a need to measure and optimize tyre-to-ground forces in order to provide best traction and suspension properties. Hydropneumatic suspensions have all the potential to meet all these requirements and provide a comfortable, safe and efficient suspension setup.
25
Wartlick, Karl, Matthias Baumann, Andras Veres i Roman Weidemann. "CFD-aided optimization of customer-specific tank systems using an innovative labyrinth deaerator". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71199.
Pełny tekst źródłaStreszczenie:
This paper introduces the comprehensive approach of ARGO-HYTOS in developing and optimizing hydraulic tanks. Starting with a detailed analysis of the application, the tank design was optimized and an innovative deaerator was developed. In a first step, various Computational Fluid Dynamics (CFD) -based analyzing methods are presented, which are used to support the optimization process of tank development with regard to complex flow conditions and unexpected influences. The main topic of this paper is the introduction of an innovative labyrinth deaerator, causing coalescence of air bubbles, slower subsequent flow conditions and finally a better deaeration. A further focus is on a customized deaeration test rig, which is used to validate improved components and tank designs on the one hand and to learn more about the complex deaeration effects on the other hand. With this comprehensive optimization approach and the innovative, compact and patented labyrinth deaerator, the size of the tank and the amount of oil can be reduced to a minimum, without impairing air separation, but on the contrary, even improving the air separation behavior.
26
Post, Peter. "Pneumatics and Industrie 4.0 - opportunity or contradiction?" Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71212.
Pełny tekst źródłaStreszczenie:
Modern industrial production processes are increasingly characterized by digital solutions in order to continuously increase their efficiency while taking sustainability aspects into account. Pneumatic components and systems have been and will continue to be an essential part of modern production plants and must face the special challenges posed by digitalization [... aus dem Text]
27
Legner, Jürgen, i Tilo Huber. "ZF view on future drivetrains for compact and medium size wheel loaders". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71219.
Pełny tekst źródłaStreszczenie:
This paper discusses an investigation on a novel hydraulic pump concept. The idea aims on a pump principle to be directly connected to highspeed electric motors to build compact highpressure drives [... aus der Einführung]
28
Erhard, Michael, Jörg Schneider i Jan Julius Stein. "Design and performance evaluation of next generation clutch control valve". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71223.
Pełny tekst źródłaStreszczenie:
Pressure reducing valves perform various control tasks in mobile machines. In many cases contamination sensitive environments require pilot-operated valves, because of its more robust performance. On the other hand, dynamic valve behavior can be critically in certain applications. Overcoming the restrictions resulting from stand-alone test rig attempts, suitable simulation principles are nowadays the state of art in valve design. Unsuitable model approaches and missing consideration of the application may result in wrong design decisions. This paper discusses two important modeling issues, in particular the solenoid and spool leakage behavior, in combination with the connected system under control, a pressure-actuated clutch. It is shown, that even for standard proportional valves a critical view on customers´excitation strategy and site of installation decides on success or failure of an already used design variant.
29
Tappe, Peter, Jürgen Heinzmann i Ralf Raupold. "On/Off solenoid with sensorless position detection". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71254.
Pełny tekst źródłaStreszczenie:
As is generally known, pressure-resistant solenoids for valves are used in hydraulics and pneumatics. These solenoids, for example, consist of a so-called pole tube with an integrated armature and a separate solenoid coil. Suitable displacement measuring systems are used in order to measure the armature´s as well as valve spool´s position constnatly; these ar directly mounted to the solenoid. Exeamples here are Hall Effect sensors or LVDT transducers. In case of lesser requirements, it is also possible to measure the valve spool´s position directly and in simplified manner. Here, partially standard proximity sensors are employed, which use the valve spool directly as measuring object. In these cases, however, only discrete position measurement is possible. A constant displacement measurement is not necessary. By means of the sensorless position-control developed by MSM, the armature´s position can be executed directly by analyzing the solenoid coil, partly replacing the usual sensors, under adapted basic conditions.
30
Dietrich, Ingo, Lukas Zinßer, Tim Müller, Gerhard Ludwig i Peter F. Pelz. "Rotor swivel motor as actuator of an innovative control valve". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71256.
Pełny tekst źródłaStreszczenie:
To minimize the complexity of existing process control valves, the authors derived a new control valve design by functional separation and functional integration of functions. One key element of this new valve design is the functional integration of teh actuator into the valve´s throttle. A hydraulic swivel motor is operated with the process fluid, in this case water. The pressure difference to operate the motor comes from the valve itself. Within this paper we present the control valve design and show in detail how we used the Fail-Early design method to develop the hydraulic swivel motor. The construction is discussed using the experience from manufacturing the prototype and the first exp erimental results are shown. The experiments yield, that the swivel motor principle is promising. Finally, the next development issues are discussed.
31
Lesage, Florian. "Etude structurale et fonctionnelle de canaux k+ de type shaker, isk et irk". Nice, 1995. http://www.theses.fr/1995NICE4824.
Pełny tekst źródłaStreszczenie:
Les canaux k#+ sont des proteines ubiquitaires responsables du maintien et de la modulation du potentiel electrique de la membrane plasmique. Ils controlent la frequence et la duree des potentiels d'action dans les cellules excitables et l'activite secretrice des cellules exocrines et endocrines. Nous avons clone et etabli la structure primaire de differents canaux k#+: les canaux kv1. 3 et kv1. 5 sont des canaux de type shaker a 6 domaines transmembranaires (s1 a s6) et un segment (h5) implique dans la formation du pore, les canaux a rectification entrante irk3 et couple aux proteines g girk2 possedent deux domaines transmembranaires (m1 et m2) et un segment h5 et enfin, la proteine i#s#k ne possede qu'un seul domaine transmembranaire. Les proprietes biophysiques, pharmacologiques et de regulation de ces canaux ont ete etudiees apres expression heterologue dans l'ovocyte de xenope et dans des cellules en culture. Par ailleurs, il a ete etabli que le courant de type n du lymphocyte t humain est produit par le canal kv1. 3. Ce clone a aussi permis de mettre en evidence un effet de la densite d'expression des canaux k#+ sur leurs proprietes biophysiques et pharmacologiques. Le clonage du canal murin kv1. 5 a permis d'etablir qu'il est le canal a rectification retardee majeur du cur adulte, que son activite est modulee par les acides gras polyinsatures et qu'une variete de canaux kv1. 5 aux proprietes distinctes est generee par epissage alternatif. L'etude de la proteine i#s#k, clonee a partir du lymphocyte humain et du cur de souris, suggere que cette proteine est un regulateur plutot qu'un canal. Cette hypothese est soutenue par l'incapacite d'exprimer un courant i#s#k ailleurs que dans l'ovocyte de xenope et par l'observation que la proteine i#s#k active aussi un canal cl#- dependant du potentiel dans l'ovocyte
32
Pellegri, Matteo, Matthew Green, Jill Macpherson, Callan McKay i Niall Caldwell. "Applying a multi-service digital displacement® pump to an excavator to reduce valve losses". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71185.
Pełny tekst źródłaStreszczenie:
Reducing the energy consumption of off-highway machinery due to poor system efficiency is an urgent challenge. Several advanced and innovative architectures have been proposed over the years to tackle this problem, but very few of them found fertile ground for commercial applications due to increased complexity and cost. In this paper, the design, implementation, and testing of a multi-service Digital Displacement ® Pump architecture applied to an excavator are presented. The Digital Displacement ® Pump allows for a dynamic physical displacement allocation to services at different pressure levels, thus reducing throttling losses required to operate multiple actuators simultaneously. A feed-forward control logic is implemented and applied to the system using a closed-centre architecture. The results indicate a fuel reduction of more than 30% compared to the baseline excavator.
33
Mkadara, Geneviève, i Jean-Charles Maré. "Development of a lumped parameter model of an aerospace pump for condition monitoring purposes". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71205.
Pełny tekst źródłaStreszczenie:
This paper presents the development of a helicopter axial piston pump model with condition monitoring in mind. Industrial constraints and needs ask for modelling with a lumped-parameter approach and require model architecture to be addressed with care. The aim of the proposed model is to assess the merits of pump leakage monitoring through measurement of case pressure. Once reviewed the state of the art in pump modelling, the slipper/swashplate interface is taken as an example to propose and implement in Simcenter AMESim a variable gap height model. The simulation results show that commonly used lumped-parameter models overestimate leakage. It also points out that average leakage at slipper may reverse at high pump displacement.
34
Thienen, Stefan, i Thomas Gellner. "Flexible and easy to engineer servo-hydraulic actuators using 3D printing manufacturing process". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71208.
Pełny tekst źródłaStreszczenie:
Already since some time, Bosch Rexroth offers solutions as compact servo hydraulic actuators (SHA). Because there are lot of requests from the market, we thought about reducing the inquiry processing time and delivery time by designing a kit system for the SHA solutions. This system should be flexible enough to cover different technical solutions (e.g. cylinder), functionalities and design styles [... aus dem Text]
35
Siwulski, Tomasz, Urszula Warzynska, Marcin Rys i Maciej Skrzypczak. "Experimental tests of fluid exchange process improvement in a new design of hydraulic cylinder with a supply system". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71090.
Pełny tekst źródłaStreszczenie:
The article presents the results of experimental tests of the liquid exchange level in a new design of a hydraulic cylinder in comparison with the classic one. Comparative results are presented, as well as the influence of the stroke range on the degree of liquid exchange. The results allow the empirical determination of the degree of real improvement of the process of liquid exchange in the cylinder during operation, and thus allow the initial determination of the reliability level increase in hydraulic cylinders. It should be emphasized that the presented results are a part of a research and implementation project carried out in cooperation between a university and an industrial partner. In addition, the presented test method of hydraulic cylinders is, in the opinion of the authors, an interesting proposition, which can be used by manufacturers of this type of components in the world.
36
Ivantysyn, Roman, Ahmed Shorbagy i Jürgen Weber. "Investigation of the wear behavior of the slipper in an axial piston pump by means of simulation and measurement". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71102.
Pełny tekst źródłaStreszczenie:
Axial piston pumps are universal displacement machines that are used in a vast variety of applications. Their high pressure resistance and ease of operation make them very popular, especially in mobile applications. Some applications require more robust pumps with an extended lifetime, particularly those that operate in remote environments such as marine type or mining operations. Especially new applications like displacement control have high demands on pumps such as through shaft operation (many pumps on one shaft), high dynamics and multi-quadrant operation. These demands create challenges in terms of lifetime expectancy and robustness for pump manufacturers and machine OEMs. Currently most axial piston pumps go through a run-in process. During this process the softer bronze parts shave off and change their shape according to the necessary one for the pumps’ proper operation. This process is highly dependent on the design of the parts and their manufacturing tolerances. In this paper the run-in process of the slippers of an axial piston pump was investigated by means of measurements of the gap height and wear profile as well as simulation. The measurements show a clear change of profile and gap heights for the first 120 h of the pumps operation. After that the gaps stabilize. The numerical simulations made with the program Caspar FSTI were coupled with contact wear models to output wear profiles. Different models will be introduced and compared with measurements. Both
the amount of material removed and the performance of the pump before and after run-in will be discussed.
37
Guo, Jihao, i Ludger Frerichs. "Development of a hydrostatic transmission with integrated supply for working hydraulics". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71237.
Pełny tekst źródłaStreszczenie:
The paper presents a study of a highly integrated hydraulic powertrain for mobile working machines. The highlight of this new concept is the replacement of separated drive and working pumps in conventional systems with only one displacement pump. After a comparison of different system architectures, the appropriate operating and control strategies for the chosen topology were applied and optimized. With the help of simulations in AMESim, a proof of the function of the hydraulic circuit and the controlling has been established. In addition, the energy saving potential of the integrated hydraulic system is also considered, by comparing the energy consumption of the new and the
conventional powertrain in different duty cycles.
38
Lauer, Peter. "Enabling sil2 safety certified applications for mobile machine oems". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71269.
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Eaton created a new safety controller architecture to allow our customers to design implement, verify and maintain a SIL-2 safety certified application for compliance with IEC 61508:2010 and ISO 13849 Functional Safety Standards. The new architecture has been implemented in a line of safety controllers SFX12 and SFX20 that extend the line of existing mobile controllers HFX12 to HFX48. The new controllers are targeted for controlling mobile and stationary machine applications with focus on steer by wire and propel by wire.
39
Weber, Jürgen. "Digital mobile machines – from cloud to earth". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71164.
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aus dem Text: 'The term „industry 4.0“ describes the transition from a classic value-added chain to dynamic value-added networks. It is driven by four main design principles:
interconnection of machines and humans
information transparency
technical assistance to support humans
decentralized decisions
This approach and its connected technologies, like IoT or cloud computing, enhance in the context of industrial production further flexibility and an increase in productivity through growing self-organisation and interlocking with logistics and planning processes. Extensive activities can be recorded in this field.
40
Richartz, Achim. "State of the art digital on-board-electronics vs. potentially disruptive control architectures for hydraulic valves". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71191.
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Currently discussed trends and new technologies regarding cloud or edge computing imply that even most recent designs and functionalities of digital on-board-control electronics may be outdated and eventually will totally disappear. Additionally, those new technologies attract potential users by promises like new use cases e.g. predictive maintenance or a simplified architecture and reduced installation efforts. On the other hand, automation levels and subsequent requirements are often mixed up or discussed too generally. Nevertheless, what is the rue situation today and in the upcoming years? This paper elaborates the potentials of both approaches – state of the art on-board-control electronics and potentially disruptive control architectures for hydraulic valves in order to take the right decision and reflect the pros and cons for each topology by:
a) Architecture of automation: In Terms of strongly hierarchical or multidimensional connected systems.
b) Requirement of installation: By reflecting the dedicated ecosystems, on levels like plant, machine, subsystems.
c) Maturity of technology: Looking on the user’s perspective.
d) Safety and security: From legal and conformity aspects.
e) Performance needs by specific task: In comparing standard to demanding real life applications.
41
Massarotti, Giorgio, Cristian Ferrari, Esteban Codina Macia i Massimiliano Ruggeri. "Mems sensors in hydraulics, an opportunity to create smart components". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71238.
Pełny tekst źródłaStreszczenie:
Modern electronic technologies allow for the design and production of Micro Electro-Mechanical Systems, also called MEMS. These microchips are widely used as sensors in many fields of application, also in embedded systems in heavy-duty and agricultural vehicles and in automotive applications. In addition to the classic uses of these sensors, new architectures and sensor topologies exploit electromechanical principles of great interest for the field of hydraulic applications. This paper presents some examples of the application of a new MEMS architecture based on self-oscillating microresonators, which offer interesting capabilities in the measurement of mechanical deformation of
mechanical components. MEMS are applied as non-invasive pressure and oil flow sensors, and represent an interesting option for creating smart components. All the applications described are intended to show the sensor potential and have a qualitative and exemplary character, but they can provide a basis for in-depth studies on the potential and applicability of these sensors.
42
Kramer, Thomas, i Jürgen Weber. "Self-Sensing position determination on a sensor-designed proportional solenoid". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71245.
Pełny tekst źródłaStreszczenie:
Proportional valves are widely used in fluid systems for controlling the volume flow rate or fluid pressure. The actuation of this valves is done by PWM-driven proportional solenoids, which enable self-sensing position determination abilities due to air gap-dependent electrical behaviour, e. g. for condition monitoring or position controlling tasks. However, the sensor properties of conventional proportional solenoids are poor due to ambiguities caused by hysteresis effects (magnetic hysteresis, eddy currents) and saturation effects. Thus, a sensor-designed actuator was developed with very low hysteresis effects and unique position determination by using electrical sheet and a particular air gap design. This paper deals with investigations of a novel self-sensing position determination approach on a demonstrator of the sensor-designed solenoid. The advantage of this method is an online consideration of transient effects such as mean current change and armature motion as well as temperature-dependent resistance. For this, a combined evaluation of the differential inductance and flux linkage during PWM periods is proposed.
43
Kreutmayr, Fabian, i Markus Imlauer. "Application of machine learning to improve to performance of a pressure-controlled system". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71076.
Pełny tekst źródłaStreszczenie:
Due to the robustness and flexibility of hydraulic components, hydraulic control systems are used in a wide range of applications under various environmental conditions. However, the coverage of this broad field of applications often comes with a loss of performance. Especially when conditions and working points change often, hydraulic control systems cannot work at their optimum. Flexible electronic controllers in combination with techniques from the field of machine learning have the potential to overcome these issues. By applying a reinforcement learning algorithm, this paper examines whether learned controllers can compete with an expert-tuned solution. Thereby, the method is thoroughly validated by using simulations and experiments as well.
44
Beckmann, Bastian. "Additive manufacturing of hydraulic manifolds - a holistic approach across the entire value chain". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71083.
Pełny tekst źródłaStreszczenie:
Manifolds usually consist of metallic, rectangular base bodies into which lines are inserted by means of drilling, thus logically linking the built-on or built-in valves according to the hydraulic circuit diagram. Using additive manufacturing methods, additional degrees of freedom can be used in the design of manifolds, resulting in further benefit in hydraulic drives and their controls. The challenge is not only to understand and apply additive manufacturing technology, but also to align the entire value chain with it.
45
Rexer, Manuel, Peter Kloft, Frank Bauer, Jakob Hartig i Peter F. Pelz. "Foam accumulators: packaging and weight reduction for mobile applications". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71088.
Pełny tekst źródłaStreszczenie:
Standardized parts like hydraulic accumulators are used in nearly every hydraulic system, in many cases even several. Therefore, even small changes in size and weight of accumulators can save considerable material costs. In mobile applications, hydraulic accumulators are used among others in hydro-pneumatic suspension systems. There is a strong focus on miniaturization and weight reduction, as the components always have to be transported with the vehicle. Energy density and energy content of conventional hydraulic accumulators cannot be maximized at the same time. This limitation can be overcome by adding a heat capacity with large surface into the gas volume of the accumulator. The heat capacity enlarges the isothermal frequency range and therefore enlarges the energy density of the accumulator at the given frequency and the given size. In this paper an experimental comparison of conventional hydraulic accumulators and accumulators with foam inserts shows, that at a specific frequency band, the stiffness of foam filled accumulators is significantly lower than of conventional accumulators. The energy density is about 11 % higher than in conventional accumulators. Consequently, a space reduction of about 18 % is possible.
46
Pasquini, Enrico, Hubertus Murrenhoff i Katharina Schmitz. "On the thermodynamic consistency of experimentally determined fluid properties". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71160.
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In the field of fluid power, accurate knowledge of fluid properties is vital for reasonable prediction of component behaviour and system performance. In general, these properties depend on the pressure and temperature levels that the respective medium is exposed to. The properties and their respective dependencies are not publicly accessible for many fluids commonly used in fluid power. If measured values – typically published in the form of mathematical fluid property models – are available at all, their quality is typically unknown. The paper aims to provide tools to objectively ascertain the quality of measured fluid properties. For this purpose, an equation is derived which establishes a relationship between the thermodynamic parameters of density, bulk modulus, heat capacity and thermal expansion coefficient. The presented equation is always satisfied by liquids as well as gases as long as they can be treated as a continuum. Based on this relationship, the degree of thermodynamic consistency of measured properties is evaluated: The less the equation is fulfilled by experimentally determined fluid properties, the more the measured values violate physical laws. The procedure of assessing the thermodynamic consistency is demonstrated by evaluating published fluid property models with the method outlined above. To aid engineers in judging which degree of thermodynamic inconsistency is acceptable, a cut-off value is suggested.
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Kärnell, Samuel, Amy Rankka, Alessandro Dell`Amicio i Liselott Ericson. "Digital pumps in speed-controlled systems – an energy study for a loader crane application". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71186.
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Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.
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Hartig, Jakob, Christian Schänzle i Peter F. Pelz. "Validation of a soft sensor network for condition monitoring in hydraulic systems". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71201.
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With increasing digitization, models are more important than ever. Especially their use as soft sensors during operation offers opportunities in cost saving, easy data acquisition and therefore additional functionality of systems. In soft sensor networks there is redundant data acquisition and consequently the occurrence of inconsistent values from different soft sensors is encouraged. The resolution of these data-induced conflicts allows for the detection of changing components characteristics. Hence soft sensor networks can be used to detect wear in system components. In this paper this approach is validated on a test rig. It is found, that the soft sensor network is capable to determine wear and its extent in eccentric screw pumps and valves via data induced conflicts with relatively simple models.
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Wahler, Matthias, i Thomas Sendelbach. "Model based engineering for electro-hydraulic solutions". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71232.
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This paper will give an overview about the technological change in Industrial Hydraulics and the impact of the Digital Twin on the related new engineering processes and methods in order to overcome the challenges coming out of that technology change. Simulation models will more and more become a decisive factor for the engineering process. The Digital Twin will be a window of opportunity for innovations and a technology push for the engineering process and the products in the Industrial Hydraulics.
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Tamburrano, Paolo, Andrew R. Plummer, Palma Pietro De, Elia Distaso i Riccardo Amirante. "Experimental and numerical study of a novel piezoelectric pilot stage for servovalves". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71259.
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Two - stage servovalves, despite being widely used in aircraft and industry because of their reliability and high performance, have a few disadvantages that are still unsolved at the state of the art, such as the power consumption caused by the quiescent flow (internal leakage) in the pilot stage, and the complexity and high number of parts of the torque motor assembly of the pilot stage. The solution to these problems can help to reduce costs, weight, power consumption, and to enhance the reliability and producibility as well as the performance of these valves. This paper presents a novel configuration of servovalve, which has the potential to overcome the above-mentioned issues. The proposed servo-valve includes a novel architecture for the pilot stage by using two piezo-electric actuators (ring benders). In this paper, the performance of this novel pilot stage is assessed. To this end, a valve prototype has been constructed and tested; the experimental results are also used to validate a numerical model obtained with the software Simscape Fluids. The results show that, acting on specific parameters, the performance of the piezo-valve can be very competitive, while ensuring very low internal leakage and complexity.