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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.
11

Autonomous Liquid Dispenser : A.L.D. / Automatisk vätskeautomat

Gan, William, Håkansson, Oliver January 2020 (has links)
Our society has become more and more digitized and futuristic in the service sector. The urge of efficiency in order to maintain a stable income and profit is increasing in various businesses. One such business is the hotel and restaurant business which heavily relies on staff members being efficient. The purpose of this report is to evaluate how automation and efficiency can be combined and integrated into this branch. The main reason being to release employees in this branch from repetitive tasks and put the focus on delivering high quality customer service instead. The main goal in this report will be on dispensing a variety of both carbonated and non-carbonated drinks using an autonomous system that strives to have the same accuracy and skill as a dispenser operated by a human. To achieve this goal an autonomous liquid dispenser consisting of two ultrasonic sensors had to be constructed. It should be able to detect when a glass needs to be filled with liquid, decrease the foam by tilting the glass and replace it to it’s original state. The system was evaluated using three different experiments, where two of them measured the accuracy of the construction. The results from the two experiments concluded that the constructed system is of high accuracy. The result from the third experiment tested the speed for one dispensation cycle and the conclusion was that improvements can be made. / Automatisering och digitalisering av olika sorters arbetsuppgifter har ökat mer och mer sedan 70-talet och fortsätter att öka. Detta för att kunna effektivisera arbetsprocesser och därmed öka lönsamheten i verksamheten. Syftet med denna rapport är att utvärdera huruvida denna effektivisering och automatisering kan tillämpas i en barmiljö. Detta för att frigöra tid från personalen från repetitiva uppgifter och därmed tillåta dem att fokusera mer på andra mer krävande arbetsuppgifter. Fokuset i denna rapport är på upphällningen av olika drycker med kolsyra och hur detta kan göras av ett autonomt system med samma precision och skicklighet som hos en människa. Detta utförs genom att tillverka en prototyp som med hjälp av en ultraljudssensor känner av att ett glas ställs på rätt plats, för att sedan vinkla glaset samtidigt som det fylls med den önskade vätskan. När glaset sedan är fyllt med önskad mängd vätska så vinklas plattformen tillbaka och uppgiften ¨ar klar.  Systemet utvärderades senare utifrån tre tester. Där två av dem testade precisionen i konstruktionen. Resultatet i dessa två tester var att precisionen i systemet är godkänd. Resultatet från det tredje testet som kollade på tiden det tar för systemet att utföra en cykel var att detta behöver arbetas vidare med och detta resultat analyseras mer i Chapter 5.
12

Développement d'un modèle de prédimensionnement d'un ensemble alternateur - machine Stirling à pistons libres / Development of a preliminary design of a free piston Stirling engine coupled with a linear electrical alternator

Salquebre, Quentin 21 March 2019 (has links)
Le moteur Stirling a été développé il y’a 200 ans. Cependant son développement n’a jamais connu un grand essor. Le contexte énergétique actuel a relancé l’intérêt porté à ces machines. En effet la possibilité de le faire fonctionner à partir de n’importe quelle source de chaleur externe lui permet d’être associé à des sources d’énergie renouvelable comme l’énergie solaire. Au-delà des avantages écologiques, le développement par W. Beale à la fin des années 1960 d’un moteur Stirling à pistons libres (ou FPSE pour Free Piston Stirling Engine) a ajouté de nouveaux intérêts à un tel moteur. Cette nouvelle architecture permet au moteur de fonctionner sans système d’entrainement des pistons. Dans de telles machines, le mouvement des pistons n’est plus déterminé par la géométrie du système d’entrainement. Ces derniers sont mis en mouvement par les forces de pressions occurrents à l’intérieur du moteur. La dynamique des pistons et la thermodynamique du système sont alors couplées, rendant plus complexe la modélisation complète du système.Cette thèse présente une nouvelle technique de modélisation des machines Stirling à pistons libres, intitulée LHA5V pour Linear Harmonic Analysis 5 Volumes, permettant de coupler la thermodynamique du système et la réponse mécanique des pistons libres. Celle-ci repose alors sur la décomposition du moteur Stirling en cinq sous systèmes ouverts : deux espaces à volume variables, deux échangeurs de chaleur et le régénérateur. Nous supposons que les variables d’état varient périodiquement et le modèle détermine comment celles-ci varient en valeur moyenne, en amplitude et en phase afin de satisfaire les équations de conservation de la masse et de l’énergie. L’aspect innovant du modèle thermique repose sur la prise en compte implicite des pertes inhérentes au fonctionnement. Celles-ci ont en effet un impact direct sur le mouvement des pistons. Par ailleurs cette thèse présente également un modèle de génératrice électrique linéaire pouvant être couplé à la partie thermique. Le modèle électrique repose sur un calcul analytique de la force de poussée du stator sur la partie mobile. Le calcul des flux et du niveau d’induction dans le circuit magnétique est effectué à partir d’un réseau de perméances judicieusement paramétré.Que ce soit pour la modélisation thermique ou la modélisation électrique, chacun des modèles a été conçu pour avoir un temps de calcul faible, tout en restant le plus précis possible sur la prédiction des performances. Ceux-ci ont à chaque fois été confrontés à des données expérimentales, ou à d’autres techniques de modélisation plus fines de façon concluante. / Though the Stirling engine was invented two centuries ago, it has never really grown to a fully marketable level. The current energy context has renewed the interest in this engine. Their ability to work with any external source of heat allow them to be associated with renewable energy such as solar energy. Beyond its ecological benefits, the invention of the free piston Stirling engine by W. Beale at the end of the 1960’s further increased the interest in Stirling engines. This novel structure allows the engine to operate without mechanical interface between pistons, which are driven entirely by the gas or other spring forces. In such engines, the pistons kinematics and the system thermodynamics are intimately coupled, thus increasing the complexity of the complete system computer modelling.This PhD presents an innovative technique to model a free piston Stirling engine that takes into account the coupling between the system thermodynamics and the mechanical response of the free pistons. This technique has been named LHA5V standing for Linear Harmonic Analysis 5 Volumes. It consists in splitting the engine in five open sub-systems: the compression and expansion spaces, the heater, the cooler and the regenerator. We hypothesize that the state variables are periodic, and the model then determines the variations of their mean, amplitude and phase values in order to satisfy the mass and energy conservation equations. This PhD also presents a model for a linear electric alternator, which can be coupled to the power piston. This electrical model is based on an analytical calculation of the thrust between the stator and the magnets. Magnetic flux and induction in the iron are determined by a carefully tuned reluctance network.Both thermal and electrical models have been designed to optimize both computing time and accuracy. The models generated have systematically been compared to experimental data or finite element analysis, with satisfactory results.
13

Actionneur linéaire rapide - Application aux soupapes électromagnétiques / Fast linear actuator - Application to electromagnetic valves

Raminosoa, Ando 11 September 2012 (has links)
Pour réduire les émissions de gaz polluants, les constructeurs automobiles cherchent à mieux contrôler le volume d'air introduit dans le moteur pour optimiser la combustion. Des dispositifs mécaniques ou hydrauliques couplés avec l'arbre à cames sont déjà en place dans certaines voitures et permettent des gains de 8 à 10% sur la consommation de carburant. L'utilisation d'un actionneur électromagnétique à la place de l'arbre à cames (application « camless ») pour commander les soupapes améliore nettement ce gain (15 à 20%). Les travaux de cette thèse consistent à modéliser une structure choisie, pour ensuite l'optimiser. Compte tenu des exigences de notre application et des contraintes d'environnement du moteur thermique, la modélisation doit être à la fois suffisamment précise et rapide pour estimer et améliorer les performances de l'actionneur. Pour la partie statique, nous avons opté pour un modèle réluctant 3D. Obtenu par extension de son homologue 2D, il reste rapide tout en donnant des résultats en accord avec les mesures. En régime transitoire, nous proposons une nouvelle approche analytique de la distribution des courants de Foucault, directement à partir de l'évolution du flux magnétique. L'équation de diffusion comporte alors des conditions aux limites de Neumann. Nous avons traité le cas d'un flux magnétique arbitraire grâce au théorème de Duhamel, ainsi que la saturation du matériau grâce à une approche semi-analytique. / Variable valve actuation is one of automotive constructors' strategies to fulfil environmental queries about emission of pollutant gases. It brings improvement to the thermal engine, and many constructors have their own devices associated to the camshaft, with a gain between 8 and 10% on fuel consumption. The use of camless actuator brings further more gain, from 15 to 20%. The established approach during this thesis consists in modelling a chosen topology of actuator, and next in optimization. However, camless specifications and constraints require fast models, but with correct accuracy. That's why we use 3D permeances network in steady state. That model is obtained from extension of its 2D version. It is still fast and gives results in good agreement with measurements. We proposed a new analytical approach of eddy currents distribution in transient state, directly from the evolution of magnetic flux. Thus we have Neumann's boundary conditions in the diffusion equation. Arbitrary magnetic flux excitation and saturated material (with semi-analytical approach) are considered.
14

Zařízení pro testování malých elektrických motorů a lineárních aktuátorů / Testing equipment for small electrical motors and linear actuators

Červínek, David January 2018 (has links)
Aktuální postup testování je příliš zdlouhavý a nepřesný, zároveň není měření některých vlastností motoru vůbec možné. Hlavním úkolem zařízení je zrychlení a zjednodušení procesu testování spolu s možností otestovat všechny vlastnosti motorů. Realizace zařízení začala definováním požadavků zákazníka, dalším krokem byla analýza daných požadavků a návrh zařízení. Následovala výroba a programovaní firmwaru spolu se softwarem. Výsledkem práce je funkční přístroj schopný automatického testování sedmi základních typů motorů, měření všech požadovaných funkcí spolu s novou možností měření počtu tiků enkodéru, periody FG signálu z řídící elektroniky BLDC motorů a napěťové úrovně těchto signálů. Dalšími rozšířeními jsou možnost uložení výsledků z uskutečněných testů pro možné budoucí využití a možnost vizualizace proudu motorem. Uživatel je tedy schopný otestovat velké množství motorů v kratším časovém úseku a zároveň se o testovaných motorech dozvědět mnohem více informací než doposud.
15

Zkušební zařízení na měření pevnosti pájeného spoje / Test Equipment for Solder Joint Strength Measuring

Čechák, Ondřej January 2019 (has links)
This master thesis introduces the problematics of the tensile strength of soldered joints and the correlative mathematical formulas and the use of mentioned problematics in the technology of die shear/pull machines designed for the solder joint tensile strength measurement. It explains the importance and reasons for the use of this technology. The emphasis is then laid on the design and construction innovations of the current laboratory manual shear/pull measuring machine, its semi-automation and the possibility of utilizing the innovated system in a laboratory class of a subject on FEEC BUT.
16

Zvedací plošina / Vehicle hoist

Dítě, Michal January 2016 (has links)
This thesis deals with searches different types of lift tables. Create design of several lift tables with different drive of platform for load capacity 800 kg and stroke 700 mm. Compare this solution. Selection suitable alternatives of Kwapil & Co GmbH company. Drafting assembly drawings of several alternatives.
17

Design and Realization of an Adjustable Fluid Powered Piston for an Active Air Spring

Hedrich, Philipp, Johe, Maik, Pelz, Peter F. January 2016 (has links)
In this paper, we present a new compact hydraulic linear actuator. The concept is developed to change the rolling piston diameter of an active air spring during usage. By doing so, the air spring can actively apply pressure and tension forces. The actuator is designed for small movements at high forces. It is insensitive to side forces, which are introduced by the bellows rolling on the rolling piston of the air spring. A diaphragm sealing is used to minimize friction. Hence a precise adjustment of small displacements at high dynamics is possible and the system is completely leakage-free. We describe the design and development of this actuator and show first measurement results from preliminary tests to show its functionality.
18

Improved Control of a Primary Linear Actuator using State-Space

Lagerström, Arvid January 2024 (has links)
This master’s thesis investigates the possibility of replacing the traditional triple cascaded Proportional-Integral (PI) controller architecture, used to regulate a PermanentMagnet Synchronous Motor (PMSM), with a state-space approach. Using theory regarding PMSMs and Electromechanical Actuators (EMAs) as a foundation, the thesisdescribes the design process of the proposed control methods up until implementation. The two state-space approaches evaluated in the thesis are: a single Linear-QuadraticRegulator (LQR) method and a torque reference generating LQR together with a setof two PI controllers for current regulation. Evaluation of the chosen methods wasdone based on simulations in Simulink/Simscape, containing verified models mimicking real hardware, with several input cases. Based on simulation results, the combined LQR and PI method was deemed promisingto replace the current cascaded PI control architecture. The open end of the reportallows for further implementation and evaluation on the real platform to confirm theresults obtaiend through simulations.
19

Metodologia de projeto de atuador eletromagnético linear para sistemas de suspensão semiativa e ativa

Eckert, Paulo Roberto January 2016 (has links)
Este trabalho apresenta uma metodologia de projeto de atuadores eletromagnéticos lineares inovadora para aplicação em sistemas de suspensão semiativa e ativa. A metodologia, apresentada na forma de fluxograma, define critérios para determinar os requisitos de força e curso que um atuador deve desenvolver considerando um sistema mecânico vibratório com um grau de liberdade com excitação harmônica de base quando o método de controle skyhook é aplicado. Um atuador eletromagnético linear de bobina móvel com duplo arranjo de quase-Halbach que apresenta elevada densidade de força, reduzida massa móvel, ausência de força de relutância e baixa ondulação de força é definido como estudo de caso. Um modelo numérico parametrizado em elementos finitos do comportamento eletromagnético de um passo polar do dispositivo é criado e analisado, considerando restrições dimensionais, com os objetivos de projeto definidos como: elevada densidade de força e reduzida ondulação de força com acionamento brushless CA. Com base no modelo de um passo polar do dispositivo, define-se o volume ativo que o mesmo deve apresentar e, a partir deste, todas as dimensões são definidas de forma a atender os requisitos de projeto. Uma vez definidas as dimensões do atuador com base no modelo eletromagnético, realiza-se a modelagem térmica numérica que permite avaliar qual a máxima densidade de corrente elétrica aplicável de forma que a temperatura, estipulada como máxima, nos enrolamentos não seja excedida. Ainda, a distribuição térmica permite determinar a temperatura de operação dos ímãs permanentes que têm curva de operação dependente da temperatura. A partir dos resultados da simulação térmica e do modelo eletromagnético para um passo polar, realizou-se o acoplamento eletromagnético-térmico por meio da correção das propriedades dos ímãs permanentes e aplicando uma densidade de corrente eficaz dependente das dimensões do modelo parametrizado. O modelo acoplado é simulado e analisado, de modo que as dimensões finais do atuador podem ser obtidas atendendo aos mesmos objetivos de projeto previamente mencionados, respeitando os limites de operação térmica. Adicionalmente, são apresentados modelos analíticos do comportamento eletromagnético e térmico do atuador que podem servir de base para implementação da metodologia proposta, se esta for baseada em modelos analíticos, e podem futuramente ser empregados para a aplicação de otimização matemática do dispositivo. Por fim, um protótipo do dispositivo é construído de forma a validar a metodologia proposta. Com este protótipo são realizados ensaios de densidade de fluxo magnético no entreferro, tensão induzida a vazio, força estática e ensaio dinâmicos com o dispositivo instalado em uma bancada de testes de vibrações controladas desenvolvida durante o projeto. Os resultados mostram a eficácia da metodologia proposta, uma vez que os resultados experimentais mostraram boa concordância com os resultados esperados. / This work presents an innovative linear electromagnetic actuator design methodology for application in semi-active and active suspension systems. The methodology, synthesized in a flowchart, sets criteria to determine requirements such as axial force and stroke that an actuator should develop considering a vibration system with one degree of freedom with harmonic base excitation when the skyhook control method is applied. A linear moving-coil electromagnetic actuator with dual quasi-Halbach arrays of permanent magnets that presents high force density, low moving-mass, no reluctance force and low force ripple is defined as a case study. A finite element numerical parameterized model that describes the electromagnetic behavior of one pole pitch of the device is created and analyzed, considering dimensional constraints, with the design objectives defined as: high force density and low ripple of force with brushless AC drive. Based on the model of one pole pitch of the device the active volume and all dimensions are defined in order to meet the design requirements. Once the actuator dimensions are defined, based on the electromagnetic model, a numerical thermal model was constructed, which allows to evaluate the maximum applicable electric current density so that the maximum temperature at the windings is not exceeded. Furthermore, the thermal distribution gives the operating temperature of the permanent magnets, which present performance highly dependent on temperature. With the results of the thermal simulation, the electromagnetic-thermal coupling is performed by correcting permanent magnet properties and by applying a parametric-dependent effective current density. The coupled model is simulated and analyzed so that the final dimensions of the actuator can be obtained with the same design objectives previously mentioned, while respecting thermal operating limits. In addition, the work presents analytical models of the electromagnetic and thermal behavior of the actuator that can be the basis for implementation of the proposed methodology, if it is based on analytical models, and can further be used for the application of mathematical optimization of the device. Finally, a prototype was built to validate the proposed method. Measurements were carried out to assess magnetic flux density in the air gap, open-circuit induced voltage, static force and dynamic tests with the device installed in a test bench that was developed during this work. The results show the effectiveness of the proposed method since experimental results have shown good agreement with the expected results.
20

Metodologia de projeto de atuador eletromagnético linear para sistemas de suspensão semiativa e ativa

Eckert, Paulo Roberto January 2016 (has links)
Este trabalho apresenta uma metodologia de projeto de atuadores eletromagnéticos lineares inovadora para aplicação em sistemas de suspensão semiativa e ativa. A metodologia, apresentada na forma de fluxograma, define critérios para determinar os requisitos de força e curso que um atuador deve desenvolver considerando um sistema mecânico vibratório com um grau de liberdade com excitação harmônica de base quando o método de controle skyhook é aplicado. Um atuador eletromagnético linear de bobina móvel com duplo arranjo de quase-Halbach que apresenta elevada densidade de força, reduzida massa móvel, ausência de força de relutância e baixa ondulação de força é definido como estudo de caso. Um modelo numérico parametrizado em elementos finitos do comportamento eletromagnético de um passo polar do dispositivo é criado e analisado, considerando restrições dimensionais, com os objetivos de projeto definidos como: elevada densidade de força e reduzida ondulação de força com acionamento brushless CA. Com base no modelo de um passo polar do dispositivo, define-se o volume ativo que o mesmo deve apresentar e, a partir deste, todas as dimensões são definidas de forma a atender os requisitos de projeto. Uma vez definidas as dimensões do atuador com base no modelo eletromagnético, realiza-se a modelagem térmica numérica que permite avaliar qual a máxima densidade de corrente elétrica aplicável de forma que a temperatura, estipulada como máxima, nos enrolamentos não seja excedida. Ainda, a distribuição térmica permite determinar a temperatura de operação dos ímãs permanentes que têm curva de operação dependente da temperatura. A partir dos resultados da simulação térmica e do modelo eletromagnético para um passo polar, realizou-se o acoplamento eletromagnético-térmico por meio da correção das propriedades dos ímãs permanentes e aplicando uma densidade de corrente eficaz dependente das dimensões do modelo parametrizado. O modelo acoplado é simulado e analisado, de modo que as dimensões finais do atuador podem ser obtidas atendendo aos mesmos objetivos de projeto previamente mencionados, respeitando os limites de operação térmica. Adicionalmente, são apresentados modelos analíticos do comportamento eletromagnético e térmico do atuador que podem servir de base para implementação da metodologia proposta, se esta for baseada em modelos analíticos, e podem futuramente ser empregados para a aplicação de otimização matemática do dispositivo. Por fim, um protótipo do dispositivo é construído de forma a validar a metodologia proposta. Com este protótipo são realizados ensaios de densidade de fluxo magnético no entreferro, tensão induzida a vazio, força estática e ensaio dinâmicos com o dispositivo instalado em uma bancada de testes de vibrações controladas desenvolvida durante o projeto. Os resultados mostram a eficácia da metodologia proposta, uma vez que os resultados experimentais mostraram boa concordância com os resultados esperados. / This work presents an innovative linear electromagnetic actuator design methodology for application in semi-active and active suspension systems. The methodology, synthesized in a flowchart, sets criteria to determine requirements such as axial force and stroke that an actuator should develop considering a vibration system with one degree of freedom with harmonic base excitation when the skyhook control method is applied. A linear moving-coil electromagnetic actuator with dual quasi-Halbach arrays of permanent magnets that presents high force density, low moving-mass, no reluctance force and low force ripple is defined as a case study. A finite element numerical parameterized model that describes the electromagnetic behavior of one pole pitch of the device is created and analyzed, considering dimensional constraints, with the design objectives defined as: high force density and low ripple of force with brushless AC drive. Based on the model of one pole pitch of the device the active volume and all dimensions are defined in order to meet the design requirements. Once the actuator dimensions are defined, based on the electromagnetic model, a numerical thermal model was constructed, which allows to evaluate the maximum applicable electric current density so that the maximum temperature at the windings is not exceeded. Furthermore, the thermal distribution gives the operating temperature of the permanent magnets, which present performance highly dependent on temperature. With the results of the thermal simulation, the electromagnetic-thermal coupling is performed by correcting permanent magnet properties and by applying a parametric-dependent effective current density. The coupled model is simulated and analyzed so that the final dimensions of the actuator can be obtained with the same design objectives previously mentioned, while respecting thermal operating limits. In addition, the work presents analytical models of the electromagnetic and thermal behavior of the actuator that can be the basis for implementation of the proposed methodology, if it is based on analytical models, and can further be used for the application of mathematical optimization of the device. Finally, a prototype was built to validate the proposed method. Measurements were carried out to assess magnetic flux density in the air gap, open-circuit induced voltage, static force and dynamic tests with the device installed in a test bench that was developed during this work. The results show the effectiveness of the proposed method since experimental results have shown good agreement with the expected results.

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