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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.
111

Optimalizace parametrů asynchronního motoru / Optimalization of Parameters of Asynchronous Motor

Hussain Mohammed, Mohammed January 2012 (has links)
The doctoral thesis is divided into two main parts.The first part deals with optimalization of the equivalent circuit parameters of induction motor for calculation steady state characteristics:- - of the equivalent circuit parameters of induction motor with normal slots. - of the equivalent circuit parameters of induction motor with deep slots. -simulation of selected chracteristics and comparison with measured values. The second part of this work deals with optimalization of the equivalent circuit parameters of induction motor for calculation of dynamic characteristics of induction motor –simulation of selected chracteristics and comparison with measured values. The optimalization is based on mutual comparison of measured and calculated torque-speed and current-speed characteristics.
112

Heterogeneous MBS forwarder modeling and co-simulation / Metodik för samsimulering av pendelarmsskotare

Yang, Liunan January 2015 (has links)
The forwarder acts as an important role in mechanized Cut-to-Length timber harvesting system. But the majority of forwarder products on the market are not suspended or simply suspended by bogies which limit the riding quality of forwarder and result in soil damage due to large tireground interaction force. The Forestry Research Institute of Sweden is developing an active controlled pendulum arm suspension system actuated by hydraulic cylinders on the forwarder prototype named XT28. The aim of this active suspension system is to compensate the inherent shortcomings of the current suspension solutions. The thesis project focuses on implementing a heterogeneous simulation methodology which integrates the Multi-Body System model of XT28 built in MSC ADAMS/View with active suspension control model developed in MATLAB/Simulink. Thus, the co-simulation process is visualized in ADAMS/View. The results show that the active controlled pendulum arm suspension could improve the riding quality in a large extend and reduce the force between tire and ground at the same time. The cosimulation between ADAMS and Simulink is proved as a feasible and efficient approach to study the active control system for pendulum arm suspension on XT28 forwarder. / Skotaren har tillsammans med skördaren en central roll i den fullt mekaniserade kortvirkesmetoden för skogsavverkning. Majoriteten av dagens skotare på marknaden har sex eller åtta hjul, som är monterade parvis på boggilådor. Det innebär att de saknar chassidämpning, vilket begränsar operatörens komfort och orsakar även stora markskador på mjuk mark. Skogforsk koordinerar realiseringen av en fullskaleprototyp, som går under arbetsnamnet XT28, med sex hjul monterade på varsin pendelarm. Pendelarmarna har varsin hydraulcylinder som möjliggör aktiv helmaskinsdämpning. Detta examensarbete är inriktat på att skapa, demonstrera och verifiera en heterogen simuleringsmetodik, som integrerar och möjliggör samsimulering av en dynamisk mekanikmodell utvecklad i MSC Adams/View med en reglermodell för aktiv styrning av pendelarmarna. Reglermodellen har utvecklats i MATLAB / Simulink. Simuleringsresultaten, som visualiseras i Adams-miljön, visar att den aktiva pendelarmregleringen skulle kunna förbättra åkkomforten signifikant, och också kraftigt markkontaktkrafterna. Det visas att samsimulering mellan ADAMS och Simulink är en effektiv metod för att verifiera prestandan hos aktiva reglersystem för pendelarmsfjädring på prototypskotaren XT28.
113

Flight Simulator Integration in Test Rig / Integrering av flygsimulator med testrigg

Sikström, Tilda January 2021 (has links)
Integrating hardware in simulations is useful in many applications, for example to investigate the performance of an aircraft with the non-ideal response of a physical system. This thesis aims to integrate a flight simulator, JSBSim, with an actuator test rig, FLUMES Iron Bird. Two aircraft models were replicated in JSBSim, a passenger aircraft and a delta winged fighter aircraft. The models were analyzed to ensure proper flight performance in regards to stability. The stability analysis was conducted from both the aerodynamic data provided as well as through state-space theory. The fighter aircraft was unstable in the subsonic region and in need of a flight control system to fly properly. The integration with the test rig was implemented using Simulink S-functions and a real-time target computer ensuring synchronous communication with the actuator test rig. The passenger aircraft was successfully integrated and tested with the actuator test rig. / Att integrera hårdvara med simuleringar är behjälpligt i många situationer, exempelvis för att undersöka hur ett flygplan reagerar med ett icke-idealt svar från ett fysiskt system. I det här examensarbetet är målet att utveckla ett gränssnitt mellan en flygsimulator, JSBSim, och en aktuatortestrigg, FLUMES Iron Bird. Två flygplansmodeller skapades i JSBSim, ett passagerarflygplan och ett stridsflygplan. För att vara säker på flygplansmodellernas prestanda analyserades modellerna med avseende på stabilitet. Stabilitetsanalysen beräknades både utifrån aerodynamisk data såväl som utifrån tillståndsanalys, där både statisk och dynamisks stabilitet inkluderades. Stridsflyget var instabilt i underljudsfart och behöver därför ett styrsystem för att vara flygbart. Integreringen med testriggen utfördes i Simulink med hjälp av S-funktioner och en realtidsdator för att garantera synkronisk kommunikation mellan flygsimulatorn och testriggen. Det modellerade passagerarflygplanet kunde integreras och testas med testriggen.
114

The Effect of Simulink Block Kalman Filters in a CubeSat ADCS / Effekten av Simulink-baserade Kalmanfilter i ett attitydsystem för en nanosatellit

Larsson, Jesper January 2020 (has links)
The purpose of this paper was to implement Kalman filtering in the form of pre-existing Simulink blocks into a CubeSat attitude determination and control system simulation and to evaluate their performance. In recent versions of Simulink, the block library has been expanded, providing a new level of abstraction for simulation engineers. The capabilities of such library filter blocks have previously not been explored for space applications and could offer a faster and more simplified filter integration process. Three types of filter implementations have been realized, being classic Kalman filter, extended Kalman filter and unscented Kalman filter. These have been applied to the outputs of the coarse Sun sensor and Earth horizon sensor, as well as to the simulation attitude estimate. State propagation functions have been defined in the form of constant and linear approximations in addition to state propagation following the same structure as the simulation reference truth. Filter efficiency was evaluated using control error, pointing knowledge, pointing accuracy and variance as performance measures. Furthermore, interventions were introduced in the form of sensor data loss and solar panel deployment. The Kalman filter blocks were successfully integrated into the simulation. Performance measures revealed that constant state transition functions provided the best performance in most cases, exceptions being the extended Kalman filter and unscented Kalman filter of the attitude estimate application. Here, the true state propagation instead outperformed the other filters. Signal data loss showed that the true state propagation was the only one that could accurately predict the attitude state in a scenario when sensors fail to provide data. Solar panel deployment could not be utilized to evaluate the filter performance as the filter implementation did not support prediction of a dynamic attitude state. Results suggest that the pre-existing Simulink filter blocks can provide an easier alternative to defining filters from scratch. However, great care needs to be taken when tuning block parameters and constructing state transition functions to assure proper behavior. / Syftet med arbetet har varit att implementera Kalmanfilter i formen av fördefinierade Simulink-block i en simulering av ett system för attitydbestämning och styrning för en CubeSat, och utvärdera prestandan. I nyare versioner av Simulink har blockbiblioteken utökats, vilket har introducerat nya nivåer av abstraktion för simuleringsingenjörer. Möjligheterna hos filterblock i sådana bibliotek har ännu inte utforskats för rymdtekniska tillämpningar, och skulle kunna leda till snabbare och enklare integrering av filter. Tre typer av filterimplementationer har genomförts: klassiska Kalmanfilter, utökat Kalmanfilter och oparfymerat Kalmanfilter. Dessa har applicerats till utdata från solsensor och jordhorisontsensor, samt till simuleringens uppskattade attityd. Funktioner för tillståndspropagering har definierats i formen av konstanta och linjära approximationer tillsammans med den verkliga tillståndspropageringen, som har samma struktur som simuleringens sanna referensvärde. Effektiviteten hos filtren har utvärderats genom kontrollfel, riktningskunskap, riktningsnoggrannhet och varians som prestandamått. Vidare har interventioner introducerats i form av förlust av sensordata och utfällning av solpaneler. Kalmanfilterblocken integrerades med framgång i simuleringen. Prestandamåtten visade att de konstanta funktionerna för tillståndspropagering gav bäst prestanda i de flesta fallen, förutom i fallet av utökat Kalmanfilter och oparfymerat Kalmanfilter i appliceringen på den uppskattade attityden. I det sistnämnda fallet var det den verkliga tillståndspropageringen som presterade bättre än de andra filtren. Förlust av signaldata visade att den verkliga tillståndspropageringen är den enda som med säkerhet kan förutsäga utvecklingen av attityden i ett läge där sensorerna inte längre levererar data. Utfällningen av solpanelerna kunde inte utnyttjas för att utvärdera prestandan hos filtren, då implementeringen av filtren inte kan förutsäga utvecklingen av ett dynamiskt attitydtillstånd. Resultaten antyder att fördefinierade Simulink-filter kan erbjuda ett enklare alternativ till att definiera filter helt från början. Dock så krävs noga omsorg vid inställning av blockparametrar och vid konstruktion av funktioner för tillståndspropagering för att säkerställa korrekt beteende
115

Tracking maximum power point of photovoltaic modules under non-uniform solar irradiance / Fotovoltinio modulio didžiausios galios taško nustatymas veikiant netiesinei saulės apšvietai

Rimkus, Lukas 16 June 2014 (has links)
This master work was focused on modelling and investigation of a photovoltaic module which operates in non-uniform solar irradiance and temperature changes which is typical to Lithuanian climate. 60 polycrystalline silicon cells were used to model photovoltaic module. Matlab®/Simulink® was used for modelling and calculating the whole system. To generate solar insolation curve, the latitude, longitude of the geographic place and a number of days in a year have to be selected. Buck-boost DC-DC converter and hill-climbing maximum power point tracking algorithm was used to produce maximum power point of the photovoltaic module. Modeled system has reached 93.95 % of maximum power from the photovoltaic module. Structure: introduction, review of maximum power point algorithms, system modelling, research results, conclusions, references. The thesis consists of: 60 pages, 41 figures, 16 tables, 37 references. Appendixes included. / Šiame magistro darbe buvo sumodeliuotas ir ištirtas fotovoltinio modulio veikimas, veikiant Lietuvoje būdingiems saulės apšvietos ir temperatūros pokyčiams. Fotovoltinį modulį sudaro 60 polikristalinių silicio celių sujungtų nuosekliai sistema. Modeliavimui ir skaičiavimas atlikti buvo naudojamas Matlab®/Simulink® programinės įrangos paketas. Įvedus vietos ilgumą, platumą ir pasirinkus metų dieną sugeneruojama saulės apšvietos kreivė paros bėgyje. Išgauti maksimalią galią iš fotovoltinio elemento buvo pasirinkta „buck-boost“ tipo įtampos keitiklis ir „Kalno-kilimo“ didžiausios galios taško algoritmas. Naudojant pasirinkto tipo įtampos keitiklį ir algoritmą galima pasiekti iki 93,95 % maksimalios galios. Darbą sudaro 7 dalys: įvadas, maksimalios galios algoritmų literatūros apžvalga, sistemos modeliavimas, maksimalios galios algoritmo sudarymas, rezultatai, išvados, literatūros sąrašas. Darbo apimtis 60 puslapiai, 2 priedai, 41 iliustracijų 16 lentelių, 37 bibliografiniai šaltiniai.
116

Modélisation et réalisation de la couche physique du système de communication numérique sans fil, WiMax, sur du matériel reconfigurable

Ezzeddine, Mazen January 2009 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
117

Contribution à l'intégration de centrales inertielles : outils d'aide à la conception et à l'optimisation

Arrijuria, Olivier 24 November 2008 (has links)
Le travail présenté dans ce mémoire concerne la réalisation d’un microsystème intégrant une centrale inertielle permettant la détection de mouvements. Le microsystème étudié est composé d’un accéléromètre capacitif associé à son électronique de traitement. L’accéléromètre capacitif a conduit à l’élaboration d’un outil logiciel afin de le pré-dimensionner. Ce pré-dimensionnement a été effectué en fonction des spécifications de l’application et de la technologie de fabrication. Cet outil intègre des modèles fluidiques et électrostatiques en vue de calculer des paramètres du modèle de l’accéléromètre pour une simulation système. L’électronique de traitement de l’accéléromètre capacitif a été conçue autour d’un convertisseur ”Sigma-Delta”. L’architecture ”Sigma-Delta” a nécessité des modifications pour pouvoir être adaptée au capteur. Nous avons alors développé, sous ”Matlab-Simulink”, une bibliothèque de composants permettant d’ajuster le fonctionnement du convertisseur. Une fois l’architecture optimisée et les caractéristiques des composants connues, la conception de l’architecture ”Sigma-Delta” est ainsi réalisable sous le logiciel CADENCE. / The aim of this thesis is the realisation of microsystem for movements detection. This microsystem is composed of capacitive accelerometers and of their electronics. The conception of capacitive accelerometers has induced developement of a software for the first dimensionnement of sensors. This software computes parameters of capacitive accelerometers thanks to electrostatic models, flow models, specifications of application and fabrication process. The electronics of capacitive accelerometer is a ”Sigma-Delta” convertor. The adaptation of convertor leads to developement of components libraries for ”Matlab-Simulink”. The simulation systems allows to fit parametres convertor for the application. After that,the conception of convertor under CADENCE software is then possible.
118

Simulação, projeto e teste de um gerador a relutância chaveado trifásico 6 x 4 / Simulation, design and test of a three-phase switched reluctance generator 6 x 4

Coelho, Alexandre 13 June 2011 (has links)
A máquina a relutância chaveada ganhou considerável atenção da comunidade científica com o desenvolvimento da eletrônica de potência e é considerada hoje uma máquina elétrica promissora para algumas aplicações, principalmente aquelas onde há a necessidade de operação em velocidade variável seja como motor ou como gerador. Sendo assim, este trabalho apresenta a dinâmica de funcionamento de uma máquina a relutância chaveada, com uma estrutura 6 x 4, ou seja contendo seis pólos no estator e quatro pólos no rotor, operando no modo gerador. A dinâmica de funcionamento é apresentada e comparada através de resultados experimentais e resultados simulados em ambiente Matlab/Simulink. Os resultados experimentais foram possíveis devido a construção de um protótipo da máquina e da montagem de uma bancada de testes. O projeto desenvolvido para construção do protótipo e da bancada de testes é apresentado neste trabalho. / Switched reluctance machines have received considerable attention from the scientific community due to advances in power electronics, and now is considered a promising electric machine for some applications, especially where variable speed operations are needed for motor or generator. Therefore, this work presents the dynamics of a switched reluctance machine, operating as a generator, with 6 x 4 structure, i.e., six stator poles and four poles in the rotor. Experimental results, which were obtained from a machine prototype installed on a test bench, were compared with Matlab/Simulink computational simulations. The designing aspects for the prototype construction are also discussed in this work.
119

Análise e simulação do sistema de comunicação WiMAX (802.16-2004) em diferentes configurações e condições de operação, com o uso do aplicativo MATLAB - SIMULINK. / Analysis and simulation of WiMAX (802.16-2004) communication system in different configurations and operating conditions, using MATLAB SIMULINK application.

Araujo, Carlos Eduardo Rodrigues de 22 June 2010 (has links)
Esta dissertação apresenta o desempenho da camada física de um sistema de comunicação sem fio baseado no padrão IEEE 802.16-2004 (WiMAX-fixo), em diferentes configurações e condições de operação. Para este propósito, foi elaborado um simulador da camada física WirelessMAN-OFDM implementado com o uso do aplicativo MATLAB® (versão R2008b) e de sua extensão SIMULINK®. Foram modeladas sete formas distintas para o canal de propagação, associando três tipos básicos de canal (sem desvanecimento, com desvanecimento seletivo e não seletivo em freqüência), duas configurações de mobilidade (sem mobilidade e mobilidade parcial) e duas condições para o ambiente de propagação (externo e interno). A propagação com desvanecimentos causados por multi-percursos empregou as especificações do ITU (International Telecommunications Union), fornecendo uma representação satisfatória de ambientes urbanos macro-celulares e possibilitando a comparação com outros sistemas de comunicação sem fio. Por meio da análise comparativa da taxa de erro de bit e da taxa de transferência efetiva de dados, estudou-se o desempenho dos esquemas de codificação e modulação especificados e a ação do controle adaptativo. O comportamento do WiMAX-fixo quando sujeito a perdas de propagação por multi-percursos e a condições de utilização caracterizadas por aplicações fixas e, adicionalmente, para aplicações parcialmente móveis, foi também avaliado. Assim, essa pesquisa permitiu uma visão complementar do padrão o que possibilitou a determinação de valores customizados para os níveis de SNR empregados no controle adaptativo, além da determinação das capacidades obteníveis nas condições de mobilidade parcial. / This thesis presents the physical layer performance of a wireless communications system based on the IEEE 802.16-2004 standard (fixed-WiMAX), in different configurations and operation conditions. For this purpose, a simulator of WirelessMAN-OFDM physical layer was designed and implemented using MATLAB® application (version R2008b) and its extension SIMULINK®. Seven different profiles for the propagation channel have been modeled, involving three basic types of channel (without fading, frequency-flat fading and frequency selective-fading), two mobility settings (without mobility and partial mobility) and two propagation environment conditions (outdoor and indoor). ITU (International Telecommunications Union) specifications were used for multipath fading propagation, providing a satisfactory representation of urban macro-cellular environments and allowing comparison with other wireless communication systems. Through comparative analysis of bit error rate and throughput, the performance of the specified modulation and coding schemes and the action of adaptive control were evaluated. The behavior of the fixed-WiMAX when subjected to a propagation environment with multipath fading and utilization conditions characterized by stationary applications and by partially mobile applications was also exploited. This research allowed a complementary vision of the standard which enabled the determination of customized values for the SNR levels employed in adaptive control, and furthermore the determination of the obtainable capacity under conditions of partial mobility.
120

Análise do desempenho na frenagem de um cavalo mecânico e semi-reboque com suspensão mecânica e sistema ABS mediante simulação em Matlab/Simulink / Analysis of the performance of tractor-semitrailer vehicles with mechanical suspension and ABS system through simulation in Matlab/Simulink

Viveros, Henry Pizarro 29 October 2010 (has links)
A presente dissertação visa analisar o desempenho na frenagem de um cavalo mecânico e semi-reboque que utiliza o sistema ABS (Antilock Braking System). Foi desenvolvido um modelo virtual de simulação utilizando a técnica dos sistemas multicorpos (Multibody System) do SimMechanics, um toolbox do Matlab/Simulink. No modelo virtual do veículo combinado foram considerados os parâmetros geométricos e mecânicos dos chassis, das suspensões, dos freios, contato pneu-pavimento e a válvula sensível à carga. São obtidas as forças normais dinâmicas no contato pneu pavimento quando o veículo está desacelerando de 20m/s até a parada completa, estas forças normais dinâmicas são entradas de uma sub-rotina em Simulink onde são calculadas as forças de frenagem, quando os freios tipo S carne são acionados. São realizadas simulações de frenagens em linha reta em pistas de média aderência (0,4) e alta aderência (0,8). As eficiências são obtidas quando o cavalo mecânico utiliza a configuração fixa de ABS tipo 6S/6M e o semi-reboque utiliza diversas configurações de ABS tipos: 2S/1M (e 4,6); 2S/2M (e 4,6); 4S/2M (e4); 4S/2M (e6); 4S/3M (e4); 4S/3M (e6); 4S/4M (e4) e 4S/4M (e6) e 6S/6M. O veículo é simulado também freando sem sistema ABS e a eficiência resultante comparada com as obtidas anteriormente. Os resultados são apresentados em figuras que mostram as forças normais dinâmicas ao pavimento, as aderências utilizadas pelos pneus e as eficiências atingidas pelas diversas configurações de ABS utilizadas no semi-reboque. Conclui-se de forma geral que configurações de ABS com mais sensores e válvulas moduladoras produzem uma eficiência maior e que a utilização de qualquer configuração de ABS como sistema complementar do sistema de freios de serviço, aumenta a eficiência de frenagem que é sempre superior ao do veículo sem sistema ABS. Esses resultados ajudam na preservação da dirigibilidade e estabilidade do veículo combinado, contribuindo assim na prevenção de acidentes de trânsito em situações de emergência. / This dissertation reports on the development of a simulation model for the analysis of the braking performance of tractor-semitrailer vehicles that use the ABS (Antilock Braking System). The model was developed using the virtual simulation technique of multibody systems with SimMechanics, a toolbox of Matlab/Simulink. In this simulation model the mechanical and geometrical parameters of the chassis, suspensions, brakes, adhesion coefficient, and load sensing valve were considered. When the vehicle is decelerating, the normal forces between the tire and road surface are obtained by the virtual model. These forces are the input of a subroutine in which the braking forces are calculated when the S Came brakes are triggered. Simulations of braking on straight line in road were made for average adhesion coefficient (0.4) and high adhesion coefficient (0.8). Efficiencies were obtained when the tractor used fixed ABS configuration of a 6S/6M type, and the semitrailer used the ABS type: 2S/lM (and 4.6); 2S/2M (and 4.6); 4S/2M (e4); 4S/2M (e6); 4S/3M (e4); 4S/3M (e6); 4S/4M (e4) and 4S/4M (e6) and 6S/6M. The results are presented in figures which show, the normal dynamic forces between tire and road, adhesions used by the tires and the efficiencies achieved by different ABS configurations installed in the semi-trailer. It is possible to conclude that in general ABS configurations with more sensors and modulating valves produce higher efficiency and the use of any configuration as a complementary system of the ABS brake system service increases the braking efficiency, which is always higher than that of a vehicle without ABS. The results help preserving the vehicle stability and maneuverability, preventing road accidents in emergency situations.

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