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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.
21

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

Henry Pizarro Viveros 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.
22

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

Alexandre Coelho 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.
23

Diagnostika stroje založena na modelech / Machine diagnostics based on models

Kapusta, Juraj January 2021 (has links)
The main idea is focused on the diagnostics of a specific hydraulic system, i.e. sensing the physical quantities of the hydraulic circuit with a tank and a centrifugal pump driven by an asynchronous motor. It is a system of pipes connected to the pump, where due to its work it creates a water flow and a pressure increase. In practice, this issue is also addressed in the energy and nuclear industries. Primary circuits in some cases cannot be designed or modified to be able measure locally the pressure value. It is necessary to measure this quantity indirectly - from the motor currents. The main idea of the work is to diagnose the system by an indirect method - specifically to detect the state of the hydraulic circuit (pressure, flow) from the values that we are able to measure and detect damage in advance. In the second part of the thesis is the application of the parts of a specific hydraulic system in the simulation environment MATLAB Simulink. The model of the hydraulic circuit contains mathematical-physical relations that simulate the course of the mentioned experiment. The results of the simulation are compared with the results of the experiment. The model also investigates the simulation of a fault condition, when we supply pressure pulsations to the hydraulic circuit. It is these changes in the hydraulic part that affect the characteristics of the pump and the asynchronous motor, so we are able to diagnose this system.
24

Dvouosý pohon s EC motory Maxon / Two-axle drive with EC Maxon motors

Nevole, Josef January 2008 (has links)
The content of this master´s thesis is compact complex piece of knowledge from semestral projects 1 and 2. These semestral projects deal with analysis two-axle servo - drive, most common methods design regulators, design regulators and their simulation. Further was analysed quality regulation integral criteria, whereupon connect simulation circular and linear interpolation. Simulation was effected by force of Matlab Simulink. In one’s chapter was tested effect feedforwards to regulation. In closing parts is acquaint with control section position EPOS, and programming environment Open PCS company Maxon. In this environment was biaxial drive with EC motors Maxon and control section EPOS P 24/5 programmed. Results was discusseds with simulation.
25

Využití virtuální reality v dynamice vozidel / The Use of Virtual Reality in Vehicle Dynamics

Mach, Břetislav January 2009 (has links)
The aim of this master’s thesis is to use virtual reality to analyze and display the vehicle and the quantities characterizing the dynamic properties of the vehicle. The simulation software tools are used Matlab/Simulink and Virtual Reality Toolbox. The measured or calculated data will the input for the simulation. The dissertation is aimed to create a virtual scene and a dynamic system for the movement of file.
26

Analysis of Different Switching Patterns to Minimize Losses in a Six- Phase Drive for Marine Application

Frei, Yanick Patrick January 2021 (has links)
Multiphase machines have gained a lot of popularity during the recent years, as they offer certain benefits over their three- phase counterparts. This work investigates the losses of a six- phase drive system for a marine application when supplied by four different switching patterns (also referred to as modulators). Using MATLAB/SIMULINK, a model was built for the machine featuring three independent frames and a nonlinear, cross coupled flux relation. It has been connected with the corresponding modulator models, where two carrier based modulators have been developed as well as two space vector modulators. The simulation data was then fed into the loss model to calculate the corresponding losses in both machine and converter. This work shows that control of the harmonics – mainly the fifth – is beneficial to reduce losses, mainly in the machine. Without control, harmonic currents cause unnecessary losses. As none of the investigated modulators strictly dominates all others, this work suggests a combination of the two carrier based methods to create a simple and robust modulator, which offers both a high voltage magnitude and control over the fifth harmonic. / Flerfasmaskiner har blivit mycket populära under dem sestate åren, då de erbjuder specifika fördelar jämfört med trefasmaskiner. Denna avhandling undersöker förlusterna för en sexfasmakin för en maritim applikation när den är kopplad med fyra olika modulatorer. En modell för maskinen byggdes i MATLAB/SIMULINK som innehåller tre oberoende nivåer samt en ickelinjär och korskopplad flödesrelation. Maskinmodellen har blivit kopplad till de fyra korresponderande modulatormodellerna, där två är baserade på bärvågor samt de resterande två är baserade på rymdvektormodulation. Data erhållen från den simulerade maskinmodellen var sedan inmatad in i en förlustmodell för att beräkna de korresponderande förlusterna för både maskinen och omvandlare. Denna avhandling visar att kontroll av övertoner – i huvudsak den femte övertonen – är fördelaktigt för att minimera förluster, främst i maskinen. Eftersom ingen av de modulatorerna som undersöktes i avhandlingen är bäst i alla funktioner, föreslår avhandlingen en kombination av de två bärvågsberoende metoderna. Den nya modulatorn antas vara bra både i kontrol över den femte övertonen men också erbjuda en hög spänning tack vare hamonisk injektion. Dessutom är modulatorn enkelt och robust, eftersom det är bärvågberoende.
27

Kvantifiering av föroreningstillskott från dagvatten inom skyddsområdet för Göta Älv : en simuleringsstudie med modellen SEWSYS / Quantification of Stormwater Pollutant Contribution within the Protection Area of River Göta Älv  : a simulation Study with the Model SEWSYS

Eliasson, Mikaela January 2004 (has links)
<p>The river Göta Älv reaches between Vänern and Gothenburg and is the main raw water source for Gothenburg that supplies about 700 000 people with water. To protect and maintain a high water quality, continuously samples and water analyses are made throughout the river. In 1998 a protection area was founded between surte and Lärjeholm where the raw water intake is. This was made to increase the awareness of the importance to protect the water. However, there is a lot of contribution of untreated stormwater to Göta Älv within the protection area.</p><p>Göteborg Water and Sewage Works commissioned this thesis where two areas, Tagene industrial area and Kärra residential area, with untreated stormwater outlets within the protection area are studied. The areas have been divided according to surface composition with different rates of pollutant contribution. Then the stormwater flow and the contribution of pollutants was simulated with the model SEWSYS. The future aim is that the model will be able to simulate the contribution of pollutants for a variety of rains, for the whole protection area.</p><p>SEWSYS (Sewer System) is built in MATLAB/Simulink and consists of three modules, a stormwater module, a sanitary wastewater module and a treatment plant module. This project only includes the stormwater module. The model simulates the stormwater flow and the pollutants total phosphorous, total nitrogen, copper, zinc, lead, cadmium and polycyclic aromatic hydrocarbons (PAH). Samples and analysis for the two areas has been carried out for another thesis work during the same period. The results from those analyses have been used for the model settings for the areas.</p><p>Simulations have been performed to adjust the model and evaluate its ability to describe the stormwater flow and the pollutant contribution within the areas. The amount of stormwater and the runoff are well simulated by the model. However, the measured and analysed data has not been enough to get reliable simulations over the pollutant contribution. Further development of the model is necessary. Generally the model simulates lower values compared to measured values, especially in the industrial area. For a more general understanding over how SEWSYS works for the two areas, simulations were carried out on a yearly basis. Those simulations have been compared with general data for stormwater pollutants. Even though the results from the simulations have shown lower values than the measured values, the model shows clearly that the contribution of pollutants from the industrial site is greater than the contribution from the residential site.</p> / <p>Göta Älv sträcker sig från Vänern ner till Göteborg och är Göteborgs huvudsakliga råvattentäkt som försörjer ca 700 000 personer med vatten dagligen. För att säkra råvattenkvaliteten görs kontinuerliga provtagningar utmed älven. Dessutom beslutade Länsstyrelsen 1998 om ett skyddsområde med skyddsföreskrifter för avrinningsområdet mellan Surte i norr till vattenintaget vid Lärjeholm i söder. Ett mål med skyddsområdet är att det ska öka medvetenheten hos boende och de som är verksamma inom området om behovet att värna om vårt vatten. Dock leds det på flera ställen ut orenat dagvatten till älven inom skyddsområdet.</p><p>Examensarbetet är ett uppdrag av Göteborgs Va-verk där två områden med orenade dagvattenutsläpp till Göta Älv studeras, Tagene industriområde samt Kärra bostadsområde. Dessa områden har karterats och dagvattenflödet samt föroreningsbelastningen från dagvattnet har simulerats med modellen SEWSYS. Målet på lång sikt är att modellen ska kunna användas för att simulera föroreningsbelastningen vid olika regn för hela skyddsområdet.</p><p>Modellen SEWSYS (Sewer System) är uppbyggd i MATLAB/Simulink och bygger på tre moduler, en dagvattenmodul, en spillvattenmodul och en reningsverksmodul. För detta projekt har endast delen för dagvatten använts. Modellen simulerar dagvattenflödet och behandlar föroreningarna totalfosfor, totalkväve, koppar, zink, bly, kadmium samt polycykliska aromatiska kolväten (PAH). I ett examensarbete parallellt med detta har provtagning och analyser av föroreningar för de båda områdena ägt rum och dessa värden ligger till grund för inställningen av modellen.</p><p>Simuleringar har utförts för att anpassa modellen samt utvärdera dess förmåga att beskriva dagvattenflödet och föroreningsbelastningen inom de aktuella områdena. Simuleringarna visar att avrinningen och dagvattenflödet simuleras bra av modellen. Det har dock visat sig att de gjorda mätningarna inte har varit tillräckliga som underlag för att få en tillförlitlig beskrivning av föroreningsbelastningen och vidare utveckling är nödvändig. Detta gäller särskilt i industriområdet där modellen generellt simulerar för låga föroreningsmängder. För en mer allmän uppfattning av SEWSYS modellen för de två områdena, har även simuleringar på årsbasis utförts och jämförts med schablonhalter för dagvattenföroreningar. Trots att simuleringsvärdena har legat lägre än de uppmätta värdena på föroreningsmängderna har det gått att visa att industriområdet bidrar till högre föroreningsbelastning än bostadsområdet på recipienten Göta Älv.</p>
28

Development of a MATLAB Simulation Environment for Vehicle-to-Vehicle and Infrastructure Communication Based on IEEE 802.11p

Shooshtary, Samaneh January 2008 (has links)
<p>This thesis describes the simulation of the proposed IEEE 802.11p Physical layer (PHY). A MATLAB simulation is carried out in order to analyze baseband processing of the transceiver. Orthogonal Frequency Division Multiplexing (OFDM) is applied in this project according to the IEEE 802.11p standard, which allows transmission data rates from 3 up to 27Mbps. Distinct modulation schemes, Binary Phase Shift Keying (BPSK), Quadrate Phase Shift Keying (QPSK) and Quadrature Amplitude modulation (QAM), are used according to differing data rates. These schemes are combined with time interleaving and a convolutional error correcting code. A guard interval is inserted at the beginning of the transmitted symbol in order to reduce the effect of Intersymbol Interference (ISI). The Viterbi decoder is used for decoding the received signal. Simulation results illustrate the Bit Error Rate (BER), Packet Error Rate (PER) for different channels. Different channel implementations are used for the simulations. In addition a ray-tracing based software tool for modelling time variant vehicular channels is integrated into SIMULINK. BER versus Signal to Noise Ratio (SNR) statistics are as the basic reference for the physical layer of the IEEE 802.11p standard for all vehicular wireless network simulations.</p>
29

Development of a MATLAB Simulation Environment for Vehicle-to-Vehicle and Infrastructure Communication Based on IEEE 802.11p

Shooshtary, Samaneh January 2008 (has links)
This thesis describes the simulation of the proposed IEEE 802.11p Physical layer (PHY). A MATLAB simulation is carried out in order to analyze baseband processing of the transceiver. Orthogonal Frequency Division Multiplexing (OFDM) is applied in this project according to the IEEE 802.11p standard, which allows transmission data rates from 3 up to 27Mbps. Distinct modulation schemes, Binary Phase Shift Keying (BPSK), Quadrate Phase Shift Keying (QPSK) and Quadrature Amplitude modulation (QAM), are used according to differing data rates. These schemes are combined with time interleaving and a convolutional error correcting code. A guard interval is inserted at the beginning of the transmitted symbol in order to reduce the effect of Intersymbol Interference (ISI). The Viterbi decoder is used for decoding the received signal. Simulation results illustrate the Bit Error Rate (BER), Packet Error Rate (PER) for different channels. Different channel implementations are used for the simulations. In addition a ray-tracing based software tool for modelling time variant vehicular channels is integrated into SIMULINK. BER versus Signal to Noise Ratio (SNR) statistics are as the basic reference for the physical layer of the IEEE 802.11p standard for all vehicular wireless network simulations.
30

Kvantifiering av föroreningstillskott från dagvatten inom skyddsområdet för Göta Älv : en simuleringsstudie med modellen SEWSYS / Quantification of Stormwater Pollutant Contribution within the Protection Area of River Göta Älv  : a simulation Study with the Model SEWSYS

Eliasson, Mikaela January 2004 (has links)
The river Göta Älv reaches between Vänern and Gothenburg and is the main raw water source for Gothenburg that supplies about 700 000 people with water. To protect and maintain a high water quality, continuously samples and water analyses are made throughout the river. In 1998 a protection area was founded between surte and Lärjeholm where the raw water intake is. This was made to increase the awareness of the importance to protect the water. However, there is a lot of contribution of untreated stormwater to Göta Älv within the protection area. Göteborg Water and Sewage Works commissioned this thesis where two areas, Tagene industrial area and Kärra residential area, with untreated stormwater outlets within the protection area are studied. The areas have been divided according to surface composition with different rates of pollutant contribution. Then the stormwater flow and the contribution of pollutants was simulated with the model SEWSYS. The future aim is that the model will be able to simulate the contribution of pollutants for a variety of rains, for the whole protection area. SEWSYS (Sewer System) is built in MATLAB/Simulink and consists of three modules, a stormwater module, a sanitary wastewater module and a treatment plant module. This project only includes the stormwater module. The model simulates the stormwater flow and the pollutants total phosphorous, total nitrogen, copper, zinc, lead, cadmium and polycyclic aromatic hydrocarbons (PAH). Samples and analysis for the two areas has been carried out for another thesis work during the same period. The results from those analyses have been used for the model settings for the areas. Simulations have been performed to adjust the model and evaluate its ability to describe the stormwater flow and the pollutant contribution within the areas. The amount of stormwater and the runoff are well simulated by the model. However, the measured and analysed data has not been enough to get reliable simulations over the pollutant contribution. Further development of the model is necessary. Generally the model simulates lower values compared to measured values, especially in the industrial area. For a more general understanding over how SEWSYS works for the two areas, simulations were carried out on a yearly basis. Those simulations have been compared with general data for stormwater pollutants. Even though the results from the simulations have shown lower values than the measured values, the model shows clearly that the contribution of pollutants from the industrial site is greater than the contribution from the residential site. / Göta Älv sträcker sig från Vänern ner till Göteborg och är Göteborgs huvudsakliga råvattentäkt som försörjer ca 700 000 personer med vatten dagligen. För att säkra råvattenkvaliteten görs kontinuerliga provtagningar utmed älven. Dessutom beslutade Länsstyrelsen 1998 om ett skyddsområde med skyddsföreskrifter för avrinningsområdet mellan Surte i norr till vattenintaget vid Lärjeholm i söder. Ett mål med skyddsområdet är att det ska öka medvetenheten hos boende och de som är verksamma inom området om behovet att värna om vårt vatten. Dock leds det på flera ställen ut orenat dagvatten till älven inom skyddsområdet. Examensarbetet är ett uppdrag av Göteborgs Va-verk där två områden med orenade dagvattenutsläpp till Göta Älv studeras, Tagene industriområde samt Kärra bostadsområde. Dessa områden har karterats och dagvattenflödet samt föroreningsbelastningen från dagvattnet har simulerats med modellen SEWSYS. Målet på lång sikt är att modellen ska kunna användas för att simulera föroreningsbelastningen vid olika regn för hela skyddsområdet. Modellen SEWSYS (Sewer System) är uppbyggd i MATLAB/Simulink och bygger på tre moduler, en dagvattenmodul, en spillvattenmodul och en reningsverksmodul. För detta projekt har endast delen för dagvatten använts. Modellen simulerar dagvattenflödet och behandlar föroreningarna totalfosfor, totalkväve, koppar, zink, bly, kadmium samt polycykliska aromatiska kolväten (PAH). I ett examensarbete parallellt med detta har provtagning och analyser av föroreningar för de båda områdena ägt rum och dessa värden ligger till grund för inställningen av modellen. Simuleringar har utförts för att anpassa modellen samt utvärdera dess förmåga att beskriva dagvattenflödet och föroreningsbelastningen inom de aktuella områdena. Simuleringarna visar att avrinningen och dagvattenflödet simuleras bra av modellen. Det har dock visat sig att de gjorda mätningarna inte har varit tillräckliga som underlag för att få en tillförlitlig beskrivning av föroreningsbelastningen och vidare utveckling är nödvändig. Detta gäller särskilt i industriområdet där modellen generellt simulerar för låga föroreningsmängder. För en mer allmän uppfattning av SEWSYS modellen för de två områdena, har även simuleringar på årsbasis utförts och jämförts med schablonhalter för dagvattenföroreningar. Trots att simuleringsvärdena har legat lägre än de uppmätta värdena på föroreningsmängderna har det gått att visa att industriområdet bidrar till högre föroreningsbelastning än bostadsområdet på recipienten Göta Älv.

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