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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

Modelagem e controle de uma garra antropomórfica de robô / Antropomorphic gripper model and control

Albuquerque, André Ribeiro Lins de 07 July 2003 (has links)
É apresentado o projeto completo de uma garra antropomórfica de robô de três dedos, com nove graus de liberdade e acionamento por cabos de aço, no qual são aplicados técnicas de modelagem computacional, simulações, controle de posição e controle de força com intuito de fornecer características de confiabilidade e destreza na manipulação com objetos. Realizando análises dinâmicas experimentais na garra, os valores de rigidez e amortecimento nas articulações de seus dedos são obtidos de forma aproximada. O modelo dinâmico do sistema é desenvolvido utilizando técnicas de sistemas multicorpos através de um software de modelagem de sistemas mecânicos. Esta abordagem possibilita analisar o comportamento da garra através de simulações em diversas condições de trabalho. Para o desenvolvimento e testes dos controladores aplicou-se a técnica de co-simulação para se unir o ambiente de modelagem e simulação ao ambiente de controle. No controle de interação das pontas dos dedos da garra com um objeto, é apresentada e implementada uma ferramenta baseada na Teoria Helicoidal juntamente com um controle PID em uma aplicação onde a tarefa é suspender um objeto de uma bancada mantendo as forças internas constantes. / A complete design of an antrophomorfic gripper is presented. The gripper has three fingers, each of them with three degrees-of-freedom. The system uses transmission by cables in order to reduce the gripper\'s weight. Modelling techniques are applied to simulate and control the position and force of the fingers gripper in order to obtain dexterity and reliability features in objects manipulation. Specials features of the gripper are included in this model e.g. the stiffness and damping characteristics of the transmition cables were estimated using multi body systems methods along with experimental techniques. This approach makes possible to analyze the behavior of the gripper through simulations in several working conditions. The co-simulation techniques are applied to develop and test the controls by the connection between modeling and control environment. It is presented and implemented a tool based in the screw theory together with a PID control to control the gripper\'s finger interaction with an object.
22

Etude des interactions dans un circuit de puissance monolithique

Dartigues, Alexandre 29 November 2001 (has links) (PDF)
L'intégration monolithique des composants de puissance se justifie par la réduction des coûts de fabrication et par l'amélioration des performances des dispositifs électroniques de puissance en termes de fonctionnalités et de fiabilité. Pour l'heure, ce domaine de l'électronique de puissance ne concerne que les applications faible et moyenne puissance. En effet l'isolation entre les différentes fonctions électriques demeure l'aspect le plus pénalisant en ce qui concerne la fiabilité de ce type de composant. Dans cette étude nous nous proposons de caractériser deux types d'isolation. Notre travail porte tout d'abord sur l'interaction puissance-commande entre un nouveau composant de puissance à grille isolée bidirectionnel en tension, le MBS (Mos Bidirectional Switch), et sa commande intégrée. Il s'agit alors de montrer les limites de l'isolation par jonction PN lorsque le niveau de tension atteint quelques centaines de volts (600 V). Des modèles sont développés pour permettre de comprendre les phénomènes de génération des perturbations durant les différents régimes de fonctionnement de l'interrupteur de puissance. Dans un second temps, nous nous intéressons à l'étude des interactions entre composants de puissance au travers de la caractérisation de l'isolation diélectrique des composants sur SOI (Silicon On Insulator). Nous déterminons alors le couplage capacitif qui existe entre deux caissons d'isolation et qui peut conduire à un déclenchement parasite des composants réalisés à l'intérieur. Enfin l'ensemble de notre réflexion sur les performances des deux types d'isolation est synthétisée dans un bilan comparatif, dont l'objectif final est de mieux cerner les domaines d'applications de ces deux choix technologiques.
23

MSC Adams modelling of mechanical system in A400M Crew Entrance Door

Lindberg, David January 2012 (has links)
Saab Aerostructures has developed the Crew Entrance Door (CED) for Airbus A400M. Airbus has decided some different load cases for which the Crew Entrance Door must be built to withstand without something breaking down. The door is maneuvered by a mechanical system and the load cases are essential for the sizing of the components in the mechanical system. Saab has previously used MS Excel to analytically calculate resulting forces in the mechanical system due to external and/or internal loads in the different load cases. This report describes how the mechanical system for A400M Crew Entrance Door instead can be modeled and solved numerically with the computer program MSC Adams/View. Creating a model of a mechanical system in MSC Adams/View proved to be easy and fairly quick. The benefit of working with MSC Adams instead of MS Excel is that it is quicker and more user friendly. The major differences when comparing results were believed to be an effect of comparing results from a kinematic model with results from a dynamic model. Therefore it is in the Authors opinion that the analytical method to calculate resulting forces with MS Excel can be replaced by numerical calculations with MSC Adams/View. However, apart from calculating reaction forces there are additional post-simulation calculations for which it is perhaps more beneficial to use MS Excel. To do these post-simulation calculations in MS Excel it is easy to use exported results from MSC Adams. If Saab Aerostructures decide to start working with MSC Adams/View and if Saab wants geometry to be imported to the model, then an advise from the Author is to have a software installed which can convert step-files (*.stp or *.step) to the MSC Adams preferred file format Parasolid (*.xmt_txt or *.x_t). The software should also be able to repair geometry which will greatly increase mass accuracy.
24

Croissance du tube pollinique chez Papaver rhoeas : de nouveaux rôles pour le cytosquelette

Gossot, Olivier January 2007 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
25

Virtual testing of articulated haulers

Piliego, Hadrien, Salari, Koorosh January 2014 (has links)
Multi-body system dynamics is one of the most important theoretical achievementsin mechanics. With the development of the theory, corresponding commercialsoftware packages have been developed and are used for modellingand simulation of complicated large systems, such as air planes and vehicles.This kind of virtual prototypes can be used for studies and assessments ofreal systems even before the real systems are built. As a result, the high costprototype building and prototype testing can be saved, so as the time can bereduced. This is just the demand of modern industry. This theory can beapplied on the vehicle-virtual road interaction study which has been used inthis thesis.This thesis suggests a target velocity prole for a heavy vehicle which driveson tough road. Having uneven and hilly road, actual driving conditions arechanged as the driver runs the vehicle. Drivers can perceive the road conditionwith their visual organ and sense of balance and then they control theirvehicles more safely by re ecting various conditions of this target velocityprole. Without this process, the driving-stabilization on slope and twistingroads would fall considerably, and the problem could be directly connected tooverturning. This thesis, moreover, will show how to acquire the road data,extract the velocity prole, and verify the performance of the suggested velocityprole through virtual road test.In vehicle-virtual road interaction simulation, multi body system (MBS) dynamicswith software Adams has been employed to model an articulatedhauler. The simulation has been validated by velocity prole test data andcompared to the former velocity prole. This method can be used for estimatingthe eects of dynamic forces on the frame so that the load design canbe assessed in vehicle design process.This project is in collaboration with Volvo Construction Equipment AB,Braas, Sweden.
26

Smooth muscle contraction by small GTPase Rho

Kawano, Yoji, Yoshimura, Takeshi, Kaibuchi, Kozo 05 1900 (has links)
No description available.
27

Modelagem e controle de uma garra antropomórfica de robô / Antropomorphic gripper model and control

André Ribeiro Lins de Albuquerque 07 July 2003 (has links)
É apresentado o projeto completo de uma garra antropomórfica de robô de três dedos, com nove graus de liberdade e acionamento por cabos de aço, no qual são aplicados técnicas de modelagem computacional, simulações, controle de posição e controle de força com intuito de fornecer características de confiabilidade e destreza na manipulação com objetos. Realizando análises dinâmicas experimentais na garra, os valores de rigidez e amortecimento nas articulações de seus dedos são obtidos de forma aproximada. O modelo dinâmico do sistema é desenvolvido utilizando técnicas de sistemas multicorpos através de um software de modelagem de sistemas mecânicos. Esta abordagem possibilita analisar o comportamento da garra através de simulações em diversas condições de trabalho. Para o desenvolvimento e testes dos controladores aplicou-se a técnica de co-simulação para se unir o ambiente de modelagem e simulação ao ambiente de controle. No controle de interação das pontas dos dedos da garra com um objeto, é apresentada e implementada uma ferramenta baseada na Teoria Helicoidal juntamente com um controle PID em uma aplicação onde a tarefa é suspender um objeto de uma bancada mantendo as forças internas constantes. / A complete design of an antrophomorfic gripper is presented. The gripper has three fingers, each of them with three degrees-of-freedom. The system uses transmission by cables in order to reduce the gripper\'s weight. Modelling techniques are applied to simulate and control the position and force of the fingers gripper in order to obtain dexterity and reliability features in objects manipulation. Specials features of the gripper are included in this model e.g. the stiffness and damping characteristics of the transmition cables were estimated using multi body systems methods along with experimental techniques. This approach makes possible to analyze the behavior of the gripper through simulations in several working conditions. The co-simulation techniques are applied to develop and test the controls by the connection between modeling and control environment. It is presented and implemented a tool based in the screw theory together with a PID control to control the gripper\'s finger interaction with an object.
28

Strukturální analýza bloku motoru / Structural Analysis of an Engine Block Design

Chevtaikin, Sergei January 2019 (has links)
This master thesis focuses on structural analysis of combustion engine block. The main goal of this work was the design and compare individual solutions of long and short engine’s blocks. First part of work shows existing engine block designs and solutions. Based on the research part, the CAD design of the engine blocks and their discretization was performed by pre-processor programs. Structural analysis and their final comparison were provided by FEM and MBS programs.
29

Hnací ústrojí řadového tříválcového vznětového motoru / Cranktrain of In-line Three-cylinder Diesel Engine

Langer, Zdeněk January 2008 (has links)
Increasing requirements on products quality e.g. internal combustion engines, and growing demand on producing major parts lead to the giant development of the engines. With the engine development also great progress in the software tools has come. By decreasing costs on production of the prototypes and by support of the measured data the verification of the computational models is possible. This development has connection with using CAE tools like CAD systems, FEM programs and multi-body systems. The subject of this thesis is about using these systems to solve cranktrain dynamic. Also cranktrain dynamic results are introduced there. Interaction between the engine block and the crankshaft is solved by the hydrodynamic bearing model. All simulation methods are presented on a diesel free-cylinder in-line engine.
30

Návrh vozidla skupiny E2 pro závody do vrchu / Design of the Group E2 Vehicle for the Hill Climb

Malchárek, Martin January 2013 (has links)
This diploma thesis describes the design of the E2 hill climb car and it is design by following the FIA rules. Next parts are focused on detailed design of the front and rear suspension and design of the frame. Diploma thesis is processed using CAD system Autodesk Inventor 2011, in which was created all sketches and models. The suspension geometry during bound and rebound movement of the wheel was made in MBS system MSC Adams 2010. FEM analysis of the frame was made in ANSYS Workbench 12.1.

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