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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.
1

Critical Evaluation and Optimization of a Hypocycloid Wiseman Engine

January 2011 (has links)
abstract: In nearly all commercially successful internal combustion engine applications, the slider crank mechanism is used to convert the reciprocating motion of the piston into rotary motion. The hypocycloid mechanism, wherein the crankshaft is replaced with a novel gearing arrangement, is a viable alternative to the slider crank mechanism. The geared hypocycloid mechanism allows for linear motion of the connecting rod and provides a method for perfect balance with any number of cylinders including single cylinder applications. A variety of hypocycloid engine designs and research efforts have been undertaken and produced successful running prototypes. Wiseman Technologies, Inc provided one of these prototypes to this research effort. This two-cycle 30cc half crank hypocycloid engine has shown promise in several performance categories including balance and efficiency. To further investigate its potential a more thorough and scientific analysis was necessary and completed in this research effort. The major objective of the research effort was to critically evaluate and optimize the Wiseman prototype for maximum performance in balance, efficiency, and power output. A nearly identical slider crank engine was used extensively to establish baseline performance data and make comparisons. Specialized equipment and methods were designed and built to collect experimental data on both engines. Simulation and mathematical models validated by experimental data collection were used to better quantify performance improvements. Modifications to the Wiseman prototype engine improved balance by 20 to 50% (depending on direction) and increased peak power output by 24%. / Dissertation/Thesis / M.S.Tech Mechanical Engineering 2011
2

Design Of A Car Door Window Regulator

Ozsipahi, Mumin 01 September 2009 (has links) (PDF)
In this thesis, design of a car door window regulator is presented. This design comprises a mechanism in order that the car door window makes a specified translational motion. First, conceptual design is carried out to obtain the best suitable concept for the design and best suitable concept comes out to be a scissor mechanism. Afterwards, detailed design of the chosen concept is given. In the detail design stage, kinematic synthesis of the mechanism is performed basically using the Cardan motion. Lastly, implementation of the design on a car door is described.
3

Complexe d'épaule dans un contexte d'analyse tridimentionnel - Modélisation et mise en garde

Michaud, Benjamin 08 1900 (has links)
L'épaule est un complexe articulaire formé par le thorax, la clavicule, la scapula et l'humérus. Alors que les orientation et position de ces derniers la rendent difficile à étudier, la compréhension approfondie de l'interrelation de ces segments demeure cliniquement importante. Ainsi, un nouveau modèle du membre supérieur est développé et présenté. La cinématique articulaire de 15 sujets sains est collectée et reconstruite à l'aide du modèle. Celle-ci s'avère être généralement moins variable et plus facilement interprétable que le modèle de référence. Parallèlement, l'utilisation de simplifications, issues de la 2D, sur le calcul d'amplitude de mouvement en 3D est critiquée. Cependant, des cas d'exception où ces simplifications s'appliquent sont dégagés et prouvés. Ainsi, ils sont une éventuelle avenue d'amélioration supplémentaire des modèles sans compromission de leur validé. / The shoulder is an articulated complex composed of the thorax, clavicle, scapula and humerus. While the relative orientation and position of the segments makes an in-depth study of the shoulder difficult, understanding the interaction between the segments remains clinically important. Thus, a new model of the upper limb is proposed. Joint kinematics of 15 subjects were collected and reconstructed using the model, and were found to be less variable and easier to interpret when compared to the reference model. Meanwhile, simplifications involving the use of 2D analysis to calculate range of motion in 3D are criticized. Exceptions where these simplifications apply, were however, shown. Thus, such simplifications can be applied to models in certain situations without compromising the models validity.
4

Complexe d'épaule dans un contexte d'analyse tridimentionnel - Modélisation et mise en garde

Michaud, Benjamin 08 1900 (has links)
L'épaule est un complexe articulaire formé par le thorax, la clavicule, la scapula et l'humérus. Alors que les orientation et position de ces derniers la rendent difficile à étudier, la compréhension approfondie de l'interrelation de ces segments demeure cliniquement importante. Ainsi, un nouveau modèle du membre supérieur est développé et présenté. La cinématique articulaire de 15 sujets sains est collectée et reconstruite à l'aide du modèle. Celle-ci s'avère être généralement moins variable et plus facilement interprétable que le modèle de référence. Parallèlement, l'utilisation de simplifications, issues de la 2D, sur le calcul d'amplitude de mouvement en 3D est critiquée. Cependant, des cas d'exception où ces simplifications s'appliquent sont dégagés et prouvés. Ainsi, ils sont une éventuelle avenue d'amélioration supplémentaire des modèles sans compromission de leur validé. / The shoulder is an articulated complex composed of the thorax, clavicle, scapula and humerus. While the relative orientation and position of the segments makes an in-depth study of the shoulder difficult, understanding the interaction between the segments remains clinically important. Thus, a new model of the upper limb is proposed. Joint kinematics of 15 subjects were collected and reconstructed using the model, and were found to be less variable and easier to interpret when compared to the reference model. Meanwhile, simplifications involving the use of 2D analysis to calculate range of motion in 3D are criticized. Exceptions where these simplifications apply, were however, shown. Thus, such simplifications can be applied to models in certain situations without compromising the models validity.
5

Ne Design Methods For Polyhedral Linkages

Kiper, Gokhan 01 September 2006 (has links) (PDF)
This thesis analyses the existing types of polyhedral linkages and presents new linkage types for resizing polyhedral shapes. First, the transformation characteristics, most specifically, magnification performances of existing polyhedral linkages are given. Then, methods for synthesizing single degree-of-freedom planar polygonal linkages are described. The polygonal linkages synthesized are used as faces of polyhedral linkages. Next, the derivation of some of the existing linkages using the method given is presented. Finally, some designs of cover panels for the linkages are given. The Cardan Motion is the key point in both analyses of existing linkages and synthesis of new linkages.
6

The telling of the unattainable attempt to avoid the {casus irreducibilis} for cubic equations: Cardano's {De Regula Aliza}. With a compared transcription of 1570 and 1663 editions and a partial English translation

Confalonieri, Sara 12 October 2013 (has links) (PDF)
Solving cubic equations by a formula that involves only the elementary operations of sum, product, and exponentiation of the coefficients is one of the greatest results in 16th century mathematics. This was achieved by Girolamo Cardano's Ars Magna in 1545. Still, a deep, substantial difference between the quadratic and the cubic formula exists: while the quadratic formula only involves imaginary numbers when all the solutions are imaginary too, it may happen that the cubic formula contains imaginary numbers, even when the three solutions are anyway all real (and different). This means that a scholar of the time could stumble upon numerical cubic equations of which he already knew three (real) solutions and the cubic formula of which actually contains square roots of negative numbers. This will be lately called the 'casus irreducibilis '. Cardano's De Regula Aliza (Basel, 1570) is (at least, partially) meant to try to overcome the problem entailed by it.
7

Fuel Efficiency in AWD-system

Fredriksson, Robert, Trkulja, Milovan January 2008 (has links)
This degree project has been made in cooperation with engineers working for GM Engineering/Saab Automobile AB in Trollhättan. The given name by Saab for the project is “Fuel efficiency improvements in All Wheel Drive(AWD)-system”. The main tasks of this thesis work were to investigate the size of the power losses in different parts on the propeller shaft, to design a computer program that calculates coordinates and angles on a propeller shaft and to investigate the possibilities to put together a simplified formula that calculates the natural frequencies on a propeller shaft. The main parts of this report are a compilation of the theory about AWD and mostly about the parts on the propeller shaft, and also a description of the developed computer program called Propeller Shaft Calculator. This report doesn’t concern power losses in the different joints because there were no such general equations to be found. The most common way to calculate the power losses inside a joint is to do tests were the power loss is measured at different angles, torque and speed and then use that data to put together an approximated equation. Most of the work on this project has been on theory studies and on programming. The main result of the project is the program Propeller Shaft Calculator. Propeller Shaft Calculator is a program that is designed in Microsoft Excel. All the menus are programmed in the visual basic editor in Excel. The program is supposed to be used as a help while designing new propeller shafts. Propeller Shaft Calculator can calculate all the coordinates, lengths, angles and directions on a propeller shaft. It also calculates natural frequencies, plunge, estimated power loss on the second shaft and angles in the joints. In the program you can choose to do calculations on four different configurations of propeller shafts but can quite easy upgrade the program with more choices. Basically the program works like this: First you choose the right propeller shaft in the main menu. Then you fill out the indata sheet with coordinates, lengths, material data and so on. As you type in the input data the output data will appear in the out-data sheet next to the in-data. Every propeller shaft has also a calculations sheet were more detailed calculations can be found. The program also has a built in help function and a warning function that lights a warning sign next to the values if they are outside the limits.
8

Fuel Efficiency in AWD-system

Fredriksson, Robert, Trkulja, Milovan January 2008 (has links)
<p>This degree project has been made in cooperation with engineers working for GM Engineering/Saab Automobile AB in Trollhättan. The given name by Saab for the project is “Fuel efficiency improvements in All Wheel Drive(AWD)-system”. The main tasks of this thesis work were to investigate the size of the power losses in different parts on the propeller shaft, to design a computer program that calculates</p><p>coordinates and angles on a propeller shaft and to investigate the possibilities to put together a simplified formula that calculates the natural frequencies on a propeller shaft.</p><p>The main parts of this report are a compilation of the theory about AWD and mostly about the parts on the propeller shaft, and also a description of the developed computer program called Propeller Shaft Calculator. This report doesn’t concern power losses in the different joints because there were no such general equations to be found. The most common way to calculate the power losses inside a joint is to do tests were the power loss is measured at different angles, torque and speed and then use that data to put together an approximated equation.</p><p>Most of the work on this project has been on theory studies and on programming. The main result of the project is the program Propeller Shaft Calculator.</p><p>Propeller Shaft Calculator is a program that is designed in Microsoft Excel. All the menus are programmed in the visual basic editor in Excel. The program is supposed to be used as a help while designing new propeller shafts.</p><p>Propeller Shaft Calculator can calculate all the coordinates, lengths, angles and directions on a propeller shaft. It also calculates natural frequencies, plunge, estimated power loss on the second shaft and angles in the joints. In the program you can choose to do calculations on four different configurations of propeller shafts but can quite</p><p>easy upgrade the program with more choices.</p><p>Basically the program works like this:</p><p>First you choose the right propeller shaft in the main menu. Then you fill out the indata sheet with coordinates, lengths, material data and so on. As you type in the input data the output data will appear in the out-data sheet next to the in-data. Every propeller shaft has also a calculations sheet were more detailed calculations can be</p><p>found.</p><p>The program also has a built in help function and a warning function that lights a warning sign next to the values if they are outside the limits.</p>
9

Pojezdový mechanismus mostového jeřábu / The bridge crane's travel mechanism

Žid, Miroslav January 2018 (has links)
The aim of this master thesis is to design replacing the central drive of the overhead crane with dislocated drives. It´s a tong crane with the lifting capacity of 63 tons, located inside the hall. In the thesis is processed functional calculation of two types of drives, the associated types of brakes and the coupling element. Next there is a strength control of a new mechanism seat and a selected components. This whole leads to the output, which is the drawing documentation.
10

[en] MECHANISM DESIGN, KINEMATIC AND DYNAMIC ANALYSIS OF A ROBOTIC MANIPULATOR DRIVEN BY AN ACTIVE CARDAN JOINT WITH THREE DEGREES OF FREEDOM / [pt] PROJETO DE MECANISMO, ANÁLISE CINEMÁTICA E DINÂMICA DE UM MANIPULADOR ROBÓTICO ACIONADO POR JUNTA CARDÂNICA ATIVA COM TRÊS GRAUS DE LIBERDADE

JEAN CARLO FERREIRA DE OLIVEIRA 24 September 2020 (has links)
[pt] O uso de juntas cardânicas ativas é restrito pela capacidade de torque de pequenos motorredutores e, atualmente, os dispositivos embarcados são obrigatórios para as aplicações robóticas. O controle dinâmico é essencial para estudar as limitações desse dispositivo, portanto, o objetivo deste estudo foi controlar a junta cardânica ativa de três graus de liberdade usando simulações numéricas e experimento em bancada de testes. O manipulador foi projetado com apenas uma junta cardânica para que a sua cinemática e dinâmica sejam exploradas; por esse motivo, a junta foi construída com sensores de carga na base e sensor de unidade de movimento inercial na parte superior do efetuador do manipulador. Além disso, foram fabricadas três placas de controle: a primeira foi projetada para controlar os três acionamentos dos motores de passo; a segunda, para ler o sensor da unidade de movimento inercial; e a última, para ler os sensores de carga. Quatro problemas foram descritos para testar os limites deste dispositivo, analisando, além da cinemática e dinâmica, o atrito do rolamento, a identificação da folga e o torque do impacto. O primeiro problema mantém a posição do efetuador do manipulador constante enquanto transmite rotação entre os eixos. O segundo problema, o efetuador recebe um caminho planejado, por exemplo, um círculo, mas não transmite rotação entre os eixos. O terceiro problema é a combinação dos movimentos anteriores, em que o efetuador transmite rotação entre os eixos, enquanto segue por um caminho planejado. Para o quarto problema: uma nova abordagem é aplicada para mover o efetuador de um ponto para outro usando rotação cônica. / [en] The use of active cardan joints is restricted by torque capacity of small motors, and currently embedded devices have been mandatory for robotic applications. The dynamic control is essential to learn the limitations of this device, thus the objective of this study is to control active cardan joints of three degrees of freedom using numerical simulations and bench experiment. The manipulator was designed with only one cardan joint to understand its kinematics and dynamics and, for this reason, it was built with load sensors on its base and inertial motion unit sensor at the top of the manipulator end-effector. Furthermore, three control boards were manufactured: the first was designed to control the three stepper motor drives, the second was designed to read the inertial motion unit sensor, and the last was designed to read the load sensors. Four problems were described to test the limits of this device, analysing not only the kinematics and dynamics, but also the bearing friction, the backlash identification, and the impact torque. The first problem keeps the position of the manipulator end-effector constant transmitting rotation between the shafts. The second problem is given a planned path to the manipulator endeffector, such as a circle, but it does not transmit rotation between the shafts. The third problem is the combination of the previous motions, where the manipulator end-effector applies the output spin, while it follows by a planned path. The fourth problem, a new approach is applied to move the manipulator end-effector from one point to another point using a conical rotation.

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