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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

Experimental studies on electrical and lift-force models of the ionic flyer with wire-plate electrode configuration.

January 2007 (has links)
Chung, Chor Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 95-97). / Abstracts in English and Chinese. / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xiii / Nomenclature --- p.xiv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Development of Micro Indoor Surveillance Flyers --- p.1 / Chapter 1.1.1 --- Overview --- p.1 / Chapter 1.1.2 --- Intrinsic Problem of Surveillance Helicopters --- p.2 / Chapter 1.2 --- Proposed Non-moving Parts and Noiseless Flyers --- p.2 / Chapter 1.3 --- Organization of the remaining dissertation --- p.5 / Chapter Chapter 2 --- The Basic Structure of the Ionic Flyers --- p.7 / Chapter 2.1 --- The Components and the Structural Parameters of the Ionic Flyers --- p.7 / Chapter 2.2 --- Proposed Operational Principles --- p.8 / Chapter 2.2.1 --- The Electrohydrodynamic Effect --- p.9 / Chapter 2.2.2 --- The Biefeld-Brown Effect --- p.10 / Chapter Chapter 3 --- Overview of Corona Discharge --- p.11 / Chapter 3.1 --- The Gaseous Discharge --- p.11 / Chapter 3.2 --- "Uniform Fields, Electrical Breakdown" --- p.12 / Chapter 3.3 --- "Non-uniform Fields, Corona Discharge" --- p.12 / Chapter 3.3.1 --- Positive Corona Discharge --- p.13 / Chapter 3.3.2 --- Negative Corona Discharge --- p.14 / Chapter 3.4 --- Conclusion --- p.15 / Chapter Chapter 4 --- Electrical Current-Voltage Model --- p.16 / Chapter 4.1 --- Experimental Setup and Measurement --- p.17 / Chapter 4.2 --- Basic Current to Voltage Relationship --- p.18 / Chapter 4.2.1 --- The Three Electrical Stages of the Ionic Flyers --- p.20 / Chapter 4.2.2 --- Proposed Quadratic Equation for the Current to Voltage Relationship --- p.22 / Chapter 4.3 --- Determination of the Current Gain C and the Onset Voltage V0 by the Structural Parameters of the Ionic Flyers --- p.22 / Chapter 4.3.1 --- The Electrode Length (L) --- p.24 / Chapter 4.3.2 --- The Gap Distance between the Wire-emitter and the Plate-collector (d) --- p.27 / Chapter 4.3.3 --- The Wire-emitter Radius (rw) --- p.31 / Chapter 4.3.4 --- The Plate-collector Height (h) --- p.36 / Chapter 4.3.5 --- The Electrode Enclosed Area (A) --- p.38 / Chapter 4.3.6 --- The Electrical Environmental Constant (Ke) --- p.43 / Chapter 4.4 --- Summary of the Experimental Derived Current-Voltage Model --- p.45 / Chapter Chapter 5 --- Mechanical Lift-force Models --- p.46 / Chapter 5.1 --- Experimental Setup and Measurement --- p.47 / Chapter 5.2 --- Basic Lift-force to Voltage Relationship --- p.49 / Chapter 5.2.1 --- The Initial Power Dissipation (IPD) --- p.50 / Chapter 5.2.2 --- The Maximum Lift-force --- p.51 / Chapter 5.2.3 --- Proposed Third-order Equation for the Lift-force to Power Relationship --- p.52 / Chapter 5.3 --- Determination of the Voltage Gain J and the Barrier Voltage Vfby the Structural Parameters of the Ionic Flyers --- p.54 / Chapter 5.3.1 --- The Electrical Length (L) --- p.55 / Chapter 5.3.2 --- The Gap Distance between the Wire-emitter and the Plate-collector (d) --- p.59 / Chapter 5.3.3 --- The Wire-emitter Radius (rw) --- p.63 / Chapter 5.3.4 --- The Plate-collector Height (h) --- p.66 / Chapter 5.3.5 --- The Electrode Enclosed Area (A) --- p.67 / Chapter 5.3.6 --- The Lift-force Environmental Constant (Kf) --- p.71 / Chapter 5.4 --- Summary of the Experimental Derived Lift-force Model --- p.73 / Chapter 5.5 --- Analysis on the Force/Power Ratio of the Ionic Flyers --- p.74 / Chapter Chapter 6 --- Further development of the Ionic Flyers --- p.76 / Chapter 6.1 --- Multi-directional Force Generation --- p.76 / Chapter 6.1.1 --- Linear Motion --- p.77 / Chapter 6.1.2 --- Rotation Motion --- p.78 / Chapter 6.2 --- Application of MEMS Motion Sensors and Wireless Signal Transmission --- p.80 / Chapter Chapter 7 --- Future Work --- p.84 / Chapter 7.1 --- Single-Emitter-Multiple-Collector Ionic Flyers --- p.84 / Chapter 7.2 --- Development of Miniaturized High-voltage Power Supply --- p.88 / Chapter Chapter 8 --- Conclusion --- p.90 / Chapter 8.1 --- The Electrical Current to Voltage Model --- p.90 / Chapter 8.2 --- The Mechanical Lift-force to Power Model --- p.91 / Chapter 8.3 --- The Force/Power Ratio Model --- p.91 / Appendix A --- p.92
2

Quantitative feedback design and construction of a two by two system with large disturbances.

Boje, Edward Sidney. January 1989 (has links)
The quantitative feedback theory (QFT) of Horowitz is theoretically well developed for multivariable systems but there is not sufficient knowledge on its application to practical problems. A "flying machine" consisting of an airframe with two independently controlled sets of wings has been designed and constructed as a 2-input 2-output control problem. The airframe is constrained to move vertically on guide wires and to rotate about a pivot. Air flow over the wings is provided by two 7.SkW fans operated without any attempt at providing non-turbulent flow. The arrangement of the wings is such that in open loop, the dynamic behaviour of the airframe from the rear set of wings to the height is non-minimum phase. Additionally, the airframe is unstable for some flight conditions. This uncertain, non-linear and highly disturbed plant provides an ideal practical environment in which to test controller design theory. The construction, modelling, parameter estimation and simulation of the flying machine is described. Three different controller structures are disGussed, with actual controller designs arrived at from QFT understanding. The controller designs for the flying machine take into account parameter uncertainty and trade off disturbance attenuation against rate and amplitude saturation at the wing angle inputs. / Thesis (Ph.D.)-University of Natal, Durban, 1989.
3

CFD analysis and validation for solution to micro air vehicle airframes /

Attari, Taher I. January 2004 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 2004. / Typescript. Includes bibliographical references (leaves 116-117).
4

Modelagem e análise de topologias para veículos aéreos não-tripulados do tipo multirotor / Modeling and analysis of topologies for unmanned aerial vehicles of the multirotor type

Sandi, Nathanyel 03 July 2017 (has links)
Com a evolução dos projetos de multirotores e dos seus componentes, os projetistas vem tendo inúmeras opções de combinações de componentes na fase de projeto do multirotor, buscando melhor performance e menor custo. Isto deixa um problema em aberto: como atingir o multirotor pode atingir uma boa performance ainda na fase de projeto. A motivação para realização deste estudo se justifica no fato que não há trabalhos relacionado ao levantamento de métricas e análise de performance dos multirotores. Assim como o fator de não haver formas de mensurar a qualidade dos projetos e ter possibilidade de comparação, uma vez que tem-se várias formas de projetar um multirotor para diferentes aplicações. Este trabalho propõe uma abordagem para a análise do projeto de multirotores em termos de sua capacidade de voo (definida como voabilidade), levando em consideração as características de seus rotores, peso e topologia. O principal objetivo é apresentar uma forma de qualificar e quantificar uma aeronave multirotor para otimizar seu projeto. A abordagem discutida tem como objetivo analisar as habilidades de voo dos multirotores em seu projeto teórico para suportar os requisitos de projeto (como tamanho da hélice, torque do motor, topologia de armação), garantindo as capacidades de voo exigidas pela tarefa. Como resultado deste trabalhos, um conjunto de índices foi proposto para avaliar a qualidade de projeto de multirotores, sendo eles: voo, estabilidade, posicionamento e flutuação. A soma destes índices compõem o índice de voabilidade. Este índice oferece a possibilidade de comparação da análise do veículo em função das especificações do conjunto motor, hélice, topologia e tamanho do quadro. Para a validação destas métricas, uma análise das topologias tradicionais foi realizada, permitindo uma comparação em função do desempenho e esforço delas. / With an evolution of the multi-curral projects and their components, the designers have been having numerous options of combinations of components in the multirotor design phase, seeking better performance and lower cost. This leaves an open problem: as what the multirotor can achieve a good performance still in the design phase. One motivation to carry out this study is justified in that there are no works related to the survey of metrics and analysis of the performance of multirotors. As well as the factor there are no ways to measure a quality of projects and possibility of comparison, since there are several ways to design a multirotor for different applications. This work proposes an approach for an analysis of the design of multirotors in terms of their flight capacity, defining as characteristics of their rotors, weight and topology. The main objective is to present a way to qualify and quantify a multirotor aircraft to optimize its design. An approach approached for design design to support design requirements (such as power size, engine torque, frame topology), ensuring as required flight capabilities. As a result of this work, a set of indexes proposed to evaluate a multirole project quality, being: flight, stability, hover and heading. The sum of these indices compose the voleability index. This index offers a possibility of comparing the vehicle analysis according to the specifications of the engine assembly, propeller, topology and frame size. For a metric validation, an analysis of the topologies was performed, allowing a comparison for the performance function and their effort.
5

Le rattachement des engins à l'Etat en droit international public (navires, aéronefs, objets spatiaux) / The connection between craft / vessels and States in public international law (ships, aircraft, space objects)

Aloupi, Niki 27 April 2011 (has links)
Contrairement aux autres biens meubles, les navires, les aéronefs et les objets spatiaux affectés à la navigation internationale sont rattachés à un Etat. Le lien de droit public établi entre ces engins et l’Etat est communément appelé « nationalité ». Mais ce terme n’exprime pas à leur propos une institution à tous égards identique à la nationalité des personnes. Le rattachement examiné ne repose en effet pas sur des éléments de fait (naissance, ascendance etc.), mais uniquement sur un acte administratif interne, l’immatriculation. L’étude de la pratique, notamment des conventions internationales et des législations nationales, montre clairement que – contrairement à ce qu’on soutient souvent – il n’y a pas lieu de subordonner ce rattachement à un lien effectif. Ce qui importe, compte tenu notamment du fait que ces engins évoluent dans des espaces soustraits à toute compétence territoriale, est d’identifier l’Etat qui est seul compétent à l’égard de l’« ensemble organisé » formé par le véhicule, les personnes et la cargaison à bord, et qui est responsable de ses activités. Le droit international interdit dès lors la double immatriculation, mais il laisse aux Etats le pouvoir discrétionnaire de déterminer les conditions d’attribution de leur « nationalité », sans subordonner l’opposabilité internationale de celle-ci à quelque autre exigence que ce soit. Le danger est toutefois que cela favorise un certain laxisme de l’Etat d’immatriculation, ce qui exposerait au risque que des dommages graves soient causés aux personnes impliquées dans les activités de ces engins et – surtout – aux tiers. Mais ce sont les obligations internationales imposées et les droits corrélatifs reconnus dans le chef de l’Etat d’immatriculation qui sont déterminants à cet égard et non quelque mystérieuse « effectivité » du rattachement. Autrement dit, s’il n’est pas nécessaire d’imposer à l’Etat d’immatriculation des conditions internationales limitant sa liberté dans l’attribution de sa « nationalité » aux engins, il est indispensable d’exiger que celui-ci respecte ses obligations, c’est-à-dire exerce effectivement son contrôle et sa juridiction. Cette constatation se vérifie quel que soit l’engin en cause. Le rattachement créé par l’immatriculation constitue donc une institution "sui generis", commune aux navires, aéronefs et objets spatiaux et dont le régime juridique est encadré par le droit international. / Unlike any other movable property, ships, aircraft and space objects that are engaged in international navigation are linked to a State. The legal connection established between these craft/vessels and the State is commonly referred to as “nationality”. However, in this case the term does not represent an institution identical in all respects to the nationality of persons. With regard to vessels, the legal connection to a State is not based on factual elements (such as birth, descent etc.), but merely on the internal administrative act of registration. The study of State practice, notably international conventions and national laws, clearly shows that – contrary to what is often argued – there is no need to make this connection dependent on a pre-existing effective link. What matters most, given that these craft navigate in international space beyond the territorial jurisdiction of sovereign States, is to identify the State that holds sole jurisdiction over said “organized entity” consisting of the vehicle, the persons and the cargo on board and that is responsible for its activities. Public international law therefore prohibits dual registration, but leaves States free to determine the conditions under which they will confer their “nationality”, without imposing any other requirement for the opposability of this legal bond to third States. The danger is that this situation encourages laxity on the part of the States of registry and therefore creates the potential for serious damage incurred by persons involved in these vessels’ activities and – mostly – by third persons. In this regard, it is the international obligations and corresponding rights of the States of registry which are critical, and not a mysterious “effectiveness” of the legal bond. In other words, it is not necessary to impose on the State of registry any international conditions which would limit its freedom with regard to the conferral of its “nationality” upon vessels. It is however indispensable to require that said State complies with its obligations, meaning that it has to effectively exercise its jurisdiction and control over those craft. This statement holds true regardless of the craft concerned. The legal bond created by the registration therefore constitutes a "sui generis" institution, common to ships, aircraft and space objects, and whose legal regime is governed by international law.

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