abstract: This thesis discusses the equilibrium conditions and static stability of a rotorcraft kite with a single main tether flying in steady wind conditions. A dynamic model with five degrees of freedom is derived using Lagrangian formulation, which explicitly avoids any constraint force in the equations of motion. The longitudinal static stability of the steady flight under constant wind conditions is analyzed analytically from the equilibrium conditions. The rotorcraft kite orientation and tether angle are correlated through the equation Γ=δ-ϑ, a necessary condition for equilibrium. A rotorcraft kite design with 3kg mass and 1.25m rotor radius is found to be longitudinally statically stable at 25,000ft with Γ>〖65〗^0 for wind speeds above 19m/s. / Dissertation/Thesis / Masters Thesis Aerospace Engineering 2017

O gavião-de-pescoço-branco Leptodon forbesi Swann, 1922, endêmico da Mata Atlântica do Centro Pernambuco, é uma espécie cujo status taxonômico ainda é controverso. Autores como Swann (1922 e 1945), Teixeira et al. (1987) e del Hoyo (1994) consideram a espécie como válida, enquanto que outros, como Grossman e Hamlet (1964), Brown e Amadon (1968), Blake (1977) e Sick (1994) optam por considerá-la como uma variante morfológica do gavião-de-cabeça-cinza L. cayanensis. As diagnoses tradicionais de L. forbesisão as coberteiras inferiores das asas, brancas ao invés de negro; píleo cinza; lados do pescoço brancos; ápice das escapulares, manto e rêmiges esbranquiçados; e a cauda com uma larga faixa branca (Swann 1945; Hellmayr e Conover 1949; Pinto 1964). O presente trabalho teve como objetivos estudar e descrever a variação morfológica e morfométrica de L. cayanensis, e testar a validade dos táxons componentes deste complexo, com especial atenção para o táxon L. forbesie sua distribuição geográfica. Foram analisados 128 espécimes do gênero Leptodon, provenientes do México até o estado do Rio Grande do Sul, Brasil. Dados morfométricos foram obtidos e analisados para se avaliar diferenças entre os sexos, o polimorfismo de coloração nas plumagens dos juvenis, e as subespécies propostas por Swann (1922) para L. cayanensis. Além disso, caracteres de plumagem também foram analisados para se testar a validade de L. forbesi. Concluiu-se que há dimorfismo sexual em L. cayanensis, sendo as fêmeas de maior porte (I); que ocorrem duas, e não três, fases de coloração nas plumagens juvenis de L. cayanensis (II); que as subespécies propostas por Swann (1922) para L. cayanensis não são válidas, sendo a variação geográfica do porte mais bem explicada por um gradiente em resposta ao módulo da latitude, como previsto pela Lei de Bergmann (III); e que a espécie L. forbesié um táxon válido, com base nos caracteres da coloração das penas coberteiras inferiores e da borda de ataque das asas, brancas em L. forbesie pretas em L. cayanensis, do contraste entre a coloração ventral das rêmiges, sendo as primárias escuras e as secundárias mais claras em L. forbesi, e da coloração das penas da região do pescoço, brancas em L. forbesie cinzas em L. cayanensis (IV). Desta forma, L. forbesi constitui mais uma espécie endêmica do Centro Pernambuco de Endemismo. / The White-collared (or Forbes) Kite Leptodon forbesi Swann, 1922 is an endemic raptor of the Centro Pernambuco, the northernmost portion of the Atlantic Forest, in Northeastern Brazil, and its taxonomic status is still a case of controversy. It is considered a valid species by Swann (1922, 1954), Teixeira et al. (1987) and del Hoyo (1994), whereas Grossman and Hamlet (1964), Brown and Amadon (1968), Blake (1977) and Sick (1994) opt to consider it a morphological variant of the widespread Grey-headed Kite L. cayanensis. The traditional diagnoses of L. forbesiare the underwing coverts, white instead of black; grey pileum; white collar; white tip of quills, mantle and scapular feathers; and a wide white band on both sides of the tail (Swann 1945; Hellmayr and Conover 1949; Pinto 1964). The present study aims to analyse and describe the morphological and morphometrical variation in L. cayanensis, and to test the validity of taxa within the complex, with a special interest in L. forbesiand its geographical distribution. 128 specimes of the genus Leptodon, from Mexico to Southern Brazil, were studied. Morphometrical data was obtained and analysed to evaluate differences between sexes, colour polymorphism in the juvenile plumage, and the subspecies described by Swann (1922) for L. cayanensis. Plumage characters were also studied to test the validity of L. forbesi. We conclude that L. cayanensis shows sexual dimorphism, the females being larger (I); that there are two, not three, coloration morphs in the juvenile plumages of L. cayanensis (II); that the subspecies described by Swann (1922) for L. cayanensis are invalid, the geographical variation in size better explained as a response to latitude module, as predicted by Bergmanns Rule (III); and that the species L. forbesi is a valid taxon, based on the coloration of underwing and leading edge coverts, white in L. forbesi and black in L. cayanensis; on the coloration of the ventral side of the rêmiges, with a contrast between dark primaries and lighter secondaries in L. forbesi; and on the collar coloration, white in L. forbesiand grey in L. cayanensis (IV). Therefore, L. forbesi constitutes another endemic and endangered species of the Centro Pernambuco, in the Brazilian Atlantic Forest.

No description available.

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-03-17T18:54:32Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese de Doutorado em Engenharia Mecânica - Edwin Lundgren - Recife 2015.pdf: 6647333 bytes, checksum: 562061d27a257684cbc87a9f44cca7a8 (MD5) / Made available in DSpace on 2016-03-17T18:54:32Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese de Doutorado em Engenharia Mecânica - Edwin Lundgren - Recife 2015.pdf: 6647333 bytes, checksum: 562061d27a257684cbc87a9f44cca7a8 (MD5) Previous issue date: 2015-07-24 / O presente trabalho apresenta como tema central o desenvolvimento e a realização de um conceito tecnológico inovador para propulsionar embarcações utilizando a força do vento por meio de uma pipa dirigível de alto desempenho aerodinâmico conhecida como Kite. Para demonstrar a eficiência da tecnologia aplicada é projetado, manufaturado e testado um barco protótipo com quatro metros de comprimento capaz de carregar uma ou duas pessoas. Kites modernos são projetados para operar em regime de sustentação aerodinâmica e podem ser movimentados de forma razoavelmente controlada em uma região denominada “janela de vento” e possibilitam a geração de forças perpendiculares á direção do vento. Assim, uma embarcação tracionada por Kites e equipada com uma quilha pode realizar cursos cruzados contra o vento. O equilíbrio hidrodinâmico da embarcação tratada neste trabalho é alcançado através de tecnologia com uso de uma plataforma giratória azimutal e um conjunto de mecanismos para o manuseio do Kite e o controle do rumo do barco. É apresentado o cálculo para relacionar o equilíbrio da embarcação com o voo do Kite. Não há necessidade de leme para controlar o rumo da embarcação, portanto o barco protótipo deste trabalho não apresenta algum leme. Os dados obtidos em teste foram relacionados, processados e os resultados quantitativos de percursos e manobras são apresentados e descritas as condições e posicionamentos das grandezas relevantes. A Propulsão do barco prototipo por meio de um Kite mostrou bons resultados em ventos acima de 18 km/h (10 nós). Nestas condições ficou comprovado a eficiência do sistema inovador para propulsionar e guiar barcos com Kites como o protótipo apresentado no presente trabalho. / This work has as its central theme the development and realization of an innovative technological concept of boat propulsion using the wind power through a steerable Kite. To demonstrate the effectiveness of the applied technology there is designed, manufactured and tested a prototype boat with four meters in length capable of carrying one or two people. Modern Kites are designed to operate in aerodynamic lift system. As a result, these devices can be moved in fairly controlled manner in a semi-spherical region called "wind window" and allow the generation of perpendicular forces to wind direction. Thus, a vessel pulled by a Kite and equipped with a good keel can perform crossed courses against the wind. The hydrodynamic balance of the vessel treated in this work is achieved through the use of a technology with azimuthal platform and a set of mechanisms for Kite handling and controlling the direction of the boat. A new method of calculation of the balance of the boat during the Kite flight is presented as well as some results of hydrodynamic simulations. Another advantage of the azimuth platform technology is the ability to control the direction of the boat only by the Kite control devices and the relative positioning of the azimuthal platform within the hull. There is no need of a rudder to control the direction of the boat, so the boat prototype of this work does not present any rudder. The test data were related, processed and quantitative results concerning courses and maneuvers are presented and the conditions and positions of the relevant magnitudes are described. The propulsion of the prototype boat by a Kite showed good results in winds over 18 km/h (10 knots). Under these conditions the efficiency of the innovative propulsion system for boats with Kites as the prototype presented in this work was testified. The innovative directional control allows the handling of the vessel at high upwind courses. The bidirectionality of the prototype boat increases the possibilities of executing maneuvers with reversal of the navigation direction and easy windward routes.

Afin de réduire les émissions de gaz à effet de serre et le coût du transport maritime, l'utilisation des cerfs-volants comme système de propulsion auxiliaire des navires est prometteuse. Pour estimer les performances et l’opérabilité d’un navire tracté par cerf-volant, une modélisation dynamique du système est alors mise en oeuvre. Une modélisation analytique de cerf-volant est utilisée. Ce modèle néglige la masse du cerf-volant et suppose que les lignes sont droites et indéformables. Ces hypothèses conduisent à un modèle cinématique dépendant du coefficient de portance et de la finesse aérodynamique. Une évolution linéaire des coefficients aérodynamiques en fonction de la courbure de la trajectoire de vol est proposée. Par ailleurs, en développant un modèle quasi analytique de ligne, il est montré qu’à partir de 2 m.s-1 de vent relatif que l’hypothèse de ligne droite est raisonnable. En se basant sur un modèle de ligne, un critère analytique de vitesse de vent minimum permettant un vol quasi-statique est présenté. Dans le but de résoudre l’ensemble des termes d’interaction entre le cerf-volant et le navire, un modèle linéarisé de tenue à la mer temporelle est développé. Le produit de convolution de la réponse impulsionnelle du navire est calculé avec des systèmes d’états. Cependant comme celle-ci représente mal les mouvements horizontaux des navires, le modèle développé est alors couplé à un modèle de manoeuvrabilité. Pour étudier les interactions entre le cerf-volant et le navire un couplage monolithique et un couplage dissocié sont comparés. Le couplage dissocié néglige l’influence des mouvements du navire sur le vol du cerf-volant. En cas de mer calme, les résultats obtenus par les deux types de couplage sont très proches. En cas de houle régulière les mouvements du navire sont principalement causés par la houle. Le couplage monolithique montre qu’un réseau de sous-harmoniques basse fréquence apparait alors dans le spectre d’excitation du navire. La fréquence fondamentale des sous-harmoniques est donnée par la différence entre la fréquence de vague et la fréquence de l’harmonique la plus proche de l’excitation du kite. Quand cette différence est suffisamment petite, un phénomène d’accrochage apparait. Ce phénomène est bénéfique pour le cerf-volant et le navire quand le décalage des harmoniques d'excitation correspond à une augmentation. Par ailleurs, une étude de la stabilité de route montre qu'il est nécessaire de contrôler activement le safran. / In order to reduce greenhouse gas emissions and shipping costs, the use of kites as an auxiliary propulsion device for ships is promising. In order to estimate the performance and the operability of a kite-towed vessel, a dynamic modeling of the system is implemented. A classical kite modeling is used. This model neglects the mass of the kite and assumes straight and inelastic tethers. These assumptions lead to a kinematic model depending on the lift coefficient and the aerodynamic lift to drag ration angle. A linear evolution of these aerodynamic coefficients as a function of the curvature of the flight path is proposed. In addition, by developing a quasi-analytical line model, it is shown that from 2 m.s-1 of relative wind the straight tether assumption is reasonable. Based on the tether model, an analytical criterion assessing the minimum wind speed to enable a quasi-static kite flight is developed. To solve all the interaction terms between the kite and the ship, a time domain seakeeping model based on the linearized ship equation of motion assuming a potential flow is developed. The convolution product of the impulse response of the ship is computed with state-space systems. However, since horizontal ship motions are not well represented by such theories, a coupling with a maneuvering model is presented.Comparisons to experimental data tests show good agreements. To study the interactions between the kite and the ship, a monolithic coupling and a dissociated coupling are compared. The dissociated coupling neglects the influence of ship motions on the kite flight. In a calm water case, results obtained by the two types of coupling are very close. In regular waves, ship motions are dominated by the wave influence. Thus, with the monolithic coupling, a network of low frequency subharmonic appears in the kite excitation spectrum. The fundamental frequency of the subharmonic is given by the difference between the wave frequency and the frequency of the nearest kite excitation harmonic. When this difference is small enough, a lock-in phenomenon appears. This phenomenon is a benefit for the kite and the ship when the shift of the excitation harmonics corresponds to an increase. Furthermore, a course keeping stability study shows that the rudder needs to be actively controlled.

Cette thèse s’inscrit dans le programme de recherche beyond the sea® visant à développer la traction de navire de commerce par des kites géants. Le but est d’utiliser l’énergie du vent, et ainsi de réduire la consommation de carburant des navires et réduire les émissions polluantes. Un tel projet demande de nombreux développements et actions scientifiques, en particulier pour prédire le comportement des cerfs-volants géants et des navires associés. Pour cela des modèles sont développés, mais ces modèles doivent être confrontés à des mesures pour en estimer la validité. Cette thèse a donc pour objectif de mesurer les interactions entre le kite et le navire, à une échelle limitée par rapports aux navires visés par le programme global. Des mesures ont donc été réalisées sur un navire de pêche de 13 m, puis sur un bateau expérimental de 6 m spécialement conçu à cet effet. De plus, des mesures ont aussi été menées à terre pour évaluer uniquement les performances du kite. Chacune de ces campagnes expérimentales mettait en oeuvre un dispositif de mesure complexe, ainsi qu’un système automatique de contrôle du vol du kite. En plus de fournir des données de qualité à destination de la science, les outils développés au cours de cette étude peuvent être utilisés directement par les partenaires industriels du projet beyond the sea®. / This study is part of the research program beyond the sea® aiming to develop kites as auxiliary propulsion devices for ships. The goal is to use the energy of the wind to save fuel and reduce harmful emissions. Such a project needs numerous developments and scientific actions, particularly to model the behavior of giant kites and associated ships. However these models must be compared to measurements to assess their validity. This study is then focus on the measurements of the interaction between kites and ships, at a limited scale in comparison to the real scope of the project. Thus measurement campaigns were carried out on a 13-meter long trawler, and on a 6-meter long experimental platform specifically designed. Another experimental campaign was also carried out onshore to assess the aerodynamic specs of the kite. Each of these three campaigns was based on a complex experimental set-up, including an automatic kite control system. In addition to provide a valuable data set for further scientific analyses, this study provided also tools which can be used by the industrial partners of the beyond the sea project®.

Kite energy systems are an emerging renewable energy technology. Unlike conventional turbines, kite energy systems extract wind power using tethered kites which can move freely in the wind or underwater in an ocean current. Due to the mobility, kite power systems can harvest power from regions with higher and steadier power density by moving in high-speed cross flow motion. An airborne kite energy system harnesses wind power at an altitude higher than the conventional wind turbines, while an undersea kite energy system extracts power close to the ocean surface. In this dissertation, the physical limitation, mathematical modeling, and control system design of the kite energy systems are studied. First, three major physical effects that are acting on the kite energy systems are investigated, including potential force, steady aero-/hydro-dynamic force and added mass effects. Furthermore, the dissipativity of the steady aero-/hydro-dynamic forces with respect to the apparent velocity is established. Based on this analysis, the power generation limit of the kite energy systems is studied. A power limit formulation is given which generalize the two-dimensional result to three-dimensional case. The different physical phenomenon is modeled in different coordinate systems, the difference of the density, viscosity between air and water are significant, and the kite energy system can operate in two distinct modes. To combine different physical effects into a single simulation framework, the equivalences of the kite model in different coordinate systems are established through kinematic analysis. Using these equivalent relations, a unified simulation model for airborne and undersea kite energy systems are derived. The control system design of kite energy systems is also investigated. The resulting equations of motion of kite energy systems are highly nonlinear. Therefore, Lyapunov methods are used to analyze the system behavior. Three different techniques are reviewed, including Lyapunov analysis for autonomous and non-autonomous systems, the ultimate boundedness and input-to-state stability and passivity methods. For the fixed tether length kite energy systems, the ultimate boundedness of the kite translation is established through the dissipativity of the steady aero-/hydro-dynamic force. For the variable tether length kite energy system, the input-to-state analysis is used to design the tether tension that guaranteed the boundedness of the kite translation. In both cases, the Lyapunov based methods are used to design kite rotational control systems which result in PD type control signals. Although this control scheme generates consecutive power cycles for kite energy systems. It is shown that the kite aero-/hydro-dynamical performance is unstable in the simulation which could result in unsteady power generation. To provide a steadier performance in kite translation and power output, the relative dynamics of the kite translation is first proposed. In this model, the kite apparent speed and attitudes, the angle of attack and side-slip angle, are used to describe the kite translation. A nonlinear control scheme is designed to regulate the angle of attack and side-slip angle using back-stepping methods by using the kite angular velocity and control inputs. However, due to the magnitude limit of the angular velocity, the residual error of the apparent attitude tracking remain large for the large desired angle of attack and side-slip angle. To achieve a better power harvesting and aero-/hydro-dynamics performance, the geometric properties of kite angle of attack and side-slip angle are studied. A geometric attitudes trajectory is constructed to track given apparent attitudes. A rotational control system is designed based on the back-stepping and sliding mode methods for the desired geometric attitude, and the high gain observer is applied to acquire the information needed for the rotational control signal. Through the geometric apparent attitudes tracking control algorithm, the angle of attack and side-slip angle act as direct control inputs to the kite translational motion. The kite translational dynamics under the geometric apparent attitude tracking is studied. These dynamics give the possibility of controlling the kite translational motion only through the rotational control scheme.

Exploiting high altitude wind energy using power kites is an emerging topic in the field of renewable energy. The claimed advantages of power kites over traditional wind power technologies are the lower construction costs, less land occupation and more importantly, the possibility of efficiently harvesting wind energy at high altitudes, where more dense and steady wind power exists. One of the most challenging issues to bring the power kite concept to real industrialization is the controller design. While traditional wind turbines can be inherently stabilized, the airborne nature of kites causes a strong instability of the systems. This thesis aims to develop a novel economic model predictive path-following control (EMPFC) framework to tackle the path-following control of power kites, as well as provide insightful stability analysis of the proposed control scheme. Chapter 3 is focused on the stability analysis of EMPFC. We proceed with a sampled-data EMPC scheme for set-point stabilization problems. An extended definition of dissipativity is introduced for continuous-time systems, followed by giving sufficient stability conditions. Then, the EMPFC scheme for output path-following problems is proposed. Sufficient conditions that guarantee the convergence of the system to the optimal operation on the reference path are derived. Finally, an example of a 2-DoF robot is given. The simulation results show that under the proposed EMPFC scheme, the robot can follow along the reference path in forward direction with enhanced economic performance, and finally converges to its optimal steady state. In Chapter 4, the proposed EMPFC scheme is applied to a challenging nonlinear kite model. By introducing additional degrees of freedom in the zero-error manifold (i.e., the space where the output error is zero), a relaxation of the optimal operation is achieved. The effectiveness of the proposed control scheme is shown in two aspects. For a static reference path, the generated power is increased while the kite is stabilized in the neighborhood of the reference path. For a dynamic reference path, the economic performance can be further enhanced since parameters for the reference path are treated as additional optimization variables. The proposed EMPFC achieves the integration of path optimization and path-following, resulting in a better economic performance for the closed-loop system. Simulation results are given to show the effectiveness of the proposed control scheme. Finally, Chapter 5 concludes the thesis and future research topics are discussed. / Graduate / 2020-05-14

The purpose of this thesis is to determine the factors that contributed to the decline of Florida apple snail ( Pomacea paludosa) populations in the A.R.M. Loxahatchee National Wildlife Refuge with the goal of devising management recommendations to the Refuge regarding population management strategies. The factors examined that could have potentially contributed to population decline include the use of copper-based herbicides, insecticide application, the occurrence of drought, the use of other herbicides, the occurrence of fire, and non-avian predation. Annual Narrative documents produced by Refuge managers and staff members, dated from 1951 to 2007, were used to collect historical data for these factors. The quality of data reporting within the Annual Narratives was also examined. To support data on droughts documented in the Annual Narratives, surface water and rainfall data were obtained and analyzed. The methodology includes the use of conceptual ecological models and historical ecology to determine whether or not the factors examined produced an ecological effect capable of affecting the Refuge population of apple snails. Evidence from the Annual Narratives suggests that the use of copper-based herbicides, the occurrence of drought, and predation by alligators were responsible for the decline of the apple snail on the Refuge. A lack of consistently reported data regarding apple snail densities makes it difficult to determine the degree to which each factor had an effect on the apple snails or to determine if any spatio-temporal relationship existed between the Florida apple snail and Everglade snail kite ( Rostrhamus sociabilis plumbeus) based on copper-based herbicide use. The overall quality of the Annual Narratives improved throughout the study period and eventually focused heavily on investigative studies. Several management recommendations were suggested to improve Florida apple snail populations on the Refuge. First, in order to monitor the health and trends of the apple snail population, a monitoring network needs to be established with results maintained in a geodatabase. Both apple snail density and egg cluster counts need to be made following an established sampling method. Second, in an attempt to sustain higher apple snail densities, stocking of the interior should be attempted. Finall, in the event that adjacent farmlands are to be restored, soil samples need to be analyzed to determine if concentrations are high enough that desorption of copper from the flooded agricultural soils could pose a serious threat to the Refuge by reintroducing toxic levels of copper.

Many new fabrication technologies, from nanotechnology and MEMS to printed organic semiconductors, center on constructing arrays of large numbers of sensors, actuators, or other devices on a single substrate. The utility of such an array could be greatly enhanced if each device could be managed by a programmable controller and all of these controllers could coordinate their actions as a massively-parallel computer. Kentucky Architecture nanocontroller array with very low per controller circuit complexity can provide efficient control of nanotechnology devices. This thesis provides a detailed description of the control hierarchy of a digital system needed to build "nanocontrollers" suitable for controlling millions of devices on a single chip. A Verilog design and FPGA prototype of a nanocontroller system is provided to meet the constraints associated with a massively-parallel programmable controller system.