<p>Solar-powered Unmanned Aerial Vehicles (UAVs) solve the problem of loiter time as aircrafts can fly as long as sufficient illumination and reserve battery power is available. However, Solar-powered UAVs still face the problem of excessive wingspan to increase solar capture area, which detracts from maneuverability and portability. As a result, a feature of merit for solar UAVs has emerged that strives to reduce the wingspan of such UAVs. The purpose of this project is to improve energy use efficiency by applying a distributed propulsion system to reduce the wingspan of solar-powered UAVs and increase payload. The research focuses on optimizing a new design analysis method applied to the distributed propulsion system and further employs the novel application of solar arrays on both top and bottom of the wings. The design methodology will result in a 2.1-meter wingspan, which is the shortest at 2020, for a 24-hour duration solar-powered UAV.</p><br>

Veículos Aéreos não tripulados (VANTs) vêm sendo cada vez mais utilizados em diversos países, tanto na área militar como na civil. O cenário considerado nesse estudo é o de um VANT realizando captura de vídeo em tempo real, transmitindo-o a uma base terrestre por meio de rede sem fio. O problema consiste no fato de não ser possível garantir uma taxa de transmissão contínua, com banda estável. Isso ocorre devido a fatores como a velocidade da aeronave (da ordem centenas de km/h), irregularidades de terreno (impedindo a linha de visada do enlace de transmissão), ou do clima, como tempestades que podem interferir na transmissão da RF. Por fim, os movimentos que o VANT pode realizar no vôo (Rolagem, Arfagem ou Guinada) podem prejudicar a disponibilidade do link. Dessa forma, é necessário que seja realizada adaptação de vídeo de acordo com a banda disponível. Assim, quando a qualidade do enlace for degradada, deverá ser realizada uma redução no tamanho do vídeo, evitando a interrupção na transmissão. Por outro lado, a adaptação também deverá fazer com que a banda disponível seja utilizada, evitando o envio de vídeos com qualidade inferior à que seria possível para determinado valor de largura de banda. Nesse trabalho será considerada a faixa de valores de largura de banda de 8 Mbps até zero. Para realizar a adaptação será utilizado o padrão H.264/AVC com codificação escalável / Unmanned Aerial Vehicles (UAVs) are being increasingly used in several countries, both in the military and civilian areas. In this study we consider an UAV equipped with a camera, capturing video for a real-time transmission to a ground-base using wireless network. The problem is that its not possible to ensure a continuous transmission rate, with stable bandwidth. That occurs due to factors like the speed of the aircraft, irregularities of terrain, or the weather (as storms, heat and fog, for instance, can interfere with RF transmission). Finally, the movements that the UAV can perform in flight (Roll, pitch and yaw) can impair link availability. Thus, it is necessary to perform an adaptation of video according to the available bandwidth. When the link quality is degraded, a reduction in the resolution of the video must be performed , avoiding interruption of the transmission. Additionally, adaptation must also provide that all the available bandwidth is used, avoiding sending the video with lower quality that would be possible for a given value bandwidth. In this work we propose a system which can vary the total amount of data being transmitted, by adjusting the compression parameters of the video. We manage to produce a system which uses the range from 8 Mbps up to zero. We use the H.264/AVC Codec, with scalable video coding

Cette thèse s'intéresse à la réalisation autonome de plans de vol cinématographiques par un quadrotor équipé d'une caméra. Ces plans de vol consistent en une série de points de passage à rejoindre successivement, en adoptant diverses méthodes de prise de vue et en respectant des références de vitesses ainsi que des couloirs de vols. Une étude approfondie de la dynamique du quadrotor est tout d'abord proposée et utilisée pour construire un modèle linéarisé du drone autour de l'équilibre de vol stationnaire. L'analyse de ce modèle linéaire permet de mettre en évidence l'impact de l'inertie des rotors du drone dans sa dynamique, notamment l'apparition d'un comportement à non minimum de phase en roulis ou tangage, lorsque les moteurs sont inclinés. Dans un second temps, deux algorithmes de génération de trajectoires lisses, faisables et adaptées à la cinématographie sont proposés. La faisabilité de la trajectoire est garantie par le respect de contraintes sur ses dérivées temporelle, adaptées pour la cinématographie et obtenue grâce à l'étude du modèle non linéaire du drone. Le premier repose sur une optimisation bi-niveaux d'une trajectoire polynomiale par morceaux, dans le but de trouver la plus rapide des trajectoires à minimum de jerk permettant d'accomplir la mission. Le second algorithme consiste en la génération de trajectoires B-spline non-uniformes à durée minimale. Pour les deux solutions, une étude de l’initialisation du problème d'optimisation est présentée, de même qu'une analyse de leurs avantages et limitations. Pour ce faire, elles sont notamment confrontées à des simulations et vols extérieurs. Enfin, une loi de commande prédictive est proposée pour asservir les mouvements de la caméra embarquée de manière douce et précise. / This thesis focuses on the autonomous performance of cinematographic flight plans by camera equipped quadrotors. These flight plans consist in a series of waypoints to join while adopting various camera behaviors, along with speed references and flight corridors. First, an in depth study of the nonlinear dynamics of the drone is proposed, which is then used to derive a linear model of the system around the hovering equilibrium. An analysis of this linear model allows us to emphasize the impact of the inertia of the propellers when the latter are tilted, such as the apparition of a nonminimum phase behavior of the pitch or roll dynamics. Then, two algorithms are proposed to generate smooth and feasible cinematographic trajectories. The feasibility of the trajectory is ensured by constraints on its time derivatives, suited for cinematography and obtained with the use of the nonlinear model of the drone. The first algorithm proposed in this work is based on a bi-level optimization of a piecewise polynomial trajectory, in order to find the fastest feasible minimum jerk trajectory to perform the flight plan. The second algorithm consists in the generation of feasible, minimum time, non-uniform B-spline trajectories. For both solutions, a study of the initilization of the optimization problem is proposed, as well as a discussion about their advantages and limitations. To this aim, they are notably confronted to simulations and outdoor flight experiments. Finally, a predictive control law is proposed to smoothly and accurately control the onboard camera.

In recent years, advances in small unmanned aerial vehicle (UAV) technology have transformed the use cases of these aircraft from hobby flying to industrial and business applications. These maneuverable, easily deployed tools can be retrofitted with a myriad of sensors and equipment, which make them suitable to perform a variety of specialized tasks. With increasing UAV capabilities, the function of small UAVs can be extended from pure monitoring or surveillance to the dual objective of monitoring an environment for events and addressing the events in some way. This thesis seeks to explore a subdomain of the dual objective problem described, referred to in this thesis as the multi-UAV persistent search and retrieval task with stochastic target appearance (PSR-STA), in which UAVs continuously search an area over a long period of time for targets of interest, which appear according to a probabilistic model, to retrieve and deliver them to a collector location. The advent of high-speed computers and agent-based modeling theory enable the simulation of multi-UAV PSR-STA. However, it can be complicated to combine parts of multi-UAV PSR-STA such as motion models and multi-UAV coordination into one integrated system, and even after they are combined successfully, it is difficult to analyze the system except with simple comparison tools. This thesis 1) proposes a framework that builds a foundation for understanding how to simulate and analyze multi-UAV PSR-STA through prescribing important design decisions and methods for simulation and 2) identifies metrics, analysis tools, and trends related to overall system effectiveness for multi-UAV PSR-STA. A case study of multi-UAV park cleanup is implemented where many simulations with input parameters chosen by a latin hypercube design of experiments are examined, algorithms for choosing the locations of collectors and charging stations based on probabilistic information are proposed, and the differences in effectiveness between four coverage search patterns are analyzed. Measures are highlighted that provide insight into performance variability over time and space. Line charts and the discrete Fourier transform are used to understand temporal patterns inherent in the data. Principal component analysis is used to analyze relevant spatial patterns in effectiveness, and a random forest surrogate model with a profiler is used to explore the non-linear influence of input parameters on the spatial patterns. The trellis chart or figure of figures method is presented for visualizing spatial and temporal data across many simulations. A second set of experiments based on the park cleanup case study are performed and examined to verify the benefits of these methods.

The thesis introduces an innovative UAV detection system. The commercial UAV market is booming. Meanwhile, the risks and threats from improper UAV usages are also booming. CUAS is to protect the public and facilities. The problem is a lack of an intelligent platform which can adapt many sensors for UAV detection. The hypothesis is that, the system can track the UAV’s movement by applying the multi-agent system (MAS) to UAV route track. The experiment proves that the multi-agent system benefits for the UAV track. <br>

Die Herstellung von optisch realistischen und hochgenauen 3D Modellen stellt eine zentrale Frage im Bereich der geodätischen und markscheiderischen Forschung dar. Mit dem zusehenden Aufkommen unbemannter Flugsysteme haben sich photogrammetrische Messsysteme als erschwingliche und flexible Alternative etabliert, wobei zur Gewährleistung definierter Genauigkeiten und somit zur Verwendung vergleichbarer Systeme für vermessungstechnische Anwendungen eine sorgfältige Flugplanung, Durchführung und Auswertung unbedingte Erfordernisse sind. Im vorliegenden Beitrag wird einerseits auf die laufenden Forschungen zu Genauigkeit und Anwendbarkeit der UAV-basierten Vermessung im Bergbau eingegangen und andererseits werden zukünftige Forschungstendenzen aufgezeigt, wodurch in neue, bislang nicht erreichbare Anwendungsfelder, vorgedrungen werden könnte. / Creating and visualizing realistic and accurate 3D models is a central ambition of research in the field of geodesy and mine surveying. Due to the increasing affordability of un-manned aerial vehicles (UAVs) photogrammetric systems have been well established as affordable and flexible alternative. In order to ensure a certain accuracy and thus to enable the usage for surveying applications, careful flight planning, implementation and evaluation are of special importance. This paper discusses the ongoing research on accuracy and applicability of UAV-based mine surveying as well as future research tendencies, whereby new, currently not achievable fields of application could be investigated.

Zur Überwachung geotechnischer Schwerpunktbereiche kommen in den Tagebauen der Lausitz Energie Bergbau AG unterschiedliche Systeme zum Einsatz. Eine hohe Flexibilität und erweitere Einsatzmöglichkeiten ergaben sich durch die Verbindung einfacher GNSS-Empfänger und geotechnischer Sensoren zu einem Gesamtsystem (A07Geo). Darüber hinaus werden A07-Empfänger zur Bewältigung vielfältiger Fragestellungen herangezogen. Zwei im Bestand der Markscheiderei befindliche UAV’s eröffnen die Möglichkeit, bei geotechnischen Ereignissen schnellstmöglich auch georeferenziertes Bild- und Videomaterial sowie daraus resultierend Volumenbestimmungen und weiterführende Messungen zur Verfügung zu stellen. Daneben werden aktuell geotechnische Einsatzszenarien für eine Wärmebildkamera näher untersucht.

Die erreichte Zerkleinerung und die Form des Haufwerks sind die beiden wichtigsten Ergebnisse einer Tagebausprengung. Schnelle Informationen über die Eigenschaften des gesprengten Haufwerks ermöglichen eine zielgerichtete und effiziente Produktionsplanung und Kenntnisse über die erreichte Zerkleinerung ermöglichen außerdem Anpassungen in der weiteren Zerkleinerungskette. Durch den Einsatz von UAVs (unmanned aerial vehicles) gemeinsam mit modernen Algorithmen aus dem Bereich Computer Vision und des maschinellen Lernens soll eine schnelle Erfassung und Interpretation der Daten bei gleichzeitiger Integration in die herkömmlichen betrieblichen Abläufe ermöglicht werden, und außerdem können Schwächen bodengebundener Systeme hinsichtlich Vollständigkeit und Repräsentativität umgangen werden. Im vorliegenden Beitrag wird einerseits auf den relevanten Stand des Wissens und der Technik eingegangen und andererseits wird die verfolgte Stoßrichtung bei der Systementwicklung dargelegt sowie erste Arbeiten präsentiert. / The fragmentation and the shape of the muck pile are the two major outcomes of open pit mine and quarry blasts. Fast information about the muck pile properties will help to improve the production scheduling and furthermore this information could be used to optimize the blasting patterns of future production blasts. The combined use of unmanned aerial vehicles (UAVs) and modern machine learning and computer vision systems offers a new way of acquiring spatial data to determine on-site fragment size distribution, while at the same time enabling integration into common work flows and mitigating the weaknesses of ground-based systems with special regard to completeness and representativeness. In the present paper, we will discuss the relevant related work, present the planned path for system development and give examples of first work.

Various remote sensing methods are being utilized to assess fundamental properties of forest stands, such as the height of trees, already for decades. Nevertheless, the use of Unmanned Aerial Vehicles in the combination with Structure from Motion software for these purposes, experiences its boom right now and thus not many pertinent studies exist yet. Such system producing image-based point clouds was utilized in this work to gain the canopy elevation data. To identify individual trees and to extract their height from these remote sensing data, a unique software tool called 'UAV Forest Explorer' was developed. Twenty forest study plots was established to acquire the field measurements ground truth data about almost 1 500 trees to thoroughly test the tool and calculate demanded statistics. The research proved, that the tool is fully applicable on all types of forest stands.

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