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Obstacle avoidance and altitude control for autonomous UAVCarlsén Stenström, Jakob, Rodén, Marcus January 2018 (has links)
Drones or UAVs are quickly becoming a bigger part of today's society. Delivery servicesand transportation are elds were big development is being done. For the UAVs to beable to perform its given tasks safely more and more sensors are implemented.This report covers the development and implementation of a sensor system to helpan UAV to keep a xed altitude and provide proximity measurements of the environ-ment to avoid obstacles. The system is build around the ATmega328P microprocessorand uses I2C to communicate with the sensors. Measurements are ltered and pub-lished into ROS where the autopilot can reach the measurements and make decisionsbased on the readings. Additionally, simple algorithms to avoid obstacles have beenimplemented and simulated in the simulation software Gazebo. The altitude controlsystem which has been the main focus of the project has been implemented with goodresults in both simulation and real ight tests. The system will be used in a competi-tion held in Arizona, USA where the project team together with two other project willcompete in the prestigious CPS-challenge.
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Unmanned geographies : drone visions and visions of the droneJackman, Anna Hamilton January 2016 (has links)
This thesis approaches the study of the (aerial) military and non-military drone through an examination of the communities that variously compel and propel it into action: that culturally constitute it. Employing the term ‘proponent communities’, this thesis approaches the drone through an empiric-led exploration of such actors, those including: manufacturers, industry, regulators, governments, militaries, trade associations and end users. These proponent communities are accessed through fieldwork at three central sites, namely military and non-military tradeshows, military conferences, and through the completion of numerous industry educational courses. Whilst by no means a homogenous group, such communities remain important in crafting, composing, (re)producing and circulating both technical and cultural knowledges of the drone. In approaching the drone’s cultural constitution, the thesis pursues two distinct analytic foci. First, in response to the tendency of extant scholarship to focus upon what the functioning drone does and its implications, thus treating it like a ‘black box’, the thesis ‘opens’ the drone through an exploration of particular proponent cultures through which it is instituted. Examining both the role of military drone operators and the employment of drones with multi-sensory payloads in emergency service settings, over two chapters the thesis explores the cultures through which the drone comes to function in framing that below it. Second, the thesis explores a series of mechanisms through which the drone is articulated, visualized and otherwise legitimated as a tool, asset, and commodity within military and non-military drone tradeshows. In approaching the drone at the tradeshow, the thesis expands extant analyses of the drone by considering its cultural constitution at such hitherto unexamined sites of consumption. In approaching the cultural constitution of the drone through these two strands of investigation the thesis offers three contributions. First, in working within a research context punctuated with access limitations, the thesis opens up different windows of access at which drone proponent communities gather, form, and (re)compose drone knowledges. Second, in approaching the drone at sites in which it is instituted and traded, the thesis engages with both proponent knowledges of employment, and articulations of expectation and potential therein. It demonstrates that such an engagement facilitates the challenging of several dominant and entrenched narratives surrounding the drone, variously revealing them as inadequate, fractured, or fantastical. Third, whilst the main contribution of this thesis is to geographies, and the wider interdisciplinary field, of drone scholarship, the thesis argues for, and demonstrates the value of, engaging with alternative geographical literatures in developing its argumentation. In situating the drone within such wider discussions and landscapes the thesis thus productively develops distinct frameworks through which to conceptually and empirically engage with the drone.
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Caracterização espectral de espécies de Mata Atlântica de Interior em nível foliar e de copa /Miyoshi, Gabriela Takahashi. January 2016 (has links)
Orientador: Nilton Nobuhiro Imai / Banca: Luiz Henrique da Silva Rotta / Banca: Veraldo Liesenberg / Resumo: Florestas têm importante papel na manutenção da biodiversidade, retenção de carbono e regulação do regime hidrológico, além de garantir proteção ao solo e às fontes d'água. Podem ser classificadas em diferentes estádios de desenvolvimento, caracterizados pela presença de espécies secundárias e clímax. Atualmente, no Brasil, as florestas estão reduzidas em fragmentos espalhados em diversas regiões do país sendo seu monitoramento necessário para realização de planos de manejo. Uma das formas de realizar o monitoramento florestal é utilizando o Sensoriamento Remoto hiperespectral, que fornece informação espectral detalhada dos alvos as quais são úteis para a discriminação das espécies de vegetação que compõem o remanescente florestal. Sensores hiperespectrais acoplados a VANTs (Veículos Aéreos Não Tripulados) possibilitam a aquisição de dados para posterior delimitação das copas das espécies de vegetação. A Mata Atlântica, bioma rico em biodiversidade, está distribuída de norte a sul do Brasil, sendo classificada conforme a localização e características de cada formação florestal, dentre elas a Mata Atlântica de Interior. O objetivo desse trabalho é a caracterização espectral de espécies de vegetação em nível foliar e de copa para contribuir com informações que possam ser utilizadas para o monitoramento florestal. Foram adquiridas imagens hiperespectrais com câmara baseada no Interferômetro de Fabry-Perot acoplada em VANT. As imagens foram adquiridas na gleba Ponte Branca, perte... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Forests have an important role to support biodiversity, carbon stocks and water regime. In addition, provide fundamental protection to soil and water resources. Pioneers and climax species characterize successional stages of forest. In Brazil, forests are reduced to fragments spread out over the country, being their monitoring necessary to perform management plans. Hyperspectral Remote Sensing provides detailed spectral information about targets and is feasible to discriminate trees species. Hyperspectral sensor attached to UAVs (Unmanned Aerial Vehicles) makes possible the delineation of trees canopies. The Atlantic Forest, biome rich in biodiversity, is distributed from north to south in Brazil, being classified according to the different locations and characteristics, such as the Interior Atlantic Forest. The main objective of this project is spectral characterization of tree species in leaf and canopy level to contribute with forest monitoring. Hyperspectral images acquired with camera based on Fabry-Perot Interferometer coupled to an UAV were acquired. The interest area, Ponte Branca, belongs to the ecological station called Estação Ecológica Mico-Leão-Preto in the western region of São Paulo State. Imaging process where realized with 5 different corrections showing the importance of geometry during image acquisition and radiometric block adjustment. Trees canopies from 12 species were manually delimited in the images mosaic and Hemispherical Conical Reflectance Factor w... (Complete abstract click electronic access below) / Mestre
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Comparação de métodos de filtragem e geração de modelos digitais de terreno a partir de imagens obtidas por veículo aéreo não-tripulado /Niemann, Rafaela Soares. January 2017 (has links)
Orientador: Thiago Sanna Freire Silva / Banca: Carlos Henrique Grohmann / Banca: Cenira Maria Lupinacci da Cunha / Resumo: Os modelos digitais de elevação são importantes para a geração de informações sobre variáveis ambientais correlacionadas à topografia, principalmente como subsídio à análises geomorfométricas. O sensoriamento remoto pode contribuir com a geração de modelos digitais de elevação, principalmente através do uso de sensores de alta resolução espacial e tecnologias avançadas. Os VANTs - Veículos Aéreos Não Tripulados - tem sido cada vez mais explorados no âmbito da cartografia e topografia, com atuação cada vez mais importante dentro da ciência, devido à capacidade de transportarem diferentes sensores e ao seu baixo custo de operação. Câmeras fotográficas simples acopladas aos VANTs podem ser combinadas com tecnologias de visão computacional, trazendo novas oportunidades para explorar a geração de modelos digitais de elevação. Algoritmos de visão computacional, como o Structure-from-Motion (SfM), permitem a extração de pontos tridimensionais a partir de imagens sobrepostas obtidas por VANTs. Esses pontos compõem nuvens de pontos capazes de subsidiar a geração de modelos digitais de superfície (MDS), quando combinadas com algoritmos de interpolação de dados. Contudo, os modelos gerados desta maneira nos retornam informações relacionadas à superfície dos objetos presentes sobre o terreno, incluindo por exemplo construções e dosséis vegetais. A filtragem e classificação das nuvens de pontos se faz assim necessária para geração de modelos digitais que descrevam mais fielmente a superfí... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Digital elevation models are important for producing information on different environmental variables correlated to topography, especially for geomorphometric analyses. Remote sensing can contribute to the generation of digital elevation models, mainly through high spatial resolution sensors and advanced technologies. UAVs - Unmanned Aerial Vehicles - have been increasingly employed in the fields of cartography and topography, and have had an increasingly prominent role in science, as they can carry different sensors and have low-cost operation. Simple cameras attached to UAVs can be combined with computer vision technologies, bringing new opportunities to explore the production of digital elevation models. Computer vision algorithms such as Structure-from-Motion (SfM) allow the extraction of threedimensional points from superimposed images obtained by UAVs. These points make up points clouds capable of supporting the production of digital surface models (DSM) when combined with interpolation algorithms. However, models generated this way give us information related to the surface of objects present on the ground, including buildings and plant canopies. Point cloud filtering and classification is thus necessary for producing digital models that more accurately describe the bare terrain surface. In this dissertation, we evaluated two methods for filtering and interpolating digital terrain models (DTM) from point clouds generated by UAVbased optical imaging. The chosen study ar... (Complete abstract click electronic access below) / Mestre
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Development of a seamless morphing wingPetersen, Michael January 2010 (has links)
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2010. / The Cape Peninsula University of Technology (CPUT) Advanced Manufacturing and
Technology Laboratory (AMTL) developed an Unmanned Aerial Vehicle (UAV)
Technology Demonstrator for the purpose of testing and maturing adaptronic
devices. Extending the flight envelope of this unmanned aerial vehicle by increasing
its range and endurance is the next step in its development. A seamless variable
angle of incidence (sVAI) morphing wing is proposed to increase the lift with little
coupling to drag during takeoff; and decrease the drag with little effect on lift during
climb, thus increasing the total flight performance of the aircraft. CAD models of the
conceptualized sVAI wing and a conventional (CON) wing, as used on the
Technology Demonstrator, were modeled. Numerical analyses on these CAD models
showed that the sVAI wing concept at a 4° twist decreased the ground roll distance
and stall velocity by ±17% and ±31% respectively, as compared to the CON wing in
standard takeoff configuration. This allowed for ± 11.7% less power required for
takeoff allowing the aircraft to get to its operational altitude quicker, thus saving fuel
and reducing energy losses; and increasing range and endurance. The results also
showed that the sVAI wing concept could reduce the drag during climb by ± 14%,
but the lift is also proportionately reduced thus having little improvement on the
climb phase of flight performance. A prototype of the morphing wing was then
conceptualized and designed, using a 3D CADmodeler, and then manufactured. The
product development chain produced for this morphing wing included two rapid
prototyping machines and reverse engineering technologies. The chain allowed for
the rapid manufacturing of light weight and intricate parts. The manufactured wing is
then incorporated into a test rig to compare the actual morphing ability of the
prototype to the theoretical morphing ability of the CADmodel, and thus make flight
performance predictions of the actual vehicle. 3D scans were taken of the prototype
and then converted to 3D CADfiles. The geometrical and topographical deformation
of the prototype was then compared to that of the CAD model showing an average difference of ±1.2% and ±3% at maximum positive and negative configurations,
respectively. This allowed one to make the prediction that the sVAI wing will increase
the performance of the Technology Demonstrator.
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Development and stabilization of an unmanned vertical takeoff and landing technology demonstrator platformOnochie, Cyprian Ogonna January 2017 (has links)
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017. / Small and micro unmanned aerial vehicles (UAV) are rapidly becoming viable platforms for surveillance, aerial photography, firefighting and even package delivery. While these UAVs that are of the rotorcraft type require little to no extra infrastructure for their deployment, they are typically saddled with short ranges and endurance, thus placing a restriction on their usage. On the other hand, UAVs that are of fixed wing type generally have longer range and endurance but often require a runway for take-off and landing which places a restriction on their usage.
This project focuses on the development of a vertical take-off and landing (VTOL) UAV demonstrator suitable for integration on a small or mini flying wing UAV (a fixed wing UAV) to counteract the take-off and landing limitations of fixed wing type UAVs.
This thesis first presents a propulsion characterisation experiment designed to determine the thrust and moment properties of a select set of propulsion system components. The results of the characterisation experiment identified that the propulsion set of a Turnigy C6374 – 200 brushless out runner electric motor driving a 22 x 10 inch three bladed propeller will provide approximately 79N (8kg) of thrust at 80% throttle (4250rpm). Therefore, two of these propulsion set would satisfy the platform requirement of 12kg maximum take-off mass (MTOM).
The result of the abovementioned experiment, together with the VTOL platform requirements were then used as considerations for the selection of the suitable VTOL method and consequently the design of the propulsion configuration. Following a comparison of VTOL methods, the tilt-rotor is identified as the most suitable VTOL method and a variable speed twin prop concept as the optimal propulsion configuration.
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Análise da qualidade cartográfica de MDS e MDE gerados por VANT e refinados com uso de dados GNSS RTK / Analysis of the cartographic quality of DSM and DEM generated by UAV and refined using GNSS RTK dataViana, Diogenes Carvalho 19 December 2017 (has links)
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Previous issue date: 2017-12-19 / Dentre as técnicas utilizadas na aquisição de dados destacam-se os levantamentos com Veículos Aéreos Não Tripulados (VANT) e levantamentos de posicionamento relativo em tempo real (RTK – Real Time Kinematic). O uso dessas duas tecnologias é de grande interesse na geração de Modelos Digitais de Elevação (MDE) pela praticidade e facilidade de aquisição de dados. O objetivo do estudo é avaliar a qualidade dos MDEs gerados com base nos dados de VANT e GNSS RTK, bem como propor e avaliar a integração de tais dados, visando o refinamento do MDE. A avaliação foi realizada através de coleta de dados com Estação Total e receptor GNSS RTK em uma área pertencente a Universidade Federal de Viçosa localizada na cidade de Viçosa-MG. O Modelo Digital de Superfície (MDS) foi filtrado utilizando o software LAStools para geração do MDE. Os dados de VANT foram refinados a partir dos dados de receptor GNSS RTK na tentativa de melhorar sua qualidade cartográfica. Na primeira abordagem foram adicionados pontos de controle obtidos por GNSS RTK nos locais onde foram geradas lacunas de dados pelo processo de filtragem. Já na segunda abordagem foram selecionados pontos de duas formas distintas: direções e malha regular. Após a seleção dos pontos calculou-se a discrepância entre os mesmos e os modelos (MDE e MDS). Assim, os valores das discrepâncias foram interpolados e cada modelo gerado foi subtraído dos modelos originais gerando um novo MDE ou MDS refinado. Todos os modelos foram validados com os pontos obtidos por topografia e classificados de acordo com o padrão de acurácia posicional definido pelo Decreto 89.817 / ET-CQDG. Ao avaliar os modelos gerados constatou-se que a integração dos dados obtidos por VANT com dados obtidos por receptor GNSS RTK apresentou melhoria na qualidade posicional na maioria dos modelos analisados indicando ser uma ferramenta promissora para alcançar modelos de maior qualidade cartográfica ou melhorar modelos já existentes. / Among the techniques used in the data acquisition, we highlight the surveys with Unmanned Aerial Vehicles (UAV) and Real Time Kinematic (RTK) positioning surveys. The use of these two technologies is of great interest in the generation of Digital Elevation Models (DEM) for the convenience and ease of data acquisition. The objective of the study is to evaluate the quality of the DEM generated based on the UAV and GNSS RTK data, as well as to propose and evaluate the integration of such data, aiming the refinement of the DEM. The evaluation was performed through data collection with Total Station and GNSS RTK receiver in an area belonging to the Federal University of Viçosa located in the city of Viçosa-MG. The Digital Surface Model (DSM) was filtered using the LAStools software to generate the DEM. The UAV data were refined from GNSS RTK receiver data in an attempt to improve their cartographic quality. In the first approach were added control points obtained by GNSS RTK in the places where data gaps were generated by the filtering process. In the second approach, points were selected in two different ways: directions and regular mesh. After selecting the points, the discrepancy between them and the models (DEM and DSM) was calculated. Thus, the discrepancy values were interpolated and each generated model was subtracted from the original models generating a new refined DEM or DSM. All models were validated with the points obtained by topography and classified according to the positional accuracy pattern defined by Decree 89.817 / ET-CQDG. When evaluating the generated models it was verified that the integration of the data obtained by UAV with data obtained by GNSS RTK receiver showed improvement in positional quality in most of the analyzed models, indicating that it is a promising tool to reach models of higher cartographic quality or to improve existing models.
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Optimisation of electric long endurance unmanned aerial vehiclesFourie, Dehann 06 June 2012 (has links)
M.Ing. / Sustained or long endurance solar powered flight is defined as an aircraft capable of main- taining flight through multiple day-night flight cycles, using only solar power and rechargable energy stores. The project is focused on developing solar powered flight theory and real-world unmanned aerial vehicle implementations. The important aspects of system design are es- tablished and studied at a fundamental theoretical level. A preliminary design is conducted with endurance optimisation as the main aim. The optimisation process aims to establish a theoretical basis for sustained solar powered flight. The project is started with a feasibility and relevance study. A literature study was used to gather the required theoretical information. A novel theoretical preliminary design basis is conducted. The study is aimed at answering many questions in the field. The study is the first to show how previously varied aircraft from 3 m to 80 m are valid solutions to the long endurance flight requirement. The optimisation results correlates well with the current state-of-the-art. The theoretical models were then characterised through the development of two unmanned aerial vehicles. The development required a multidisciplinary integration of various fields. The development process was characterised and discussed. Flight automation was successfully integrated into the system. Multiple test flights were conducted. An interpretation of multi- faceted results are given. This project has contributed to international theory regarding solar powered and sustained endurance aircraft. Many specific contributions were made to the field. The project has achieved multiple unofficial records from the flight tests in the Southern Hemisphere and African continent.
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Flying Penguins : Building and Evaluating the Viability of a Linux-based DroneMårtensson, Anders January 2016 (has links)
Traditional quadcopter flight controllers use microcontrollers to run the code that keeps the drone in the air, and when more processing power or versatility is needed the same microcontrollers are used in tandem with Linux-based single-board computers. It would be cheaper and reduce complexity if the single-board computer could entirely replace the microcontrollers. We investigate whether it is possible to run a quadcopter using a Linux single-board computer as the flight controller, with no microcontrollers and otherwise the same hardware as used in hobby-grade quadcopters. We attempt to find out what the potential issues are and how to get around or mitigate them. To test it, a quadcopter will be built from hobby parts and the flight control software to be run on the flight controller will be developed. More specifically, the pulse-width modulation signals to the motor speed controllers are checked for stability and various methods of acquiring the radio control input in the form of pulse-width modulation signals are evaluated. The speed at which the flight control software is running is measured under different circumstances—with and without load and with and without mitigative measures active. We conclude that it was not possible to run a quadcopter using only the chosen Linux SBC as flight controller. The reason was because we could not accurately measure the radio control input, although there may be other additional issues. We did find that CPU time did not seem to be an issue even when an artificial stress was placed on the system, despite not being a real time system, and even less of an issue when the mitigation techniques discussed were applied.
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Long-term spatial-temporal eelgrass (Zostera marina) habitat change (1932-2016) in the Salish Sea using historic aerial photography and unmanned aerial vehicleNahirnick, Natasha K. 18 May 2018 (has links)
Eelgrass (Zostera marina) is a critical nearshore marine habitat for juvenile Pacific salmon (Oncorhynchus spp.) as they depart from their natal streams. Given the poor marine survival of Coho (O. kisutch) and Chinook (O. tshawytscha) salmon juveniles in recent decades, it is hypothesized that deteriorating eelgrass habitats could contribute to their low survival. The primary goal of this research was to investigate the possible long-term spatial-temporal trends in eelgrass habitat in the Salish Sea and was addressed by two main objectives: (1) Define a methodology for mapping eelgrass habitats using UAV imagery to create a baseline for long-term mapping; and (2) Assess changes in eelgrass area coverage and fragmentation over the period of 1932-2016 using historic aerial photographs and Unmanned Aerial Vehicle (UAV) imagery, and assess the relationship between eelgrass and residential housing density and shoreline activities. Three study sites in the Southern Gulf Islands of the Salish Sea were chosen for analysis. The overall accuracies of eelgrass delineation from UAV imagery were 95.3%, 88.9%, and 90.1% for Village Bay, Horton Bay, and Lyall Harbour, respectively. The UAV method was found to be highly effective for this size of study site, however results were impacted by the environmental conditions at the time of acquisition, namely: sun angle, tidal height, cloud cover, water clarity, and wind speed. The results from the first objective were incorporated into a long-term dataset of historic aerial photography and used to evaluate changes in eelgrass area and fragmentation. All three eelgrass meadows showed a deteriorating trend in eelgrass condition. On average, eelgrass area coverage decreases by 41% while meadow complexity as indicated by the shape index increases by 76%. Shoreline activities (boats, docks, log booms, and shoreline armouring) and residential housing density increased markedly at all sites over the study period. By using a linear correlation model, it was revealed that eelgrass areal coverage and fragmentation (Shape Index) were, in general, very strongly correlated to these landscape-level coastal environmental indicators. While this correlation model is not meant to show a direct causative impact on eelgrass at these sites, these results suggest an overall deterioration of coastal environmental health in the Salish Sea due to a dramatic increase in the use of the coastal zone, as well as likely declines in water quality due to urbanization. / Graduate
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