Dissertation (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2011 / This paper presents the development of a data collection system for a small unmanned Aerial Vehicle (UAV) flight. The following three facets comprise of a UAV system: (1) a UAV aircraft; (2) onboard avionics; and (3) a ground control station subsystem (Taha et al., 2010:1). In this project, the UAV aircraft is based on the low-cost autonomous quad-rotator system named “Arducopter Quad”, where the onboard avionic system utilizes both an ArduPilot Mega (APM) on-board controller and IMU sensor shield, while the “Mission Planner” software operates as GCS software to gather essential flight data (Xiang & Tian, 2011:176). The approach provides the UAV system structure and both hardware and software with a small UAV data collection system, which is examined throughout the study. And introduce the concept of Arducopter dynamics for better understanding with its flight control. The study also considers the communication process between the UAV and the ground control station. The radio wave is an important aspect in the UAV data collection system (Austin, 2010:143). The literature review introduced the basis of the radio wave in respect of its travelling speed, and its characteristics of propagation, including how different frequencies will affect radio wave propagation. The aim of this project was to develop a platform for a small UAV real-time data collection system. The pendulum system was involved to simulate the “Roll” movement of the small UAV, while real-time IMU sensor data was successfully collected at ground control station (GCS), both serial communication and wireless communication, which was applied in the data collection process. The microwave generator interference test proves that the 2.4 GHz XBee module is capable of establishing reliable indoor communication between the APM controller and the GCS. The work of this project is towards development of additional health monitoring technology to prevent the safety issue of the small UAV. The data collection system can be used as basis for the future research of real-time health monitoring for various small UAVs.

In order to successfully compete against the use of fossil fuels to generate electricity, one of the challenges in the photovoltaic (PV) business currently in focus is on the asset management of large PV plants, in which developing control techniques to prognosticate and evaluate the future energy performance will be essential. Infrared thermography inspections can give meaningful support to assess the quality and performance of PV modules. However, the implementation of a cost-effective method to scan and check huge PV plants represents different challenges, such as the cost and time of detecting PV module defects with their classification and exact localization within the solar plant. In this context, it has recently been investigated the potential of a new innovative technology in the PV plants monitoring operations by using drones. The main purpose of this work is to establish a scientific basis for the interpretation of thermographic images taken by drones, in particular, regarding the influence of thermographic irregularities which will negatively influence the performance of PV plants. The drone is employed to monitor PV modules conditions by using special thermography sensors mounted on it in order to scan images. The captured images are then automatically sent to a technical office database for the image processing software. This special software receives, stores and analyses the captured images to detect the specific defect on the PV modules. Then, all information is processed and reported to the final decision-making team to decide about the best solution for the particular degraded PV module, in relation with the requirements from the operation and maintenance (O&M) services. In this particularly study project of the inspected PV plant situated in the UK, which has been carried out by trained personnel at Quintas Energy (QE), the majority of identified faults, which influence the PV module performance (especially the power output significantly), are on a sub-panel level, either individual cells or uneven hot spots. There are also some modules with bypass diode faults as well as a string fault was detected. Such faults must be repaired by the PV module manufacturer, in relation to the manufacturer’s warranties, without any cost at all since the PV modules are indeed still in warranty. It has been concluded that, in comparison with traditional manned systems by using hand-held cameras, the main functionality of using drones is the early fault diagnosis which could reduce corrective maintenance activities, since defects are easily and quickly identified and, then, repaired. This fact could reduce defects to become more serious and, thus, more difficult to be repaired, along with their correspondent production losses and costs. QE has learned by making mistakes during this project study and gained experience of this unmanned aerial vehicles (UAV) technology. Currently, they are in the process of improving this technique and will continue to implement it to all their PV plants since the efficiency of PV systems can be significantly improved by appropriate use of O&M instruments and benefit from innovative monitoring tools, such as the unmanned aerial technology.

Este trabalho dedica-se ao projeto e desenvolvimento de um veículo aéreo não tripulado. Tais veículos podem ser utilizados em diversas aplicações como monitoramento, vigilância, transporte, resgate, entre outros. Dentre os diversos tipos de veículos aéreos, este trabalho irá focar no modelo do quadrirotor, composto por quatro hélices contra-rotoras que estabilizam e movimentam o veículo. Para alcançar o objetivo de controlar este tipo de veículo, várias propostas e metodologias podem ser aplicadas, todas buscando contemplar o controle de todas ou parte das variáveis de estado presentes nesta planta. Neste texto serão descritas: as equações cinemáticas e dinâmicas que regem este sistema; o projeto e composição mecânica da aeronave; definição de sensores e atuadores juntamente com seus métodos de utilização; implementação de controlador linear por alocação direta de polos e Regulador Linear Quadrático juntamente com observador de estados de ordem plena e filtro de Kalman, para recuperação de estados não mensurados e filtragem de ruídos. Serão apresentados resultados em simulações para cada método de controle selecionado visando optar pelo melhor controlador para a aplicação da aeronave. O método selecionado será implementado para controlar a aeronave com os sensores e atuadores selecionados. Esta implementação será realizada a partir da técnica HIL Hardware in The Loop juntamente com o software MATLAB/Simulink visando validar o controlador em conjunto com a planta real, bem como o modelo dinâmico construído. / This work is dedicated to the project and development of an unmanned aerial vehicle. Such vehicles can be employed in various applications such as monitoring, surveillance, transportation, rescue and others. Among the types of aerial vehicles, this work is focused on the quadrotor, composed by four counter-rotating propellers which stabilize and displace the vehicle. In order to fulfill the objective of controlling this vehicle, many methodologies and propositions can be applied, seeking the control of all or a snippet of the state variables present in the system. There will be described in this work: the cinematic and dynamic equations that govern this system; the mechanical project and construction of the aircraft; sensors and actuators definition, along with its usage methods; linear control implementation of the pole placement and Linear Quadratic Regulator techniques along full order state observer and Kalman filtering in order to recover and filter non-measured states. Performance results in simulations will be presented on each control implementation to validate the best controller for the application and this implementation will be applied on the projected aircraft using the sensors and actuators selected. This implementation will be given through the HIL - Hardware in the Loop method using MATLAB/Simulink software to validate the control technique applied and the constructed dynamic model.

Sistemas de Transportes Inteligentes (STIs) englobam um conjuntos de tecnologias (Sensoriamento Remoto, Tecnologia da Informação, Eletrônica, Sistemas de Comunicação de Dados entre outros) que visam oferecer serviços e gerenciamento de tráfego avançado para meios de transporte rodoviário, aéreo e outros. A obtenção de informações a respeito das características e das condições do pavimento das estradas constitui uma parte importante dentro do sensoriamento nesses STIs. Investigar novas técnicas, metodologias e meios de automatizar a obtenção dessas informações é parte deste trabalho. Uma vez que existem diferentes tipos de defeitos em vias pavimentadas, esta tese apresenta a proposta de uma metodologia que permite a obtenção, de forma automática, das condições dos pavimentos asfálticos. A obtenção dos dados foi realizada por meio do Sensoriamento Remoto com uso de Veículos Aéreos Não Tripulados. A utilização de técnicas de Aprendizado de Máquina na detecção automática possibilitou alcançar uma acurácia de 99% na detecção de pavimentos asfálticos flexíveis e 92% na identificação de defeitos em alguns experimentos. Como resultado obteve-se o diagnóstico automático, não só das condições da via, mas de diferentes tipos de defeitos presentes em pavimentos. / Intelligent Transport Systems (ITS) is a set of integrated technologies (Remote Sensing, Information Technology, Electronics, Data Communication Systems among others) that aims to provide services and advanced traffic management for road, air, rail and others transportation systems. Obtaining information about characteristics and road pavement conditions is an important part within the sensing these ITS. Investigating new techniques, methods and means to optimize and automate obtaining these information are part of this work, since there are different types of defects on paved roads. Thus, this thesis proposes a methodology that allows automatically obtain information about the condition of the pavement. Data collection was performed with remote sensing technology using Unmanned Aerial Vehicles. Automatic detection was possible through the use of Machine Learning techniques with 99% of accuracy in pavements and 92% in distress identification. As a result we obtained the self-diagnosis, not just the pavement, but different types of distress present in the pavement.

L'objet de cette thèse est de démonter la faisabilité de conception d'un mini-drone longue endurance sans recourir à des véhicules de grande envergure qui nécessite des infrastructures supplémentaires, des systèmes de lancement complexes et un personnel d'exploitation important. Pour ce faire, une approche d'optimisation globale du problème a été utilisée, en s'appuyant sur les spécificités de chacun des aspects de la conception de mini-drones. Ce concept de mini-drone longue endurance doit repousser les limites dans plusieurs disciplines telles que l'aérodynamique, la propulsion, les structures, les sources d'énergies et le stockage, le contrôle et la navigation, ainsi que la miniaturisation de l'électronique embarquée. Un programme de conception baptisé Cdsgn a été développé et prend en compte les problèmes spécifiques de chaque discipline consacrées aux mini-drones. Il permet de voir l’influence de chaque paramètre de conception sur la performance finale de la conception, menant à la sélection optimale des paramètres. Cdsgn génère et analyse rapidement de nombreuses configurations de l'avion tout en simulant la performance de chaque configuration pour un pro fil de mission donnée. Un outil de post-traitement a également été développé afin de filtrer et sélectionner de manière interactive les paramètres de conception parmi les nombreuses configurations pour répondre à des applications pratiques. Le programme proposé a été utilisé dans le développement et la conception de plusieurs projets, tels que Solar Storm, premier mini-drone hybride au monde à énergie solaire d'une envergure de cinquante centimètre, SPOC, un mini-drone longue distance conçu pour voler au-dessus de la mer Méditerranée de Nice jusqu'en Corse (Calvii) et enfin Eternity, mini-drone de longue endurance d'une envergure d'un mètre, avec une configuration classique. Capable d'une autonomie de quatre heures avec les batteries embarquées, son temps de vol peut être amélioré jusqu’à huit heures avec l'utilisation de l’énergie solaire. En utilisant les évaluations de chaque projet, Cdsgn a été amélioré à la fois pour l'exactitude des calculs et pour la performance opérationnelle afin de développer le plus petit véhicule aérien pour une mission d'endurance donnée. / This thesis shows the feasibility of designing a long endurance mini UAV without resorting to large scale vehicles which requires additional infrastructure, complex launching systems and numerous operating crew. To do so is possible by using a global optimisation approach concentrated specifically on each aspect of the mini-UAV design with their particular challenges. So called Long Endurance Mini UAV Concept has to push the limits in several disciplines such as aerodynamics, propulsion, structures, energy source and storage, control and navigation, miniaturised electronics. A conceptual design program called Cdsgn is developed which takes into account each discipline's specific problems devoted to mini UAVs and making it possible to see the influence of each design parameter on the final performance of the complete design leading to the optimum selection of parameters. Cdsgn generates and analyse numerous aircraft configurations rapidly while simulating the performance of each configuration for a given mission profile. A post processing tool is also developed in order to interactively filter and select the final design parameters among numerous analysed aircraft configurations for practical applications. The proposed program is used in the development and design of several projects, such as Solar Storm, the world's first hybrid solar powered micro UAV in half a meter scale, SPOC, a long range mini UAV which is designed to fly across the Mediterranean sea from Nice to Corsica (Calvi) and finally the Eternity, the long endurance mini UAV concept which is an electrically powered, one-meter span aircraft with a conventional configuration having an endurance of four hours with the on-board batteries which can be enhanced up to eight hours with the use of solar-cells. Using the feedback of each project, Cdsgn has been improved both for the accuracy and for the operational performance in order to develop the smallest aerial vehicle for a given endurance mission.

A aplicação de defensivos químicos em áreas agrícolas é de primordial importância para o rendimento de lavouras. O uso de aeronaves é cada vez mais comum em tal tarefa, principalmente pelo fato de aumentar a agilidade na operação. Entretanto, características climáticas, como intensidade e orientação do vento, podem causar prejuízo aos produtores (e.g. aplicação sobreposta dos defensivos e multas por aplicação de defensivos na borda exterior da lavoura). Essa lacuna motivou este trabalho de mestrado, que tem por objetivo avaliar um sistema integrado de veículos aéreos não tripulados (VANTs) e redes de sensores sem fio (RSSFs) para aumentar a eficiência da aplicação de defensivos químicos em campos agrícolas. Um VANT é utilizado para percorrer o campo enquanto aplica defensivos químicos. Uma RSSF com nós capazes de sensoriar a concentração de defensivos químicos é instalada no solo do campo. Os nós da RSSF e o VANT são equipados com módulos de rádio, possibilitando a troca de informação entre eles. Desse modo, o VANT consegue obter a distribuição de defensivos químicos aplicados no campo, podendo então tomar decisões para aumentar a eficiência da aplicação. Para análise desse sistema, dois experimentos foram realizados utilizando o simulador OMNeT++ e o framework MiXiM. Em um primeiro experimento é comparada a eficiência do sistema proposto com o sistema tradicional de pulverização agrícola, mostrando que é possível aumentar, em média, 16% a quantidade de defensivos químicos aplicados dentro do campo agrícola. E, em alguns casos, é possível obter um aumento de até 118,25%. No segundo experimento são analisados cinco diferentes protocolos de comunicação, mostrando que é possível otimizar o uso da bateria nos nós sensores sem fio em até 10 vezes, sem diminuir a eficiência do sistema / The use of chemical defensives in crop fields is important for the agricultural production. Often airplanes are used for spraying these products, because it adds agility in such task. But climatic characteristics, such as wind speed, may cause loss to farmers (e.g. superimposed application and fines for environment contamination). This text details an integrated system of unmanned aerial vehicle (UAV) and wireless sensor network (WSN) with the purpose of letting the aerial spraying process more precise. An UAV is used to spray chemicals in the crop field. A WSN composed of sensor nodes capable of sensoring quantities of chemical defensives is installed in the crop. Both UAV and sensor nodes are equipped with radio modules, this way they can communicate each other. Thus, the UAV may obtain the information of where the chemicals are being applied, then the UAV may take some action to performs a better spraying. This system were developed in the simulator OMNET++ using the framework MiXiM and two experiments were executed. In the first experiment the objective is to compare the efficiency of this system with the tradicional system, without the WSN. Results shown that the proposed system can improve the spraying process in 16% on average, and 118.25% on some cases. In the second experiment, five different WSN protocols were evaluated in means of battery usage of the sensor nodes. Results shown that its possible to reduce the battery usage in 10 times without intervene in the system efficiency

Veículos Aéreos não Tripulados (VANTs) são aeronaves que voam sem tripulação e são capazes de realizar diversos tipos de missões, como vigilância, coleta de dados topográficos e monitoramento ambiental. Este é um domínio que tem muito a ganhar com a aplicação da abordagem de Linha de Produtos de Software (LPS), uma vez que é rico em variabilidades e cada modelo de VANT tem também muitas partes comuns. Neste trabalho é apresentada uma infraestrutura tecnológica e de configuração de ativos em Simulink, gerenciados pelas ferramentas Pure::variant e Hephaestos para uma LPS de VANTs. Um conjunto de padrões para especificação de variabilidades em Simulink é proposto, bem como uma extensão para a ferramenta Hephaestus. Uma comparação entre as ferramentas Pure::variants e Hephaestus é apresentada / Unmanned Aerial Vehicles (UAVs) are aircrafts that can fly without any crew and are capable to realize several types of missions such as surveillance, topographic data collection and environmental monitoring. This is a domain which can benefit very much with the adoption of the Software Product Lines (SPL) approach, as each UAV model is rich in variabilities and has many common parts. In this work it is presented a software asset configuration infrastructure for the Simulink environment, managed by the tools Pure::variants and Hephaestus for a UAV SPL. A set of patterns of variability specification in Simulink is proposed as well as an extension to Hephaestus to support a SPL product engineering for Simulink. A comparison between Pure::variants and Hephaestus is also presented

No description available.

Leaf area index (LAI) is a versatile indicator of crop growth that is used to estimate evapotranspiration (ET), monitor nitrogen status, and estimate crop yield. Traditional methods for measuring LAI can be improved using high resolution remote sensing. The aim of this study was to compare approaches for estimating LAI from UAV-derived visible vegetation indices. Coincident ground-based and remotely sensed data were obtained from two irrigated wheat fields and were sampled at a total of 5 events in 2019 and 2020. Ground-based LAI was measured with a ceptometer and remotely sensed images were collected using a consumer-grade UAV. Mosaiced orthophotos were resampled from native (0.06m) spatial resolution to increasingly coarser spatial resolutions up to 3 m by either a direct or ladder resampling method. Visible band color information (RGB) was extracted from the orthophotos at the points that LAI was collected within field and 12 different visible vegetation indices (VVIs) were calculated. Linear regression was performed to evaluate the relationships between wheat LAI and each calculated VVI for all spatial resolutions and resampling methods. Three VVIs, visible atmospherically resistant index (VARI), normalized green-red difference index (NGRDI), and modified green-red vegetation index (MGRVI), estimated LAI equally well (R2= 0.66, 0.66,0.66; RMSE=0.74,0.73,0.73; MAE=0.57,0.56,0.56) when resampled to 3 m spatial resolution with the ladder resampling method. These results demonstrate the potential to remotely estimate LAI using only RGB cameras and consumer grade drones. An additional aim of this study was to evaluate use of a remotely sensed visible vegetation index to characterize the spatial variability of LAI within irrigated wheat fields. Variation of LAI was measured with a ceptometer on random nested grids at two sites with pre-determined management zones in 2019 and 2020. Coincident digital imagery was collected using a consumer-grade unmanned aerial vehicle (UAV). A visible atmospherically resistant index (VARI) LAI estimation model was applied to red, green, blue (RGB) UAV imagery using a ladder resampling approach from 0.06 m to 3 m spatial resolution. There was significant within-field spatial and temporal variation of mean LAI. For example, in May at the Grace, ID location measured LAI ranged from 0.21 to 2.58 and in June from 1.68 to 4.15. The relationship of measured and estimated LAI among management zones was strong (R2=0.84), validating the remote sensing approach to characterize LAI differences among management zones. There were statistically significant differences in estimated LAI among zones for all sampling dates (P=0.05). We assumed a minimum difference of 15% between zone LAI and the field mean for justifying variable rate irrigation among zones, a threshold that corresponds with approximately a 10% difference in evapotranspiration rate. Three of the five sampling dates had LAI differences that exceeded the threshold for at least one zone, with all three having mean LAI of less than 2.5. The VARI model for estimating LAI remotely is more effective at identifying LAI differences among management zones at lower LAI. Application of this approach has potential for applications such as estimating evapotranspiration of irrigated fields and delineation of zones for variable rate irrigation.

The implementation of Unmanned Aerial Vehicles (UAVs) and Structure‐from‐Motion (SfM) photogrammetry in assessing forest structures for forest inventory and biomass estimations has shown great promise in reducing costs and labour intensity while providing relative accuracy. Tree Height (TH) and Diameter at Breast Height (DBH) are two major variables in biomass assessment. UAV-based TH estimations depend on reliable Digital Terrain Models (DTMs), while UAV-based DBH estimations depend on reliable dense photogrammetric point cloud. The main aim of this study was to evaluate the performance of multirotor UAV photogrammetric point cloud in estimating homogeneous and heterogeneous forest structures, and their comparison to more accurate LiDAR data obtained from Aerial Laser Scanners (ALS), Terrestrial Laser Scanners (TLS), and more conventional means like manual field measurements. TH was assessed using UAVSfM and LiDAR point cloud derived DTMs, while DBH was assessed by comparing UAVSfM photogrammetric point cloud to LiDAR point cloud, as well as to manual measurements. The results obtained in the study indicated that there was a high correlation between UAVSfM TH and ALSLiDAR TH (R2 = 0.9258) for homogeneous forest structures, while a lower correlation between UAVSfM TH and TLSLiDAR TH (R2 = 0.8614) and UAVSfM TH and ALSLiDAR TH (R2 = 0.8850) was achieved for heterogeneous forest structures. A moderate correlation was obtained between UAVSfM DBH and field measurements (R2 = 0.5955) for homogenous forest structures, as well as between UAVSfM DBH and TLSLiDAR DBH (R2 = 0.5237), but a low correlation between UAVSfM DBH and UAVLiDAR DBH (R2 = 0.1114). This research has demonstrated that UAVSfM can be adequately used as a cheaper alternative in forestry management compared to more highcost and accurate LiDAR, as well as traditional technologies, depending on accuracy requirements.