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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Tracking ground targets with measurements obtained from a single monocular camera mounted on an Unmanned Aerial Vehicle

Deneault, Dustin January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Dale E. Schinstock / The core objective of this research is to develop an estimator capable of tracking the states of ground targets with observation measurements obtained from a single monocular camera mounted on a small unmanned aerial vehicle (UAV). Typical sensors on a small UAV include an inertial measurement unit (IMU) with three axes accelerometer and rate gyro sensors and a global positioning system (GPS) receiver which gives position and velocity estimates of the UAV. Camera images are combined with these measurements in state estimate filters to track ground features of opportunity and a target. The images are processed by a keypoint detection and matching algorithm that returns pixel coordinates for the features. Kinematic state equations are derived that reflect the relationships between the available input and output measurements and the states of the UAV, features, and target. These equations are used in the development of coupled state estimators for the dynamic state of the UAV, for estimation of feature positions, and for estimation of target position and velocity. The estimator developed is tested in MATLAB/SIMULINK, where GPS and IMU data are generated from the simulated states of a nonlinear model of a Navion aircraft. Images are also simulated based upon a fabricated environment consisting of features and a moving ground target. Target observability limitations are overcome by constraining the target vehicle to follow ground terrain, defined by local features, and subsequent modification of the target's observation model. An unscented Kalman filter (UKF) provides the simultaneous localization and mapping solution for the estimation of aircraft states and feature locations. Another filter, a loosely coupled Kalman filter for the target states, receives 3D measurements of target position with estimated covariance obtained by an unscented transformation (UT). The UT uses the mean and covariance from the camera measurements and from the UKF estimated aircraft states and feature locations to determine the estimated target mean and covariance. Simulation results confirm that the new loosely coupled filters are capable of estimating target states. Experimental data, collected from a research UAV, explores the effectiveness of the terrain estimation techniques required for target tracking.
62

Photomosaicing and automatic topography generation from stereo aerial photography

Buckley, Craig January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Dale E. Schinstock, Chris Lewis / The Autonomous Vehicle Systems Lab specializes in using autonomous planes for remote sensing applications. By developing an inexpensive image acquisition platform and the algorithms to post process the data, remote sensing can be performed at a lower monetary cost with shorter lead times. This thesis presents one algorithm that has shown to be an effective alternative to the traditional Bundle Adjustment (BA) algorithm used for making composite images from many individual overlapping images. BA simultaneously estimates camera poses and visible feature locations from blocks of overlapping imagery, but is computationally expensive. The alternate algorithm (ABA) uses a cost function that does not explicitly include the feature locations. For photographic sets covering large areas, but having overlap only between adjacent photos, the search space and consequently the computational cost is significantly reduced when compared to typical BA. The usefulness of the algorithm is demonstrated by comparing a digital elevation model created through the ABA with LIDAR data.
63

Využitie dronov v logistike / Usage of drones in the Logistics of the company SKODA AUTO a.s.

Čajko, Adam January 2017 (has links)
This Master´s Thesis Usage of drones in the Logistics of the company SKODA AUTO a.s. reacts to the current trend of unmanned aerial vehicles (drones) which are being used in many areas. Aim of this thesis is to analyse laws which regulate the operation of drones in selected countries, to assess suitability of drones for specific process of inventory of empty containers in the company SKODA AUTO a.s. and to suggest an alternative solution for this process. Thesis investigates usage of drones in the Logistics mainly for goods delivery and stock inventory. Mass drone delivery is currently not feasible due to many problems and challenges. Stock inventory has become a reality. Analysis of legislation is focused on EU, Czech Republic, Germany and China. Technology for inventory of empty containers using drones in SKODA AUTO a.s. has a long payback period (21 years) and author does not recommend drones for this process based on this criterion. As an alternative solution, the technology designed at AUDI company is recommended (camera placed on forklift and software for automated container identification).
64

Autonomous Hybrid Powered Long Ranged Airship for Surveillance and Guidance

Recoskie, Steven January 2014 (has links)
With devastating natural disasters on the rise, technological improvements are needed in the field of search and rescue (SAR). Unmanned aerial vehicles (UAVs) would be ideal for the search function such that manned vehicles can be prioritized to distributing first-aid and ultimately saving lives. One of the major reasons that UAVs are under utilized in SAR is that they lack a long flight endurance which compromises their effectiveness. Dirigibles are well suited for SAR missions since they can hover and maintain lift without consuming energy and can be easily deflated for packaging and transportation. This research focuses on extending flight endurance of small-scale airship UAVs through improvements to the infrastructure design and flight trajectory planning. In the first area, airship design methodologies are reviewed leading to the development and experimental testing two hybrid fuel-electric power plants. The prevailing hybrid power plant design consists of a 4-stroke 14cc gasoline engine in-line with a brushless DC motor/generator and variable pitch propeller. The results show that this design can produce enough mechanical and electrical power to support 72 hours of flight compared to 1-4 hours typical of purely electric designs. A power plant configuration comparison method was also developed to compare its performance and endurance to other power plant configurations that could be used in dirigible UAVs. Overall, the proposed hybrid power plant has a 600% increase in energy density over that of a purely electric configuration. In the second area, a comprehensive multi-objective cost function is developed using spatially variable wind vector fields generated from computational fluid dynamic analysis on digital elevations maps. The cost function is optimized for time, energy and collision avoidance using a wavefront expansion approach to produce feasible trajectories that obey the differential constraints of the airship platform. The simulated trajectories including 1) variable vehicle velocity, 2) variable wind vector field (WVF) data, and 3) high grid resolutions were found to consume 50% less energy on average compared to planned trajectories not considering one of these three characteristics. In its entirety, this research addresses current UAV flight endurance limitations and provides a novel UAV solution to SAR surveillance.
65

Design and implementation of a power system for a solar unmanned aerial vehicle

Wilkins, Grant 04 June 2012 (has links)
M. Ing. / Solar powered UAV's have gained world wide attention with aircraft such as Solar Impulse and Quinetiq's Zephyr. UAV's in general are becomming increasingly popular, in 2006 80% of all US military ights over Iraq were UAV ights [38]. UAV's are the the most dynamic growth sector in the world aerospace industry having spent $3:4 billion in 2008 and is expected to be $5:8 billion in 2014. Solar Impulse has a budget of $94 million, Quinetiq has been awarded a $44:9 million contract to build 7 zephyrs. NASA has had several solar powered UAV projects. With advancements in solar and battery technologies solar powred UAV's are fast becomming a reality. The disadvantage of projects such as the Solar Impulse, Zephyr, Solong and Sky Sailor is they have extremely large budgets and have access to non commercial and highy specialized Chapter 1 | Problem Statement 10 products. The main purpose of the project is to develop a solar power system using only commercial products which can substancially increase the ight time of a UAV under sunny conditions. The project has several advantages: The project also provides a clean, green energy aspect. Because the energy provided by the solar cells is free and has no carbon footprint, the project is environmentally friendly; The project uses only commercially available products so it can easily be implemented and reproduced; The system developed for the project is not only limited to UAV's/ the project can be used in other applications such as Solar powered cars or robots. Due to the commercial nature of the big 4 solar aircraft information about their solar power systems is not easily available. The work presented here is an acedemic venture and will be freely available The project has many unknowns such as the size of the UAV, power requirements and available components. The research methodolgy used allows the unknowns to be determined using mathematical models and simulations. The models and simulations are further veri ed and altered accordingly to the actual implementation of the system. The project provides a step by step procedure to building a power system for a solar powered UAV. There are several building blocks in the project. Each building block forms a vital part of the system but can also be designed and implemented as a sigle entity. Only once each building block has achieved its own indavidual speci cations will they be integrated together to form the complete system. There are many risks and limitations within the project. The project is dependant on the type of UAV with respect to power requirements. Therefore the power system needs to provide as much solar power as possible to the UAV. If the available solar power is not su cient for level ight, the solar power must supliment the original power supply of the aircraft in a safe manner. There are many dangers when ying a UAV, if the UAV loses control it could potentially injure or even kill a person. Therefore outmost care needs to be taken to mitigate these risks. By the end of the project a solar power supply, capable of powering a UAV, will be delivered. With the given resources and the current state of technology the project should be a success.
66

Modeling and Nonlinear Control of Quadrotor UAVs for Inspection and Manipulation Tasks / 検査や操作など多様なタスク遂行のためのクワッドローター飛行口ボットのモデリングと非線形制御

Wang, Tiehua 24 September 2021 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23504号 / 工博第4916号 / 新制||工||1768(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 松野 文俊, 教授 泉田 啓, 教授 藤本 健治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
67

Vyhodnocení dat pořízených bezpilotním prostředkem / Evaluation of data acquired by UAV

Setnický, Viktor January 2016 (has links)
This thesis deals with the application of unmanned aerial vehicles (UAV) in photogrammetric purposes useful in geodesy. The UAV that was used for imaging is described in the first part, also there are introduced two programs which were used for data processing. A system of mission planning and data collecting is shown on the ortofoto creating as an example. The second part of this thesis deals with testing of the accuracy through terrestrially independently measured points. The main aim of the work is to demonstrate the high potential of UAV devices for geodesy purposes.
68

Evaluation of hybrid-electric propulsion systems for unmanned aerial vehicles

Matlock, Jay Michael Todd 14 January 2020 (has links)
The future of aviation technology is transitioning to cleaner, more efficient and higher endurance aircraft solutions. As fully electric propulsion systems still fall short of the operational requirements of modern day aircraft, there is increasing pressure and demand for the aviation industry to explore alternatives to fossil fuel driven propulsion systems. The primary focus of this research is to experimentally evaluate hybrid electric propulsion systems (HEPS) for Unmanned Aerial Vehicles (UAV) which combine multiple power sources to improve performance. HEPS offer several potential benefits over more conventional propulsion systems such as a smaller environmental impact, lower fuel consumption, higher endurance and novel configurations through distributed propulsion. Advanced operating modes are also possible with HEPS, increasing the vehicle’s versatility and redundancy in case of power source failure. The primary objective of the research is to combine all of the components of a small-scale HEPS together in a modular test bench for evaluation. The test bench uses components sized for a small-scale UAV including a 2.34kW two-stroke 35cc engine and a 1.65kW brushless DC motor together with an ESC capable of regenerative braking. Individual components were first tested to characterize performance, and then all components were assembled together in a parallel configuration to observe system-level performance. The parallel HEPS is capable of functioning in the four required operating modes: EM Only, ICE Only, Dash Mode (combined EM and ICE power) as well as Regenerative Mode where the onboard batteries get recharged. Further, the test bench was implemented with a supervisory controller to optimize system performance and run each component in the most efficient region to achieve torque requirements programmed into mission profiles. The logic based controller operates with the ideal operating line (IOL) concept and is implemented with a custom LabView GUI. The system is able to run on electric power or ICE power interchangeably without making any modifications to the transmission as the one-way bearing assembly engages for whichever power source is rotating at the highest speed. The most impressive of these sets of tests is the Dash mode testing where the output torque of the propeller is supplied from both the EM and ICE. Working in tandem, it was proved that the EM was drawing 19.9A of current which corresponds to an estimated 0.57Nm additional torque to the propeller for a degree of hybridization of 49.91%. Finally, the regenerative braking mode was proven to be operational, capable of recharging the battery systems at 13A. All of these operating modes attest to the flexibility and convenience of having a hybrid-electric propulsion system. The results collected from the test bench were validated against the models created in the aircraft simulation framework. This framework was created in MATLAB to simulate the performance of a small UAV and compare the performance by swapping in various propulsion systems. The purpose of the framework is to make direct comparisons of HEPS performance for parallel and series architectures against conventional electric and gasoline configuration UAVs, and explore the trade-offs. Each aircraft variable in the framework was modelled parametrically so that parameter sweeps could be run to observe the impact on the aircraft’s performance. Finally, rather than comparing propulsion systems in steady-state, complex mission profiles were created that simulate real life applications for UAVs. With these experiments, it was possible to observe which propulsion configurations were best suited for each mission type, and provide engineers with information about the trade-offs or advantages of integrating hybrid-electric propulsion into UAV design. In the Pipeline Inspection mission, the exact payload capacities of each aircraft configuration could be observed in the fuel burn versus CL,cruise parameter sweep exercise. It was observed that the parallel HEPS configuration has an average of 3.52kg lower payload capacity for the 35kg aircraft (17.6%), but has a fuel consumption reduction of up to 26.1% compared to the gasoline aircraft configuration. In the LIDAR Data collection mission, the electric configuration could be suitable for collection ranges below 100km but suffers low LIDAR collection times. However, at 100km LIDAR collection range, the series HEPS has an endurance of 16hr and the parallel configuration has an endurance of 19hr. In the Interceptor mission, at 32kg TOW, the parallel HEPS configuration has an endurance/TOW of 1.3[hr/kg] compared to 1.15[hr/kg] for the gasoline aircraft. This result yields a 13% increase in endurance from 36.8hr for gasoline to 41.6hr for the parallel HEPS. Finally, in the Communications Relay mission, the gasoline configuration is recommended for all TOW above 28kg as it has the highest loiter endurance. / Graduate
69

Movement and Structure of Atmospheric Populations of Fusarium

Lin, Binbin 23 May 2013 (has links)
Fusarium is one of the most important genera of fungi on earth. Many species of Fusarium are well-suited for atmospheric dispersal, yet little is known about their aerobiology. Previous research has shown that large-scale features known as atmospheric transport barriers (Lagrangian coherent structures) guide the transport and mixing of atmospheric populations of Fusarium. The overall goal of this work is to expand our knowledge on the movement and structure of atmospheric populations of Fusarium. The first objective was to monitor changes in colony forming units (CFUs) in atmospheric populations of Fusarium over small time intervals (10 min to several hours). We hypothesized that consecutive collections of Fusarium with unmanned aerial vehicles (UAVs) demonstrate small variations in colony counts. To test this hypothesis, sampling devices on UAVs were separated into two groups, four inner sampling devices opened during the first 10 minutes and four outer sampling devices opened during the second 10 minutes. Results indicated that (1) consecutive collections of Fusarium at 100 m demonstrated small variations in counts and (2) the similarity between collections decreased as the time between sampling intervals increased. The second objective was to determine the structure of atmospheric populations of Fusarium species and relate this to potential source regions. We hypothesized that diverse atmospheric populations of Fusarium are associated with multiple source regions. To test this hypothesis, Fusarium samples were collected with UAVs and identified to the level of species by sequencing a portion of the translation elongation factor 1-alpha gene (TEF-1•). Potential source regions were identified using the atmospheric transport model HYSPLIT. Results indicated that (1) diverse atmospheric populations of Fusarium appeared to be associated with multiple source regions, and (2) the number of Fusarium species collected with UAVs increased with back-trajectory distance of the sampled air. The third objective was to examine the associations between concentrations of populations of Fusarium at ground level (1 m) and in the lower atmosphere (100 m). We hypothesized that concentrations of Fusarium in the atmosphere vary between 1m and 100m. To test this hypothesis, Fusarium was collected with a Burkard volumetric sampler (BVS) and UAVs. Colony counts were converted to spore concentrations (spores per cubic meter of air). Sampling efficiency was used to correct spore concentrations. Results indicated that (1) the distribution of spore concentrations was similar for both samplers over different times of the day, (2) spore concentrations were generally higher in the fall, spring, and summer, and lower in the winter, and (3) spore concentrations were generally higher with BVS samplers than those with UAVs for both hourly and seasonal data. The fourth objective was to assess the ability of strains of Fusarium collected in the lower atmosphere to cause plant disease. We hypothesized that certain isolates of Fusarium collected with UAVs cause plant diseases. To test this hypothesis, we randomly selected isolates of three different species (F. circinatum, F. avenaceum, and F. sporotrichioides) of Fusarium collected with UAVs to inoculate three different hosts (wheat, corn, and pine). Known Fusarium strains were obtained from J. Leslie at Kansas State University as controls. Results indicated showed that the three different isolates tested were able to cause plant diseases in three different hosts (wheat, corn, and pine), confirming that these were potential agents of disease. This work sets the stage for future work examining potential source regions, transport distances, and seasonal patterns of Fusarium. An increased understanding of the dynamics and population structure of plant pathogenic Fusarium in the lower atmosphere is essential for predicting the spread of plant disease and optimizing disease management strategies in the future. / Ph. D.
70

The Condor UAV System : A Concept Study

Ramirez Alvarez, Dennis André January 2016 (has links)
In this degree project in aerospace engineering, a preliminary design of a UAV (Unmanned Aerial Vehicle) was performed. The UAV was intended to be used as a complement to the Swedish maritime administration’s helicopters, which cannot operate under limited visibility conditions. Its main mission would consist of surveillance. The UAV was therefore designed for some series criteria that were based on the customers’ requirements. The primary literature that was used was John D. Andersons Aircraft performance and design. Otherwise, historical statistical data from other aircraft was used and numerous assumptions were made. The result was a relatively small UAV named The Condor, weighing 25.6 kg with a wingspan of 2.5 m and operational in an altitude of 3500 m with a cruise speed of 81 knots. The UAV’s range is 70 nautical miles and is also able to operate in up to six hours. It should be able to manage a 300 m long runway. The chosen wing profile was the NACA 1412 with a maximal thickness and camber of 12 % and 1 % of the chord length, respectively. As for the stabilizer, the symmetric wing profile NACA 0012 was chosen. A so called constraint analysis was performed in order to determine the engine choice and thewing loading. The chosen engine was a 3.1 horsepower piston engine provided by Ricardo. The dimensions of the fuselage were designed only to fit the payload and no detailed analysis was done. It became 2.3 m long and with a maximal diameter of 0.3 m. / I det här kandidatexamensarbetet i flygteknik gjordes en preliminär design av en drönare. Drönaren skulle användas som komplettering till sjöfartsverkets helikoptrar, som inte kan användas vid mycket begränsad sikt. Dess huvudsakliga uppdrag skulle bestå av övervakning. Drönarens utformades därför efter en rad kriterier som baserades på uppdragsgivarens krav. Den huvudsakliga litteraturen som användes var John D. Andersons Aircraft performanceand design. I övrigt användes historisk statistisk data från andra flygplan och ett flertal antaganden gjordes. Resultatet blev en relativt liten drönare som döptes till The Condor och fick en vikt på 25.6 kg, med ett vingspann på 2.5 m och som opererar på 3500 m flyghöjd med en marschfart på 81 knop. Drönarens räckvidd är 70 nautiska mil och den kan därutöver operera i upp till sex timmar. Den bör klara av en landningsbana på 300 m. Som vingprofil valdes NACA 1412 med en maximal tjocklek och camber på 12 % respektive 1 % av kordalängden. För stabilisatorn valdes den symmetriska profilen NACA 0012. En så kallad ”constraint analysis” genomfördes för fastställande av motorval och vingbelastning. Motorn som valdes blev en 3.1 hästkrafters pistongmotor från Ricardo. Flygplanskroppens dimensioner utformades endast för att få plats med nyttolasten och ingen noggrannare analys genomfördes. Den blev 2.3 m lång med en maximal diameter på0.3 m.

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