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Alfaro, Richard Alfonso Andrade. "Predictive control strategies por unmanned aerial vehicles in cargo transportation tasks." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/168229.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2016.Made available in DSpace on 2016-09-20T05:05:05Z (GMT). No. of bitstreams: 1 341818.pdf: 7805468 bytes, checksum: 24215969efc6a9cd28721f5d8831d2ef (MD5) Previous issue date: 2016
O desenvolvimento de veículos aéreos não tripulados (VANTs) vem despertando um grande interesse tanto no meio acadêmico quanto na indústria nas últimas décadas. Muitos campos da robótica e da teoria de controle vem sendo explorados visando melhorar o desempenho destes sistemas. Existem vários cenários onde estas aeronaves são utilizadas, tais como monitoramento de ambientes, agricultura de precisão, busca e resgate, entre outras. Dentre as diferentes aplicações destas aeronaves temos o transporte de carga suspensa por cabo, o qual tem promovido várias pesquisas relacionadas com transporte de alimentos, medicamentos e suprimentos em geral, para zonas de risco. Neste sentido, este trabalho tem como foco o uso de VANTs em tarefas de transporte de carga, considerando perturbações externas e incertezas paramétricas. A aeronave utilizada é um birotor na configuração Tilt-rotor que carrega uma carga suspensa. Um Tilt-rotor é um veículo movimentado por dois rotores inclináveis, os quais geram e direcionam forças de impulso para sustentar a aeronave. Neste estudo, é importante que a aeronave seja capaz de seguir uma trajetória predefinida enquanto estabiliza a carga suspensa mesmo quando afetada por perturbações externas ou incertezas paramétricas. Além disso, um modelo não linear multicorpo é obtido via formulação Euler-Lagrange para o VANT Tilt-rotor considerando a carga suspensa. Neste modelo foi considerado que a aeronave é composta por quatro corpos rígidos e tem dez graus de liberdade. O problema de controle é solucionado com um controlador preditivo (MPC) incremental e um não incremental, baseados no modelo linear do erro do sistema, o qual é linearizado em torno a uma trajetória genérica. Além disso, os MPCs consideram custo terminal, com o objetivo de garantir estabilidade e por consequência reduzir o horizonte de predição. Devido ao fato do sistema linear ser variante no tempo (LVT), o custo terminal é calculado mediante desigualdades matriciais lineares (LMI). Por outro lado, restrições são impostas na formulação do MPC, relacionadas com as limitações físicas dos atuadores e considerando que o VANT está confinado numa área específica. Finalmente, simulações foram realizadas para avaliar o desempenho dos controladores propostos, considerando perturbações constantes em diferentes instantes de tempo, e levando em conta incertezas paramétricas.
Abstract : The development of unmanned aerial vehicles (UAVs) has arousedgreat interest in both academia and industry in the recent decades.Many aereas of robotics and control theory have been exploited toimprove the performance of these systems. There are several scenarioswhere these aerial vehicles are used, like monitoring environment,precision agriculture, construction, search and rescue. Transportationof cable-suspended loads with UAVs is another application. This haspromoted research related to load transportation of food, medicine,and supplies in general for unsafe areas. This research is focused onthis topic, where it is necessary that the UAV follows a predenedtrajectory while stabilizing the suspended load, even if it is aectedby external disturbances. In this dissertation, two model predictivecontrollers (MPCs) are used to solve the path tracking problem of asmall scale Tilt-rotor Unmanned Aerial Vehicle (UAV) while carryinga suspended load. A Tilt-rotor is a vehicle lifted and propelled bytwo tiltable rotors, in order to control the direction of thrust forces.In the present study, it is important that the aircraft able to follow apredened trajectory while maintaining the suspended load stable evenin the presence of external disturbances and parametric uncertainties.Moreover, a rigorous multibody non-linear dynamic model is obtainedvia Euler-Lagrange formulation for the Tilt-rotor UAV with suspendedload, assuming four rigid bodies and ten degrees of freedom (DOF)of the vehicle. The control problem is solved with incremental andnon-incremental model predictive controllers, based on the linear errormodel of the system, which is linearized around a generic trajectory.Furthermore, the MPCs consider a terminal cost in order to ensurestability, allowing the prediction horizon reduction. As the linear modelis a linear time-varying (LTV) system, the terminal cost is calculatedvia linear matrix inequalities (LMI). In addition, some constraintsare imposed on the formulation, related to physical limitations of theactuators and assuming that the aircraft is conned to a particulararea. Finally, numerical simulations are performed in order to evaluatethe controllers, considering constant disturbances at dierent instantsof time, and modeling errors.
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Fordham, Joseph P. "Design and Monte Carlo analysis of an unmanned aerial vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA277648.
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Hauss, Jean-Marc C. (Jean-Marc Claude) 1975. "Design of a unmanned aerial vehicle." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50380.
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Susuz, Umut. "Aeroelastic Analysis Of An Unmanned Aerial Vehicle." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609225/index.pdf.
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In this thesis aeroelastic analysis of a typical Unmanned Aerial Vehicle (UAV) using MSC®FlightLoads and Dynamics module and MSC®
NASTRAN Aero 1 solver was performed. The analyses were carried out at sea level, 1000m, 2000m and 4000m altitudes for Mach Numbers M=0.2, 0.4 and 0.6 for the full model of the UAV. The flutter characteristics of the UAV for different flight conditions were obtained and presented. The effect of altitude on flutter characteristics has been examined and compared with the theoretical and experimental trends in the literature. Also the divergence characteristics of the full model UAV was obtained. In the study, some verification and test cases are also included. The results of the analyses of an untapered swept-wing and AGARD 445.6 wing models were compared with wind tunnel data and a maximum error of 1.3 % in the flutter speed prediction was obtained. In two different wing models the effect of taper was investigated.
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Valente, Evandro Gurgel do Amaral. "Composite construction of an unmanned aerial vehicle." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3930.
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Thesis (M.S.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Waugh, Edward Michael. "An unmanned aerial vehicle for oceanographic applications." Thesis, University of Southampton, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538988.
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Watkiss, Eric John. "Flight dynamics of an unmanned aerial vehicle." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28222.
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Approved for public release; distribution is unlimited.Moments of inertia were experimentally determined and longitudinal and lateral/directional static and dynamic stability and control derivatives were estimated for a fixed wing Unmanned Air Vehicle (UAV). Dynamic responses to various inputs were predicted based upon the estimated derivatives. A divergent spiral mode was revealed, but no particularly hazardous dynamics were predicted. The aircraft was then instrumented with an airspeed indicator, which when combined with the ability to determine elevator deflection through trim setting on the flight control transmitter, allowed for the determination of the aircraft's neutral point through flight test. The neutral point determined experimentally corresponded well to the theoretical neutral point. However, further flight testing with improved instrumentation is planned to raise the confidence level in the neutral point location. Further flight testing will also include dynamic studies in order to refine the estimated stability and control derivatives
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Lee, Matthew, Daniel Lierz, and Jerome Younger. "Video Tracking System for Unmanned Aerial Vehicle." International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581754.
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ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaSurveillance and tracking using unmanned aerial vehicles (UAVs) is a growing field and to visually track an object independent of a flight path requires a video transmission and control system. Applications utilizing UAVs to track a stationary or moving target are plentiful, from military to local law enforcement; every application introduces an alternative to placing a human into an aircraft and increases the usefulness over a fixed position recorded video. Here we have introduced a cost effective video tracking system that will provide a constant video transmission, manual control for tracking, and further implement an automatic control system to automatically correct for the UAV's roll and yaw. The video tracking system has been designed to be cost friendly while constrained to be applicable for small UAV applications. We have detailed the successful design of our system that overcomes the imposed constraints in great detail in the sections that follow.
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Guerra, Elia. "Unmanned Aerial Vehicle (UAV) per applicazioni geomatiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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La tesi tratta i dispositivi UAV, in particolare i droni di peso inferiore ai 25 kg, facendo riferimento alla normativa ENAC. Vengono descritte le applicazioni pratiche in campo civile, concentrandosi sulle geomatiche, delineando i principali sensori esterni utilizzati come Camere digitali, termiche e multispettrali.
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Allegretti, Marcello. "Unmanned Aerial Vehicle: tecnologie e prospettive future." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11979/.
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Partendo dalla definizione di UAV e UAS, arrivando a quella di drone, nella tesi saranno definiti i termini precedenti, ossia un sistema aereo senza pilota a bordo, la nascita del termine drone e le tendenze attuali. Dopo una precisa classificazione nelle quattro categorie principali (droni per hobbisti, commerciali e militari di me- dia grandezza, militari specifici di grandi dimensioni e stealth da combattimento) saranno descritti gli ambiti di utilizzo: da un lato quello militare e della sicurezza, dall’altro quello civile e scientifico. I capitoli centrali della tesi saranno il cuore dell’opera: l’architettura dell’UAV sarà descritta analizzando la totalità delle sue componenti, sia hardware che software. Verranno, quindi, analizzati i problemi relativi alla sicurezza, focalizzandosi sull’hacking di un UAV, illustrandone le varie tecniche e contromisure (tra cui anche come nascondersi da un drone). Il lavoro della tesi prosegue nei capitoli successivi con un’attenta trattazione della normativa vigente e dell’etica dei droni (nonché del diritto ad uccidere con tali sistemi). Il
capitolo relativo alla tecnologia stealth sarà importante per capire le modalità di occultamento, le tendenze attuali e i possibili sviluppi futuri degli UAV militari da combattimento. Il capitolo finale sugli sviluppi futuri esporrà le migliorie tecnologiche e gli obiettivi degli UAV negli anni a venire, insieme ad eventuali utilizzi
sia militari che civili. La ricerca sarà orientata verso sistemi miniaturizzati, multiple UAV e swarming.
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Tell, Fredrik. "CCUAV : Cloud Center for Unmanned Aerial Vehicle." Thesis, Högskolan i Halmstad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-36304.
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Projektets syfte är att bryta kopplingen mellan en specifik användare och drönare. Målet med projektet är att flera användare ska kunna hantera flera drönare från en central. En länk mellan en internetbaserad plattform vid namn Thingworx och en drönare med en inbyggd styrenhet, som kallas Pixhawk, sammankopplas med mikrodatorn Raspberry Pi 3. Sjöräddningssällskapet i Sverige önskar ett interface där flera av deras drönare med den inbyggda styrenheten kan hanteras och se dess position och videoström. PDSVisions mål är att skapa en demonstrator i en nyutvecklad plattform som förenklar uppkoppling med enheter med hjälp av ett begrepp som kallas IoT (Internet of Things). Resultat har resulterat i en prototyp av Sjöräddningssällskapets drönare ämnad att kontrolleras via den internetbaserade plattformen Thingworx. Drönaren startar, lyfter från marken och flyger en planerad rutt utan pilot. Slutsatsen visade att projektet kunde genomföras samt att det är möjligt att kommunicera med drönare via Thingworx
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Bradley, Justin, and Breton Prall. "AN UNMANNED AERIAL VEHICLE PROJECT FOR UNDERGRADUATES." International Foundation for Telemetering, 2006. http://hdl.handle.net/10150/604143.
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ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, CaliforniaBrigham Young University recently introduced a project for undergraduates in which a miniature unmanned aerial vehicle system is constructed. The system is capable of autonomous flight, takeoff, landing, and navigation through a planned path. In addition, through the use of video and telemetry collected by the vehicle, accurate geolocation of specified targets is performed. This paper outlines our approach and successes in facilitating this accomplishment at the undergraduate level.
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Ward, Paul A. "Coordinated search with unmanned aerial vehicle teams." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:37407b90-51e7-4814-936c-4817ea0c711f.
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Advances in mobile robot technology allow an increasing variety of applications to be imagined, including: search and rescue, exploration of unknown areas and working with hazardous materials. State of the art robots are able to behave autonomously and without direct human control, using on-board devices to perceive, navigate and reason about the world. Unmanned Aerial Vehicles (UAVs) are particularly well suited to performing advanced sensing tasks by moving rapidly through the environment irrespective of the terrain. Deploying groups of mobile robots offers advantages, such as robustness to individual failures and a reduction in task completion time. However, to operate efficiently these teams require specific approaches to enable the individual agents to cooperate. This thesis proposes coordinated approaches to search scenarios for teams of UAVs. The primary application considered is Wilderness Search and Rescue (WiSaR), although the techniques developed are applicable elsewhere. A novel frontier-based search approach is developed for rotor-craft UAVs, taking advantage of available terrain information to minimise altitude changes during flight. This is accompanied by a lightweight coordination mechanism to enable cooperative behaviour with minimal additional overhead. The concept of a team rendezvous is introduced, at which all team members attend to exchange data. This also provides an ideal opportunity to create a comprehensive team solution to relay newly gathered data to a base station. Furthermore, the delay between sensing and the acquired data becoming available to mission commanders is analysed and a technique proposed for adapting the team to meet a latency requirement. These approaches are evaluated and characterised experimentally through simulation. Coordinated frontier search is shown to outperform greedy walk methods, reducing redundant sensing coverage using only a minimal coordination protocol. Combining the search, rendezvous and relay techniques provides a holistic approach to the deployment of UAV teams, meeting mission objectives without extensive pre-configuration.
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Sakarya, Arzu. "Multidisciplinary Design Of An Unmanned Aerial Vehicle Wing." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613606/index.pdf.
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In this thesis, the structural design, structural analysis and producibility analysis of an unmanned aerial vehicle wing were performed. Three different wing models, made of different materials, were designed. The wings were aluminum wing model and composite wing modelsmade of prepreg and wet lay-up. All wings have the same aerodynamic geometry and structural configuration under the same flight conditions. The structural designs of three wings were done by using Unigraphics NX. The finite element modeling of the wings were built by using MSC Patran package program. After the application of the loads on models, structural analyses were performed by MSC Nastran. Finally, the producibility analysis of prepreg wing model was conducted by using FiberSIM package program. The prepreg wing model was selected as optimum design with studies conducted in the study considering weight, producibility, cruise and gust stress and displacement conditions.
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Söderman, Johan. "High Level Control for an Unmanned Aerial Vehicle." Thesis, Uppsala universitet, Signaler och System, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-156043.
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This thesis work was undertaken to develop a new high level command for an unmanned aerial vehicle. The command is assumed to make the UAV follow a reference position that is placed on a certain distance to an object. At the same time the UAV is assumed to move more smoothly than the reference position and the UAV is allowed to follow the reference position with margin. The problem was solved with an automatic control system that takes the reference position as input signal and has a fictitious position as output signal. The fictitious position moves smoothly inside the margin and irregular behavior of the reference position is smoothed out by the automatic control system. The fictitious position is affected by strong feedback outside the margin and weak feedback inside the margin. This makes the fictitious position to stay inside the margin and moves smoothly inside the margin. The UAV follows the fictitious position instead of the reference position. In this way the UAV holds a certain distance to an object and at the same time moves smoother than the object.
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Hammar, Marcus. "Controller Design for an Unmanned Reconnaissance Aerial Vehicle." Thesis, KTH, Reglerteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-107514.
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The overall objective with this thesis is to evaluate a method for designing nonlinear controllers in aircrafts with concern in robustness against modelling insecurities and also to minimize the design effort. The later objective is of great importance since there exists, in the industry, an ambition to automatize the design for as far extend as possible. The nonlinear method, State Dependent Riccati Equation (SDRE), used in this thesis is a nonlinear version of classic LQ design and both are evaluated and compared for a few flying conditions. Also another nonlinear control method, Two Timescale Separation (TSS), is tested. LQ and SDRE shows equal performance during both looping and more complicated maneuvers, such as high angle of attack wind-vector roll. Further it is possible to automatize the LQ design as well as it is possible for SDRE. Still SDRE is preferable since it will always be somewhat more accurate than LQ. A comparison with the nonlinear method Two Timescale Separation shows results in favor of LQ/SDRE mostly due to relatively slow dynamics and bad accuracy of TSS. A Monte Carlo simulation is made on LQ and SDRE showing that the model is robust against relatively large modelling error of 40%.
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Hammerseth, Vegard B. "Autonomous Unmanned Aerial Vehicle In Search And Rescue." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22880.
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This report presents a way of using autonomous drones to enhance search and rescue operations and takes the first steps in bringing the system to life. By using autonomous drones, less experience is required by the rescue personnel and drone specialists become excessive in this matter. Due to autonomy a drone can operate outside a valid radio link. Hence, when signal is lost, the craft can continue to search, buffer the information and send it when the link becomes active. By creating affordable drones the threshold decreases for deploying a unit in bad weather or other missions where the feedback is more important than drone return.Because the drones must sweep a large area, an aeroplane is the best suitable airframe. To generate less drag and increase stability; long, slender and thin-as-possible wings are recommended. To achieve aerodynamic stability, non-swept wings and a small positive dihedral angle is also advised. The wings should be attached on top of a slender and small-as-possible fuselage. However, due to the difficulties in landing and vulnerabilities related to this, a flying wing which obey the same design requirements, may be a better choice. A prototype for a flying wing made in expanded polypropylene was put together and tested. It proved to be resilient, able to withstand significant abuse, quickly recover to its former structure and be repaired in minutes. Highly convenient for various landing areas.An attitude and heading reference system (AHRS) is required to tell which orientation a vehicle may have. An affordable version has been realised by using micro electro mechanical sensors and a micro controller. Since the vehicle must orient itself within a search area, a NAVSTAR Global Positioning System (GPS) and way-point approach were drones are pre-programmed to follow a path has been developed together with a complete flight system.The drones search path must be programmed automatically from the given search area by the rescue personnel. This requires software and active communication link between a ground station and drones. An intuitive graphical user interface has been developed and verified to work by marking an area in the program and send coordinates over a commercial communication link to a prototype drone.A thermal imaging camera can be used to detect humans. It will make mammals stand out in an environment when viewed in the produced image (thermogram). Together with an arbitrarily threshold limit, the operators can be notified with coordinates when the threshold is reached. An experiment was carried out by placing a human at known coordinates. A drone with self position equipment was sent over the human repeatedly, automatically locating the person and reporting its location. It was concluded that the drone would be within 20 meters radius of the person.The generality and affordability of the airframe, AHRS and vision system can be useful for the university in the years ahead and the threshold for realising applications which uses any of these systems has therefore been reduced. A drone based system like this can enhance search and rescue and assist the majority by saving time, money and lives.
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Watson, Mark T. "Vision guidance controller for an Unmanned Aerial Vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA359702.
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Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School, December 1998."December 1998." Thesis advisor(s): Isaac I. Kaminer. Includes bibliographical references (p. 77). Also available online.
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Toazza, Denny Antonio, and Tae Hyun Kim. "Navigation Control of an Unmanned Aerial Vehicle (UAV)." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3730.
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The thesis covers a new navigation algorithm for UAV to fly through several given GPS coordinates without any human interference. The UAV first gets its current position from GPS receiver via Bluetooth connection with the navigator computer. With this GPS point, it draws an optimal trajectory to next destination. During the flight, the navigator computer issues the information about which direction to turn and how much to turn. This information will be used to steer the airplane servos.
The algorithm is programmed in Java LeJOS. It uses built-in Java classes about GPS and Bluetooth. The main computer, where the navigation program runs, is a LEGO Mindstorms NXT and it is used a GPSlim240 from HOLUX as a GPS receiver.
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Rao, Srinivas K. Driessen Brian. "Protective shroud for an autonomous unmanned aerial vehicle." Diss., A link to full text of this thesis in SOAR, 2006. http://soar.wichita.edu/dspace/handle/10057/677.
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Thesis (M.S.)--Wichita State University, College of Engineering, Dept. Mechanical of Engineering."December 2006." Title from PDF title page (viewed on Nov. 4, 2007). Thesis adviser: Brian Driessen. Includes bibliographic references (leaves 63-65).
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Dono, Thomas F. "Optimized Landing of Autonomous Unmanned Aerial Vehicle Swarms." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/7331.
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Approved for public release; distribution is unlimited.This research explores a future concept requiring the efficient and safe, landing and recovery of a swarm of unmanned aerial vehicles (UAVs). The presented work involves the use of an overarching (centralized) airspace optimization model, formulated analytically as a network-based model with side constraints describing a time-expanded network model of the terminal airspace in which the UAVs navigate to one or more (possibly moving) landing zones. This model generates optimal paths in a centralized manner such that the UAVs are properly sequenced into the landing areas. The network-based model is grown using agent based simulation with simple flocking rules. The resulting solution is compared to another agent-based model which uses similar avoidance rules for the landing of these UAVs, exploring the benefit of distributed computation and decision-making characteristic of swarming models. Relevant measures of performance include, e.g., the total time necessary to land the swarm. Extensive simulation studies and sensitivity analyses are conducted to demonstrate the relative effectiveness of the proposed approaches.
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Kersop, Stefanus Jacobus. "Short range reconnaissance unmanned aerial vehicle / S.J. Kersop." Thesis, North-West University, 2009. http://hdl.handle.net/10394/9171.
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Unmanned aerial vehicles (UAVs) have been used increasingly over the past few years. Special Forces of various countries utilise these systems successfully in war zones such as Afghanistan. The biggest advantage is rapid information gathering without endangering human lives.
The South African National Defence Force (SANDF) also identified the need for local short range aerial reconnaissance and information gathering. A detailed literature survey identified various international players involved in the development of small hand-launch UAV systems. Unfortunately, these overseas systems are too expensive for the SANDF. A new system had to be developed locally to comply with the unique requirements, and budget, of the SANDF.
The survey of existing systems provided valuable input to the detailed user requirement statement (URS) for the new South African development. The next step was to build a prototype using off-the-shelf components. Although this aircraft flew and produced good video images, it turned out to be unreliable.
The prototype UAV was then replaced with a standard type model aircraft, purchased from Micropilot. Some modifications were needed to ensure better compliance with the URS. Laboratory and field tests proved that the aircraft can be applied for aerial images, within range of 10 km from the ground control station (GCS). The major limitation is that it can only fly for 40 minutes. Furthermore, the airframe is not robust, needing repairs after only 15 flights.
Although the system has shortcomings, it has already been used successfully. It is expected that improved battery technologies and sturdier light-weight materials will further help to improve the system beyond user specifications.Thesis (MIng (Electrical Engineering))--North-West University, Potchefstroom Campus, 2010.
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Dalbakk, Lars-Eirik. "Antenna System for Tracking of Unmanned Aerial Vehicle." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26837.
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Target tracking is a critical part of any mobile communication system with a directive receiver antenna. Some popular tracking methods use the detected phase difference between signals received by several antennas to find the signal’s direction of arrival. The measured direction of arrival is used to adjust the directive antenna’s radiation pattern towards the transmitter. Thus, the radio link between the receiver and the transmitter is kept optimal at all times.This thesis presents the design and implementation of a tracking system, that is based on the phase difference between a QPSK modulated signal received at two distinct antennas. The objective of the tracking system were to improve the existing radio link at Andøya Rocket Range, and have a range of 20 km. For this system, the direction of arrival was measured between 60 degrees and 120 degrees angle of arrival, allowing a maximum estimated direction of arrival error of 2 degrees. The tracking algorithm was implemented in NI LabVIEW, with two universal software radio peripherals as receivers.Accuracy measurements of the tracking system were taken in an anechoic chamber, fordifferent power specifications. With a received power of -45.9 dBm and higher, the measured direction of arrival error varied between 0 degrees to 2 degrees, fulfilling the accuracy requirement. At a received power of -56 dBm, the error was between 2 degrees to 7 degrees. Although it did not fulfill the accuracy requirement, the estimation was still within the half power beamwidth of the directive receiver antenna. Thus it was defined as the lower power limit for a functioning tracking system. Assuming that there are no interference or loss due to reflections in the channel, the maximum range of the tracking system is 680 m. Hence, the range requirement of 20 km are not fulfilled.
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Serrano, Nathan E. "Autonomous quadrotor unmanned aerial vehicle for culvert inspection." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67752.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 69).
This document presents work done to lay the foundation for an Unmanned Aerial Vehicle (UAV) system for inspecting culverts. By expanding upon prior progress creating an autonomous indoor quadrotor, many basic hardware and software issues are solved. The main new functionality needed for the culvert inspection task was to utilize the Global Positioning System (GPS) available outdoors to make up for the relative scarcity of objects visible to the Light Detection And Ranging sensor (LIDAR). The GPS data is fused in a new state estimator, which also incorporates data from the scan matcher running on the LIDAR data, as well as the data from the quadrotor's Inertial Measurement Unit (IMU). This data is combined into a single estimate of the current state (position, orientation, velocity, angular velocity, and acceleration) of the quadrotor by an Extended Kalman Filter (EKF). This new state estimate enables autonomous outdoor navigation and operation of this micro-UAV.
by Nathan E. Serrano.
M.Eng.
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Pereira, Coutinho Walton. "Unmanned Aerial Vehicle routing and trajectory optimisation problems." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/426341/.
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In recent years, employing Unmanned Aerial Vehicles (UAV) to collect data and making measurements has gained popularity. Often, the use of UAVs allows for a reduction in costs and improvements of other performance criteria. The academic routing community has acknowledged the interest of companies and organisations in adopting UAVs in their operations. However, constraints due to the flight dynamics of UAVs have often been neglected. Finding feasible trajectories for UAVs in a routing problem is a complex task, but it is necessary to ensure the feasibility of the routes. In this thesis we introduce the Unmanned Aerial Vehicle Routing and Trajectory Optimisation Problem (UAVRTOP), the problem of optimising the routes and trajectories of a fleet of UAVs subject to flight dynamics constraints. Motivated by a disaster assessment application, we propose a variant of the UAVRTOP, in which a fleet of autonomous aerial gliders is required to photograph a set of points of interest in the aftermath of a disaster. This problem is referred to as the Glider Routing and Trajectory Optimisation Problem (GRTOP). In this work, we propose a single-phase Mixed-Integer Non-linear Programming (MINLP) formulation for the GRTOP. Our formulation simultaneously optimises routes and the flight trajectories along these routes while the flight dynamics of the gliders are modelled as ordinary differential equations. We avoid dealing with non-convex dynamical constraints by linearising the gliders’ Equations of Motion (EOMs), reducing the proposed MINLP into a Mixed-Integer Second-Order Cone Programming (MISOCP) problem. Another contribution of this work consists of proposing a multi-phase MINLP formulation for a modified version of the GRTOP. We do not attempt to solve this formulation directly, instead we propose a hybrid heuristic method that is composed of two main building blocks: (i) a Sequential Trajectory Optimisation (STO) heuristic, designed to cope with the challenging task of finding feasible (flyable) trajectories for a given route; and (ii) a routing matheuristic, capable of generating routes that can be evaluated by STO. We perform computational experiments with real-life instances based on flood risk maps of cities in the UK as well as in a large number of randomly generated instances.
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Åkesson, Elsa, Maximilian Kempe, Oskar Nordlander, and Rosa Sandén. "Unmanned Aerial Vehicle Powered by Hybrid Propulsion System." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277115.
Full textAbstract:
I samband med den globala uppvärmningen ökar efterfrågan för rena och förnybara bränslen alltmer i dagens samhälle. Eftersom flygindustrin idag är ansvarig för samma mängd växthusgaser som all motortrafik i Sverige, skulle ett byte till en avgasfri energikälla för flygfarkoster vara ett stort framsteg. Därför har projektet genom modellering framtagit ett hybridsystem av ett batteri och en bränslecell och undersökt hur kombinationen av olika storlekar på dem presterar i en driftcykel. Då batterier har hög specifik effekt men är tunga, kompletteras de med fördel av bränsleceller, som är lättviktiga och bidrar med uthållig strömförsörjning. På så sätt blir hybriden optimal för flygfarkoster. Kandidatarbetet är en del av projektet Green Raven, ett tvärvetenskapligt samarbete mellan instutitionerna Tillämpad Elektrokemi, Mekatronik och Teknisk Mekanik på Kungliga Tekniska Högskolan. Driftcykelmodelleringen gjordes i Simulink, och flera antaganden gjordes beträffande effektprofilen, samt bränslecellens mätvärden och effekt. Tre olika energihushållningsscheman skapades, vilka bestämde bränslecellseffekten beroende på vätgasnivån och batteriets laddningstillstånd. Skillnaden på systemen var vilka intervall av laddningstillstånd hos batteriet som genererade olika effekt hos bränslecellen. Det bästa alternativet visade sig vara 0/100-systemet, eftersom det var det enda som inte orsakede någon degradering av bränslecellens kapacitet.In today’s society, with several environmental challenges such as global warming, the demand for cleanand renewable fuels is ever increasing. Since the aviation industry in Sweden is responsible for the sameamount of greenhouse gas emissions as the motor traffic, a change to a non-polluting energy source forflying vehicles would be considerable progress. Therefore, this project has designed a hybrid system of abattery and a fuel cell and investigated how different combinations of battery and fuel cell sizes perform ina drive cycle, through computer modelling. As batteries possess a high specific power but are heavy, thefuel cells with high specific energy complement them with a sustained and lightweight power supply,which makes the hybrid perfect for aviation. The bachelor thesis is a part of Project Green Raven, aninterdisciplinary collaboration with the institutions of Applied Electrochemistry, Mechatronics andEngineering Mechanics at KTH Royal Institute of Techology. The drive cycle simulations were done inSimulink, and several assumptions regarding the power profile, fuel cell measurements and power weremade. Three different energy management strategies were set up, determining the fuel cell powerdepending on hydrogen availability and state of charge of the battery. The strategies were called 35/65,20/80 and 0/100, and the difference between them was at which state of charge intervals the fuel cellchanged its power output. The best strategy proved to be 0/100, since it was the only option which causedno degradation of the fuel cell whatsoever.
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Wilkman, Dennis, and Oscar Andersson. "Propulsion system for a small unmanned aerial vehicle." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276078.
Full textAbstract:
For unmanned aerial vehicles there is a wide variety of selection for propulsion systems. Depending on the specific choice of system, the characteristics of the aircraft vary significantly. The choice is also dependent on the size of the UAV itself as well as desired performance and utility. Propulsion systems have made significant advancements over the last decades in the UAV sector. The Skywalker X8 is a popular small UAV and most commonly flown electrically. What propulsion would then be fitting for the originally 2 m wingspan Skywalker X8 if its size in dimensions were doubled. This study presents an early suggestion of a propulsion system for the double sized Skywalker X8. The final propulsion system is a hybrid system consisting of a fuel cell and batteries, giving a time of operational flight of 19 hrs. The results show that the method of choice works as an early design solution of selecting a propulsion system and determining performance. However, it may be an inaccurate representation of the physical model and needs to be followed up by more detailed analysis of the UAV. It is concluded that further experimentation should be done in order to verify the data calculated with this model.För obemannade flygfordon finns ett stort urval av framdrivningssystem. Beroende på det specifika valet av system varierar flygplanets egenskaper väsentligt. Valet är också beroende av storleken på farkosten själv och önskad prestanda och användbarhet. Framdrivningssystem har gjort betydande framsteg under de senaste decennierna. Skywalker X8 är en populär obemannad luftfarkost och flygs oftast elektriskt. Vilken framdrivning skulle då passa för den ursprungliga Skywalker X8 med 2 m vingspann om dess storlek i dimensioner fördubblats. Denna studie presenterar ett tidigt förslag om ett framdrivningssystem för den dubbelt så stora Skywalker X8. Det slutliga framdrivningssystemet är ett hybridsystem som består av en bränslecell och batterier, vilket ger en drifttid på 19 timmar. Resultaten visar att valmetoden fungerar som en tidig designlösning för att välja ett framdrivningssystem och bestämma dess prestanda. Det kan dock vara en felaktig representation av den fysiska modellen och måste följas upp av en mer detaljerad analys av farkosten. Det dras slutsatsen att ytterligare experiment bör göras för att verifiera de data som beräknats med denna modell.
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Wikman, Dennis, and Oscar Andersson. "Propulsion system for a small unmanned aerial vehicle." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276078.
Full textAbstract:
For unmanned aerial vehicles there is a wide variety of selection for propulsion systems. Depending on the specific choice of system, the characteristics of the aircraft vary significantly. The choice is also dependent on the size of the UAV itself as well as desired performance and utility. Propulsion systems have made significant advancements over the last decades in the UAV sector. The Skywalker X8 is a popular small UAV and most commonly flown electrically. What propulsion would then be fitting for the originally 2 m wingspan Skywalker X8 if its size in dimensions were doubled. This study presents an early suggestion of a propulsion system for the double sized Skywalker X8. The final propulsion system is a hybrid system consisting of a fuel cell and batteries, giving a time of operational flight of 19 hrs. The results show that the method of choice works as an early design solution of selecting a propulsion system and determining performance. However, it may be an inaccurate representation of the physical model and needs to be followed up by more detailed analysis of the UAV. It is concluded that further experimentation should be done in order to verify the data calculated with this model.För obemannade flygfordon finns ett stort urval av framdrivningssystem. Beroende på det specifika valet av system varierar flygplanets egenskaper väsentligt. Valet är också beroende av storleken på farkosten själv och önskad prestanda och användbarhet. Framdrivningssystem har gjort betydande framsteg under de senaste decennierna. Skywalker X8 är en populär obemannad luftfarkost och flygs oftast elektriskt. Vilken framdrivning skulle då passa för den ursprungliga Skywalker X8 med 2 m vingspann om dess storlek i dimensioner fördubblats. Denna studie presenterar ett tidigt förslag om ett framdrivningssystem för den dubbelt så stora Skywalker X8. Det slutliga framdrivningssystemet är ett hybridsystem som består av en bränslecell och batterier, vilket ger en drifttid på 19 timmar. Resultaten visar att valmetoden fungerar som en tidig designlösning för att välja ett framdrivningssystem och bestämma dess prestanda. Det kan dock vara en felaktig representation av den fysiska modellen och måste följas upp av en mer detaljerad analys av farkosten. Det dras slutsatsen att ytterligare experiment bör göras för att verifiera de data som beräknats med denna modell.
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Valente, João Ricardo Pereira. "Autonomous behaviors for an unmanned mini-aerial vehicle." Master's thesis, FCT - UNL, 2008. http://hdl.handle.net/10362/1869.
Full textAbstract:
This thesis aims at addressing the development of autonomous behaviors, for search and exploration with a mini-UAV (Unmanned Aerial Vehicle), or also called MAV (Mini Aerial Vehicle) prototype, in order to gather information in rescue scenarios.
The platform used in this work is a four rotor helicopter, known as quad-rotor from the German company Ascending Technologies GmbH, which is later assembled with a on-board processing unit (i.e. a tiny light weight computer) and a on-board sensor suite (i.e. 2D-LIDAR and Ultrasonic Sonar).
This work can be divided into two phases. In the first phase an Indoor Position Tracking system was settled in order to obtain the Cartesian coordinates (i.e. X, Y, Z) and orientation (i.e.heading) which provides the relative position and orientation of the platform.
The second phase was the design and implementation of medium/high level controllers on each command input in order to autonomously control the aircraft position, which is the first step
towards an autonomous hovering flight, and any autonomous behavior (e.g. Landing, Object
avoidance, Follow the wall).
The main work is carried out in the Laboratory ”Intelligent Systems for Emergencies and Civil Defense”, in collaboration with ”Dipartimento di Informatica e Sistemistica” of Sapienza Univ. of Rome and ”Istituto Superiore Antincendi” of the Italian Firemen Department.
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Wagner, Anthony Julian. "Online Unmanned Ground Vehicle Mission Planning using Active Aerial Vehicle Exploration." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90785.
Full textAbstract:
This work presents a framework for the exploration and path planning for a collaborative
UAV and UGV system. The system is composed of a UAV with a stereo system for obstacle
detection and a UGV with no sensors for obstacle detection. Two exploration algorithms
were developed to guide the exploration of the UAV. Both identify frontiers for exploration
with the Dijkstra Frontier method using Dijkstra's Algorithm to identify a frontier with
unknown space, and the other uses a bi-directional RRT to identify multiple frontiers for
selection. The final algorithm developed was for to give the UGV partial plans when an entire
plan is not yet found. This improves the overall mission tempo. The algorithm is designed
to keep the UGV a safe distance from the unknown frontier to prevent backtracking. All the
algorithms were tested in Gazebo using the ROS framework. The Dijkstra Frontier method
was also tested on the hardware system. The results show the RRT Explore algorithm to
work well for exploring the environment, performing equally or better than the Dijkstra
Frontier method. The UGV partial plan method showed a decreased traveled distance for
the UGV but increases in UGV mission time with more conservative distances from danger.
Overall, the framework showed a good exploration of the environment and performs the
intended missions.Master of Science
This work presents a framework for the exploration and path planning for a collaborative aerial and ground vehicle robotic system. The system is composed of an aircraft with a camera system for obstacle detection and a ground vehicle with no sensors for obstacle detection. Two exploration algorithms were developed to guide the exploration of the aircraft. Both identify frontiers for exploration with the Dijkstra Frontier method using path planning algorithms to identify a frontier with unknown space (Dijkstra Frontier), and the other uses a sampling based path planning method (RRT Explore) to identify multiple frontiers for selection. The final algorithm developed was for to give the ground vehicle intermediate plans when an entire plan is not yet found. The algorithm is designed to keep the ground vehicle a safe distance from the unknown frontier to prevent backtracking. All the algorithms were tested in a simulation framework using Robot Operating System and one exploration method was tested on the hardware system. The results show the RRT Explore algorithm to work well for exploring the environment, performing equally or better than the Dijkstra Frontier method. The ground vehicle intermediate plan method showed a decreased traveled distance for the ground vehicle but increases in ground vehicle mission time with more conservative distances from danger. Overall, the framework showed a good exploration of the environment and performs the intended missions.
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Dingus, Benjamin Ross. "Development of an Autonomous Unmanned Aerial Vehicle for Aerobiological Sampling." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33119.
Full textAbstract:
The ability to detect, monitor, and forecast the movement of airborne plant pathogens in agricultural ecosystems is essential for developing rational approaches to managing these habitats. We developed an autonomous (self-controlling) unmanned aerial vehicle (UAV) platform for aerobiological sampling tens to hundreds of meters above agricultural fields. Autonomous UAVs have the potential to extend the range of aerobiological sampling, improve positional accuracy of sampling paths, and enable coordinated flight with multiple aircraft at different altitudes.
We equipped a Senior Telemaster model airplane with two spore-sampling devices and a MicroPilot autonomous system, and we conducted over 60 autonomous microbe-sampling flights at Virginia Techâ s Kentland Farm. To determine the most appropriate sampling path for aerobiological sampling, we explored a variety of different sampling patterns for our autonomous UAVs including multiple GPS waypoints plotted over a variety of spatial scales.
We conducted a total of 25 autonomous aerobiological sampling flights for five different aerobiological sampling patterns. The pattern of a single waypoint exhibited the best flight characteristics with good positional accuracy and standard deviations in altitude from 1.6 to 2.8 meters. The four point pattern configured as a rectangle also demonstrated good flight characteristics and altitude standard deviations from 1.6 to 4.7 meters.Master of Science
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Scheber, Robert Thomas. "Engineering Senior Design Project: Ducted Unmanned Aerial Vehicle Development." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/555566.
Full textAbstract:
Team 1313 of the Honeywell sponsored Unmanned Aerial Vehicle Development (UAV) project completed the following report during the Fall 2013 and Spring 2014 semesters as part of ENGR 498A/B. The main purpose of the project was to investigate the potential benefits of a ducted UAV versus a nonducted UAV. The product was initially designed for use by emergency responders such as firefighting crews. The team was also responsible for updating the electronic and avionic systems as well as redesigning a more stable flight platform. Team 1313 converted the original two motor UAV to a four motor quad copter design. The team also upgraded the electronics and flight software. The following report displays Team 1313’s success in developing the ducted UAV system and details the different design components, software architecture, graphical user interface, design analysis, acceptance testing, and challenges.
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Schmidt, Michael David. "SIMULATION AND CONTROL OF A QUADROTOR UNMANNED AERIAL VEHICLE." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/93.
Full textAbstract:
The ANGEL project (Aerial Network Guided Electronic Lookout) takes a systems engineering approach to the design, development, testing and implementation of a quadrotor unmanned aerial vehicle. Many current research endeavors into the field of quadrotors for use as unmanned vehicles do not utilize the broad systems approach to design and implementation. These other projects use pre-fabricated quadrotor platforms and a series of external sensors in a mock environment that is unfeasible for real world use. The ANGEL system was designed specifically for use in a combat theater where robustness and ease of control are paramount. A complete simulation model of the ANGEL system dynamics was developed and used to tune a custom controller in MATLAB and Simulink®. This controller was then implemented in hardware and paired with the necessary subsystems to complete the ANGEL platform. Preliminary tests show successful operation of the craft, although more development is required before it is deployed in field. A custom high-level controller for the craft was written with the intention that troops should be able to send commands to the platform without having a dedicated pilot. A second craft that exhibits detachable limbs for greatly enhanced transportation efficiency is also in development.
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Basson, Willem Albertus. "Fault tolerant adaptive control of an unmanned aerial vehicle." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17898.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: This thesis presents the development of an adaptive longitudinal control system for an unmanned aerial vehicle (UAV). The project forms part of a research effort at Stellenbosch University into different fault-tolerant control techniques for UAVs. In order to demonstrate the usefulness of fault-tolerant adaptive control, the control system was designed to handle damage-induced longitudinal shifts in the centre of gravity (CG) of the aircraft, which are known to have a dramatic effect on the stability of a fixed-wing aircraft. Using a simplified force and moment model, equations were derived which model the effect of longitudinal CG shifts on the behaviour of the aircraft. A linear analysis of the longitudinal dynamics using these equations showed that the short period mode can become unstable for backward CG shifts. An adaptive pitch rate controller with the model reference adaptive control structure was designed to re-stabilise the short period mode when the CG shifts backwards. The adaptive law was designed using Lyapunov stability theory. Airspeed, climb rate and altitude controllers were designed around the pitch rate controller to allow full autonomous control of the longitudinal dynamics of the UAV. These outer loops were designed with constant parameters, since they would be unaffected by CG shifts if the adaptive pitch rate controller performed as desired. Pure software simulations as well as hardware-in-the-loop simulations showed that the adaptive control system is able to handle instantaneous shifts in the centre of gravity which would destabilise a fixed-gain control system. These simulation results were validated in flight tests, where the aircraft was destabilised using positive feedback and re-stabilised by the adaptive control system. Thus the simulation and flight test results showed that an adaptive control can re-stabilise an unstable aircraft without explicit knowledge of the change in the aircraft dynamics, and therefore could be effective as part of an integrated fault-tolerant control system.
AFRIKAANSE OPSOMMING: Hierdie tesis bied die ontwikkeling aan van ’n aanpassende longitudinale beheerstelsel vir ’n onbemande vliegtuig. Die projek is deel van navorsing by die Universiteit van Stellenbosch oor verskillende fout-tolerante beheertegnieke vir onbemande vliegtuie. Om die doeltreffendheid van aanpassende beheer te demonstreer, is die beheerstelsel ontwerp om situasies te kan hanteer waar die vliegtuig só beskadig word dat sy massamiddelpunt agtertoe skuif, wat ’n groot invloed op die stabiliteit van ’n vastevlerk-vliegtuig kan hê. ’n Vereenvoudigde model van die kragte en momente wat op die vliegtuig inwerk is gebruik om vergelykings af te lei wat beskryf hoe die gedrag van die vliegtuig verander as die massamiddelpunt agtertoe verskuif. Hierdie vergelykings is gebruik in ’n lineêre analise van die longitudinale dinamika van die vliegtuig, wat getoon het dat die kortperiode-modus onstabiel kan raak as die massamiddelpunt agtertoe verskuif. ’n Aanpassende heitempobeheerder met die modelverwysings-aanpassende beheerstruktuur is ontwerp om die kortperiode-modus weer te stabiliseer wanneer die massamiddelpunt agtertoe verskuif. Die aanpassingswet is ontwerp deur die gebruik van Lyapunov se stabiliteitsteorie. Lugspoed-, klimtempo- en hoogtebeheerders is rondom die aanpassende heitempobeheerder ontwerp sodat die longitudinale dinamika van die vliegtuig heeltemal outonoom beheer kan word. Hierdie buitelusse is ontwerp met vaste parameters, aangesien hulle nie geraak sal word deur verskuiwings in die massamiddelpunt as die aanpassende heitempobeheerder na wense werk nie. Suiwer sagteware-simulasies, sowel as hardeware-in-die-lus-simulasies, het getoon dat die aanpassende beheerstelsel oombliklike verskuiwings in die massamiddelpunt goed kan hanteer, waar sulke verskuiwings ’n beheerstelsel met vaste parameters onstabiel sou maak. Hierdie simulasie-resultate is bevestig deur vlugtoetse te doen, waar die vliegtuig onstabiel gemaak is deur positiewe terugvoer, en weer deur die aanpassende beheerstelsel stabiel gemaak is. Die simulasie- en vlugtoetsresultate wys dus dat aanpassende beheer ’n onstabiele vliegtuig weer kan stabiliseer sonder eksplisiete kennis van die veranderinge in die dinamika van die vliegtuig. Aanpassende beheer kan dus doeltreffend wees as deel van ’n geïntegreerde fout-tolerante beheerstelsel.
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Chaturapruek, Sorathan. "A Mathematical Framework for Unmanned Aerial Vehicle Obstacle Avoidance." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/60.
Full textAbstract:
The obstacle avoidance navigation problem for Unmanned Aerial Vehicles (UAVs) is a very challenging problem. It lies at the intersection of many fields such as probability, differential geometry, optimal control, and robotics. We build a mathematical framework to solve this problem for quadrotors using both a theoretical approach through a Hamiltonian system and a machine learning approach that learns from human sub-experts' multiple demonstrations in obstacle avoidance. Prior research on the machine learning approach uses an algorithm that does not incorporate geometry. We have developed tools to solve and test the obstacle avoidance problem through mathematics.
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Fuglaas, Simen. "Precision Airdrop from a Fixed-Wing Unmanned Aerial Vehicle." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25909.
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Accurate mapping of the polar regions requires reliable placement ofwireless transmitting sensors, also known as beacons, on icebergs anddrift ice. This thesis considers the use of a specific fixed-wing unmannedaerial vehicle, known as the Penguin B, to accurately deploysaid beacons from the air. An analysis of the possible precision airdropmethods was conducted and the decision was made to release thebeacon in free fall from the aircraft. The estimated trajectory was calculatedand used to decide the optimal release position and direction.Combined this is known as the release configuration. Moreover, twodifferent aircraft path planning algorithms were developed in order toachieve the desired configuration.The final system, including the necessary hardware and software, wasimplemented into the provided framework. This system was furthertested through simulations in the laboratory in addition to some fieldtesting. The simulations revealed that with the most advanced pathplanning algorithm, it was possible to achieve a close to optimal releaseconfiguration. This further resulted in an airdrop where the accuracyof the impact depended primarily on the altitude of release, in additionto the unpredictable environmental factors, such as wind gusts. Thefield tests displayed that the system was successfully implemented intothe provided framework. However, unforeseen technical difficultiesrelated to the aircraft, outside the control of this project, preventedin-air testing.Under the assumptions made throughout this thesis, the simulationsrevealed that the implemented system was able to reliably deploy thebeacon such that it landed within a relatively small perimeter aroundthe target.
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Lee, Kyuho. "Development of unmanned aerial vehicle (UAV) for wildlife surveillance." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008979.
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Edwards, Barrett Bruce. "An Onboard Vision System for Unmanned Aerial Vehicle Guidance." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2381.
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The viability of small Unmanned Aerial Vehicles (UAVs) as a stable platform for specific application use has been significantly advanced in recent years. Initial focus of lightweight UAV development was to create a craft capable of stable and controllable flight. This is largely a solved problem. Currently, the field has progressed to the point that unmanned aircraft can be carried in a backpack, launched by hand, weigh only a few pounds and be capable of navigating through unrestricted airspace. The most basic use of a UAV is to visually observe the environment and use that information to influence decision making. Previous attempts at using visual information to control a small UAV used an off-board approach where the video stream from an onboard camera was transmitted down to a ground station for processing and decision making. These attempts achieved limited results as the two-way transmission time introduced unacceptable amounts of latency into time-sensitive control algorithms. Onboard image processing offers a low-latency solution that will avoid the negative effects of two-way communication to a ground station. The first part of this thesis will show that onboard visual processing is capable of meeting the real-time control demands of an autonomous vehicle, which will also include the evaluation of potential onboard computing platforms. FPGA-based image processing will be shown to be the ideal technology for lightweight unmanned aircraft. The second part of this thesis will focus on the exact onboard vision system implementation for two proof-of-concept applications. The first application describes the use of machine vision algorithms to locate and track a target landing site for a UAV. GPS guidance was insufficient for this task. A vision system was utilized to localize the target site during approach and provide course correction updates to the UAV. The second application describes a feature detection and tracking sub-system that can be used in higher level application algorithms.
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Peppa, Maria Valasia. "Morphology-based landslide monitoring with an unmanned aerial vehicle." Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/4115.
Full textAbstract:
Landslides represent major natural phenomena with often disastrous consequences. Monitoring landslides with time-series surface observations can help mitigate such hazards. Unmanned aerial vehicles (UAVs) employing compact digital cameras, and in conjunction with Structure-from-Motion (SfM) and modern Multi-View Stereo (MVS) image matching approaches, have become commonplace in the geoscience research community. These methods offer a relatively low-cost and flexible solution for many geomorphological applications. The SfM-MVS pipeline has expedited the generation of digital elevation models at high spatio-temporal resolution. Conventionally ground control points (GCPs) are required for co-registration. This task is often expensive and impracticable considering hazardous terrain. This research has developed a strategy for processing UAV visible wavelength imagery that can provide multi-temporal surface morphological information for landslide monitoring, in an attempt to overcome the reliance on GCPs. This morphological-based strategy applies the attribute of curvature in combination with the scale-invariant feature transform algorithm, to generate pseudo GCPs. Openness is applied to extract relatively stable regions whereby pseudo GCPs are selected. Image cross-correlation functions integrated with openness and slope are employed to track landslide motion with subsequent elevation differences and planimetric surface displacements produced. Accuracy assessment evaluates unresolved biases with the aid of benchmark datasets. This approach was tested in the UK, in two sites, first in Sandford with artificial surface change and then in an active landslide at Hollin Hill. In Sandford, the strategy detected a ±0.120 m 3D surface change from three-epoch SfM-MVS products derived from a consumer-grade UAV. For the Hollin Hill landslide six-epoch datasets spanning an eighteen-month duration period were used, providing a ± 0.221 m minimum change. Annual displacement rates of dm-level were estimated with optimal results over winter periods. Levels of accuracy and spatial resolution comparable to previous studies demonstrated the potential of the morphology-based strategy for a time-efficient and cost-effective monitoring at inaccessible areas.
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Craparo, Emily M. (Emily Marie) 1980. "Natural language processing for unmanned aerial vehicle guidance interfaces." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16656.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 73-78).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
In this thesis, the opportunities and challenges involved in applying natural language processing techniques to the control of unmanned aerial vehicles (UAVs) are addressed. The problem of controlling an unmanned aircraft via natural language inputs is formulated as a feedback control problem, and notions of state, controllability, and observability are defined under this model. An implementation of such a system is also described. The phraseology of the existing air traffic control language is used as a base command set; to form this command set, a corpus of air traffic control commands was gathered from recorded exchanges between pilots and controllers at Boston's Logan Airport, as well as Laurence G. Hanscom Field in Bedford, MA, and these were used as the "target language" for this implementation. Knowledge of air traffic control and airport operations, combined with existing natural language processing techniques, is used to achieve a higher recognition success rate than a traditional natural language processor designed for a more general domain of discourse would. This :is the first known attempt at formalizing air traffic control phraseology for use in an unmanned system.
by Emily M. Craparo.
S.M.
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Meyer, Danielle L. "Energy Optimization of a Hybrid Unmanned Aerial Vehicle (UAV)." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523493111005807.
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Dowd, Garrett E. "Improving Autonomous Vehicle Safety using Communicationsand Unmanned Aerial Vehicles." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574861007798385.
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Mize, Lloyd B. IV. "Development of a Multiple Vehicle Collaborative Unmanned Aerial System." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2527.
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The purpose of this research was to design a multiple UAV system with collaborative operation. This project is built on work that has been done in the field of Unmanned Systems at VCU and is aimed at providing a starting point for research into collaborative control of multiple UAVs. The current GCS software was extended to include multiple vehicles per single controller via a new communication protocol. Many changes were made to the user interface to facilitate controlling multiple vehicles with a single operator. A second processor, called an MCS, was added to each vehicle to allow for greater flexibility and processing power, while maintaining backwards-compatibility and limiting infringement on the real-time processing of the FCS itself. The system was fully simulated via both hardware and software simulators, and ultimately the system was field tested using multiple vehicles collaboratively searching a defined area.
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Raza, Syed Ali. "Design and control of a quadrotor unmanned aerial vehicle." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28373.
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This research work is focused on the different steps of designing, building, simulating, and testing an intelligent flight control module for an increasingly popular unmanned aerial robot vehicle (UAV), known as a quadrotor. Also an in-depth view of the modeling of the kinematics, dynamics, and control of such an interesting UAV is presented. Eventually, a quadrotor UAV test-bed is built from scratch using custom off-the-shelf components.
In order to achieve autonomous flight, fuzzy logic is adopted for building the flight controller of the quadrotor. It has been witnessed that fuzzy logic control may offer several advantages over certain types of conventional control methods, specifically in dealing with highly nonlinear systems and modeling uncertainties. Some of these advantages are explained and compared with other conventional control techniques. Two types of fuzzy inference engines are employed in the design of the flight controller each method of which is explained and evaluated.
A helium balloon of calculated size is added to the frame of the quadrotor so that the lifting gas cancels some of the dead weight. A feasible ratio of buoyancy force and weight is found to maintain the stability of the quadrotor. A feasible size and pitch of propellers is also explored to minimize the power usage as well as providing sufficient thrust for desired maneuverability.
A bank of supercapacitors is also added to the existing power supply design. The idea is to exploit the advantages of super capacitors such as fast-charging and discharging and high power density. The proposed design of power supply provides longer operational time when compared to the conventional battery based circuits. Also the design is cost effective and improves the battery life by preventing deep discharges from the lithium-polymer battery power source.
The experimental results demonstrated a successful control performance under both inference engines. When compared to other conventional techniques applied for a similar purpose, the proposed methodology showed a higher robustness despite the induced disturbances. Also a slight improvement was observed in the overall flight-time of the quadrotor after applying the hybrid UAV design as well as the hybrid power supply unit (PSU) module to the quadrotor.
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Duberg, Daniel. "Safe Navigation of a Tele-operated Unmanned Aerial Vehicle." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-221701.
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Unmanned Aerial Vehicles (UAVs) can navigate in indoor environments and through environments that are hazardous or hard to reach for humans. This makes them suitable for use in search and rescue missions and by emergency response and law enforcement to increase situational awareness. However, even for an experienced UAV tele-operator controlling the UAV in these situations without colliding into obstacles is a demanding and difficult task. This thesis presents a human-UAV interface along with a collision avoidance method, both optimized for a human tele-operator. The objective is to simplify the task of navigating a UAV in indoor environments. Evaluation of the system is done by testing it against a number of use cases and a user study. The results of this thesis is a collision avoidance method that is successful in protecting the UAV from obstacles while at the same time acknowledges the operator’s intentions.Obemannad luftfarkoster (UAV:er) kan navigera i inomhusmiljöer och genom miljöer som är farliga eller svåra att nå för människor. Detta gör dem lämpliga för användning i sök- och räddningsuppdrag och av akutmottagning och rättsväsende genom ökad situationsmedvetenhet. Dock är det även för en erfaren UAV-teleoperatör krävande och svårt att kontrollera en UAV i dessa situationer utan att kollidera med hinder. Denna avhandling presenterar ett människa-UAV-gränssnitt tillsammans med en kollisionsundvikande metod, båda optimerade för en mänsklig teleoperatör. Målet är att förenkla uppgiften att navigera en UAV i inomhusmiljöer. Utvärdering av systemet görs genom att testa det mot ett antal användningsfall och en användarstudie. Resultatet av denna avhandling är en kollisionsundvikande metod som lyckas skydda UAV från hinder och samtidigt tar hänsyn till operatörens avsikter.
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Owen, Mark Andrew. "Aerial Rendezvous Between an Unmanned Air Vehicle and an Orbiting Target Vehicle." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2881.
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In this thesis we develop methods that facilitate an aerial rendezvous between two air vehicles. The objective of this research is to produce a method that can be used to insert a miniature air vehicle behind a rendezvous vehicle and then track that vehicle to enable a visual rendezvous. For this research we assume the rendezvous vehicle is following a relatively stable and roughly elliptical orbit. Path planners and controllers have been developed that can be used to effectively intercept the rendezvous vehicle by inserting the MAV onto the orbit of interest. A method for planning and following time-optimal Dubins airplane interception paths between a miniature air vehicle and the rendezvous vehicle is presented. We demonstrate how a vector field path following a scheme can be used for navigation along these time-optimal Dubins airplane paths. A post-orbit insertion tracking method is also presented which can be used to track the target vehicle on an arbitrarily oriented elliptical orbit while maintaining a specified following distance. We also present controllers that can be used for disturbance rejection during the orbit-insertion and interception operations. All of these methods were implemented in simulation and with hardware. Results from these implementations are presented and analyzed.
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Källström, Alexander, and Jagesten Albin Andersson. "Autonomous Landing of an Unmanned Aerial Vehicle on an Unmanned Ground Vehicle in a GNSS-denied scenario." Thesis, Linköpings universitet, Reglerteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167924.
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An autonomous system consisting of an unmanned aerial vehicle (UAV) in cooperation with an unmanned ground vehicle (UGV) is of interest in applications for military reconnaissance, surveillance and target acquisition (RSTA). The basic idea of such a system is to take advantage of the vehicles strengths and counteract their weaknesses. The cooperation aspect suggests that the UAV is capable of autonomously landing on the UGV. A fundamental part of the landing is to localise the UAV with respect to the UGV. Traditional navigation systems utilise global navigation satellite system (GNSS) receivers for localisation. GNSS receivers have many advantages, but they are sensitive to interference and spoofing. Therefore, this thesis investigates the feasibility of autonomous landing in a GNSS-denied scenario. The proposed landing system is divided into a control and an estimation system. The control system uses a proportional navigation (PN) control law to approach the UGV. When sufficiently close, a proportional-integral-derivative (PID) controller is used to match the movements of the UGV and perform a controlled descent and landing. The estimation system comprises an extended Kalman filter that utilises measurements from a camera, an imu and ultra-wide band (UWB) impulse radios. The landing system is composed of various results from previous research. First, the sensors used by the landing system are evaluated experimentally to get an understanding of their characteristics. The results are then used to determine the optimal sensor placements, in the design of the EKF, as well as, to shape the simulation environment and make it realistic. The simulation environment is used to evaluate the proposed landing system. The combined system is able to land the UAV safely on the moving UGV, confirming a fully-functional landing system. Additionally, the estimation system is evaluated experimentally, with results comparable to those obtained in simulation. The overall results are promising for the possibility of using the landing system with the presented hardware platform to perform a successful landing.
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Boulekchour, M. "Robust convex optimisation techniques for autonomous vehicle vision-based navigation." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/9412.
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This thesis investigates new convex optimisation techniques for motion and pose estimation. Numerous computer vision problems can be formulated as optimisation problems. These optimisation problems are generally solved via linear techniques using the singular value decomposition or iterative methods under an L2 norm minimisation. Linear techniques have the advantage of offering a closed-form solution that is simple to implement. The quantity being minimised is, however, not geometrically or statistically meaningful. Conversely, L2 algorithms rely on iterative estimation, where a cost function is minimised using algorithms such as Levenberg-Marquardt, Gauss-Newton, gradient descent or conjugate gradient. The cost functions involved are geometrically interpretable and can statistically be optimal under an assumption of Gaussian noise. However, in addition to their sensitivity to initial conditions, these algorithms are often slow and bear a high probability of getting trapped in a local minimum or producing infeasible solutions, even for small noise levels. In light of the above, in this thesis we focus on developing new techniques for finding solutions via a convex optimisation framework that are globally optimal. Presently convex optimisation techniques in motion estimation have revealed enormous advantages. Indeed, convex optimisation ensures getting a global minimum, and the cost function is geometrically meaningful. Moreover, robust optimisation is a recent approach for optimisation under uncertain data. In recent years the need to cope with uncertain data has become especially acute, particularly where real-world applications are concerned. In such circumstances, robust optimisation aims to recover an optimal solution whose feasibility must be guaranteed for any realisation of the uncertain data. Although many researchers avoid uncertainty due to the added complexity in constructing a robust optimisation model and to lack of knowledge as to the nature of these uncertainties, and especially their propagation, in this thesis robust convex optimisation, while estimating the uncertainties at every step is investigated for the motion estimation problem. First, a solution using convex optimisation coupled to the recursive least squares (RLS) algorithm and the robust H filter is developed for motion estimation. In another solution, uncertainties and their propagation are incorporated in a robust L convex optimisation framework for monocular visual motion estimation. In this solution, robust least squares is combined with a second order cone program (SOCP). A technique to improve the accuracy and the robustness of the fundamental matrix is also investigated in this thesis. This technique uses the covariance intersection approach to fuse feature location uncertainties, which leads to more consistent motion estimates. Loop-closure detection is crucial in improving the robustness of navigation algorithms. In practice, after long navigation in an unknown environment, detecting that a vehicle is in a location it has previously visited gives the opportunity to increase the accuracy and consistency of the estimate. In this context, we have developed an efficient appearance-based method for visual loop-closure detection based on the combination of a Gaussian mixture model with the KD-tree data structure. Deploying this technique for loop-closure detection, a robust L convex posegraph optimisation solution for unmanned aerial vehicle (UAVs) monocular motion estimation is introduced as well. In the literature, most proposed solutions formulate the pose-graph optimisation as a least-squares problem by minimising a cost function using iterative methods. In this work, robust convex optimisation under the L norm is adopted, which efficiently corrects the UAV’s pose after loop-closure detection. To round out the work in this thesis, a system for cooperative monocular visual motion estimation with multiple aerial vehicles is proposed. The cooperative motion estimation employs state-of-the-art approaches for optimisation, individual motion estimation and registration. Three-view geometry algorithms in a convex optimisation framework are deployed on board the monocular vision system for each vehicle. In addition, vehicle-to-vehicle relative pose estimation is performed with a novel robust registration solution in a global optimisation framework. In parallel, and as a complementary solution for the relative pose, a robust non-linear H solution is designed as well to fuse measurements from the UAVs’ on-board inertial sensors with the visual estimates. The suggested contributions have been exhaustively evaluated over a number of real-image data experiments in the laboratory using monocular vision systems and range imaging devices. In this thesis, we propose several solutions towards the goal of robust visual motion estimation using convex optimisation. We show that the convex optimisation framework may be extended to include uncertainty information, to achieve robust and optimal solutions. We observed that convex optimisation is a practical and very appealing alternative to linear techniques and iterative methods.
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Helmick, Daniel Martin. "Engine modeling, control, and synchronization for an unmanned aerial vehicle." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/16750.
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Dittrich, Joerg S. "Design and integration of an unmanned aerial vehicle navigation system." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15669.
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