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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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McAree, Owen. "Autonomous terminal area operations for unmanned aerial systems." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12535.
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After many years of successful operation in military domains, Unmanned Aerial Systems (UASs) are generating significant interest amongst civilian operators in sectors such as law enforcement, search and rescue, aerial photography and mapping. To maximise the benefits brought by UASs to sectors such as these, a high level of autonomy is desirable to reduce the need for highly skilled operators. Highly autonomous UASs require a high level of situation awareness in order to make appropriate decisions. This is of particular importance to civilian UASs where transparency and equivalence of operation to current manned aircraft is a requirement, particularly in the terminal area immediately surrounding an airfield. This thesis presents an artificial situation awareness system for an autonomous UAS capable of comprehending both the current continuous and discrete states of traffic vehicles. This estimate forms the basis of the projection element of situation awareness, predicting the future states of traffic. Projection is subject to a large degree of uncertainty in both continuous state variables and in the execution of intent information by the pilot. Both of these sources of uncertainty are captured to fully quantify the future positions of traffic. Based upon the projection of future traffic positions a self separation system is designed which allows an UAS to quantify its separation to traffic vehicles up to some future time and manoeuvre appropriately to minimise the potential for conflict. A high fidelity simulation environment has been developed to test the performance of the artificial situation awareness and self separation system. The system has demonstrated good performance under all situations, with an equivalent level of safety to that of a human pilot.
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Östman, Christian, and Anna Forsberg. "Support System for Landing with an Autonomous Unmanned Aerial Vehicle." Thesis, Linköping University, Linköping University, Linköping University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16278.
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There are a number of ongoing projects developing autonomous vehicles, both helicopters and airplanes. The purpose of this thesis is to study a concept for calculating the height and attitude of a helicopter. The system will be active during landing. This thesis includes building an experimental setup and to develop algorithms and software.
The basic idea is to illuminate the ground with a certain pattern and in our case we used laser pointers to create this pattern. The ground is then filmed and the images are processed to extract the pattern. This provides us with information about the height and attitude of the helicopter. Furthermore, the concept implies that no equipment on the ground is needed. With further development the sensor should be able to calculate the movement of the underlying surface relative to the helicopter. This is very important when landing on a moving surface, e.g. a ship at sea.
To study the concept empirically an experimental setup was constructed. The setup provides us with the necessary information to evaluate how well the system could perform in reality. The setup is built with simple and cheap materials. In the setup an ordinary web camera and laser pointers that are avaliable for everyone have been used.
Det finns flera pågående projekt inom autonomflygande farkoster, både för helikoptrar och flygplan. Syftet med vårt examensarbetet är att undersöka ett koncept för en landningssensor för autonom landning med helikopter. Examensarbetet innebär att bygga en fysisk modell för test av konceptet samt att utveckla mjukvara.
Konceptet för sensorn består av att belysa marken med ett speciellt mönster, i vårt fall skapas mönstret av laserpekare, som därefter fotograferas och bildbehandlas. Detta mönster ger sedan information om helikopterns höjd och attityd i luften. Vidare innebär konceptet också att ingen markutrustning krävs för att sensorn ska fungera. I förlängningen ska man med detta koncept kunna beräkna hur underlaget rör sig relativt helikoptern, vilket är väldigt viktigt vid landning på objekt som rör sig, till exempel ett fartyg.
För att undersöka hur bra sensorn presterar i verkligheten så har en rigg byggts. Riggen är byggd med enkla och billiga material. I det här fallet används en webbkamera och laserpekare som går att köpa i vanliga elektronikaffärer.
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OSMAN, OSMAN ABDALLA SIDAHMED. "Autonomous Navigation for Unmanned Aerial Systems - Visual Perception and Motion Planning." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2971114.
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Patchett, Charles H. "On the derivation and analysis of decision architectures for uninhabited air systems." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/8033.
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Operation of Unmanned Air Vehicles (UAVs) has increased significantly over the past few years. However, routine operation in non-segregated airspace remains a challenge, primarily due to nature of the environment and restrictions and challenges that accompany this. Currently, tight human control is envisaged as a means to achieve the oft quoted requirements of transparency , equivalence and safety. However, the problems of high cost of human operation, potential communication losses and operator remoteness remain as obstacles. One means of overcoming these obstacles is to devolve authority, from the ground controller to an on-board system able to understand its situation and make appropriate decisions when authorised. Such an on-board system is known as an Autonomous System. The nature of the autonomous system, how it should be designed, when and how authority should be transferred and in what context can they be allowed to control the vehicle are the general motivation for this study. To do this, the system must overcome the negative aspects of differentiators that exist between UASs and manned aircraft and introduce methods to achieve required increases in the levels of versatility, cost, safety and performance. The general thesis of this work is that the role and responsibility of an airborne autonomous system are sufficiently different from those of other conventionally controlled manned and unmanned systems to require a different architectural approach. Such a different architecture will also have additional requirements placed upon it in order to demonstrate acceptable levels of Transparency, Equivalence and Safety. The architecture for the system is developed from an analysis of the basic requirements and adapted from a consideration of other, suitable candidates for effective control of the vehicle under devolved authority. The best practices for airborne systems in general are identified and amalgamated with established principles and approaches of robotics and intelligent agents. From this, a decision architecture, capable of interacting with external human agencies such as the UAS Commander and Air Traffic Controllers, is proposed in detail. This architecture has been implemented and a number of further lessons can be drawn from this. In order to understand in detail the system safety requirements, an analysis of manned and unmanned aircraft accidents is made. Particular interest is given to the type of control moding of current unmanned aircraft in order to make a comparison, and prediction, with accidents likely to be caused by autonomously controlled vehicles. The effect of pilot remoteness on the accident rate is studied and a new classification of this remoteness is identified as a major contributor to accidents A preliminary Bayesian model for unmanned aircraft accidents is developed and results and predictions are made as an output of this model. From the accident analysis and modelling, strategies to improve UAS safety are identified. Detailed implementations within these strategies are analysed and a proposal for more advanced Human-Machine Interaction made. In particular, detailed analysis is given on exemplar scenarios that a UAS may encounter. These are: Sense and Avoid , Mission Management Failure, Take Off/Landing, and Lost Link procedures and Communications Failure. These analyses identify the nature of autonomous, as opposed to automatic, operation and clearly show the benefits to safety of autonomous air vehicle operation, with an identifiable decision architecture, and its relationship with the human controller. From the strategies and detailed analysis of the exemplar scenarios, proposals are made for the improvement of unmanned vehicle safety The incorporation of these proposals into the suggested decision architecture are accompanied by analysis of the levels of benefit that may be expected. These suggest that a level approaching that of conventional manned aircraft is achievable using currently available technologies but with substantial architectural design methodologies than currently fielded.
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Towler, Jerry Alwynne. "Autonomous Aerial Localization of Radioactive Point Sources via Recursive Bayesian Estimation and Contour Analysis." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43465.
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The rapid, accurate determination of the positions and strengths of sources of dangerous radioactivity takes high priority after a catastrophic event to ensure the safety of personnel, civilians, and emergency responders. This thesis presents approaches and algorithms to autonomously investigate radioactive material using an unmanned aerial vehicle.Performing this autonomous analysis comprises five major steps: ingress from a base of operations to the danger zone, initial detection of radioactive material, measurement of the strength of radioactive emissions, analysis of the data to provide position and intensity estimates, and finally egress from the area of interest back to the launch site. In all five steps, time is of critical importance: faster responses promise potentially saved lives.
A time-optimal ingress and egress path planning method solves the first and last steps. Vehicle capabilities and instrument sensitivity inform the development of an efficient search path within the area of interest. Two algorithmsâ a grid-based recursive Bayesian estimator and a novel radiation contour analysis methodâ are presented to estimate the position of radioactive sources using simple gross gamma ray event count data from a nondirectional radiation detector. The latter procedure also correctly estimates the number of sources present and their intensities.
Ultimately, a complete unsupervised mission is developed, requiring minimal initial operator interaction, that provides accurate characterization of the radiation environment of an area of interest as quickly as reasonably possible.
Master of Science
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Van, Horne Chris. "Machine Vision and Autonomous Integration Into an Unmanned Aircraft System." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579707.
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ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NVThe University of Arizona's Aerial Robotics Club (ARC) sponsors the development of an unmanned aerial vehicle (UAV) able to compete in the annual Association for Unmanned Vehicle Systems International (AUVSI) Seafarer Chapter Student Unmanned Aerial Systems competition. Modern programming frameworks are utilized to develop a robust distributed imagery and telemetry pipeline as a backend for a mission operator user interface. This paper discusses the design changes made for the 2013 AUVSI competition including integrating low-latency first-person view, updates to the distributed task backend, and incremental and asynchronous updates the operator's user interface for real-time data analysis.
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Kang, Keeryun. "Online optimal obstacle avoidance for rotary-wing autonomous unmanned aerial vehicles." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44820.
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This thesis presents an integrated framework for online obstacle avoidance of rotary-wing unmanned aerial vehicles (UAVs), which can provide UAVs an obstacle field navigation capability in a partially or completely unknown obstacle-rich environment. The framework is composed of a LIDAR interface, a local obstacle grid generation, a receding horizon (RH) trajectory optimizer, a global shortest path search algorithm, and a climb rate limit detection logic.
The key feature of the framework is the use of an optimization-based trajectory generation in which the obstacle avoidance problem is formulated as a nonlinear trajectory optimization problem with state and input constraints over the finite range of the sensor. This local trajectory optimization is combined with a global path search algorithm which provides a useful initial guess to the nonlinear optimization solver. Optimization is the natural process of finding the best trajectory that is dynamically feasible, safe within the vehicle's flight envelope, and collision-free at the same time. The optimal trajectory is continuously updated in real time by the numerical optimization solver, Nonlinear Trajectory Generation (NTG), which is a direct solver based on the spline approximation of trajectory for dynamically flat systems. In fact, the overall approach of this thesis to finding the optimal trajectory is similar to the model predictive control (MPC) or the receding horizon control (RHC), except that this thesis followed a two-layer design; thus, the optimal solution works as a guidance command to be followed by the controller of the vehicle.
The framework is implemented in a real-time simulation environment, the Georgia Tech UAV Simulation Tool (GUST), and integrated in the onboard software of the rotary-wing UAV test-bed at Georgia Tech. Initially, the 2D vertical avoidance capability of real obstacles was tested in flight. Then the flight test evaluations were extended to the benchmark tests for 3D avoidance capability over the virtual obstacles, and finally it was demonstrated on real obstacles located at the McKenna MOUT site in Fort Benning, Georgia. Simulations and flight test evaluations demonstrate the feasibility of the developed framework for UAV applications involving low-altitude flight in an urban area.
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Alexander, Josh, Sam Blake, Brendan Clasby, Anshul Jatin Shah, Horne Chris Van, and Horne Justin Van. "Machine Vision and Autonomous Integration Into an Unmanned Aircraft System." International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581850.
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The University of Arizona's Aerial Robotics Club (ARC) sponsored two senior design teams to compete in the 2011 AUVSI Student Unmanned Aerial Systems (SUAS) competition. These teams successfully design and built a UAV platform in-house that was capable of autonomous flight, capturing aerial imagery, and filtering for target recognition but required excessive computational hardware and software bugs that limited the systems capability. A new multi-discipline team of undergrads was recruited to completely redesign and optimize the system in an attempt to reach true autonomous real-time target recognition with reasonable COTS hardware.
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Puttige, Vishwas Ramadas Engineering & Information Technology Australian Defence Force Academy UNSW. "Neural network based adaptive control for autonomous flight of fixed wing unmanned aerial vehicles." Awarded by:University of New South Wales - Australian Defence Force Academy. Engineering & Information Technology, 2009. http://handle.unsw.edu.au/1959.4/43736.
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This thesis presents the development of small, inexpensive unmanned aerial vehicles (UAVs) to achieve autonomous fight. Fixed wing hobby model planes are modified and instrumented to form experimental platforms. Different sensors employed to collect the flight data are discussed along with their calibrations. The time constant and delay for the servo-actuators for the platform are estimated. Two different data collection and processing units based on micro-controller and PC104 architectures are developed and discussed. These units are also used to program the identification and control algorithms. Flight control of fixed wing UAVs is a challenging task due to the coupled, time-varying, nonlinear dynamic behaviour. One of the possible alternatives for the flight control system is to use the intelligent adaptive control techniques that provide online learning capability to cope with varying dynamics and disturbances. Neural network based indirect adaptive control strategy is applied for the current work. The two main components of the adaptive control technique are the identification block and the control block. Identification provides a mathematical model for the controller to adapt to varying dynamics. Neural network based identification provides a black-box identification technique wherein a suitable network provides prediction capability based upon the past inputs and outputs. Auto-regressive neural networks are employed for this to ensure good retention capabilities for the model that uses the past outputs and inputs along with the present inputs. Online and offline identification of UAV platforms are discussed based upon the flight data. Suitable modifications to the Levenberg-Marquardt training algorithm for online training are proposed. The effect of varying the different network parameters on the performance of the network are numerically tested out. A new performance index is proposed that is shown to improve the accuracy of prediction and also reduces the training time for these networks. The identification algorithms are validated both numerically and flight tested. A hardware-in-loop simulation system has been developed to test the identification and control algorithms before flight testing to identify the problems in real time implementation on the UAVs. This is developed to keep the validation process simple and a graphical user interface is provided to visualise the UAV flight during simulations. A dual neural network controller is proposed as the adaptive controller based upon the identification models. This has two neural networks collated together. One of the neural networks is trained online to adapt to changes in the dynamics. Two feedback loops are provided as part of the overall structure that is seen to improve the accuracy. Proofs for stability analysis in the form of convergence of the identifier and controller networks based on Lyapunov's technique are presented. In this analysis suitable bounds on the rate of learning for the networks are imposed. Numerical results are presented to validate the adaptive controller for single-input single-output as well as multi-input multi-output subsystems of the UAV. Real time validation results and various flight test results confirm the feasibility of the proposed adaptive technique as a reliable tool to achieve autonomous flight. The comparison of the proposed technique with a baseline gain scheduled controller both in numerical simulations as well as test flights bring out the salient adaptive feature of the proposed technique to the time-varying, nonlinear dynamics of the UAV platforms under different flying conditions.
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Sandino, Mora Juan David. "Autonomous decision-making for UAVs operating under environmental and object detection uncertainty." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/232513/1/Juan%20David_Sandino%20Mora_Thesis.pdf.
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This study established a framework that increases cognitive levels in small UAVs (or drones), enabling autonomous navigation in partially observable environments. The UAV system was validated under search and rescue by locating victims last seen inside cluttered buildings and in bushlands. This framework improved the decision-making skills of the drone to collect more accurate statistics of detected victims. This study assists validation processes of detected objects in real-time when data is complex to interpret for UAV pilots and reduces human bias on scouting strategies.
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Mercado-Ravell, Diego Alberto. "Autonomous navigation and teleoperation of unmanned aerial vehicles using monocular vision." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2239/document.
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Ce travail porte, de façon théorétique et pratique, sur les sujets plus pertinents autour des drones en navigation autonome et semi-autonome. Conformément à la nature multidisciplinaire des problèmes étudies, une grande diversité des techniques et théories ont été couverts dans les domaines de la robotique, l’automatique, l’informatique, la vision par ordinateur et les systèmes embarques, parmi outres.Dans le cadre de cette thèse, deux plates-formes expérimentales ont été développées afin de valider la théorie proposée pour la navigation autonome d’un drone. Le premier prototype, développé au laboratoire, est un quadrirotor spécialement conçu pour les applications extérieures. La deuxième plate-forme est composée d’un quadrirotor à bas coût du type AR.Drone fabrique par Parrot. Le véhicule est connecté sans fil à une station au sol équipé d’un système d’exploitation pour robots (ROS) et dédié à tester, d’une façon facile, rapide et sécurisé, les algorithmes de vision et les stratégies de commande proposés. Les premiers travaux développés ont été basés sur la fusion de donnés pour estimer la position du drone en utilisant des capteurs inertiels et le GPS. Deux stratégies ont été étudiées et appliquées, le Filtre de Kalman Etendu (EKF) et le filtre à Particules (PF). Les deux approches prennent en compte les mesures bruitées de la position de l’UAV, de sa vitesse et de son orientation. On a réalisé une validation numérique pour tester la performance des algorithmes. Une tâche dans le cahier de cette thèse a été de concevoir d’algorithmes de commande pour le suivi de trajectoires ou bien pour la télé-opération. Pour ce faire, on a proposé une loi de commande basée sur l’approche de Mode Glissants à deuxième ordre. Cette technique de commande permet de suivre au quadrirotor de trajectoires désirées et de réaliser l’évitement des collisions frontales si nécessaire. Etant donné que la plate-forme A.R.Drone est équipée d’un auto-pilote d’attitude, nous avons utilisé les angles désirés de roulis et de tangage comme entrées de commande. L’algorithme de commande proposé donne de la robustesse au système en boucle fermée. De plus, une nouvelle technique de vision monoculaire par ordinateur a été utilisée pour la localisation d’un drone. Les informations visuelles sont fusionnées avec les mesures inertielles du drone pour avoir une bonne estimation de sa position. Cette technique utilise l’algorithme PTAM (localisation parallèle et mapping), qui s’agit d’obtenir un nuage de points caractéristiques dans l’image par rapport à une scène qui servira comme repère. Cet algorithme n’utilise pas de cibles, de marqueurs ou de scènes bien définies. La contribution dans cette méthodologie a été de pouvoir utiliser le nuage de points disperse pour détecter possibles obstacles en face du véhicule. Avec cette information nous avons proposé un algorithme de commande pour réaliser l’évitement d’obstacles. Cette loi de commande utilise les champs de potentiel pour calculer une force de répulsion qui sera appliquée au drone. Des expériences en temps réel ont montré la bonne performance du système proposé. Les résultats antérieurs ont motivé la conception et développement d’un drone capable de réaliser en sécurité l’interaction avec les hommes et les suivre de façon autonome. Un classificateur en cascade du type Haar a été utilisé pour détecter le visage d’une personne. Une fois le visage est détecté, on utilise un filtre de Kalman (KF) pour améliorer la détection et un algorithme pour estimer la position relative du visage. Pour réguler la position du drone et la maintenir à une distance désirée du visage, on a utilisé une loi de commande linéaireThe present document addresses, theoretically and experimentally, the most relevant topics for Unmanned Aerial Vehicles (UAVs) in autonomous and semi-autonomous navigation. According with the multidisciplinary nature of the studied problems, a wide range of techniques and theories are covered in the fields of robotics, automatic control, computer science, computer vision and embedded systems, among others. As part of this thesis, two different experimental platforms were developed in order to explore and evaluate various theories and techniques of interest for autonomous navigation. The first prototype is a quadrotor specially designed for outdoor applications and was fully developed in our lab. The second testbed is composed by a non expensive commercial quadrotor kind AR. Drone, wireless connected to a ground station equipped with the Robot Operating System (ROS), and specially intended to test computer vision algorithms and automatic control strategies in an easy, fast and safe way. In addition, this work provides a study of data fusion techniques looking to enhance the UAVs pose estimation provided by commonly used sensors. Two strategies are evaluated in particular, an Extended Kalman Filter (EKF) and a Particle Filter (PF). Both estimators are adapted for the system under consideration, taking into account noisy measurements of the UAV position, velocity and orientation. Simulations show the performance of the developed algorithms while adding noise from real GPS (Global Positioning System) measurements. Safe and accurate navigation for either autonomous trajectory tracking or haptic teleoperation of quadrotors is presented as well. A second order Sliding Mode (2-SM) control algorithm is used to track trajectories while avoiding frontal collisions in autonomous flight. The time-scale separation of the translational and rotational dynamics allows us to design position controllers by giving desired references in the roll and pitch angles, which is suitable for quadrotors equipped with an internal attitude controller. The 2-SM control allows adding robustness to the closed-loop system. A Lyapunov based analysis probes the system stability. Vision algorithms are employed to estimate the pose of the vehicle using only a monocular SLAM (Simultaneous Localization and Mapping) fused with inertial measurements. Distance to potential obstacles is detected and computed using the sparse depth map from the vision algorithm. For teleoperation tests, a haptic device is employed to feedback information to the pilot about possible collisions, by exerting opposite forces. The proposed strategies are successfully tested in real-time experiments, using a low-cost commercial quadrotor. Also, conception and development of a Micro Aerial Vehicle (MAV) able to safely interact with human users by following them autonomously, is achieved in the present work. Once a face is detected by means of a Haar cascade classifier, it is tracked applying a Kalman Filter (KF), and an estimation of the relative position with respect to the face is obtained at a high rate. A linear Proportional Derivative (PD) controller regulates the UAV’s position in order to keep a constant distance to the face, employing as well the extra available information from the embedded UAV’s sensors. Several experiments were carried out through different conditions, showing good performance even under disadvantageous scenarios like outdoor flight, being robust against illumination changes, wind perturbations, image noise and the presence of several faces on the same image. Finally, this thesis deals with the problem of implementing a safe and fast transportation system using an UAV kind quadrotor with a cable suspended load. The objective consists in transporting the load from one place to another, in a fast way and with minimum swing in the cable
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Han, Yiding. "An Autonomous Unmanned Aerial Vehicle-Based Imagery System Development and Remote Sensing Images Classification for Agricultural Applications." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/513.
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This work concentrates on the topic of remote sensing using a multispectral imag-ing system for water management and agriculture applications. The platform, which is alight-weight inexpensive runway-free unmanned aerial vehicle (UAV), namely, AggieAir, ispresented initially. A major portion of this work focuses on the development of a light-weight multispectral imager payload for the AggieAir platform, called GhostFoto. Theimager is band-recongurable, covering both visual red, green, and blue (RGB) and nearinfrared (NIR) spectrum, and interfaced with UAV on-board computer. The developmentof the image processing techniques, which are based on the collected multispectral aerialimages, is also presented in this work. One application is to perform fully autonomous rivertracking for applications such as river water management. Simulation based on aerial mul-tispectral images is done to demonstrate the feasibility of the developed algorithm. Othereort is made to create a systematic method to generate normalized difference vegetationindex (NDVI) using the airborne imagery. The GhostFoto multispectral imaging systembased on AggieAir architecture is proven to be an innovative and useful tool.
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Stepien, Hubert, and Martin Bilger. "Diverse Time Redundant Triplex Parallel Convolutional Neural Networks for Unmanned Aerial Vehicle Detection." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-54596.
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Safe airspace of airports worldwide is crucial to ensure that passengers, workers, and airplanes are safe from external threats, whether malicious or not. In recent years, several airports worldwide experienced intrusions into their airspace by unmanned aerial vehicles. Based on this observation, there is a need for a reliable detection system capable of detecting unmanned aerial vehicles with high accuracy and integrity. This thesis proposes time redundant triplex parallel diverse convolutional neural network architectures trained to detect unmanned aerial vehicles to address the aforementioned issue. The thesis aims at producing a system capable of real-time performance coupled with previously mentioned networks. The hypothesis in this method will result in lower mispredictions of objects other than drones and high accuracy compared to singular convolutional neural networks. Several improvements to accuracy, lower mispredictions, and faster detection times were observed during the performed experiments with the proposed system. Furthermore, a new way of interpreting the intersection over union results for all neural networks is introduced to ensure the correctness and reliability of results. Lastly, the system produced by this thesis is analyzed from a dependability viewpoint to provide an overview of how this contributes to dependability research.
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Peddle, Iain K. "Acceleration based manoeuvre flight control system for unmanned aerial vehicles." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1172.
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Thesis (PhD (Electrical and Electronic Engineering))--Stellenbosch University, 2008.A strategy for the design of an effective, practically feasible, robust, computationally efficient autopilot for three dimensional manoeuvre flight control of Unmanned Aerial Vehicles is presented. The core feature of the strategy is the design of attitude independent inner loop acceleration controllers. With these controllers implemented, the aircraft is reduced to a point mass with a steerable acceleration vector when viewed from an outer loop guidance perspective. Trajectory generation is also simplified with reference trajectories only required to be kinematically feasible. Robustness is achieved through uncertainty encapsulation and disturbance rejection at an acceleration level. The detailed design and associated analysis of the inner loop acceleration controllers is carried out for the case where the airflow incidence angles are small. For this case it is shown that under mild practically feasible conditions the inner loop dynamics decouple and become linear, thereby allowing the derivation of closed form pole placement solutions. Dimensional and normalised non-dimensional time variants of the inner loop controllers are designed and their respective advantages highlighted. Pole placement constraints that arise due to the typically weak non-minimum phase nature of aircraft dynamics are developed. A generic, aircraft independent guidance control algorithm, well suited for use with the inner loop acceleration controllers, is also presented. The guidance algorithm regulates the aircraft about a kinematically feasible reference trajectory. A number of fundamental basis trajectories are presented which are easily linkable to form complex three dimensional manoeuvres. Results from simulations with a number of different aircraft and reference trajectories illustrate the versatility and functionality of the autopilot. Key words: Aircraft control, Autonomous vehicles, UAV flight control, Acceleration control, Aircraft guidance, Trajectory tracking, Manoeuvre flight control.
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Holt, Ryan S. "Three Enabling Technologies for Vision-Based, Forest-Fire Perimeter Surveillance Using Multiple Unmanned Aerial Systems." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/931.
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The ability to gather and process information regarding the condition of forest fires is essential to cost-effective, safe, and efficient fire fighting. Advances in sensory and autopilot technology have made miniature unmanned aerial systems (UASs) an important tool in the acquisition of information. This thesis addresses some of the challenges faced when employing UASs for forest-fire perimeter surveillance; namely, perimeter tracking, cooperative perimeter surveillance, and path planning. Solutions to the first two issues are presented and a method for understanding path planning within the context of a forest-fire environment is demonstrated. Both simulation and hardware results are provided for each solution.
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Adler, Benjamin [Verfasser], and Jianwei [Akademischer Betreuer] Zhang. "System Design and Real-Time Guidance of an Unmanned Aerial Vehicle for Autonomous Exploration of Outdoor Environments / Benjamin Adler. Betreuer: Jianwei Zhang." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://d-nb.info/1068931221/34.
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Holtby, Johan. "Autonom UAV." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-168611.
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In Abisko National Park there are a numberof weather stations. To be able toretrieve the data from the nodes in thefuture a Quadrocopter-prototype has beendeveloped during this master thesisproject as a first step. A quadrocopter isa helicopter with four rotors placed in across formation. The quadrocopter cannavigate autonomous between different GPSpositionsthat are updated during flighttrough Xbee-modules. All levels fromsources code, design of the electronics todevelopment of the chassis was performedduring the project. During GPS-navigationthe quadrocopter can achieve a stationaryposition with a mean stationary offset ofless than 0.5 meters even in light winds.I Abisko Nationalpark finns det ett antal väderstationer. För att på sikt kunna läsa av väderdata från dessa har en quadrocopter-prototyp utvecklats i detta examensarbete. En quadrocopter är en helikopter med fyra rotorer placerade i ett kryss. Quadrocoptern kan navigera autonomt mellan olika GPS-positioner som ges trådlöst via Xbee-moduler. Alla nivåer från källkod, design av elektronik till utformning och tillverkning av chassit har gjorts inom detta projekt. Vid GPS-navigering kan quadrocoptern uppnå en stationär position med en medelvärdesavvikelse mindre än 0.5 meter trots lättare vindar.
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Hamren, Rasmus. "APPLYING UAVS TO SUPPORT THE SAFETY IN AUTONOMOUS OPERATED OPEN SURFACE MINES." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-53376.
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Unmanned aerial vehicle (UAV) is an expanding interest in numerous industries for various applications. Increasing development of UAVs is happening worldwide, where various sensor attachments and functions are being added. The multi-function UAV can be used within areas where they have not been managed before. Because of their accessibility, cheap purchase, and easy-to-use, they replace expensive systems such as helicopters- and airplane-surveillance. UAV are also being applied into surveillance, combing object detection to video-surveillance and mobility to finding an object from the air without interfering with vehicles or humans ground. In this thesis, we solve the problem of using UAV on autonomous sites, finding an object and critical situation, support autonomous site operators with an extra safety layer from UAVs camera. After finding an object on such a site, uses GPS-coordinates from the UAV to see and place the detected object on the site onto a gridmap, leaving a coordinate-map to the operator to see where the objects are and see if the critical situation can occur. Directly under the object detection, reporting critical situations can be done because of safety-distance-circle leaving warnings if objects come to close to each other. However, the system itself only supports the operator with extra safety and warnings, leaving the operator with the choice of pressing emergency stop or not. Object detection uses You only look once (YOLO) as main object detection Neural Network (NN), mixed with edge-detection for gaining accuracy during bird-eye-views and motion-detection for supporting finding all object that is moving on-site, even if UAV cannot find all the objects on site. Result proofs that the UAV-surveillance on autonomous site is an excellent way to add extra safety on-site if the operator is out of focus or finding objects on-site before startup since the operator can fly the UAV around the site, leaving an extra-safety-layer of finding humans on-site before startup. Also, moving the UAV to a specific position, where extra safety is needed, informing the operator to limit autonomous vehicles speed around that area because of humans operation on site. The use of single object detection limits the effects but gathered object detection methods lead to a promising result while printing those objects onto a global positions system (GPS) map has proposed a new field to study. It leaves the operator with a viewable interface outside of object detection libraries.
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Lundblad, Oscar. "The autonomous crewmate : A sociotechnical perspective to implementation of autonomous vehicles in sea rescue." Thesis, Linköpings universitet, Interaktiva och kognitiva system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166452.
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The usage of autonomous vehicles is starting to appear in several different domains and the domain of public safety is no exception. Wallenberg Artificial Intelligence, Autonomous Systems and Software Program (WASP) has created a research arena for public safety (WARA-PS) to explore experimental features, usages, and implementation of autonomous vehicles within the domain of public safety. Collaborating in the arena are several companies, universities, and researchers. This thesis examines, in collaboration with Combitech, a company partnered in WARA-PS, how the implementation of autonomous vehicles affects the sociotechnical system of a search and rescue operation during a drifting boat with potential castaways. This is done by creating a case together with domain experts, analyzing the sociotechnical system within the case using cognitive work analysis and then complementing the analyses with the unmanned autonomous vehicles of WARA-PS. This thesis has shown how the WARA-PS vehicles can be implemented in the case of a drifting boat with potential castaways and how the implementation affects the sociotechnical system. Based on the analyses and opinions of domain experts’ future guidelines has been derived to further the work with sociotechnical aspects in WARA-PS.WARA-PS
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Lizarraga, Mariano I. "Autonomous landing system for a UAV." Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1655.
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Approved for public release, distribution is unlimitedThis thesis is part of an ongoing research conducted at the Naval Postgraduate School to achieve the autonomous shipboard landing of Unmanned Aerial Vehicles (UAV). Two main problems are addressed in this thesis. The first is to establish communication between the UAV's ground station and the Autonomous Landing Flight Control Computer effectively. The second addresses the design and implementation of an autonomous landing controller using classical control techniques. Device drivers for the sensors and the communications protocol were developed in ANSI C. The overall system was implemented in a PC104 computer running a real-time operating system developed by The Mathworks, Inc. Computer and hardware in the loop (HIL) simulation, as well as ground test results show the feasibility of the algorithm proposed here. Flight tests are scheduled to be performed in the near future.
Lieutenant Junior Grade, Mexican Navy
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Swart, Andre Dewald. "Monocular vision assisted autonomous landing of a helicopter on a moving deck." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80134.
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Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The landing phase of any helicopter is the most critical part of the whole flight envelope, particularly on a moving flight deck. The flight deck is usually located at the stern of the ship, translating to large heave motions. This thesis focuses on the three fundamental components required for a successful landing: accurate, relative state-estimation between the helicopter and the flight deck; a prediction horizon to forecast suitable landing opportunities; and excellent control to safely unite the helicopter with the flight deck. A monocular-vision sensor node was developed to provide accurate, relative position and attitude information of the flight deck. The flight deck is identified by a distinct, geometric pattern. The relative states are combined with the onboard, kinematic state-estimates of the helicopter to provide an inertial estimate of the flight deck states. Onboard motion prediction is executed to forecast a possible safe landing time which is conveyed to the landing controller. Camera pose-estimation tests and hardware-in-the-loop simulations proved the system developed in this thesis viable for flight tests. The practical flight tests confirmed the success of the monocular-vision sensor node.
AFRIKAANSE OPSOMMING: Die mees kritiese deel van die hele vlug-duurte van ’n helikopter is die landings-fase, veral op ’n bewegende vlugdek. Die vlugdek is gewoonlik geleë aan die agterstewe-kant van die skip wat groot afgee bewegings mee bring. Hierdie tesis ondersoek die drie fundamentele komponente van ’n suksesvolle landing: akkurate, relatiewe toestand-beraming tussen die helikopter en die vlugdek; ’n vooruitskatting horison om geskikte landings geleenthede te voorspel; en uitstekended beheer om die helikopter en vlugdek veilig te verenig. ’n Monokulêre-visie sensor-nodus was ontwikkel om akkurate, relatiewe-posisie en oriëntasie informasie van die vlugdek te verwerf. Die vlugdek is geidentifiseer deur ’n kenmerkende, geometriese patroon. Die relatiewe toestande word met die aan-boord kinematiese toestandafskatter van die helikopter gekombineer, om ’n beraming van die inertiale vlugdek-toestande te verskaf. Aan-boord beweging-vooruitskatting is uitgevoer om moontlike, veilige landingstyd te voorspel en word teruggevoer na die landingsbeheerder. Kamera-orientasie afskat-toetse en hardeware-in-die-lus simulasies het die ontwikkelde sisteem van hierdie tesis lewensvatbaar vir vlug-toetse bewys. Praktiese vlug-toetse het die sukses van die monokulêre-visie sensor-nodus bevestig.
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Sattigeri, Ramachandra Jayant. "Adaptive Estimation and Control with Application to Vision-based Autonomous Formation Flight." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16272.
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The role of vision as an additional sensing mechanism has received a lot of attention in recent years in the context of autonomous flight applications. Modern Unmanned Aerial Vehicles (UAVs) are equipped with vision sensors because of their light-weight, low-cost characteristics and also their ability to provide a rich variety of information of the environment in which the UAVs are navigating in. The problem of vision based autonomous flight is very difficult and challenging since it requires bringing together concepts from image processing and computer vision, target tracking and state estimation, and flight guidance and control.
This thesis focuses on the adaptive state estimation, guidance and control problems involved in vision-based formation flight. Specifically, the thesis presents a composite adaptation approach to the partial state estimation of a class of nonlinear systems with unmodeled dynamics. In this approach, a linear time-varying Kalman filter is the nominal state estimator which is augmented by the output of an adaptive neural network (NN) that is trained with two error signals. The benefit of the proposed approach is in its faster and more accurate adaptation to the modeling errors over a conventional approach.
The thesis also presents two approaches to the design of adaptive guidance and control (G&C) laws for line-of-sight formation flight. In the first approach, the guidance and autopilot systems are designed separately and then combined together by assuming time-scale separation. The second approach is based on integrating the guidance and autopilot design process. The developed G&C laws using both approaches are adaptive to unmodeled leader aircraft acceleration and to own aircraft aerodynamic uncertainties.
The thesis also presents theoretical justification based on Lyapunov-like stability analysis for integrating the adaptive state estimation and adaptive G&C designs. All the developed designs are validated in nonlinear, 6DOF fixed-wing aircraft simulations.
Finally, the thesis presents a decentralized coordination strategy for vision-based multiple-aircraft formation control. In this approach, each aircraft in formation regulates range from up to two nearest neighboring aircraft while simultaneously tracking nominal desired trajectories common to all aircraft and avoiding static obstacles.
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Robinson, Andreas. "Implementation and evaluation of a 3D tracker." Thesis, Linköpings universitet, Datorseende, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-111887.
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Many methods have been developed for visual tracking of generic objects. The vast majority of these assume the world is two-dimensional, either ignoring the third dimension or only dealing with it indirectly. This causes difficulties for the tracker when the target approaches or moves away from the camera, is occluded or moves out of the camera frame. Unmanned aerial vehicles (UAVs) are increasingly used in civilian applications and some of these will undoubtedly carry tracking systems in the future. As they move around, these trackers will encounter both scale changes and occlusions. To improve the tracking performance in these cases, the third dimension should be taken into account. This thesis extends the capabilities of a 2D tracker to three dimensions, with the assumption that the target moves on a ground plane. The position of the tracker camera is established by matching the video it produces to a sparse point-cloud map built with off-the-shelf structure-from-motion software. A target is tracked with a generic 2D tracker and subsequently positioned on the ground. Should the target disappear from view, its motion on the ground is predicted. In combination, these simple techniques are shown to improve the robustness of a tracking system on a moving platform under target scale changes and occlusions.
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Herold, Fredrick W. "Total Border Security Surveillance." International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/605061.
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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, CaliforniaThis paper describes a system of Total Border Surveillance, which is cost effective, closes existing gaps and is less manpower intensive than the current techniques. The system utilizes a fleet of commercially available aircraft converted to unmanned capability, existing GPS and surveillance systems and autonomous ground stations to provide the desired coverage.
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Hibbs, Jeremy, Travis Kibler, Jesse Odle, Rachel Powers, Thomas Schucker, and Alex Warren. "Autonomous Mapping Using Unmanned Aerial Systems." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596464.
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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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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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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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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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Valente, João Ricardo Pereira. "Autonomous behaviors for an unmanned mini-aerial vehicle." Master's thesis, FCT - UNL, 2008. http://hdl.handle.net/10362/1869.
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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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Melega, Marco. "Autonomous Collision avoidance for Unmanned aerial systems." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9251.
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Unmanned Aerial System (UAS) applications are growing day by day and this will lead Unmanned Aerial Vehicle (UAV) in the close future to share the same airspace of manned aircraft.This implies the need for UAS to define precise safety standards compatible with operations standards for manned aviation. Among these standards the need for a Sense And Avoid (S&A) system to support and, when necessary, sub¬stitute the pilot in the detection and avoidance of hazardous situations (e.g. midair collision, controlled flight into terrain, flight path obstacles, and clouds).
This thesis presents the work come out in the development of a S&A system taking into account collision risks scenarios with multiple moving and fixed threats. The conflict prediction is based on a straight projection of the threats state in the future. The approximations introduced by this approach have the advantage of high update frequency (1 Hz) of the estimated conflict geometry. This solution allows the algorithm to capture the trajectory changes of the threat or ownship. The resolution manoeuvre evaluation is based on a optimisation approach considering step command applied to the heading and altitude autopilots. The optimisation problem takes into account the UAV performances and aims to keep a predefined minimum separation distance between UAV and threats during the resolution manouvre. The Human-Machine Interface (HMI) of this algorithm is then embedded in a partial Ground Control Station (GCS) mock-up with some original concepts for the indication of the flight condition parameters and the indication of the resolution manoeuvre constraints.
Simulations of the S&A algorithm in different critical scenarios are moreover in-cluded to show the algorithm capabilities. Finally, methodology and results of the tests and interviews with pilots regarding the proposed GCS partial layout are covered.
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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.
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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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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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Sjöberg, Mattias. "Analysis of autonomous flight algorithms for an unmanned aerial vehicle." Thesis, Umeå universitet, Institutionen för fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-147625.
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Unmanned Aerial Vehicles (UAV) have been heavily studied in the past decade, where autonomous flights have been a popular subject. More complex applications have led to higher requirements on the autonomous flight algorithms and the absence of performance data complicates the selection of what algorithm to use for various applications. Therefore, this thesis focused in analyzing the performance difference between two methods, Simultaneous Localization AndMapping (SLAM) and Artificial Potential Field Approach (APFA), which are planning and reactive algorithms, respectively. Fundamental dynamics were applied, Feedback Linear Controllers (FBLC)s for stabilization and an odometry position model combined with an inverse dynamics technique that linearizes the non-linear odometry model. The SLAM approach was set up in four steps: landmark extraction which uses a point distance based method for segment separation, combined with a Split-And-Merge algorithm for extracting linear landmarks, data association that validates the landmarks, Extended Kalman Filter (EKF) that uses the landmarks together with the odometry model for estimating the position of the UAV, and a modified TangentBug as the reactive algorithm. The APFA was constructed of two functions, an attractive and a repulsive function. The two methods were implemented on the robotics simulation platform Virtual Robot Experimentation Platform (V-REP), where a quadcopter was used as the model for the UAV. All theory was implemented onto the quadcopter model and embedded scripts were used for communication within V-REP, mainly through internal Application Programming Interface (API)-functions. Furthermore, a script was written that randomly generates three different types of simulation environments. The implementation of both methods was analyzed in reaching an arbitrary goal position in terms of: the most successful, the most time efficient and the safest navigation path. Another thing analyzed was the time- and space-complexity of both implemented methods. The results stated that the implemented APFA and the SLAM approach had approximately equal success rate, SLAM had the safest navigation, was the most time efficient, and had the highest time- and space-complexity for a worst case scenario. One of the conclusions were that improvements could be done in the implementations. Future work includes adding a proper damping method, improving the flaws in the implemented methods as well as to use V-REP as a Robot Operating System (ROS)-node for creating a Software In The Loop (SITL)-simulation, in order to achieve more realistic simulations.
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Hough, Willem J. "Autonomous aerobatic flight of a fixed wing unmanned aerial vehicle." Thesis, Link to online version, 2007. http://hdl.handle.net/10019/428.
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Watts-Willis, Tristan A. "Autonomous model selection for surface classification via unmanned aerial vehicle." Scholarly Commons, 2017. https://scholarlycommons.pacific.edu/uop_etds/224.
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In the pursuit of research in remote areas, robots may be employed to deploy sensor networks. These robots need a method of classifying a surface to determine if it is a suitable installation site. Developing surface classification models manually requires significant time and detracts from the goal of automating systems. We create a system that automatically collects the data using an Unmanned Aerial Vehicle (UAV), extracts features, trains a large number of classifiers, selects the best classifier, and programs the UAV with that classifier. We design this system with user configurable parameters for choosing a high accuracy, efficient classifier. In support of this system, we also develop an algorithm for evaluating the effectiveness of individual features as indicators of the variable of interest. Motivating our work is a prior project that manually developed a surface classifier using an accelerometer; we replicate those results with our new automated system and improve on those results, providing a four-surface classifier with a 75% classification rate and a hard/soft classifier with a 100% classification rate. We further verify our system through a field experiment that collects and classifies new data, proving its end-to-end functionality. The general form of our system provides a valuable tool for automation of classifier creation and is released as an open-source tool.
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Alberts, Frederik Nicolaas. "Accurate autonomous landing of a fixed-wing unmanned aerial vehicle." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71672.
Full textAbstract:
Thesis (MScEng)-- Stellenbosch University, 2012.ENGLISH ABSTRACT: This thesis presents the analysis, design, simulation and practical implementation of a control system to achieve an accurate autonomous landing of a fixed-wing unmanned aerial vehicle in the presence of wind gust atmospheric disturbances. Controllers which incorporate the concept of direct-lift control were designed based on a study of the longitudinal dynamics of the UAV constructed as a testbed. Direct-lift control offers the prospect of an improvement in the precision with which aircraft height and vertical velocity can be controlled by utilising actuators which generate lift directly, instead of the conventional method whereby the moment produced by an actuator results in lift being indirectly generated. Two normal specific acceleration controllers were designed. The first being a conventional moment-based controller, and the second a direct-lift-augmented controller. The moment-based controller makes use of the aircraft’s elevator while the direct-lift augmented controller in addition makes use of the flaps of the aircraft which serve as the direct-lift actuator. Controllers were also designed to regulate the airspeed, altitude, climb rate, and roll angle of the aircraft as well as damp the Dutch roll mode. A guidance controller was implemented to allow for the following of waypoints. A landing procedure and methodology was developed which includes the circuit and landing approach paths and the concept of a glide path offset to calibrate the touchdown point of a landing. All controllers and the landing procedure were tested in a hardware-in-the-loop simulation environment as well as practically in a series of flight tests. Five fully autonomous landings were performed, three of these using the conventional NSA controller, and the final two the direct-lift-augmented NSA controller. The results obtained during the landing flight tests show that the project goal of a landing within five meters along the runway and three meters across the runway was achieved in both normal wind conditions as well as in conditions where wind gusts prevailed. The flight tests also showed that the direct-lift-augmented NSA controller appears to achieve a more accurate landing than the conventional NSA controller, especially in the presence of greater wind disturbances. The direct-lift augmented NSA controller also exhibited less pitch angle rotation during landing.
AFRIKAANSE OPSOMMING: Hierdie tesis verteenwoordig die analise, ontwerp, simulasie en praktiese implementering van ’n beheerstelsel wat ten doel het om ’n akkurate en outonome landing van ’n onbemande vastevlerk vliegtuig in rukwind atmosferiese toestande te bewerkstellig. Gegrond op ’n studie van die longitudinale dinamika van die vliegtuig wat as proeftuig gebruik is, is beheerders ontwerp wat die beginsel van direkte-lig insluit. Direkte-lig beheer hou die potensiaal in om die vliegtuig se hoogte en vertikale snelheid akkuraat te beheer deur gebruik te maak van aktueerders wat lig direk genereer in teenstelling met die konvensionele metode waar die moment van die aktueerder indirek lig genereer. Twee normaal-versnellings beheerders is ontwerp. Die eerste is ’n konvensionele moment-gebaseerde beheerder wat gebruik maak van die hys-aktueerder van die vliegtuig, en die tweede is ’n direkte-lig-bygestaande beheerder wat addisioneel gebruik maak van die flappe van die vliegtuig wat as die direkte-lig aktueerder dien. Vedere beheerders is ontwerp wat die lugspoed, hoogte, klimkoers, en rolhoek van die vliegtuig reguleer asook die “Dutch roll” gedrag afklam. ’n Leiding-beheerder wat die volg van vliegbakens hanteer, is ingestel. Die landingsprosedure en -metodologie is ontwikkel wat die landingspad sowel as die sweef-pad bepaal en wat terselfdertyd ’n metode daarstel om die posisie van die landingspunt te kalibreer. Die beheerders en landingsprosedure is in ’n hardeware-in-die-lus omgewing gesimuleer en deur middel van ’n reeks proefvlugte getoets. Vyf ten volle outonome landings is uitgevoer waarvan drie van die konvensionele normaal-versnellings beheerder gebruik gemaak het, en die laaste twee die direkte-lig-bygestaande normaal-versnellings beheerder. Die vlugtoetsuitslae bevestig dat die navorsingsdoel om ’n landing binne vyf meter in lyn met en drie meter dwarsoor die landingstrook te bewerkstellig, behaal is. Hierdie akkuraatheid is verkry in beide goeie atmosferiese toestande sowel as toestande met rukwinde. Volgens die vlugtoetse blyk dit dat die direkte-lig-bygestaande normaalversnellings beheerder ’n meer akkurate landing kan bewerkstellig as die konvensionele normaal-versnellings beheerder, veral dan in toestande met rukwinde. Die direkte-ligbygestaande normaal-versnellings beheerder het ook ’n laer hei-hoek rotasie tydens die landing vertoon.
39
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.
Full textAbstract:
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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Hermansson, Joel. "Vision and GPS based autonomous landing of an unmanned aerial vehicle." Thesis, Linköping University, Automatic Control, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57735.
Full textAbstract:
A control system for autonomous landing of an unmanned aerial vehicle (UAV)with high precision has been developed. The UAV is a medium sized model he-licopter. Measurements from a GPS, a camera and a compass are fused with anextended Kalman filter for state estimation of the helicopter. Four PID-controllers,one for each control signal of the helicopter, are used for the helicopter control.During the final test flights fifteen landings were performed with an average land-ing accuracy of 35 cm. A bias in the GPS measurements makes it impossible to land the helicopter withhigh precision using only the GPS. Therefore, a vision system using a camera anda pattern provided landing platform has been developed. The vision system givesaccurate measurement of the 6-DOF pose of the helicopter relative the platform.These measurements are used to guide the helicopter to the landing target. Inorder to use the vision system in real time, fast image processing algorithms havebeen developed. The vision system can easily match up the with the camera framerate of 30 Hz.
Ett kontrolsystem för att autonomt landa en modellhelikopter har utvecklats.Mätdata från en GPS, en kamera samt en kompass fusioneras med ett Extend-ed Kalman Filter för tillståndsestimering av helikoptern. Fyra PID-regulatorer,en för varje kontrolsignal på helikoptern, har används för regleringen. Under densista provflygningen gjordes tre landingar av vilken den minst lyckade slutade35 cm från målet. På grund av en drift i GPS-mätningarna är det omöjligt att landa helikopternmed hög precision med bara en GPS. Därför har ett bildbehandlingssystem som an-vänder en kamera samt ett mönster på platformen utvecklats. Bidbehandlingssys-temet mäter positionen och orienteringen av helikoptern relativt platformen. Dessamätningar används kompensera för GPS-mätningarnas drift. Snabba bildbehan-dlingsalgoritmer har utvecklats för att kunna använda bildbehandlingssystemet irealtid. Systemet är mycket snabbare än 30 bilder per sekund vilket är kameranshastighet.
41
Khantsis, Sergey, and s3007192@student rmit edu au. "Control System Design Using Evolutionary Algorithms for Autonomous Shipboard Recovery of Unmanned Aerial Vehicles." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070518.135536.
Full textAbstract:
The capability of autonomous operation of ship-based Unmanned Aerial Vehicles (UAVs) in extreme sea conditions would greatly extend the usefulness of these aircraft for both military and civilian maritime purposes. Maritime operations are often associated with Vertical Take-Off and Landing (VTOL) procedures, even though the advantages of conventional fixed-wing aircraft over VTOL aircraft in terms of flight speed, range and endurance are well known. In this work, current methods of shipboard recovery are analysed and the problems associated with recovery in adverse weather conditions are identified. Based on this analysis, a novel recovery method is proposed. This method, named Cable Hook Recovery, is intended to recover small to medium-size fixed-wing UAVs on frigate-size vessels. It is expected to have greater operational capabilities than the Recovery Net technique, which is currently the most widely employed method of recovery for similar class of UAVs, potentially providing safe recovery even in very rough sea and allowing the choice of approach directions. The recovery method is supported by the development of a UAV controller that realises the most demanding stage of recovery, the final approach. The controller provides both flight control and guidance strategy that allow fully autonomous recovery of a fixed-wing UAV. The development process involves extensive use of specially tailored Evolutionary Algorithms and represents the major contribution of this work. The Evolutionary Design algorithm developed in this work combines the power of Evolutionary Strategies and Genetic Programming, enabling automatic evolution of both the structure and parameters of the controller. The controller is evolved using a fully coupled nonlinear six-degree-of-freedom UAV model, making linearisation and trimming of the model unnecessary. The developed algorithm is applied to both flight control and guidance problems with several variations, from optimisation of a routine PID controller to automatic control laws synthesis where no a priori data available. It is demonstrated that Evolutionary Design is capable of not only optimising, but also solving automatically the real-world problems, producing human-competitive solutions. The designed UAV controller has been tested comprehensively for both performance and robustness in a nonlinear simulation environment and has been found to allow the aircraft to be recovered in the presence of both large external disturbances and uncertainty in the simulation models.
42
Ruini, Fabio. "Distributed control for collective behaviour in micro-unmanned aerial vehicles." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1549.
Full textAbstract:
The work presented herein focuses on the design of distributed autonomous controllers for collective behaviour of Micro-unmanned Aerial Vehicles (MAVs). Two alternative approaches to this topic are introduced: one based upon the Evolutionary Robotics (ER) paradigm, the other one upon flocking principles. Three computer simulators have been developed in order to carry out the required experiments, all of them having their focus on the modelling of fixed-wing aircraft flight dynamics. The employment of fixed-wing aircraft rather than the omni-directional robots typically employed in collective robotics significantly increases the complexity of the challenges that an autonomous controller has to face. This is mostly due to the strict motion constraints associated with fixed-wing platforms, that require a high degree of accuracy by the controller. Concerning the ER approach, the experimental setups elaborated have resulted in controllers that have been evolved in simulation with the following capabilities: (1) navigation across unknown environments, (2) obstacle avoidance, (3) tracking of a moving target, and (4) execution of cooperative and coordinated behaviours based on implicit communication strategies. The design methodology based upon flocking principles has involved tests on computer simulations and subsequent experimentation on real-world robotic platforms. A customised implementation of Reynolds’ flocking algorithm has been developed and successfully validated through flight tests performed with the swinglet MAV. It has been notably demonstrated how the Evolutionary Robotics approach could be successfully extended to the domain of fixed-wing aerial robotics, which has never received a great deal of attention in the past. The investigations performed have also shown that complex and real physics-based computer simulators are not a compulsory requirement when approaching the domain of aerial robotics, as long as proper autopilot systems (taking care of the ”reality gap” issue) are used on the real robots.
43
Smit, Samuel Jacobus Adriaan. "Autonomous landing of a fixed-wing unmanned aerial vehicle using differential GPS." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80122.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This dissertation presents the design and practical demonstration of a flight control system (FCS) that is capable of autonomously landing a fixed-wing, unmanned aerial vehicle (UAV) on a stationary platform aided by a high-precision differential global positioning system. This project forms part of on-going research with the end goal of landing a fixed-wing UAV on a moving platform (for example a ship’s deck) in windy conditions. The main aim of this project is to be able to land the UAV autonomously, safely and accurately on the runway. To this end, an airframe was selected and equipped with an avionics payload. The equipped airframe’s stability derivatives were analysed via AVL and the moment of inertia was determined by the double pendulum method. The aircraft model was developed in such a way that the specific force and moment model (high bandwidth) is split from the point-mass dynamics of the aircraft (low bandwidth) [1]. The advantage of modelling the aircraft according to this unique method, results in a design that has simple decoupled linear controllers. The inner-loop controllers control the high-bandwidth specific accelerations and roll-rate, while the outer-loop controllers control the low-bandwidth point-mass dynamics. The performance of the developed auto-landing flight control system was tested in software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulations. A Monte Carlo non-linear landing simulation analysis showed that the FCS is expected to land the aircraft 95% of the time within a circle with a diameter of 1.5m. Practical flight tests verified the theoretical results of the developed controllers and the project was concluded with five autonomous landings. The aircraft landed within a circle with a 7.5m radius with the aiming point at the centre of the circle. In the practical landings the longitudinal landing error dominated the landing performance of the autonomous landing system. The large longitudinal error resulted from a climb rate bias on the estimated climb rate and a shallow landing glide slope.
AFRIKAANSE OPSOMMING: Hierdie skripsie stel die ontwikkeling en praktiese demonstrasie van ʼn self-landdende onbemande vastevlerkvliegtuigstelsel voor, wat op ʼn stilstaande platform te lande kan kom met behulp van ʼn uiters akkurate globale posisionering stelsel. Die projek maak deel uit van ʼn groter projek, waarvan die doel is om ʼn onbemande vastevlerkvliegtuig op ʼn bewegende platform te laat land (bv. op ʼn boot se dek) in onstuimige windtoestande. Die hoofdoel van die projek was om die vliegtuig so akkuraat as moontlik op die aanloopbaan te laat land. ʼn Vliegtuigraamwerk is vir dié doel gekies wat met gepaste avionica uitgerus is. Die uitgeruste vliegtuig se aerodinamsie eienskappe was geanaliseer met AVL en die traagheidsmoment is deur die dubbelependulum metode bepaal. Die vliegtuigmodel is op so ‘n manier onwikkel om [1] die spesifieke krag en momentmodel (vinnige reaksie) te skei van die puntmassadinamiek (stadige reaksie). Die voordeel van hierdie wyse van modulering is dat eenvoudige ontkoppelde beheerders ontwerp kon word. Die binnelusbeheerders beheer die vinnige reaksie-spesifieke versnellings en die rol tempo van die vliegtuig. Die buitelusbeheerders beheer die stadige reaksie puntmassa dinamiek. Die vliegbeheerstelsel is in sagteware-in-die-lus en hardeware-in-die-lus simulasies getoets. Die vliegtuig se landingseienskappe is ondersoek deur die uitvoer van Monte Carlo simulasies, die simulasie resultate wys dat die vliegtuig 95% van die tyd binne in ʼn sirkel met ʼn diameter van 1.5m geland het. Praktiese vlugtoetse het bevestig dat die teoretiese uitslae en die prakties uitslae ooreenstem. Die vliegtuig het twee suksesvolle outomatiese landings uitgevoer, waar dit binne ʼn 7.5m-radius sirkel geland het, waarvan die gewenste landingspunt die middelpunt was. In die outomatiese landings is die longitudinale landingsfout die grootse. Die groot longitudinale landingsfout is as gevolg van ʼn afset op die afgeskatte afwaartse spoed en ʼn lae landings gradiënt.
44
Allegretti, Marcello. "Unmanned Aerial Vehicle: tecnologie e prospettive future." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11979/.
Full textAbstract:
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.
45
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.
Full textAbstract:
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.
46
Hughes, Thomas Carroll. "Sources of Adaptive Capacity during Multi-Unmanned Aerial Vehicle Operations." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354621762.
Full text
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Werenskjold, Craig J. "The effect of unmanned aerial vehicle systems on precision engagement." Thesis, Monterey, California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/5720.
Full textAbstract:
Approved for public release; distribution is unlimitedThe effect of integrating unmanned aerial vehicles (UAV) systems into today's battlespace is promoting concepts of precision engagement by enhancing our information advantage. This thesis explores the new paradigm evolving around UAV technology that has enabled UAV systems to become a central node for accelerated sensor-to-shooter capabilities involved with precision engagement by accelerating the integration of communications, command, control, computers intelligence, surveillance, reconnaissance (C4ISR) systems with recent innovations in time-critical targeting. The increased information advantage and precision engagement strategies recently demonstrated in Operation Enduring Freedom have catalyzed further UAV system integration and highlighted the synergistic effects. Future technological advancements associated with UAV systems will allow new capabilities to evolve that increase our real-time intelligence capabilities and precision engagement strategies.
48
Kersop, Stefanus Jacobus. "Short range reconnaissance unmanned aerial vehicle / S.J. Kersop." Thesis, North-West University, 2009. http://hdl.handle.net/10394/9171.
Full textAbstract:
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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Karunarathne, Lakmal. "An intelligent power management system for unmanned aerial vehicle propulsion applications." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8038.
Full textAbstract:
Electric powered Unmanned Aerial Vehicles (UAVs) have emerged as a promi- nent aviation concept due to the advantageous such as stealth operation and zero emission. In addition, fuel cell powered electric UAVs are more attrac- tive as a result of the long endurance capability of the propulsion system. This dissertation investigates novel power management architecture for fuel cell and battery powered unmanned aerial vehicle propulsion application. The research work focused on the development of a power management system to control the hybrid electric propulsion system whilst optimizing the fuel cell air supplying system performances. The multiple power sources hybridization is a control challenge associated with the power management decisions and their implementation in the power electronic interface. In most applications, the propulsion power distribu- tion is controlled by using the regulated power converting devices such as unidirectional and bidirectional converters. The amount of power shared with the each power source is depended on the power and energy capacities of the device. In this research, a power management system is developed for polymer exchange membrane fuel cell and Lithium-Ion battery based hybrid electric propulsion system for an UAV propulsion application. Ini- tially, the UAV propulsion power requirements during the take-off, climb, endurance, cruising and maximum velocity are determined. A power man- agement algorithm is developed based on the UAV propulsion power re- quirement and the battery power capacity. Three power states are intro- duced in the power management system called Start-up power state, High power state and Charging power state. The each power state consists of the power management sequences to distribute the load power between the battery and the fuel cell system. A power electronic interface is developed Electric powered Unmanned Aerial Vehicles (UAVs) have emerged as a promi- nent aviation concept due to the advantageous such as stealth operation and zero emission. In addition, fuel cell powered electric UAVs are more attrac- tive as a result of the long endurance capability of the propulsion system. This dissertation investigates novel power management architecture for fuel cell and battery powered unmanned aerial vehicle propulsion application. The research work focused on the development of a power management system to control the hybrid electric propulsion system whilst optimizing the fuel cell air supplying system performances. The multiple power sources hybridization is a control challenge associated with the power management decisions and their implementation in the power electronic interface. In most applications, the propulsion power distribu- tion is controlled by using the regulated power converting devices such as unidirectional and bidirectional converters. The amount of power shared with the each power source is depended on the power and energy capacities of the device. In this research, a power management system is developed for polymer exchange membrane fuel cell and Lithium-Ion battery based hybrid electric propulsion system for an UAV propulsion application. Ini- tially, the UAV propulsion power requirements during the take-off, climb, endurance, cruising and maximum velocity are determined. A power man- agement algorithm is developed based on the UAV propulsion power re- quirement and the battery power capacity. Three power states are intro- duced in the power management system called Start-up power state, High power state and Charging power state. The each power state consists of the power management sequences to distribute the load power between the battery and the fuel cell system. A power electronic interface is developed with a unidirectional converter and a bidirectional converter to integrate the fuel cell system and the battery into the propulsion motor drive. The main objective of the power management system is to obtain the controlled fuel cell current profile as a performance variable. The relationship between the fuel cell current and the fuel cell air supplying system compressor power is investigated and a referenced model is developed to obtain the optimum compressor power as a function of the fuel cell current. An adaptive controller is introduced to optimize the fuel cell air supplying system performances based on the referenced model. The adaptive neuro-fuzzy inference system based controller dynamically adapts the actual compressor operating power into the optimum value defined in the reference model. The online learning and training capabilities of the adaptive controller identify the nonlinear variations of the fuel cell current and generate a control signal for the compressor motor voltage to optimize the fuel cell air supplying system performances. The hybrid electric power system and the power management system were developed in real time environment and practical tests were conducted to validate the simulation results.
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Aribal, Seckin. "Development Of An Autopilot For Automatic Landing Of An Unmanned Aerial Vehicle." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613391/index.pdf.
Full textAbstract:
This thesis presents the design of an autopilot and guidance system for an unmanned aerial vehicle. Classical (PID) and modern control (LQT, Sliding Mode) methods for autonomous navigation and landing in adverse weather conditions are implemented. Two different guidance systems are designed in order to navigate through waypoints during normal and/or emergency flight. The nonlinear Pioneer UAV model is used in controller development and simulations.
Aircraft is linearized at different trim points and total airspeed, altitude, roll and yaw autopilots are designed using Matlab/Simulink environment for lateral and longitudinal control of the aircraft. Gain scheduling is used to combine controllers designed for different trim points. An optimal landing trajectory is determined using &ldquoSteepest Descent&rdquo
Algorithm according to the dynamic characteristics of the aircraft. Optimal altitude trajectory is used together with a lateral guidance against cross-wind disturbance. Finally, simulations including landing under crosswind, tailwind, etc., are run and the results are analyzed in order to demonstrate the performance and effectiveness of the controllers.