Dissertations / Theses on the topic 'Autonomous vehicle systems'
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Hejase, Mohammad. "Dynamic Probabilistic Risk Assessment of Autonomous Vehicle Systems." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1546473181365722.
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Chen, Qi. "Studies in autonomous ground vehicle control systems structure and algorithms /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1165959992.
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Fithian, Jeff E. "A laser-guided, autonomous automated guided vehicle." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/42957.
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The purpose of this research was to determine the feasibility of a laser-based positioning system as a primary navigation method. The system developed for this research consisted of an automated guided vehicle which navigated solely with the use of the laser-based positioning system in real-time. To date, there are no systems which can navigate a pre-defined path using such a positioning system. Some lessons were learned by the researcher, however, concerning the viability of this system in an industrial environment. The system should have had the following advantages over previous systems: 1) Greater range, 2) no prior structuring of environment, 3) real-time navigation, and 4) no reliance on dead-reckoning for navigation.
The results showed that goals two through four had been met and are advantages of this system over current systems. The range of this system is limited, however, but it is believed that the next generation system should have greater range than the system used in this research.
Master of Science
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Yan, Jingsheng. "Platoon modal operations under vehicle autonomous adaptive cruise control model." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07102009-040612/.
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Korkmaz, Ozan. "Modeling And Control Of Autonomous Underwater Vehicle Manipulator Systems." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615051/index.pdf.
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In this thesis, dynamic modeling and nonlinear control of autonomous underwater vehicle manipulator systems are presented. Mainly, two types of systems consisting of a 6-DOF AUV equipped with a 6-DOF manipulator subsystem (UVMS) and with an 8-DOF redundant manipulator subsystem (UVRMS) are modeled considering hydrostatic forces and hydrodynamic effects such as added mass, lift, drag and side forces. The shadowing effects of the bodies on each other are introduced when computing the hydrodynamic forces. The system equations of motion are derived recursively using Newton&ndashEuler formulation. The inverse dynamics control algorithms are formulated and trajectory tracking control of the systems is achieved by assigning separate tasks for the end effector of the manipulator and for the underwater vehicle. The proposed inverse dynamics controller utilizes the full nonlinear model of the system and consists of a linearizing control law that uses the feedback of positions and velocities of the joints and the underwater vehicle in order to cancel off the nonlinearities of the system. The PD control is applied after this complicated feedback linearization process yielding second order error dynamics. The thruster dynamics is also incorporated into the control system design. The stability analysis is performed in the presence of parametric uncertainty and disturbing ocean current. The effectiveness of the control methods are demonstrated by simulations for typical underwater missions.
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Kang, Yong Suk. "Development of Predictive Vehicle Control System using Driving Environment Data for Autonomous Vehicles and Advanced Driver Assistance Systems." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85106.
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In the field of modern automotive engineering, many researchers are focusing on the development of advanced vehicle control systems such as autonomous vehicle systems and Advanced Driver Assistance Systems (ADAS). Furthermore, Driver Assistance Systems (DAS) such as cruise control, Anti-Lock Braking Systems (ABS), and Electronic Stability Control (ESC) have become widely popular in the automotive industry. Therefore, vehicle control research attracts attention from both academia and industry, and has been an active area of vehicle research for over 30 years, resulting in impressive DAS contributions. Although current vehicle control systems have improved vehicle safety and performance, there is room for improvement for dealing with various situations.
The objective of the research is to develop a predictive vehicle control system for improving vehicle safety and performance for autonomous vehicles and ADAS. In order to improve the vehicle control system, the proposed system utilizes information about the upcoming local driving environment such as terrain roughness, elevation grade, bank angle, curvature, and friction. The local driving environment is measured in advance with a terrain measurement system to provide terrain data. Furthermore, in order to obtain the information about road conditions that cannot be measured in advance, this work begins by analyzing the response measurements of a preceding vehicle. The response measurements of a preceding vehicle are acquired through Vehicle-to-Vehicle (V2V) or Vehicle-to-Infrastructure (V2I) communication. The identification method analyzes the response measurements of a preceding vehicle to estimate road data. The estimated road data or the pre-measured road data is used as the upcoming driving environment information for the developed vehicle control system. The metric that objectively quantifies vehicle performance, the Performance Margin, is developed to accomplish the control objectives in an efficient manner. The metric is used as a control reference input and continuously estimated to predict current and future vehicle performance. Next, the predictive control algorithm is developed based on the upcoming driving environment and the performance metric. The developed system predicts future vehicle dynamics states using the upcoming driving environment and the Performance Margin. If the algorithm detects the risks of future vehicle dynamics, the control system intervenes between the driver's input commands based on estimated future vehicle states. The developed control system maintains vehicle handling capabilities based on the results of the prediction by regulating the metric into an acceptable range. By these processes, the developed control system ensures that the vehicle maintains stability consistently, and improves vehicle performance for the near future even if there are undesirable and unexpected driving circumstances. To implement and evaluate the integrated systems of this work, the real-time driving simulator, which uses precise real-world driving environment data, has been developed for advanced high computational vehicle control systems. The developed vehicle control system is implemented in the driving simulator, and the results show that the proposed system is a clear improvement on autonomous vehicle systems and ADAS.Ph. D.
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Sarton, Christopher J. "Autopilot using differential thrust for ARIES autonomous underwater vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FSarton.pdf.
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Strandell, Erstorp Elias. "Evaluation of the LSTS Toolchain for Networked Vehicle Systems on KTH Autonomous Maritime Vehicles." Thesis, KTH, Marina system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185273.
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The department of Naval Architecture at the Royal Institute of Technology is in posession of one Autonomous Underwater Vehicle (AUV) and a second is under construction. A project for doing hydrographic mapping using an Autonomous Surface Vehicle (ASV) is also initiated. These projects raises the need for a software to easily send commands to vehicles and to review collected data. The ability to use each vehicle as a node in a network of vehicles is also requested. This thesis examines a software toolchain developed at the Underwater Systems and Technology Laboratory (LSTS) in Portugal for mission planning and control of networked autonomous vehicles. The toolchain constitutes primarily of Neptus, which provides an operator with a user interface for realtime control and feedback from vehicles, and DUNE. DUNE is a software running on-board vehicles and communicates with Neptus over a wireless network. As a first step, and as a limitation to this thesis, the toolchain has been used to control an autonomous rover. An autopilot receives waypoints in form of latitude/longitude coordinates from DUNE and periodically sends position and various sensor readings back. DUNE is running on a GNU/Linux computer and is responsible for storing a mission of multiple waypoints and to keep track of the progress. DUNE forwards vehicle location and sensor data to Neptus for feedback in the user interface and generation of plots. In conclusion the author was able to create and execute missions of an arbitrary number of waypoints. Graphs of basically any sensor reading could be generated through the Mission Review and Analysis tool contained by Neptus. Implementing the toolchain on the departments marine vehicles releases valuable time during field tests and will in the future provide a way for experimentation with deliberate planning tools; the next natural step toward complete autonomy.
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RAHMAN, SHAHNUR. "Visual Perception in Autonomous Vehicles." Thesis, KTH, Hållbarhet och industriell dynamik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189346.
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The human factor accounts for nine out of ten out of all traffic accidents, and because more vehicles are being deployed on the roads, the number of accidents will increase. Because of this, various automated functions have been implemented in vehicles in order to minimize the human factor in driving. In recent year, this development has accelerated and vehicles able to perform the complete driving task without any human assistance have begun to emerge from different projects around the world. However, the autonomous vehicle still has many barriers to overcome before safe driving in traffic becomes a reality. One of these barriers is the difficulty to visually perceive the surrounding. This is partly because of the fact that something can cover the camera sensors, but it is also problematic to translate the perceived data, that the sensors are collecting, into something valuable for the passenger. The situation could be improved if wireless communications were available to the autonomous vehicle. Instead of trying to understand the surrounding by the use of camera sensors, the autonomous vehicle could obtain the necessary data via wireless communication, which was the subject of this study. The study showed that wireless communication will be significant for the autonomous vehicle in the future. The conclusion is based on the fact that wireless communication was a solution in other transport systems that have had the similar barrier as for the autonomous vehicle. There are also plans on managing the barrier via wireless communication in pilot projects related to autonomous vehicles.Den mänskliga faktorn står för nio av tio utav alla trafikolyckor, och eftersom att allt fler fordon kommer ut på vägarna så leder det till att olycksantalet ökar. På grund av detta så har olika automatiserade funktioner applicerats i fordonet för att undvika den mänskliga faktorn i körningen. Denna utveckling har accelererat och fordon som ska kunna utföra hela det dynamiska framförandet utan mänsklig assistans har börjat utvecklas i olika projekt runt om i världen. Dock så har det autonoma fordonet många barriärer kvar att övervinna, för säkert framförande, varav en av dessa barriärer är fordonets förmåga att visuellt uppfatta omgivningen. Dels genom att något kan täcka kamerasensorerna men även att kunna omsätta det sensorerna uppfattar till något värdefullt för passageraren. Situationen skulle dock kunna förbättras om trådlös kommunikation gjordes tillgänglig för det autonoma fordonet. Istället för att försöka uppfatta omgivningen via kamerasensorer, skulle det autonoma fordonet kunna få den information som behövs via trådlös kommunikation, vilket är vad denna studie behandlade. Studien visade att trådlös kommunikation kommer att ha en betydelse för det autonoma fordonet i framtiden. Slutsatsen grundar sig på att trådlös kommunikation varit en lösning inom andra transportsystem som haft en liknande barriär som för det autonoma fordonet. Man planerar dessutom på att hantera det autonoma fordonets barriär via trådlös kommunikation i pilotprojekt i dagsläget
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Biondani, Luca. "Control system for agricultural autonomous electric vehicle." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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The subject of this thesis is the realization of the control system of an autonomous electric vehicle for agricultural applications. The robot will be used for field experimentation of innovative agricultural techniques.
The software is developed in LabVIEW programming language, and is employed on an embedded system manufactured by National Instruments that is used as Platform Control Unit. MATLAB and Simulink software are used for simulations and processing of the collected experimental data.
As a secondary activity, the electrical circuit was realized including both high-power and signal control wiring harness.
The result of the thesis is a working prototype that will be used in a first section of the experimental plant, located at the DISTAL Experimental Center in Cadriano.
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Wright, Landon Blaine. "Simulation Framework and Potential Field Relocation for Systems of Shared Autonomous Vehicles." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8629.
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Shared autonomous vehicles present a significant opportunity to change the way that urban mobility is viewed by society. By providing a shared mobility platform at a cost lower than has previously been obtainable there are significant possibilites to enable a new era of mobility for consumers. This opportunity, however, comes with significant risks in the form of emissions and increased road usage. Understanding how the risks and benefits of shared autonomous vehicles can be balanced is crucial to be able to adequately prepare for their introduction. One of the primary ways to understand the interplay between the risks and benefits of autonomous vehicles is through the use of computer simulations. However, typically simulations must be defined for a specific area and provide results that are not applicable to a wide range of areas and situations. This work presents the development of a framework that can be used to simulate SAV behaviour at any given region of interest. This framework automates the process of generating a directed non-planar graph using data gathered from the OpenStreetMap project. It further provides tools to generate activity based trips that are statistically similar in time and density to provided data that reflects the trips in the simulation area. In the absence of this data, this work has identified the 2009 National Household Travel Survey as an acceptable surrogate for data specific to a region. The framework then provides methods by which the trip origins and destinations are mapped into the directed non-planar graph representation of the area of interest. This mapping is performed using real-world data including business locations and census data. Finally the framework is capable of simulating the activity of SAV in response to the defined trips given a variety of starting conditions and relocation strategies. In addition to the simulation framework this work presents a novel relocation strategy for unoccupied SAV based on the potential field methods that have been used in robotic navigation. This method provides a continously differentiable function that describes the unmet demand in the service area for a network of shared autonomous vehicles. The tunable parameters of the method are explored by using a design of experiments, and optimal values reflecting different scenarios are identified.The method is also evaluated in the context of both and over- and under-supply of vehicles for the given demand. As a result this method has been shown to provide substantial reductions in the wait time for a vehicle to service a trip with a minimal increase in the total distance that is traveled by all vehicles in the network.
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Evans, Katherine. "The Implementation of Ethical Decision Procedures in Autonomous Systems : the Case of the Autonomous Vehicle." Thesis, Sorbonne université, 2021. http://www.theses.fr/2021SORUL003.
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Les problèmes éthiques liés à l’arrivée de formes d’intelligence artificielles différentes a sollicité beaucoup d’attention aussi bien académique que publique. Cependant, ces inquiétudes se concentrent sur un problème particulier : comment assurer que les décisions prises par les agents artificiels comme des voitures autonomes ne nuisent pas aux êtres humains présents dans leur environnement ? Cette question a incité la création de ceux qui sont communément appelés les agents moraux artificiels dans la littérature, la prise de décision desquels est contrainte par une moralité artificielle : un système de principes normatifs implémenté dans le processus de raisonnement de la machine. A ce jour, la forme que prend cette moralité artificielle relève de deux approches différentes : soit une forme maximalement éthique, qui dépend de l’implémentation stricte des théories morales préexistantes comme la déontologie Kantienne ou l’Utilitarisme, soit une forme minimaliste, qui applique des techniques de l’IA stochastique à l’analyse et agrégation de données portant sur les préférences morales d’une population, afin d’en tirer des principes généraux mobilisés ensuite dans la prise de décision des machines. Prises individuellement, aucune des deux approches n’arrivent à pondérer l’importance des contraintes morales avec la pertinence de l’acceptabilité publique des agents moraux artificiels. Nous proposons une approche alternative à la moralité artificielle, la théorie des valences éthiques, qui s’efforce d’accommoder ce genre de pondération, et nous l’appliquons au cas du véhicule autonomeThe ethics of emerging forms of artificial intelligence has become a prolific subject in both academic and public spheres. A great deal of these concerns flow from the need to ensure that these technologies do not cause harm—physical, emotional or otherwise—to the human agents with which they will interact. In the literature, this challenge has been met with the creation of artificial moral agents: embodied or virtual forms of artificial intelligence whose decision procedures are constrained by explicit normative principles, requiring the implementation of what is commonly called artificial morality into these agents. To date, the types of reasoning structures and principles which inform artificial morality have been of two kinds: first, an ethically maximal vision of artificial morality which relies on the strict implementation of traditional moral theories such as Kantian deontology or Utilitarianism, and second, a more minimalist vision which applies stochastic AI techniques to large data sets of human moral preferences so as to illicit or intuit general principles and preferences for the design of artificial morality. Taken individually, each approach is unable to fully answer the challenge of producing inoffensive behavior in artificial moral agents, most especially since both forms are unable to strike a balance between the ideal set of constraints which morality imposes on one hand, and the types of constraints public acceptability imposes, on the other. We provide an alternative approach to the design of artificial morality, the Ethical Valence Theory, whose purpose is to accommodate this balance, and apply this approach to the case of autonomous vehicles
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Plew, Jason. "Development of a flight avionics system for an autonomous Micro Air Vehicle." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008540.
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Darr, Matthew John. "DEVELOPMENT AND EVALUATION OF A CONTROLLER AREA NETWORK BASED AUTONOMOUS VEHICLE." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/192.
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Through the work of researchers and the development of commercially availableproducts, automated guidance has become a viable option for agricultural producers.Some of the limitations of commercially available technologies are that they onlyautomate one function of the agricultural vehicle and that the systems are proprietary toa single machine model.The objective of this project was to evaluate a controller area network (CAN bus)as the basis of an automated guidance system. The prototype system utilized severalmicrocontroller-driven nodes to act as control points along a system wide CAN bus.Messages were transferred to the steering, transmission, and hitch control nodes from atask computer. The task computer utilized global positioning system data to determinethe appropriate control commands.Infield testing demonstrated that each of the control nodes could be controlledsimultaneously over the CAN bus. Results showed that the task computer adequatelyapplied a feedback control model to the system and achieved guidance accuracy levelswell within the range sought. Testing also demonstrated the system's ability tocomplete normal field operations such as headland turning and implement control.
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Lind, Oros Martin. "Designing for Calibrated Trust Towards Operators of Highly Autonomous Vehicle Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-283355.
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Appropriate levels of trust in highly autonomous vehicles contributes to a safer human-machine relationship. Through increased correctness in interactions trust can be calibrated. Trust is formed via interactions that needs to be designed from a Human-Machine relationship with the purpose of maintaining it at an acceptable level. When failing calibrating trust to an appropriate level accidents and risks may arise due to over-reliance on, or the opposite, distrust on the system's capabilities. This study aims to investigate what factors of trust that can influence design decisions and the design process in order to let user's trust levels match the system's capabilities (i.e. calibrating trust) from a human-machine interface (HMI) perspective. The method of semi-structured expert interviews have given a basis to stand on in an idea generation workshop. The main results from this study are various ways to achieve transparency which in turn can be used to design for appropriate trust with the help of the generated concepts.Lämpliga nivåer av tillit i högautomatiserade fordon bidrar till ökad säkerhet ur ett människa-maskin perspektiv. Genom att förbättra samverkan i automationen kan tillit kalibreras. Ur en människa-maskin relation och den samverkan som sker kan tillit formas med syftet att tillhandahållas på en acceptabel nivå. När kalibrering av tillit misslyckas och inte motsvarar denna nivå, vilket sker när det finns övertro, eller det motsatta, undertro på automationens förmågor kan säkehetsrisker uppstå. Den här studien undersöker vilka tillitsfaktorer som kan påverka designbeslut och designprocesser med syfte att låta användarnas tillitsnivå motsvara systemets förmåga genom fokus på ett människa-maskin gränssnitt. Semi-strukturerade expertintervjuer har lagt grunden till att genomföra en ”workshop” som givit upphov till ett antal koncept för att möjliggöra lämpliga nivåer av tillit. De huvudsakliga resultaten består följaktligen av ett flertal sätt att uppnå transparens samt flera koncept som kan användas för att designa lämpliga nivåer av tillit.
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Munoz, Alex. "Exploring Strategies for Adapting Traditional Vehicle Design Frameworks to Autonomous Vehicle Design." ScholarWorks, 2020. https://scholarworks.waldenu.edu/dissertations/7944.
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Fully autonomous vehicles are expected to revolutionize transportation, reduce the cost of ownership, contribute to a cleaner environment, and prevent the majority of traffic accidents and related fatalities. Even though promising approaches for achieving full autonomy exist, developers and manufacturers have to overcome a multitude of challenged before these systems could find widespread adoption. This multiple case study explored the strategies some IT hardware and software developers of self-driving cars use to adapt traditional vehicle design frameworks to address consumer and regulatory requirements in autonomous vehicle designs. The population consisted of autonomous driving technology software and hardware developers who are currently working on fully autonomous driving technologies from or within the United States, regardless of their specialization. The theory of dynamic capabilities was the conceptual framework used for the study. Interviews from 7 autonomous vehicle hard and software engineers, together with 15 archival documents, provided the data points for the study. A thematic analysis was used to code and group results by themes. When looking at the results through the lens of dynamic capability theory, notable themes included regulatory uncertainty, functional safety, rapid iteration, and achieving a competitive advantage. Based on the findings of the study, implications for social change include the need for better regulatory frameworks to provide certainty, consumer education to manage expectations, and universal development standards that could integrate regulatory and design needs into a single approach.
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Priestley, Michael D. J. "The initialisation and control of a visually guided autonomous road-following vehicle." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281751.
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Magnusson, Filip. "Evaluating Deep Learning Algorithms for Steering an Autonomous Vehicle." Thesis, Linköpings universitet, Programvara och system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-153450.
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With self-driving cars on the horizon, vehicle autonomy and its problems is a hot topic. In this study we are using convolutional neural networks to make a robot car avoid obstacles. The robot car has a monocular camera, and our approach is to use the images taken by the camera as input, and then output a steering command. Using this method the car is to avoid any object in front of it. In order to lower the amount of training data we use models that are pretrained on ImageNet, a large image database containing millions of images. The model are then trained on our own dataset, which contains of images taken directly by the robot car while driving around. The images are then labeled with the steering command used while taking the image. While training we experiment with using different amounts of frozen layers. A frozen layer is a layer that has been pretrained on ImageNet, but are not trained on our dataset. The Xception, MobileNet and VGG16 architectures are tested and compared to each other. We find that a lower amount of frozen layer produces better results, and our best model, which used the Xception architecture, achieved 81.19% accuracy on our test set. During a qualitative test the car avoid collisions 78.57% of the time.
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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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Veeramani, Lekamani Sarangi. "Model Based Systems Engineering Approach to Autonomous Driving : Application of SysML for trajectory planning of autonomous vehicle." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254891.
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Model Based Systems Engineering (MBSE) approach aims at implementing various processes of Systems Engineering (SE) through diagrams that provide different perspectives of the same underlying system. This approach provides a basis that helps develop a complex system in a systematic manner. Thus, this thesis aims at deriving a system model through this approach for the purpose of autonomous driving, specifically focusing on developing the subsystem responsible for generating a feasible trajectory for a miniature vehicle, called AutoCar, to enable it to move towards a goal. The report provides a background on MBSE and System Modeling Language (SysML) which is used for modelling the system. With this background, an MBSE framework for AutoCar is derived and the overall system design is explained. This report further explains the concepts involved in autonomous trajectory planning followed by an introduction to Robot Operating System (ROS) and its application for trajectory planning of the system. The report concludes with a detailed analysis on the benefits of using this approach for developing a system. It also identifies the shortcomings of applying MBSE to system development. The report closes with a mention on how the given project can be further carried forward to be able to realize it on a physical system.Modellbaserade systemteknikens (MBSE) inriktning syftar till att implementera de olika processerna i systemteknik (SE) genom diagram som ger olika perspektiv på samma underliggande system. Detta tillvägagångssätt ger en grund som hjälper till att utveckla ett komplext system på ett systematiskt sätt. Sålunda syftar denna avhandling att härleda en systemmodell genom detta tillvägagångssätt för autonom körning, med särskild inriktning på att utveckla delsystemet som är ansvarigt för att generera en genomförbar ban för en miniatyrbil, som kallas AutoCar, för att göra det möjligt att nå målet. Rapporten ger en bakgrund till MBSE and Systemmodelleringsspråk (SysML) som används för modellering av systemet. Med denna bakgrund, MBSE ramverket för AutoCar är härledt och den övergripande systemdesignen förklaras. I denna rapport förklaras vidare begreppen autonom banplanering följd av en introduktion till Robot Operating System (ROS) och dess tillämpning för systemplanering av systemet. Rapporten avslutas med en detaljerad analys av fördelarna med att använda detta tillvägagångssätt för att utveckla ett system. Det identifierar också bristerna för att tillämpa MBSE på systemutveckling. Rapporten stänger med en omtale om hur det givna projektet kan vidarebefordras för att kunna realisera det på ett fysiskt system.
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Young, Stuart Harry. "A Model-Based Framework for Predicting Autonomous Unmanned Ground Vehicle System Performance." Thesis, The George Washington University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10124164.
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The past decade has seen the rapid development and deployment of unmanned systems throughout the world in both civilian and military applications. Significant development has been led by the Department of Defense (DoD), which has sought to develop and field military systems, such as unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs), with elevated levels of autonomy to accomplish their mission with reduced funding and manpower. As their role increases, such systems must be able to adapt and learn, and make nondeterministic decisions. Current unmanned systems exhibit minimal autonomous behaviors. As their autonomy increases and their behaviors become more intelligent (adapting and learning from previous experiences), the state space for their behaviors becomes non deterministic or intractably complex.
Consequently, fielding such systems requires extensive testing and evaluation, as well as verification and validation to determine a system’s performance and the acceptable level of risk to make it releasable – a challenging task. To address this, I apply a novel systems perspective to develop a model-based framework to predict future system performance based on the complexity of the operating environment using newly introduced complexity measures and learned costs. Herein I consider an autonomous military ground robot navigating in complex off-road environments. Using my model and data from Defense Advanced Research Projects Agency (DARPA)-led experiments, I demonstrate the accuracy with which my model can predict system performance and then validate my model against other experimental results.
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Dhake, Pravin. "A real time operating system based test-bed for autonomous vehicle navigation." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Dhake_09007dcc803c20b4.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 28, 2007) Includes bibliographical references (p. 86-87).
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Currier, Patrick Norman. "A Method for Modeling and Prediction of Ground Vehicle Dynamics and Stability in Autonomous Systems." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/27632.
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A future limitation of autonomous ground vehicle technology is the inability of current algorithmic techniques to successfully predict the allowable dynamic operating ranges of unmanned ground vehicles. A further difficulty presented by real vehicles is that the payloads may and probably will change with unpredictably time as will the terrain on which it is expected to operate. To address this limitation, a methodology has been developed to generate real-time estimations of a vehicleâ s instantaneous Maneuvering Manifold. This approach uses force-moment method techniques to create an adaptive, parameterized vehicle model. A technique is developed for estimation of vehicle load state using internal sensors combined with low-magnitude maneuvers. An unscented Kalman filter based estimator is then used to estimate tire forces for use in determining the ground/tire coefficient of friction. Probabilistic techniques are then combined with a combined-slip pneumatic trail based estimator to estimate the coefficient of friction in real-time. This data is then combined to map out the instantaneous maneuvering manifold while applying techniques to account for dynamic rollover and stability limitations. The algorithms are implemented in MATLAB, simulated against TruckSim models, and results are shown to demonstrate the validity of the techniques. The developed methodology is shown to be a novel approach that is capable of addressing the problem of successfully estimating the available maneuvering manifold for autonomous ground vehicles.Ph. D.
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Baity, Sean Marshall. "Development of a Next-generation Experimental Robotic Vehicle (NERV) that Supports Intelligent and Autonomous Systems Research." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36102.
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Recent advances in technology have enabled the development of truly autonomous ground vehicles capable of performing complex navigation tasks. As a result, the demand for practical unmanned ground vehicle (UGV) systems has increased dramatically in recent years. Central to these developments is maturation of emerging mobile robotic intelligent and autonomous capability. While the progress UGV technology has been substantial, there are many challenges that still face unmanned vehicle system developers. Foremost is the improvement of perception hardware and intelligent software that supports the evolution of UGV capability.
The development of a Next-generation Experimentation Robotic Vehicle (NERV) serves to provide a small UGV baseline platform supporting experimentation focused on progression of the state-of-the-art in unmanned systems. Supporting research and user feedback highlight the needs that provide justification for an advanced small UGV research platform. Primarily, such a vehicle must be based upon open and technology independent system architecture while exhibiting improved mobility over relatively structured terrain.
To this end, a theoretical kinematic model is presented for a novel two-body multi degree-of-freedom, four-wheel drive, small UGV platform. The efficacy of the theoretical kinematic model was validated through computer simulation and experimentation on a full-scale proof-of-concept mobile robotic platform. The kinematic model provides the foundation for autonomous multi-body control. Further, a modular system level design based upon the concepts of the Joint Architecture for Unmanned Systems (JAUS) is offered as an open architecture model providing a scalable system integration solution. Together these elements provide a blueprint for the development of a small UGV capable of supporting the needs of a wide range of leading-edge intelligent system research initiatives.Master of Science
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Collins, Robert James. "Design of a Helicopter Slung Vehicle for Actuated Payload Placement." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/31882.
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Helicopters have been used in applications where they need to carry a slung load for years. More recently, unmanned (UAV) helicopters are being used to deliver supplies to military units on the ground in theaters of war. This thesis presents a helicopter slung vehicle used to carry the payload and furthermore, provide a means of actuation for the payload. This provides more control authority to the system and may ultimately allow a helicopter to fly higher with a longer tether.
The vehicle designed in this thesis was designed for use with 100kg class helicopters, such as the Yamaha RMAX operated by the Virginia Tech Unmanned Systems Lab. Each system on the vehicle was custom designed â including the propulsion system, wall detection / localization system, and controller. Three shrouded propellers provided thruster actuation. A scanning laser range finder and inertial measurement unit (IMU) were used to provide localization. A first attempt at a linear full state feedback controller with a complementary filter was used to control the vehicle.
All of the systems were tested individually for functionality. The shrouded propellers met their design goals and were capable of producing .7lbf of thrust each. The wall detection system was able to detect walls and windows reliably and with repeatability. Results from the controller however were less than ideal, as it was only able to control yaw in an oscillatory motion, most likely due to model deficiencies. A reaction wheel was used to control yaw of the vehicle with more success.Master of Science
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Ireland, Robert D. "Autonomous vehicle systems implications for maritime operations, warfare capabilities, and Command and Control /." Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Jun/10Jun%5FIreland.pdf.
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Thesis (M.S. in Systems Technology (Command, Control, and Communications))--Naval Postgraduate School, June 2010.Thesis Advisor(s): Gallup, Shelley P.; Second Reader: MacKinnon, Douglas J. "June 2010." Description based on title screen as viewed on July 14, 2010. Author(s) subject terms: Machine Autonomy, AVS, USV, UUV, Navy Tactical Task List, Situational Awareness, Congruence Model, Decision Superiority, Maritime ISR. Includes bibliographical references (p. 49-51). Also available in print.
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Watts, Christopher Mark. "A comparison study of biologically inspired propulsion systems for an autonomous underwater vehicle." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/1672/.
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The field of Autonomous Underwater Vehicles (AUVs) has increased dramatically in size and scope over the past two decades. Application areas for AUVs are numerous and varied; from deep sea exploration, to pipeline surveillance to mine clearing. However, one limiting factor with the current technology is the duration of missions that can be undertaken and one contributing factor to this is the efficiency of the propulsion system, which is usually based on marine propellers. As fish are highly efficient swimmers greater propulsive efficiency may be possible by mimicking their fish tail propulsion system. The main concept behind this work was therefore to investigate whether a biomimetic fish-like propulsion system is a viable propulsion system for an underwater vehicle and to determine experimentally the efficiency benefits of using such a system. There have been numerous studies into biomimetic fish like propulsion systems and robotic fish in the past with many claims being made as to the benefits of a fish like propulsion system over conventional marine propulsion systems. These claims include increased efficiency and greater manoeuvrability. However, there is little published experimental data to characterise the propulsive efficiency of a fish like propulsive system. Also, very few direct experimental comparisons have been made between biomimetic and conventional propulsion systems. This work attempts to address these issues by directly comparing experimentally a biomimetic underwater propulsion system to a conventional propulsion system to allow for a better understanding of the potential benefits of the biomimetic system. This work is split into three parts. Firstly, the design and development of a novel prototype vehicle called the RoboSalmon is covered. This vehicle has a biomimetic tendon drive propulsion system which utilizes one servo motor for actuation and has a suite of onboard sensors and a data logger. The second part of this work focuses on the development of a mathematical model of the RoboSalmon vehicle to allow for a better understanding of the dynamics of the system. Simulation results from this model are compared to the experimental results and show good correlation. The final part of the work presents the experimental results obtained comparing the RoboSalmon prototype with the biomimetic tail system to the propeller and rudder system. These experiments include a study into the straight swimming performance, recoil motion, start up transients and power consumption. For forward swimming the maximum surge velocity of the RoboSalmon was 0.18ms-1 and at this velocity the biomimetic system was found to be more efficient than the propeller system. When manoeuvring the biomimetic system was found to have a significantly reduced turning radius. The thesis concludes with a discussion of the main findings from each aspect of the work, covering the benefits obtained from using the tendon drive system in terms of efficiencies and manoeuvring performance. The limitations of the system are also discussed and suggestions for further work are included.
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Williams, Stefan Bernard. "Efficient solutions to autonomous mapping and navigation problems." Connect to full text, 2001. http://hdl.handle.net/2123/809.
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Thesis (Ph. D.)--University of Sydney, 2002.Title from title screen (viewed Apr. 24, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Australian Centre for Field Robotics, Dept. of Mechanical and Mechatronic Engineering, Faculty of Engineering. Degree awarded 2002; thesis submitted 2001. Includes bibliography. Also available in print form.
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Pizarro, Oscar. "Large scale structure from motion for autonomous underwater vehicle surveys." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/39185.
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Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 2004.Includes bibliographical references (p. 177-190).
Our ability to image extended underwater scenes is severely limited by attenuation and backscatter. Generating a composite view from multiple overlapping images is usually the most practical and flexible way around this limitation. In this thesis we look at the general constraints associated with imaging from underwater vehicles for scientific applications - low overlap, non-uniform lighting and unstructured motion - and present a methodology for dealing with these constraints toward a solution of the problem of large area 3D reconstruction. Our approach assumes navigation data is available to constrain the structure from motion problem. We take a hierarchical approach where the temporal image sequence is broken into subsequences that are processed into 3D reconstructions independently. These submaps are then registered to infer their overall layout in a global frame. From this point a bundle adjustment refines camera and structure estimates. We demonstrate the utility of our techniques using real data obtained during a SeaBED AUV coral reef survey. Test tank results with ground truth are also presented to validate the methodology.
by Oscar Pizarro.
Ph.D.
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Woldu, Essayas Gebrewahid, and Fareed Ahmed Jokhio. "Experiments with Vehicle Platooning." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-5621.
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This thesis is concerned with an experimental platform for studying cooperative driving and techniques for embedded systems programming. Cooperative driving systems use vehicle-to-vehicle and vehicle-to-infrastructure communication for safe, smooth and efficient transportation. Cooperative driving systems are considered as a promising solution for traffic situations such as blind crossings. For the thesis work we use a robotic vehicle known as PIE (Platform for Intelligent Embedded Systems) equipped with a wireless communication device, electrical motors and controlled via a SAM7-P256 development board. For the infrastructure side we use a SAM7-P256 development board equipped with nRF24l01. Vehicle to vehicle and base station to vehicle communication is established and different platooning scenarios are implemented. The scenarios are similar to platooning scenarios from the Grand Cooperative Driving Challenge GCDC1. The performance of the platoon control algorithm is measured in terms of throughput (a measure of string stability), smoothness and safety, where the safety requirements serve as pass/fail criteria.
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Kepler, Jr Michael Eugene. "Dynamics of a Small Autonomous Underwater Vehicle That Tows a Large Payload." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/84915.
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This thesis presents the derivation of the dynamic model of an autonomous underwater vehicle that tows a large payload. Our analysis is motivated by the fact that the payload is so large that it cannot be modeled by simply appending its dynamics to the dynamics of the autonomous underwater vehicle. Hence, the coupling between the vehicle and payload must be fully modeled. Furthermore, several approximation techniques based on analytic and empirical formulations are investigated for computing the hydrodynamic coefficients of the vehicle. Efficacy and limitations of the approximation techniques are assessed by comparison with hydrodynamic coefficients that are estimated using high-fidelity computational fluid dynamics simulations.Master of Science
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Flores, Javier Alejandro. "Autonomous vehicle navigation a comparative study of classical logic and neural network technique /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Freudinger, Lawrence C., Filiberto Macias, and Harold Cornelius. "Frequency Agile Transceiver for Advanced Vehicle Data Links." International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/605968.
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ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, NevadaEmerging and next-generation test instrumentation increasingly relies on network communication to manage complex and dynamic test scenarios, particularly for uninhabited autonomous systems. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. Frequency agility is one characteristic of reconfigurable radios that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate a promising chipset that performs conversion of RF signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit, programmable for any frequency band between 1 MHz and 6 GHz.
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Aslansefat, K., Sohag Kabir, Amr R. A. Abdullatif, Vinod Vasudevan, and Y. Papadopoulos. "Toward Improving Confidence in Autonomous Vehicle Software: A Study on Traffic Sign Recognition Systems." IEEE, 2021. http://hdl.handle.net/10454/18591.
Full textAbstract:
YesThis article proposes an approach named SafeML II, which applies empirical cumulative distribution function-based statistical distance measures in a designed human-in-the loop procedure to ensure the safety of machine learning-based classifiers in autonomous vehicle software. The application of artificial intelligence (AI) and data-driven decision-making systems in autonomous vehicles is growing rapidly. As autonomous vehicles operate in dynamic environments, the risk that they can face an unknown observation is relatively high due to insufficient training data, distributional shift, or cyber-security attack. Thus, AI-based algorithms should make dependable decisions to improve their interpretation of the environment, lower the risk of autonomous driving, and avoid catastrophic accidents. This paper proposes an approach named SafeML II, which applies empirical cumulative distribution function (ECDF)-based statistical distance measures in a designed human-in-the-loop procedure to ensure the safety of machine learning-based classifiers in autonomous vehicle software. The approach is model-agnostic and it can cover various machine learning and deep learning classifiers. The German Traffic Sign Recognition Benchmark (GTSRB) is used to illustrate the capabilities of the proposed approach.
This work was supported by the Secure and Safe MultiRobot Systems (SESAME) H2020 Project under Grant Agreement 101017258.
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Gadre, Aditya Shrikant. "Observability Analysis in Navigation Systems with an Underwater Vehicle Application." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26154.
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Precise navigation of autonomous underwater vehicles (AUV) is one of the most important challenges in the realization of distributed and cooperative algorithms for marine applications. We investigate an underwater navigation technology that enables an AUV to compute its trajectory in the presence of unknown currents in real time and simultaneously estimate the currents, using range or distance measurements from a single known location. This approach is potentially useful for small AUVs which have severe volume and power constraints.
The main contribution of this work is observability analysis of the proposed navigation system using novel approaches towards uniform observability of linear time-varying (LTV) systems. We utilize the notion of limiting systems in order to address uniform observability of LTV systems. Uniform observability of an LTV system can be studied by assessing finite time observability of its limiting systems. A new definition of uniform observability over a finite interval is introduced in order to address existence of an observer whose estimation error is bounded by an exponentially decaying function on the finite interval. We also show that for a class of LTV systems, uniform observability of a lower dimensional subsystem derived from an LTV system is sufficient for uniform observability of the LTV system.Ph. D.
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Luusua, Emil. "Vehicle Detection, at a Distance : Done Efficiently via Fusion of Short- and Long-Range Images." Thesis, Linköpings universitet, Datorseende, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167073.
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Object detection is a classical computer vision task, encountered in many practical applications such as robotics and autonomous driving. The latter involves serious consequences of failure and a multitude of challenging demands, including high computational efficiency and detection accuracy. Distant objects are notably difficult to detect accurately due to their small scale in the image, consisting of only a few pixels. This is especially problematic in autonomous driving, as objects should be detected at the earliest possible stage to facilitate handling of hazardous situations. Previous work has addressed small objects via use of feature pyramids and super-resolution techniques, but the efficiency of such methods is limited as computational cost increases with image resolution. Therefore, a trade-off must be made between accuracy and cost. Opportunely though, a common characteristic of driving scenarios is the predominance of distant objects in the centre of the image. Thus, the full-frame image can be downsampled to reduce computational cost, and a crop can be extracted from the image centre to preserve resolution for distant vehicles. In this way, short- and long-range images are generated. This thesis investigates the fusion of such images in a convolutional neural network, particularly the fusion level, fusion operation, and spatial alignment. A novel framework — DetSLR — is proposed for the task and examined via the aforementioned aspects. Through adoption of the framework for the well-established SSD detector and MobileNetV2 feature extractor, it is shown that the framework significantly improves upon the original detector without incurring additional cost. The fusion level is shown to have great impact on the performance of the framework, favouring high-level fusion, while only insignificant differences exist between investigated fusion operations. Finally, spatial alignment of features is demonstrated to be a crucial component of the framework.
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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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Davis, Duane T. "Precision control and maneuvering of the Phoenix autonomous underwater vehicle for entering a recovery tube." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA325015.
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Thesis (M.S. in Computer Science) Naval Postgraduate School, September 1996.Thesis advisor(s): Robert McGhee and Don Brutzman. "September 1996." Appendix videotape located at Circulation Desk, call number VHS 5000067. Includes bibliographical references (p. 179-184). Also available online.
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Stigenius, Erik. "Map Engine with Route and Slope Prediction for Autonomous Vehicles in Offroad Applications." Thesis, Uppsala universitet, Signaler och System, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328753.
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With an imminent future of fully autonomous heavy duty vehicles in offroad applications, the need for advanced control system will increase accordingly. By implementing a raster map with tiles and pixels, to which a vehicle can record slope and position data while driving, it is possible to map earth's surface. By adding a heat parameter to every pixel, i.e. the number of passings through it historically, it is possible in future visits of the same are to generate a route prediction made up by the "hottest" pixels. By fetching the slope values in the hottest pixels, it is possible to generate a slope horizon that can be utilized by control systems, e.g. when planning gear shifts in hilly offroad terrain. To mange the incrementally growing map, a memory management system was implemented. It buffers the relevant map data from the database, i.e. the vehicles closest surroundings, which is then used for route prediction and horizon generation. As the vehicle moves into other areas, new data is read from the database, and the recently passed area is written back to the database, however updated from the recent passing. The system is implemented so that it runs through another application in the telematics electrical controller unit (ECU) in a Scania vehicle. The ECU contains a GNSS module from which the vehicle fetches satellite positioning data. Slope data is fetched from a slope sensor mounted on the truck. Due to implications during testing and debugging of the resulting application developed and implemented during this thesis project, the application's performance couldn't be assessed properly. However, it is concluded that the background the application is built on is reliable, although tweaks to get the application fit for usage in offroad terrain had to be made. Mainly, the horizon length and map building techniques should not be the same as in similar applications for onroad driving.
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Pettersson, Jesper. "Exploring interaction with unmanned systems : A case study regarding interaction with an autonomous unmanned vehicle." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166302.
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Unmanned systems (US:s) of various kinds are becoming more and more sought after resources as they do not have an onboard driver, and thus, can be employed in situations that are either dangerous or impossible for humans to engage in. Consequently, US:s are envisioned to play a large role both in civilian and military contexts in the future, which presents new challenges regarding how humans should interact with these new systems. The purpose with this thesis was to explore different ways of interaction between human and artificial agents and how interfaces of autonomous systems supports this interaction. To investigate this, a literature overview of previous research regarding various ways of interacting with unmanned systems was conducted. This illustrated that a multimodal interface offers a more robust and natural form of interaction compared to fixed interaction principles that have their advantages and disadvantages depending on both context and situation. Moreover, a case study was conducted to explore human-autonomy interaction in a realistic battle mission, simulated in Virtual Battle Simulator 3. The results from the study indicate that speech is an essential mode of communication for controlling an unmanned autonomous ground vehicle in a mounted setting. Furthermore, problems were identified with the visual and auditory feedback from the unmanned vehicle in which verbal feedback was identified as a possible solution. Experience regarding both the simulation environment and as a commander of mechanised units was also identified as an important factor to adhere to in future studies.
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Marielle, Gallardo, and Chakraborty Sweta. "DECISION-MAKING FOR AUTONOMOUS CONSTRUCTION VEHICLES." Thesis, Mälardalens högskola, Inbyggda system, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-44250.
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Autonomous driving requires tactical decision-making while navigating in a dynamic shared space environment. The complexity and uncertainty in this process arise due to unknown and tightly-coupled interaction among traffic users. This thesis work formulates an unknown navigation problem as a Markov decision process (MDP), supported by models of traffic participants and userspace. Instead of modeling a traditional MDP, this work formulates a Multi-policy decision making (MPDM) in a shared space scenario with pedestrians and vehicles. The employed model enables a unified and robust self-driving of the ego vehicle by selecting a desired policy along the pre-planned path. Obstacle avoidance is coupled within the navigation module performing a detour off the planned path and obtaining a reward on task completion and penalizing for collision with others. In addition to this, the thesis work is further extended by analyzing the real-time constraints of the proposed model. The performance of the implemented framework is evaluated in a simulation environment on a typical construction (quarry) scenario. The effectiveness and efficiency of the elected policy verify the desired behavior of the autonomous vehicle.
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Roberson, David Gray. "Environmental Tracking and Formation Control for an Autonomous Underwater Vehicle Platoon with Limited Communication." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26175.
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A platoon of autonomous underwater vehicles provides a compelling platform for studying many challenging issues in multi-agent cooperative control. These challenges include developing cooperative algorithms suitable to practical multi-vehicle applications. They also include addressing intervehicle communication issues, such as sharing information via limited bandwidth channels and selecting network architecture to facilitate control design. This work addresses problems in each of these areas.
Environmental tracking and formation control serves as the main application upon which this work focuses. In the tracking and formation control application, a team of vehicles obtains a spatial average of an environmental feature by collecting and sharing local measurements. To achieve this objective, vehicles track a desired environmental field contour with their average position while maintaining a desired spatial formation about the average. A decentralized consensus-based algorithm is developed for controlling the platoon. In a novel two-level consensus approach, each vehicle estimates a virtual leader trajectory using local and shared measurements at one level, then positions itself about the virtual leader at a second level.
Due to very low bandwidth underwater communication, vehicles share information intermittently, and the platoon network is effectively disconnected at every instant of time. This issue is addressed by modeling the platoon as a periodic switched system whose frozen-time subsystems possess disconnected networks, but whose time-averaged system is connected. The stability and input-output properties of the switched system are related to those of the corresponding average system. Under sufficiently fast switching, asymptotic stability of the average system implies asymptotic stability of the switched system and the existence of an L2 gain. Estimates of the slowest stabilizing switching rate and the L2 gain are derived.
Controller and estimator design are complicated by the lack of a separation principle for decentralized systems and by the effects of intervehicle coupling. The potential for choosing the communication topology in a manner that leads to design simplifications is investigated. In particular, a transformation is presented that converts the platoon state coefficient matrix to block diagonal form when the communication network has a circulant structure.Ph. D.
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Wadoo, Sabiha Amin. "Feedback Control and Nonlinear Controllability of Nonholonomic Systems." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/30963.
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In this thesis we study the methods for motion planning for nonholonomic systems. These systems are characterized by nonholonomic constraints on their generalized velocities. The motion planning problem with constraints on the velocities is transformed into a control problem having fewer control inputs than the degrees of freedom. The main focus of the thesis is on the study of motion planning and design of the feedback control laws for an autonomous underwater vehicle: a nonholonomic system. The nonlinear controllability issues for the system are also studied. For the design of feedback controllers, the system is transformed into chained and power forms. The methods of transforming a nonholonomic system into these forms are discussed. The work presented in this thesis is a step towards the initial study concerning the applicability of kinematic-based control on underwater vehicles.Master of Science
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Markgren, Jonas. "Creating a self-driving terrain vehicle in a simulated environment." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-173273.
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Outside of the city environment, there are many unstructured and rough environments that are challenging in vehicle navigation tasks. In these environments, vehicle vibrations caused by rough terrain can be harmful for humans. In addition, a human operator can not work around the clock. A promising solution is to use artificial intelligence to replace human operators. I test this by using the artificial intelligence technique know as reinforcement learning, with the algorithm Proximal Policy Optimization, to perform some basic locomotion tasks in a simulated environment with a simple terrain vehicle. The terrain vehicle consists of two chassis, each having two wheels attached, connected to each other with an articulation joint that can rotate to turn the vehicle. I show that a trained model can learn to operate the terrain vehicle and complete basic tasks, such as finding and following a path while avoiding obstacles. I tested robustness by evaluating performance on sloped terrains with a model trained to operate on flat ground. The results from the tests with different slopes show that, for most environments, the trained model could handle slopes up to around 7.5-10 degrees without much issue, even though it had no way of detecting the slope. This tells us that the models can perform their tasks quite well even when disturbances are introduced, as long as these disturbances doesn't require them to significantly change their behaviors.
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Evestedt, Niclas. "Sampling Based Motion Planning for Heavy Duty Autonomous Vehicles." Licentiate thesis, Linköpings universitet, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132769.
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The automotive industry is undergoing a revolution where the more traditional mechanical values are replaced by an ever increasing number of Advanced Driver Assistance Systems (ADAS) where advanced algorithms and software development are taking a bigger role. Increased safety, reduced emissions and the possibility of completely new business models are driving the development and most automotive companies have started projects that aim towards fully autonomous vehicles. For industrial applications that provide a closed environment, such as mining facilities, harbors, agriculture and airports, full implementation of the technology is already available with increased productivity, reliability and reduced wear on equipment as a result. However, it also gives the opportunity to create a safer working environment when human drivers can be removed from dangerous working conditions. Regardless of the application an important part of any mobile autonomous system is the motion planning layer. In this thesis sampling-based motion planning algorithms are used to solve several non-holonomic and kinodynamic planning problems for car-like robotic vehicles in different application areas that all present different challenges. First we present an extension to the probabilistic sampling-based Closed-Loop Rapidly exploring Random Tree (CL-RRT) framework that significantly increases the probability of drawing a valid sample for platforms with second order differential constraints. When a tree extension is found infeasible a new acceleration profile that tries to brings the vehicle to a full stop before the collision occurs is calculated. A resimulation of the tree extension with the new acceleration profile is then performed. The framework is tested on a heavy-duty Scania G480 mining truck in a simple constructed scenario. Furthermore, we present two different driver assistance systems for the complicated task of reversing with a truck with a dolly-steered trailer. The first is a manual system where the user can easily construct a kinematically feasible path through a graphical user interface. The second is a fully automatic planner, based on the CL-RRT algorithm where only a start and goal position need to be provided. For both approaches, the internal angles of the trailer configuration are stabilized using a Linear Quadratic (LQ) controller and path following is achieved through a pure-pursuit control law. The systems are demonstrated on a small-scale test vehicle with good results. Finally, we look at the planning problem for an autonomous vehicle in an urban setting with dense traffic for two different time-critical maneuvers, namely, intersection merging and highway merging. In these situations, a social interplay between drivers is often necessary in order to perform a safe merge. To model this interaction a prediction engine is developed and used to predict the future evolution of the complete traffic scene given our own intended trajectory. Real-time capabilities are demonstrated through a series of simulations with varying traffic densities. It is shown, in simulation, that the proposed method is capable of safe merging in much denser traffic compared to a base-line method where a constant velocity model is used for predictions.
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Miller, Erik. "Implementation of a Scale Semi-Autonomous Platoon to Test Control Theory Attacks." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2057.
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With all the advancements in autonomous and connected cars, there is a developing body of research around the security and robustness of driving automation systems. Attacks and mitigations for said attacks have been explored, but almost always solely in software simulations.
For this thesis, I led a team to build the foundation for an open source platoon of scale semi-autonomous vehicles. This work will enable future research into implementing theoretical attacks and mitigations. Our 1/10 scale car leverages an Nvidia Jetson, embedded microcontroller, and sensors. The Jetson manages the computer vision, networking, control logic, and overall system control; the embedded microcontroller directly controls the car. A lidar module is responsible for recording distance to the preceding car, and an inertial measurement unit records the velocity of the car itself. I wrote the software for the networking, interprocess, and serial communications, as well as the control logic and system control.
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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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Moret, Eric N. "Dynamic Modeling and Control of a Car-Like Robot." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31535.
Full textAbstract:
The Flexible Low-cost Automated Scaled Highway (FLASH) laboratory at the Virginia Tech Transportation Institute (VTTI) is one of many facilities dedicated to the field of Intelligent Transportation Systems (ITS). The goal of the FLASH lab is to provide small-scale development and implementation of autonomous control strategies for today's vehicles.
The current controller used on the scale vehicles is based solely on the kinematics of the system. This body of work was aimed to develop a dynamic control law to enhance the performance of the existing kinematic controller. This control system is intended to automatically maintain the vehicle's alignment on the road as well as keep the speed of the vehicle constant. Implementation of such systems could conceivably reduce driver fatigue by removing nearly all the burden of the driving process from the driver while on the highway.
System dynamics of car-like robots with nonholonomic constraints were employed in this research to create a controller for an autonomous path following vehicle. The application of working kinematic and dynamic models describing car-like robotic systems allowed the development of a nonlinear controller.
Simulations of the vehicle and controller were done using MATLAB. Comparisons of the kinematic controller and the dynamic controller presented here were also done. In order to make the simulations model the actual system more closely, measures were taken to approximate actual sensor readings.
Master of Science
50
Batmanian, Saro, and Pasam Naga. "Control and balancing of a small vehicle with two wheels for autonomous driving." Thesis, KTH, Fordonsdynamik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265618.
Full textAbstract:
Control and balancing of an inverted pendulum has gained a lot of attention over the past few decades due to its unstable properties. This has become a great challenge for control engineers to verify and test the control theory. To control and balance an inverted pendulum, proportional integrated derivative (PID) method or linear quadratic regulator (LQR) method can be used through which a lot of simulations can be done using the represented theories.Since urban population is increasing at a very alarming rate, there is a need to discover new ways of transportation to meet the future challenges and demands. Scania has come up with a new conceptual bus called NXT which aims to develop a modular vehicle that should configure and re-configure themselves between different transportation tasks. NXT vehicle has front and rear drive modules which can be represented as single axle, two-wheeled vehicles which in-turn can be viewed as an inverted pendulum with a huge Center of Gravity. Controlling and balancing of the pod or drive module precisely and accurately is an interesting challenge since it is an unstable inverted pendulum with huge center of gravity (COG). This behaviour of the system has created a research question whether the module is controllable or not.Therefore this thesis focuses on the possibility of controlling the pod which is a two-wheeled inverted pendulum vehicle with a COG offset. Also, the thesis focuses on the construction, mod-elling, testing and validation of a down-scaled model, what sensors are needed to balance the pod precisely, how the sensors must be integrated with the system and how the pod can be controlled remotely from a certain distance by a human. The developed pod houses the technologies like sensors, BLDC motor controllers, hoverboard, Arduino board and Bluetooth transmitters.The Master Thesis starts by presenting an introduction to the inverted pendulum theories, Scania NXT project, information about the research methods, thesis outline and structure . It continues by describing related literature about the inverted pendulums, segways, hoverboards, motor controllers and Arduino boards. Afterwards, the process of deriving a mathematical model, together with simulation in Matlab, Simulink and Simscape is described. Later, construction of the pod is made and lot of effort is put to run the pod. Since the pod needs to be controlled remotely by a human, a remote controlled systemis implemented via mobile phone using an app and finally the thesis is finished with a conclusion and ideas for future work.Reglering och balancering av en inverterad pendel har väckt stor uppmärksamhet över de senaste decennierna på grund av dess instabila egenskaper. Det har skapat stora utmaningar för regleringenjörer eftersom området tillåter test och verifikation av diverese lösningar. För reglering och balansering av en inverterad pendel, så kan en regulator med proportionell, integral och derivat (PID) konstanter eller en linjär kvadratisk regulator (LQR) användas tillsammans med simuleringar för att bekräfta teorin.I och med att stadsbefolkningen ökar i mycket hög takt, så uppstår behovet av att uppfinna nya transportmedel för att lösa framtida utmaningar och krav. Scania har tagit fram en ny konceptbuss som heter NXT, med målet att utveckla ett modulfordon som kommer att konfigurera och rekonfigurera sig själva mellan olika transportuppgifter. NXT-fordonet har fram- och bakdriv-moduler som kan representeras som enaxlade tvåhjuliga fordon, vilka i sin tur kan betraktas som en inverterad pendel med en stor massa. Att reglera och balansera drivmodulen på ett noggrant sätt är en utmaning eftersom det är ett mycket instabilt system med enorm massa och en okänd tyngdpunkt. Systemets beteende har skapat en forskningsfråga om modulen är reglerbar eller inte.Denna uppsats fokuserar därmed på möjligheterna att kunna reglera drivmodulen samt vilka begränsningar det finns. Uppsatsen fokuserar också på konstruktion, modellering, testning och validering av en nedskalad modell, vilka sensorer som krävs för att balansera drivmodulem, samt hur sensorerna måste integreras med systemet för att kunna fjärstyra fordonet från ett visst avstånd. Utveckingen av en sådan nedskalad modell berör olika områden såsom sensorer, BLDC-motorstyrenheter, hoverboard balanserings scootrar, Arduino kretskort och Bluetooth-sändare/mottagare.Uppsasten börjar med en introduction om olika inverterade pendel teorier, Scania NXT project, forskningsmetoder, en översikt och övergripande struktur. Vidare fortsätter beskrivining av relaterade litteratur om inverterade pendel, Segway, hoverboard, borstlösa motor styrenheter och Arduino kretskort. Senare fortsätter processen för att härleda matematiska modeller som beskirver systemet, tillsammans med simuleringar i Matlab, Simulink och Simscape. Därefter beskrivs konstruktionen av en nedskalad modell av drivmodulen och beskrivning av nödvändiga processer för att få hårdvara och mjkukvara att fungera ihop. Då fordonen ska ha möjlighet att fjärrstyras, så implementerades en bluetooth enhet tillsammans med en programmerbar mobil applikation. Slutligen avlutas uppsatsen med resultat, slutsats och diskussioner och förslag till framtida arbeten.