Dissertations / Theses on the topic 'Autonomous vehicles'
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Manuzzi, Nicolas. "Autonomous Vehicle and Internet on Vehicles." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9211/.
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Pérez, Tellez Adriel, and Jonas Roth. "Mobile autonomous ground vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199348.
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Arutselvan, Kuralamudhan. "Assistive Autonomous Ground Vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200530.
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Anderson, Jonathan D. "Semi Autonomous Vehicle Intelligence: Real Time Target Tracking For Vision Guided Autonomous Vehicles." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1750.pdf.
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Rahman, Md Mahbubar. "Two-Echelon Vehicle Routing Problems Using Unmanned Autonomous Vehicles." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28423.
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In this thesis, we investigate new multi-echelon vehicle routing problems for logistics operations using unmanned autonomous vehicles. This can provide immediate tangible outcomes, especially in high-demand areas that are otherwise difficult or costly to serve. This type of problem differs from the commonly used multi-echelon supply chain management systems in that here there exist no intermediate facilities that consolidate/separate products for delivery; instead all decisions are made on a per-vehicle basis. We describe here how we can obtain the necessary parameters (data collection) to evaluate the performance of such multi-echelon systems. We also provide three mathematical formulations based on different assumptions and case scenarios. We then study the differences between the three models in practice, as far as routing cost and duration of operations are concerned. We finally show that there are savings to be had by properly employing unmanned vehicles for logistics operations.
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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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Pedreira, Carabel Carlos Javier. "Terrain Mapping for Autonomous Vehicles." Thesis, KTH, Datorseende och robotik, CVAP, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174132.
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Autonomous vehicles have become the forefront of the automotive industry nowadays, looking to have safer and more efficient transportation systems. One of the main issues for every autonomous vehicle consists in being aware of its position and the presence of obstacles along its path. The current project addresses the pose and terrain mapping problem integrating a visual odometry method and a mapping technique. An RGB-D camera, the Kinect v2 from Microsoft, was chosen as sensor for capturing information from the environment. It was connected to an Intel mini-PC for real-time processing. Both pieces of hardware were mounted on-board of a four-wheeled research concept vehicle (RCV) to test the feasibility of the current solution at outdoor locations. The Robot Operating System (ROS) was used as development environment with C++ as programming language. The visual odometry strategy consisted in a frame registration algorithm called Adaptive Iterative Closest Keypoint (AICK) based on Iterative Closest Point (ICP) using Oriented FAST and Rotated BRIEF (ORB) as image keypoint extractor. A grid-based local costmap rolling window type was implemented to have a two-dimensional representation of the obstacles close to the vehicle within a predefined area, in order to allow further path planning applications. Experiments were performed both offline and in real-time to test the system at indoors and outdoors scenarios. The results confirmed the viability of using the designed framework to keep tracking the pose of the camera and detect objects in indoor environments. However, outdoor environments evidenced the limitations of the features of the RGB-D sensor, making the current system configuration unfeasible for outdoor purposes.Autonoma fordon har blivit spetsen för bilindustrin i dag i sökandet efter säkrare och effektivare transportsystem. En av de viktigaste sakerna för varje autonomt fordon består i att vara medveten om sin position och närvaron av hinder längs vägen. Det aktuella projektet behandlar position och riktning samt terrängkartläggningsproblemet genom att integrera en visuell distansmätnings och kartläggningsmetod. RGB-D kameran Kinect v2 från Microsoft valdes som sensor för att samla in information från omgivningen. Den var ansluten till en Intel mini PC för realtidsbehandling. Båda komponenterna monterades på ett fyrhjuligt forskningskonceptfordon (RCV) för att testa genomförbarheten av den nuvarande lösningen i utomhusmiljöer. Robotoperativsystemet (ROS) användes som utvecklingsmiljö med C++ som programmeringsspråk. Den visuella distansmätningsstrategin bestod i en bildregistrerings-algoritm som kallas Adaptive Iterative Closest Keypoint (AICK) baserat på Iterative Closest Point (ICP) med hjälp av Oriented FAST och Rotated BRIEF (ORB) som nyckelpunktsutvinning från bilder. En rutnätsbaserad lokalkostnadskarta av rullande-fönster-typ implementerades för att få en tvådimensionell representation av de hinder som befinner sig nära fordonet inom ett fördefinierat område, i syfte att möjliggöra ytterligare applikationer för körvägen. Experiment utfördes både offline och i realtid för att testa systemet i inomhus- och utomhusscenarier. Resultaten bekräftade möjligheten att använda den utvecklade metoden för att spåra position och riktning av kameran samt upptäcka föremål i inomhusmiljöer. Men utomhus visades begränsningar i RGB-D-sensorn som gör att den aktuella systemkonfigurationen är värdelös för utomhusbruk.
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Dever, Christopher W. (Christopher Walden) 1972. "Parametrized maneuvers for autonomous vehicles." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30328.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 197-209).
This thesis presents a method for creating continuously parametrized maneuver classes for autonomous vehicles. These classes provide useful tools for motion planners, bundling sets of related vehicle motions based on a low-dimensional parameter vector that describes the fundamental high-level variations within the trajectory set. The method follows from a relaxation of nonlinear parametric programming necessary conditions that discards the objective function, leaving a simple coordinatized feasible space including all dynamically admissible vehicle motions. A trajectory interpolation algorithm uses projection and integration methods to create the classes, starting from arbitrary user-provided maneuver examples, including those obtained from standard nonlinear optimization or motion capture of human-piloted vehicle flights. The interpolation process, which can be employed for real-time trajectory generation, efficiently creates entire maneuver sets satisfying nonlinear equations of motion and nonlinear state and control constraints without resorting to iterative optimization. Experimental application to a three degree-of-freedom rotorcraft testbed and the design of a stable feedforward control framework demonstrates the essential features of the method on actual hardware. Integration of the trajectory classes into an existing hybrid system motion planning framework illustrates the use of parametrized maneuvers for solving vehicle guidance problems. The earlier relaxation of strict optimality conditions makes possible the imposition of affine state transformation constraints, allowing maneuver sets to fit easily into a mixed integer-linear programming path planner.
(cont.) The combined scheme generalizes previous planning techniques based on fixed, invariant representations of vehicle equilibrium states and maneuver elements. The method therefore increases the richness of available guidance solutions while maintaining problem tractability associated with hierarchical system models. Application of the framework to one and two-dimensional path planning examples demonstrates its usefulness in practical autonomous vehicle guidance scenarios.
by Christopher Walden Dever.
Ph.D.
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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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Alhuttaitawi, Saif. "Intersection coordination for Autonomous Vehicles." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20936.
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Connected Autonomous Vehicles require intelligent autonomous intersection management for safe and efficient operation. Given the uncertainty in vehicle trajectory, intersection management techniques must consider a safety buffer among the vehicles, which must also account for the network and computational delay, queue and determine the best solution to avoid traffic congestions (smart intersection management), in this paper we model traffic by using Poisson distribution method then add a birth-death processes for each state and combine both two in one queuing system (The Markovian chain) to model the traffic.Also, this paper will compare some autonomous vehicles communication techniques in intersections to draw the best scenario for autonomous vehicle network communication in order to reduce the traffic congestion in an intersection.The Connected Autonomous Vehicles and a normal autonomous vehicle, as well from the third line of the intersection a mix between the both will be provided into the intersection.The last section is about applying the results from the first and second research question into a simulator and compare the simulation results to approve the advantage of using the next generation of transportation technology (The connected autonomous vehicles) over the normal conventional vehicles.
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Hultgren, Andree, and Muhammed Memedi. "Autonomous Vehicles With Obstacle Avoidance." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254202.
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Autonomous ground vehicles are becoming prevalent in this modern society due to economical and environmental benefits. This paper investigates trajectory tracking control for a two-wheel autonomous vehicle first, and then a decentralised control approach is implemented where each vehicle can maintain a formation with other vehicles. Collision avoidance is also taken into account, where both moving and stationary obstacles are considered. This enables arbitrary fleets of vehicles to manoeuvre in a set formation without colliding with each other or other obstacles. The proposed controllers are presented theoretically and verified using simulation examples.
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Mikesell, David Russell. "Portable automated driver for universal road vehicle dynamics testing." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1198722243.
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Phang, Nyit Sin. "Tethered operation of autonomous aerial vehicles to provide extended field of view for autonomous ground vehicles." Thesis, (2 MB), 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FPhang.pdf.
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Thesis (M.S.)--Naval Postgraduate School, 2006."December 2006." Includes bibliographical references (p. 47-48). Also available online from the Web site of the Naval Postgraduate School (http://www.nps.edu).
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Savage, Elizabeth. "Cooperative control of autonomous underwater vehicles." [College Station, Tex. : Texas A&M University, 2003. http://hdl.handle.net/1969.1/236.
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Thesis (MS)--Texas A&M University, 2003."Major Subject: Aerospace Engineering" Title from author supplied metadata (automated record created on Jul. 18, 2005.) Vita. Abstract. Includes bibliographical references.
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Shanmugavel, Madhavan. "Path planning of multiple autonomous vehicles." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/1745.
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Safe and simultaneous arrival of constant speed, constant altitude UAVs on target is solved by design of paths of equal lengths. The starting point of the solution is the well-known Dubins path which is composed of circular arcs and line segments, thus requiring only one simple manoeuvre - constant rate turn. An explicit bound can be imposed on the rate during the design and the resulting paths are the minimum time solution of the problem. However, transition between arc and line segment entails discontinuous changes in lateral accelerations (latax), making this approach impractical for real fixed wing UAVs. Therefore, the Dubins solution is replaced with clothoid and also a novel one, based on quintic Pythagorean Hodograph (PH) curves, whose latax demand is continuous. The clothoid solution is direct as in the case of the Dubins path. The PH path is chosen for its rational functional form. The clothoid and the PH paths are designed to have lengths close to the lengths of the Dubins paths to stay close to the minimum time solution. To derive the clothoid and the PH paths that way, the Dubins solution is first interpreted in terms of Differential Geometry of curves using the path length and curvature as the key parameters. The curvature of a Dubins path is a piecewise constant and discontinuous function of its path length, which is a differential geometric expression of the discontinuous latax demand involved in transitions between the arc and the line segment. By contrast, the curvature of the PH path is a fifth order polynomial of its path length. This is not only continuous, also has enough design parameters (polynomial coefficients) to meet the latax (curvature) constraints (bounds) and to make the PH solution close to the minimum time one. The offset curves of the PH path are used to design a safety region along each path. The solution is simplified by dividing path planning into two phases. The first phase produces flyable paths while the second phase produces safe paths. Three types of paths are used: Dubins, clothoid and Pythagorean Hodograph (PH). The paths are produced both in 2D and 3D. In two dimensions, the Dubins path is generated using Euclidean and Differential geometric principles. It is shown that the principles of Differential geometry are convenient to generalize the path with the curvature. Due to the lack of curvature continuity of the Dubins path, paths with curvature continuity are considered. In this respect, initially the solution with the Dubins path is extended to produce clothoid path. Latter the PH path is produced using interpolation technique. Flyable paths in three dimensions are produced with the spatial Dubins and PH paths. In the second phase, the flyable paths are tuned for simultaneous arrival on target. The simultaneous arrival is achieved by producing the paths of equal lengths. Two safety conditions: (i) minimum separation distance and (ii) non-intersection of paths at equal distance are defined to maneuver in free space. In a cluttered space, an additional condition, threat detection and avoidance is defined to produce safe paths. The tuning is achieved by increasing the curvature of the paths and by creating an intermediate way-point. Instead of imposing safety constraints, the flyable paths are tested for meeting the constraints. The path is replanned either by creating a new way-point or by increasing the curvature between the way-points under consideration. The path lengths are made equal to that of a reference path.
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Smart, Royce Raymond, and roycesmart@hotmail com. "Evolutionary Control of Autonomous Underwater Vehicles." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090331.143104.
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The goal of Evolutionary Robotics (ER) is the development of automatic processes for the synthesis of robot control systems using evolutionary computation. The idea that it may be possible to synthesise robotic control systems using an automatic design process is appealing. However, ER is considerably more challenging and less automatic than its advocates would suggest. ER applies methods from the field of neuroevolution to evolve robot control systems. Neuroevolution is a machine learning algorithm that applies evolutionary computation to the design of Artificial Neural Networks (ANN). The aim of this thesis is to assay the practical characteristics of neuroevolution by performing bulk experiments on a set of Reinforcement Learning (RL) problems. This thesis was conducted with the view of applying neuroevolution to the design of neurocontrollers for small low-cost Autonomous Underwater Vehicles (AUV). A general approach to neuroevolution for RL problems is presented. The is selected to evolve ANN connection weights on the basis that it has shown competitive performance on continuous optimisation problems, is self-adaptive and can exploit dependencies between connection weights. Practical implementation issues are identified and discussed. A series of experiments are conducted on RL problems. These problems are representative of problems from the AUV domain, but manageable in terms of problem complexity and computational resources required. Results from these experiments are analysed to draw out practical characteristics of neuroevolution. Bulk experiments are conducted using the inverted pendulum problem. This popular control benchmark is inherently unstable, underactuated and non-linear: characteristics common to underwater vehicles. Two practical characteristics of neuroevolution are demonstrated: the importance of using randomly generated evaluation sets and the effect of evaluation noise on search performance. As part of these experiments, deficiencies in the benchmark are identified and modifications suggested. The problem of an underwater vehicle travelling to a goal in an obstacle free environment is studied. The vehicle is modelled as a Dubins car, which is a simplified model of the high-level kinematics of a torpedo class underwater vehicle. Two practical characteristics of neuroevolution are demonstrated: the importance of domain knowledge when formulating ANN inputs and how the fitness function defines the set of evolvable control policies. Paths generated by the evolved neurocontrollers are compared with known optimal solutions. A framework is presented to guide the practical application of neuroevolution to RL problems that covers a range of issues identified during the experiments conducted in this thesis. An assessment of neuroevolution concludes that it is far from automatic yet still has potential as a technique for solving reinforcement problems, although further research is required to better understand the process of evolutionary learning. The major contribution made by this thesis is a rigorous empirical study of the practical characteristics of neuroevolution as applied to RL problems. A critical, yet constructive, viewpoint is taken of neuroevolution. This viewpoint differs from much of the reseach undertaken in this field, which is often unjustifiably optimistic and tends to gloss over difficult practical issues.
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Hague, Tony. "Motion planning for autonomous guided vehicles." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358592.
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Petres, Clement. "Trajectory planning for autonomous underwater vehicles." Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/2091.
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Efficient trajectory planning algorithms are a crucial issue for modern autonomous underwater vehicles. Classical trajectory planning algorithms in artificial intelligence are not designed to deal with wide continuous environ~ents prone to currents. Furthermore torpedo-like underwater vehicles are strongly nonholonomic. A novel Fast Marching based approach is proposed to address the following theoretical issues. First, an algorithm called FM* is developed to efficiently extract a 2D continuous and derivable curve from a discrete representation of the environment. Second, underwater currents are taken into account thanks to an anisotropic extension of the original Fast Marching algorithm. Third, the vehicle turning radius is introduced as a constraint on the curvature of the optimal.trajeCtory for both isotropic and anisotropic media. FUrther developments are proposed to optimize the Fast Marching based method to real-time constraints. On one hand, a fast multiresolution method is introduced to extract suboptimal trajectories. On the other hand, a dynamic version of the Fast Marching algorithm called DFM is developed to efficiently replan trajectories in dynamic unpredictable environments. Besides, it is shown that DFM algorithm is an excellent tool for visibility-based trajectory planning in a-priori unknown domains. The overall Fast Marching based trajectory planning method has been tested on simulated underwater environments and validated on a real experimental platform in open water. Keywords: artificial intelligence, trajectory planning, Fast Marching algorithm, autonomous underwater vehicle, isotropic and anisotropic ordered upwind methods, functional minimization, curvature radius, unknown environment, multiresolution method, dynamic replanning, visibility-based navigation.
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Kala, Rahul. "Motion planning for multiple autonomous vehicles." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602709.
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Unorganized traffic is characterized by the vehicles not adhering to the marked lanes, and is a reality in various countries like India. Such traffic can lead to higher traffic efficiency when the vehicles are diverse in sizes and speed capabilities - a factor currently absent in most countries. Autonomous driving technology can lead to application specialized vehicles which may introduce diversity into the presently organized traffic, necessitating a shift to unorganized traffic. Technology also has the potential to make the entire transportation system more efficient. Given a map produced by vision systems, the outcome of motion planning is then responsible for all vehicle decisions, which includes a mechanism to avoid static obstacles and other vehicles. This " planning needs to be cooperatively performed between vehicles. This is handled by the coordination mechanism. Communication, if available (in an autonomous vehicles only scenario), enables the deployment of a common planning algorithm distributed across the vehicles thereby resulting in better coordination. The literature on autonomous vehicles largely assumes lanes, while the literature on mobile robots lacks the notions of overtaking and vehicle following. This thesis takes popular algorithms from the mobile robotics literature, models them as per traffic scenarios, embeds in them the notions of overtaking and vehicle following as heuristics for faster and better planning, and analyzes all the algorithms hence produced. The study is broadened to the intelligent management of transportation systems with intelligent agents performing in diverse traffic. The thesis also considers a typical city road infrastructure for which an efficient routing strategy is devised which can lead to congestion avoidance. Cities may witness a large number of vehicles and a limited road infrastructure and hence the problem of vehicle scheduling is studied. The transportation system is made cooperative to enable all vehicles to reach their destination on time.
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Shirasaka, Masahide. "Optimizing safe motion for autonomous vehicles." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28432.
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Approved for public release; distribution is unlimitedThere are two goals for autonomous vehicle navigation planning: shortest path and safe path. These goals are often in conflict; path safety is more important. Safety of the autonomous vehicle's navigation is determined by the clearances between the vehicle and obstacles. Because a Voronoi boundary is the set of points locally maximizing the clearance from obstacles, safety is maximized on it. Therefore Voronoi Diagrams are suitable for motion planning of autonomous vehicles. We use the derivative of curvature k of the vehicle motion (dk/ds) as the only control variable for the vehicle where s is the length along the vehicle trajectory. Previous motion planning of the autonomous mobile robot Yamabico-11 at Naval Postgraduate School used a path tracking method. Before the mission began the vehicle was given a track to follow; motion planning consisted of calculating the point on the track closest to the vehicle and calculating dk/ ds then steering the vehicle to get onto track. We propose a method of planning safe motions of the vehicle to calculate optimal dk/ds at each point directly from the information of the world without calculating the track to follow. This safe navigation algorithm is fundamentally different from the path tracking using a path specification. Additionally motion planning is simpler and faster than the path tracking method. The effectiveness of this steering function for vehicle motion control is demonstrated by algorithmic simulation and by use on the autonomous mobile robot Yamabico 11 at the Naval Postgraduate School
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El-Hameid, Hossam Hassan Abd. "Motion parameter estimation for autonomous vehicles." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265750.
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Vengerov, David 1976. "Context-sensitive planning for autonomous vehicles." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47510.
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Schouwenaars, Tom. "Safe trajectory planning of autonomous vehicles." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35298.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 153-163).
This thesis presents a novel framework for safe online trajectory planning of unmanned vehicles through partially unknown environments. The basic planning problem is formulated as a receding horizon optimization problem using mixed-integer linear programming (MILP) to incorporate kino-dynamic, obstacle avoidance and collision avoidance constraints. Agile vehicle dynamics are captured through a hybrid control architecture that combines several linear time-invariant modes with a discrete set of agile maneuvers. The latter are represented by affine transformations in the state space and can be described using a limited number of parameters. We specialize the approach to the case of a small-scale helicopter flying through an urban environment. Next, we introduce the concept of terminal feasible invariant sets in which a vehicle can remain for an indefinite period of time without colliding with obstacles or other vehicles. These sets are formulated as affine constraints on the last state of the planning horizon and as such are computed online. They guarantee feasibility of the receding horizon optimization at future time steps by providing an a priori known backup plan that is dynamically feasible and obstacle-free.
(cont.) Vehicle safety is ensured by maintaining a feasible return trajectory at each receding horizon iteration. The feasibility and safety constraints are essential when the vehicle is maneuvering through environments that are only partially characterized and further explored online. Such a scenario was tested on an unmanned Boeing aircraft using scalable loiter circles as feasible invariant sets. The terminal feasible invariant set concept forms the basis for the construction of a provably safe distributed planning algorithm for multiple vehicles. Each vehicle then only computes its own trajectory while accounting for the latest plans and invariant sets of the other vehicles in its vicinity, i.e., of those whose reachable sets intersect with that of the planning vehicle. Conflicts are solved in real-time in a sequential fashion that maintains feasibility for all vehicles over all future receding horizon iterations. The algorithm is applied to the free flight paradigm in air traffic control and to a multi-helicopter relay network aimed at maintaining wireless line of sight communication in a cluttered environment.
by Tom Schouwenaars.
Ph.D.
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Bahr, Alexander. "Cooperative localization for autonomous underwater vehicles." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/55326.
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Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), February 2009.Includes bibliographical references (p. 133-140).
Self-localization of an underwater vehicle is particularly challenging due to the absence of Global Positioning System (GPS) reception or features at known positions that could otherwise have been used for position computation. Thus Autonomous Underwater Vehicle (AUV) applications typically require the pre-deployment of a set of beacons.This thesis examines the scenario in which the members of a, group of AUVs exchange navigation information with one another so as to improve their individual position estimates. We describe how the underwater environment poses unique challenges to vehicle navigation not encountered in other environments in which robots operate and how cooperation can improve the performance of self-localization. As intra-vehicle communication is crucial to cooperation, we also address the constraints of the communication channel and the effect that these constraints have on the design of cooperation strategies. The classical approaches to underwater self-localization of a single vehicle, as well as more recently developed techniques are presented. We then examine how methods used for cooperating land-vehicles can be transferred to the underwater domain. An algorithm for distributed self-localization, which is designed to take the specific characteristics of the environment into account, is proposed. We also address how correlated position estimates of cooperating vehicles can lead to overconfidence in individual position estimates. Finally, key to any successful cooperative navigation strategy is the incorporation of the relative positioning between vehicles. The performance of localization algorithms with different geometries is analyzed and a distributed algorithm for the dynamic positioning of vehicles, which serve as dedicated navigation beacons for a fleet of AUVs, is proposed.
by Alexander Bahr.
Ph.D.
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Hallqvist, Erik, and Sebastian Håkansson. "Networked control of autonomous ground vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199347.
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Ehrlin, E., and M. Törnqvist. "Networked control of autonomous ground vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199313.
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Athari, Kayvan. "Networked control of autonomous ground vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199389.
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Bakutis, Vladas, and Qiao Jin. "Networked Control of Autonomous Ground Vehicles." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200572.
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Shastry, Akshay Kumar. "Functional Safety Assessment in Autonomous Vehicles." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83483.
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Autonomous vehicles (AVs) are a class of safety-critical systems that are capable of decision-making and operate with little or no human intervention. For such complex systems designed to function in diverse operational domains such as rain, snow, freeway, urban roads, etc., system safety is paramount. Management of the system's safety throughout its life-cycle, from the conceptualization stage to the end of the lifecycle, is of primary importance. We describe a revision of functional safety standard ISO 26262 to support autonomous vehicles and the underlying electronic/electrical control architecture. There is a need to modify the Automotive Safety Integrity Levels (ASILs) defined in the ISO 26262 as "Controllability", a factor in determining an ASIL, is no longer applicable; the driver is no longer in a position to control the vehicle. The vehicle has taken over the responsibility of evaluating the environment and determines its next course of action to complete its current mission. These decisions have a tremendous impact on the overall safety of the system during a hazardous event and can be the difference between a successful journey and a traffic incident. To better enable the designers of such systems, we introduce a new method to assess the functional safety and derive safety goals, which are the top level safety requirement. We present a new metric-Risk Mitigation Factor to assess the decision making capability of the vehicle and to replace controllability in the ASIL definition. The case study presented highlights the advantages of using the introduced metric in defining safety goals for the autonomous vehicle.Master of Science
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Shanmugavel, M. "Path planning of multiple autonomous vehicles." Thesis, Cranfield University, 2007. http://hdl.handle.net/1826/1745.
Full textAbstract:
Safe and simultaneous arrival of constant speed, constant altitude UAVs on target is
solved by design of paths of equal lengths. The starting point of the solution is the
well-known Dubins path which is composed of circular arcs and line segments, thus
requiring only one simple manoeuvre - constant rate turn. An explicit bound can
be imposed on the rate during the design and the resulting paths are the minimum
time solution of the problem. However, transition between arc and line segment
entails discontinuous changes in lateral accelerations (latax), making this approach
impractical for real fixed wing UAVs. Therefore, the Dubins solution is replaced with clothoid and also a novel one, based on quintic Pythagorean Hodograph (PH) curves,
whose latax demand is continuous. The clothoid solution is direct as in the case of
the Dubins path. The PH path is chosen for its rational functional form. The clothoid
and the PH paths are designed to have lengths close to the lengths of the Dubins
paths to stay close to the minimum time solution.
To derive the clothoid and the PH paths that way, the Dubins solution is first interpreted
in terms of Differential Geometry of curves using the path length and curvature
as the key parameters. The curvature of a Dubins path is a piecewise constant
and discontinuous function of its path length, which is a differential geometric expression of the discontinuous latax demand involved in transitions between the arc
and the line segment. By contrast, the curvature of the PH path is a fifth order
polynomial of its path length. This is not only continuous, also has enough design parameters (polynomial coefficients) to meet the latax (curvature) constraints (bounds)
and to make the PH solution close to the minimum time one. The offset curves of the
PH path are used to design a safety region along each path.
The solution is simplified by dividing path planning into two phases. The first phase
produces flyable paths while the second phase produces safe paths. Three types of
paths are used: Dubins, clothoid and Pythagorean Hodograph (PH). The paths are
produced both in 2D and 3D. In two dimensions, the Dubins path is generated using Euclidean and Differential geometric principles. It is shown that the principles of Differential geometry are convenient to generalize the path with the curvature. Due
to the lack of curvature continuity of the Dubins path, paths with curvature continuity
are considered. In this respect, initially the solution with the Dubins path is
extended to produce clothoid path. Latter the PH path is produced using interpolation
technique. Flyable paths in three dimensions are produced with the spatial Dubins and PH paths.
In the second phase, the flyable paths are tuned for simultaneous arrival on target.
The simultaneous arrival is achieved by producing the paths of equal lengths. Two
safety conditions: (i) minimum separation distance and (ii) non-intersection of paths
at equal distance are defined to maneuver in free space. In a cluttered space, an additional condition, threat detection and avoidance is defined to produce safe paths.
The tuning is achieved by increasing the curvature of the paths and by creating an
intermediate way-point. Instead of imposing safety constraints, the flyable paths are
tested for meeting the constraints. The path is replanned either by creating a new
way-point or by increasing the curvature between the way-points under consideration.
The path lengths are made equal to that of a reference path.
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Williams, Douglas L. "Loitering behaviors of autonomous underwater vehicles." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FWilliams%5FDouglas.pdf.
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Keller, Joseph J. "Tracking control of autonomous underwater vehicles." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FKeller.pdf.
Full textAbstract:
Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2002.Thesis advisor(s): Anthony J. Healey. Includes bibliographical references (p. 67-68). Also available online.
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Nicholson, John W. "Autonomous optimal rendezvous of underwater vehicles." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FNicholson.pdf.
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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.
Full textAbstract:
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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Cao, Yongcan. "Decentralized Coordination of Multiple Autonomous Vehicles." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/652.
Full textAbstract:
This dissertation focuses on the study of decentralized coordination algorithms of multiple autonomous vehicles. Here, the term decentralized coordination is used to refer to the behavior that a group of vehicles reaches the desired group behavior via local interaction. Research is conducted towards designing and analyzing distributed coordination algorithms to achieve desired group behavior in the presence of none, one, and multiple group reference states. Decentralized coordination in the absence of any group reference state is a very active research topic in the systems and controls society. We first focus on studying decentralized coordination problems for both single-integrator kinematics and double-integrator dynamics in a sampled-data setting because real systems are more appropriate to be modeled in a sampled-data setting rather than a continuous setting. Two sampled-data consensus algorithms are proposed and the conditions to guarantee consensus are presented for both fixed and switching network topologies. Because a number of coordination algorithms can be employed to guarantee coordination, it is important to study the optimal coordination problems. We further study the optimal consensus problems in both continuous-time and discrete-time settings via an linear-quadratic regulator (LQR)-based approach. Noting that fractional-order dynamics can better represent the dynamics of certain systems, especially when the systems evolve under complicated environment, the existing integer-order coordination algorithms are extended to the fractional-order case. Decentralized coordination in the presence of one group reference state is also called coordinated tracking, including both consensus tracking and swarm tracking. Consensus tracking refers to the behavior that the followers track the group reference state. Swarm tracking refers to the behavior that the followers move cohesively with the external leader while avoiding inter-vehicle collisions. In this part, consensus tracking is studied in both discrete-time setting and continuous-time settings while swarm tracking is studied in a continuous-time setting. Decentralized coordination in the presence of multiple group reference states is also called containment control, where the followers will converge to the convex hull, i.e., the minimal geometric space, formed by the group references states via local interaction. In this part, the containment control problem is studied for both single-integrator kinematics and double-integrator dynamics. In addition, experimental results are provided to validate some theoretical results.
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Frölin, Alexander, and Carl Säflund. "Advanced Filter Design for Autonomous Vehicles." Thesis, KTH, Fordonsdynamik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265620.
Full textAbstract:
The introduction of autonomous vehicles comes with many benefits related to safety and quality-of-life, the implementation of which is a challenging task for engineers to solve; one part of this aforementioned task is the requirement for precise positioning.Firstly, this thesis work investigated the contemporary fields of science rel-evant for the task of position estimation. The paper then dissertated the theory, implementation and the experimental evaluation of three di˙erent methods of estimating position. The individual properties was then examined for the dif-ferent vehicle filters and the optimal method of estimating position was then determined with regards to its specified use case, the autonomous truck appli-cation.The methods chosen for evaluation were the Unscented Kalman Filter (UKF), the Controller Output Observer (COO) and the Washout filter method. These methods were evaluated using physical experiments carried out on roads and the result of which showed that the Controller Output Observer (COO) and the Washout filter methods shared significant disadvantages compared to the supe-rior Unscented Kalman Filter (UKF). Based on the experimental results a new filter constellation were proposed whereby two modified position evaluating filters are connected in series.Introduceringen av autonoma fordon kommer med många fördelar inom såväl säkerhet som livskvalité; implementationen av denna teknik innebär en mängd utmaningar för ingenjörer inom området. En av dessa utmaningar är kravet på nogrann positionering.Detta examensarbete undersöker först de discipliner inom vetenskapen re-levanta för positioneringsuppgiften för att sedan på detaljnivå beskriva teorin, implementationen och sedan den experimentella utvärderingen av dessa olika estimeringsmetoder. De individuella egenskaperna undersöktes och den opti-mala metoden utsågs för det valda användarfallet; autonoma lastbilar.De valda estimeringsfiltrena var Unscented Kalman Filter (UKF), Control-ler Output Observer (COO) och Washout-filter metoden. Dessa koncept blev utvärderade med hjälp av vägburna experiment varav resultaten visade att bå-de Washout- och COO metoderna delade tydliga nackdelar i jämförelse med det överlägsna UKF konceptet. De experimentellt härledda resultaten ligger till grund för ett nytt föreslaget filterkoncept för att estimera position där två modifierade fordonsfilter kombineras i serie.
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SINI, JACOPO. "Novel Validation Techniques for Autonomous Vehicles." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2950482.
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Zhang, Shangyuan. "Trajectory optimization under uncertainty for autonomous vehicles." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASG044.
Full textAbstract:
Des progrès significatifs ont été réalisés dans le domaine de la conduite autonome et de l'optimisation des trajectoires. L'un des principaux défis dans ce domaine est de faire face à l'incertitude des données d'entrée et de réduire son impact sur le processus de génération de trajectoires. Les chercheurs ont consacré leurs efforts à la construction de différents modèles qui abordent les différents types d'incertitudes liées à la précision des capteurs et aux environnements de conduite complexes, dans le but d'améliorer la sécurité de la technologie des véhicules autonomes. Cette thèse explore différentes méthodes pour traiter les incertitudes dans l'optimisation des trajectoires. Nous commençons par analyser des scénarios de régulateur de vitesse adaptatif (ACC), où les données d'entrée sont traitées comme une variable aléatoire. Deux modèles d'optimisation sont développés pour trouver des trajectoires optimales qui évitent les collisions potentielles et satisfont toutes les contraintes de conduite. La dépendance de la variable aléatoire est également étudiée à travers la théorie des copules. En outre, nous étudions des scénarios dans lesquels seules des informations partielles sur l'incertitude sont disponibles et nous appliquons des techniques d'optimisation distributionnellement robustes (DRO) pour résoudre le problème. En plus du scénario de conduite de l'ACC, nous appliquons des méthodes de contrôle optimal pour créer un modèle plus complet qui prend en compte à la fois les facteurs de sécurité et d'efficacité requis dans différents scénarios de conduite. Des simulations numériques basées sur des scénarios de conduite générés démontrent que le modèle stochastique est plus performant que le modèle déterministe en cas d'incertitude.Nous explorons également les systèmes multi-joueurs afin d'exploiter leurs propriétés dans la prise de décision collective pour les véhicules autonomes. Plus précisément, nous étudions le jeu à contraintes de hasard à n joueurs, en explorant l'existence d'un équilibre de Nash et son lien avec l'inégalité variationnelle. Le jeu est transformé en un problème de complémentarité non linéaire, qui est résolu efficacement. En outre, nous examinons le jeu à contraintes de hasard sous DRO et menons des expériences numériques pour évaluer leur performanceSignificant progress has been made in the field of autonomous driving and trajectory optimization. One of the key challenges in this field is dealing with the uncertainty in input data and reducing its impact on the decision-making process of trajectory generation. Researchers have dedicated their efforts to building various models that address different types of uncertainties arising from sensor precision and complex driving environments, aiming to enhance the safety of autonomous vehicle technology. This thesis explores different methods for handling uncertainties in trajectory optimization. We begin by analysing adaptive cruise control (ACC) scenarios, where the input data is treated as a random variable. Two optimization models are developed to find optimal trajectories that avoid potential collisions and satisfy all driving constraints. the dependency of the random variable is also investigated through copula theory. Furthermore, we study scenarios where only partial information about the uncertainty is available and apply distributionally robust optimization (DRO) techniques to tackle the problem. In addition to ACC driving scenario, we apply optimal control methods to create a more comprehensive model that considers both safety and effectiveness factors required in different driving scenarios. Numerical simulations based on generated driving scenarios demonstrate that the stochastic model outperforms the deterministic model when the uncertainty is present. We also explore multi-player systems to leverage their properties in collective decision-making for autonomous vehicles. Specifically, we study the n-player chance-constrained game, exploring the existence of Nash equilibrium and its connection with variational inequality. The game is transformed into a nonlinear complementarity problem, which is efficiently solved. Furthermore, we examine the chance-constrained game under DRO and conduct numerical experiments to evaluate their performance
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Petillo, Stephanie Marie. "Autonomous & adaptive oceanographic feature tracking on board autonomous underwater vehicles." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97772.
Full textAbstract:
Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis. Vita.
Includes bibliographical references (pages 203-213).
The capabilities of autonomous underwater vehicles (AUVs) and their ability to perform tasks both autonomously and adaptively are rapidly improving, and the desire to quickly and efficiently sample the ocean environment as Earth's climate changes and natural disasters occur has increased significantly in the last decade. As such, this thesis proposes to develop a method for single and multiple AUVs to collaborate autonomously underwater while autonomously adapting their motion to changes in their local environments, allowing them to sample and track various features of interest with greater efficiency and synopticity than previously possible with preplanned AUV or ship-based surveys. This concept is demonstrated to work in field testing on multiple occasions: with a single AUV autonomously and adaptively tracking the depth range of a thermocline or acousticline, and with two AUVs coordinating their motion to collect a data set in which internal waves could be detected. This research is then taken to the next level by exploring the problem of adaptively and autonomously tracking spatiotemporally dynamic underwater fronts and plumes using individual and autonomously collaborating AUVs.
by Stephanie Marie Petillo.
Ph. D.
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Realpe, Robalino Miguel Andres. "Fault Tolerant Perception for Urban Autonomous Vehicles." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365655.
Full textAbstract:
Road driving environments are complex, unstructured and highly changeable. A safe driving is, thus, becoming quite challenging task, in particular from the view point of development and deployment of autonomous vehicles-based urban transport systems. And, in that context, the reliable perception appears as a one of the main enabling strategies in developing safe autonomous driving.
Currently, many autonomous vehicles are being tested on public roads with the objective of demonstrating the capability of operating in real world situations. A big effort has been focused towards creating fault-free autonomous vehicles. Nevertheless, fault tolerant perception for autonomous vehicles still needs to be further developed in order to create autonomous vehicles capable of driving under real road traffic conditions since on-board vehicle sensors may fail due to bad calibration, erroneous readings, physical or electrical failures, etc.
A multi-sensor based vehicle architecture is a logical response to this issue. While the multi- sensor concept often relates to the strategy of using a variety of sensor types, this research has been focused on to the case when all sensors are vision sensors, either identical or different from each other.
This thesis proposes a Fault Tolerant Perception paradigm that deals with possible sensor faults by defining the Federated Data Fusion Architecture designed to detect a faulty sensor and reduce its impact on to the safe autonomous driving. The proposed architecture minimises the influence of faulty data allowing the system to enter in a tolerated error state, where a recovery action can be performed to avoid failures. The developed architecture was then adapted towards meeting requirements of the KITTI Vision Benchmark Suite. Experimental results demonstrated the feasibility of the developed fault tolerant perception paradigm to successfully detect early faulty data from a singular sensor and to minimise the influence of that faulty sensor in the fusion process.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Aksaray, Derya. "Autonomous Hopping Rotochute." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39578.
Full textAbstract:
The Hopping Rotochute is a promising micro vehicle with the capability of exploring rough and complex terrains with minimum energy consumption. While it is able to fly over obstacles via thrust produced by its coaxial rotor, its physical architecture, inspired from a "Weebles Wooble," provides re-orientation wherever it hits the ground. Therefore, this aerial and ground vehicle represents a potential hybrid vehicle capable of reconnaissance and surveillance missions in complex environments.
The most recent version of the Hopping Rotochute is manually controlled to follow a trajectory. The control commands, listed in a file prior to the particular mission, are executed exactly as defined, like a "batch job," regardless of the uncertain external events. This control scheme is likely to cause great deviations from the route. Consequently, the vehicle may finish the mission very far away from the desired end point. However, if a vehicle is capable of receiving the control commands during a mission, "interactive processing" can be realized and efficient path tracking would be achieved. Hence, the development of the Hopping Rotochute that follows a trajectory autonomously reveals the foundation of this thesis.
Two control approaches inspired the proposed methodology for developing an autonomous trajectory-following algorithm. The first approach is rule-based control that enables decision making through conditional statements. In this thesis, rule-based control is used to select a target point for a particular hop based on the existence of an obstacle and/or wind in the environment. The second approach is model predictive control employed to predict future outputs from hop performance models. In other words, this technique approaches the problem by providing intelligence pertaining to how a particular hop will end up before being attempted. Hence, the optimum control commands are selected based on the predicted performance of a particular hop.
This research demonstrates that the autonomous Hopping Rotochute can be realized by rule-based control embedded with some performance models. In the assumption of known boundaries such as wall and ceiling information, this study has two aims: (1) to avoid obstacles by creating a smaller operational volume inside the real boundaries so that the vehicle is restricted from exiting the operational volume and no violation occurs within the real boundaries; (2) to estimate the wind by previous hops to select the next hopping point with respect to the estimated wind information. Based on the developed methodology, simulations are conducted for four different scenarios in the existence of obstacles and/or wind, and the results of the simulations are analyzed. Finally, based on the statistics of simulation results, the effectiveness of the proposed methodology is discussed.
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Lackey, Nathan. "Simulating Autonomous Vehicles in a Microscopic Traffic Simulator to Investigate the Effects of Autonomous Vehicles on Roadway Mobility." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555072367385629.
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Garro, Alexandra. "Connected Vehicle Co-Simulation for Autonomous Vehicles in Airsim using Ns-3." DigitalCommons@CalPoly, 2021. https://digitalcommons.calpoly.edu/theses/2332.
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Vehicle-to-everything (V2X) communications enables vehicles to communicate directly with each other, as well as roadside infrastructure. Vehicle-to-vehicle (V2V) communication, a subset of V2X communication, enables the vehicle to not solely rely on on-board sensors and allows the vehicle to share information directly to any nearby vehicles. Information shared between vehicles may include a vehicle's position, velocity, and direction, as well as other data. As these are safety-critical applications, rigorous security assessments are needed, yet it can be very expensive, dangerous, and complex to test security vulnerabilities of autonomous vehicles. Therefore, we aim to leverage realistic open-sourced simulators to carry out testing for multiple features, such as security attacks as well as cooperative autonomous driving algorithms. Since there is no open-sourced simulator capable of visually and physically simulating a vehicle and accurately representing its network, this thesis aims to combine a vehicle simulator and network simulator in real-time. Specifically, we incorporate Network Simulator 3 (Ns-3) and Unreal Engine's plugin, Airsim. To run this type of simulation accurately requires high computation power and time, and these requirements can cause delays between the two simulators. To handle the delays during simulation, we propose a system using a time step synchronization technique to pair Airsim and Ns-3. We further elaborate on our incorporation of delaying network packets that arrive earlier than the ideal packet delay. Additionally, we validate our system by demonstrating proof-of-concept attacks. Specifically, we simulate a replay attack and a jamming attack on our system, as well as show that a sybil attack is possible.
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Kirsch, Patricia Jean. "Autonomous swarms of unmanned vehicles software control system and ground vehicle testing /." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2993.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Aulinas, Masó Josep M. "Selective submap joining SLAM for autonomous vehicles." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/48718.
Full textAbstract:
Simultaneous Localization and Mapping (SLAM) do not result in consistent maps of large areas because
of gradual increase of the uncertainty for long term missions. In addition, as the size of the map grows
the computational cost increases, making SLAM solutions unsuitable for on-line applications. This thesis
surveys SLAM approaches paying special attention to those approaches aimed to work on large
scenarios. Special focus is given to existing underwater SLAM applications. A technique based on using
independent local maps together with a global stochastic map is presented. This technique is called
Selective Submap Joining SLAM (SSJS). A global map contains relative transformations between local
maps, which are updated once a new loop is detected. Maps sharing several features are fused,
maintaining the correlation between landmarks and vehicle's pose. The use of local maps reduces
computational costs and improves map consistency as compared to state of the art techniques.Els algoritmes de localització i creació de mapes simultàniament (Simultaneous Localization and Mapping - SLAM) no produeixen mapes correctes de grans àrees a causa de l'augment gradual de la incertesa en les missions de llarga durada. El cost de computació augmenta a mesura que el mapa creix. Aquesta tesi presenta un estudi de les tècniques de SLAM en entorns grans. També s'estudien aquells treballs centrats en ambients submarins. Es proposa una nova tècnica basada en l'ús de submapes independents i un mapa estocàstic global. Aquesta tècnica s'ha anomenat Unió Selectiva de Submapes en SLAM (SSJS). El mapa global conté les transformacions relatives entre mapes, que s'actualitzen en revisitar zones conegudes. Així doncs, els submapes que comparteixen informació es fusionen, mantenint les correlacions entre el vehicle i les fites. L'ús de submapes redueix el cost de càlcul i millora la consistència del mapa en comparació a les tècniques existents.
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Galceran, Yebenes Enric. "Coverage path planning for autonomous underwater vehicles." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/133832.
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This thesis proposes new methods to find collision-free paths allowing an AUV to cover an area of the ocean floor with its sensors, which is known as coverage path planning. First, we propose a coverage path planning method to plan 2D, safe-altitude surveys which provides a principled way to account for obstacles in AUV survey planning. Its main advantage is that it minimizes redundant coverage when the vehicle navigates at constant depth, leading to shorter paths. Second, we provide a method to account for the uncertainty in the vehicle position estimates when planning 2D surveys. The method minimizes the uncertainty induced by the path and leads to better maps of the ocean floor as a result. Third, we provide a coverage path planning method suitable for inspecting areas of the ocean floor including 3D structures. The resulting coverage paths enable applications requiring close proximity and allow viewpoints for full 3D sensing of the structure. Moreover, by contrast to most existing methods, we provide two techniques to adapt the planned path in realtime using sensor information acquired on-line during the mission, rather than only planning the path off-line and relying on the unrealistic assumption of an idealized path execution by the AUV. The proposed methods are validated in simulation and in experiments with a real-world AUVAquesta tesi proposa nous mètodes per generar camins lliures de col·lisions per a vehicles submarins autònoms que permeten cobrir una àrea del fons de l'oceà usant els sensors del vehicle, tasca coneguda com a planificació de camins de cobertura. Primer, proposem un mètode de planificació de camins de cobertura per a planificar missions en un espai 2D a una altitud segura, proporcionant una manera fonamentada de tenir en compte obstacles en la planificació de missions per a vehicles submarins autònoms. L'avantatge principal del mètode proposat és que minimitza la cobertura redundant sorgida quan el vehicle navega a profunditat constant, obtenint camins més curts com a resultat. Segon, presentem un mètode per tenir en compte la incertesa de les estimacions de posició del vehicle durant la planificació de missions 2D. Aquest mètode minimitza la incertesa induïda pel camí i genera mapes més acurats del fons oceànic com a resultat. Tercer, presentem un mètode de planificació de camins de cobertura adequat per inspeccionar àrees del fons oceànic amb estructures 3D. Els camins de cobertura resultants permeten tasques que requereixen proximitat al fons i permeten una completa percepció 3D de les estructures d'interès. A més, a diferència de la majoria dels mètodes existents, proporcionem dues tècniques per adaptar els camins planificats en temps real utilitzant informació sensorial adquirida durant la missió, per contra de planificar només abans de l'execució de la missió i confiar en la poc realista assumpció d'una execució idealitzada del camí per part del vehicle. Els mètodes proposats han estat validats en simulació i en experiments amb un vehicle submarí autònom real
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Chuang, Chien-Liang. "Layered safe motion planning for autonomous vehicles." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA303875.
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Dissertation (Ph.D. in Computer Science) Naval Postgraduate School, September 1995.Dissertation supervisor(s): Yutaka Kanayama. "September 1995." Includes bibliographical references (p. 219-220). Also available online.
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Lerider, Malcolm. "Autonomous Calibration and Control of Mine Vehicles." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-91034.
Full textAbstract:
The mining industry desires to cut costs and to operate in more dangerous mines, which is why companies such as Atlas Copco are developing autonomous vehicles. The problem to navigate autonomously is however complex, so the vehicles have in the recent years become more intelligent; the number of computers, actuators and sensors are increasing. For example, an autonomous LHD (Loading – Hauling – Dump) vehicle has sensors including: inertial measurement unit (IMU), odometer, hinge angle sensor, laser range finders and cameras. The parameters for the sensors needs to be calibrated before the vehicle can be used in a mine. There are also a number of electrical currents which needs to be calibrated for the actuators.The calibration of parameters has traditionally been made manually, but Atlas Copco realizes that manual calibration is not feasible once the sales of intelligent mine vehicles increases. Effort is therefore put into automation of the calibration procedures.Interviews with employees were carried out at Atlas Copco to identify the most time consuming procedures during calibration and installation of autonomous mine vehicles. The calibration of steering currents was not only identified as the most time consuming procedure, but also as one of the most complex procedures.The goal of this thesis is to enable easier and quicker installation of mine vehicles. This is done through investigation of methods for automatic calibration of steering currents. The problem is approached from two angles: a grey box model using system identification and a black box model using neural network with resilient backpropagation. The models are compared to a search algorithm, used for simulation of the manual calibration method. In the end, the models are evaluated with regard to performance and ease of implementation.The hypothesis was that the more complex grey box or black box model would have higher accuracy than a simple search algorithm. However, the search algorithm proves to outperform the other models both with regard to accuracy and calibration time, and is also easier to implement. The search algorithm is thus suggested to be implemented instead of a complex model. Moreover, it is suggested that a straightforward mapping of 20 currents may outperform even the search calibration. It is also concluded that calibration of steering currents can be done when the vehicle is standing still.
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Burusa, Akshay Kumar. "Visual-Inertial Odometry for Autonomous Ground Vehicles." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217284.
Full textAbstract:
Monocular cameras are prominently used for estimating motion of Unmanned Aerial Vehicles. With growing interest in autonomous vehicle technology, the use of monocular cameras in ground vehicles is on the rise. This is especially favorable for localization in situations where Global Navigation Satellite System (GNSS) is unreliable, such as open-pit mining environments. However, most monocular camera based approaches suffer due to obscure scale information. Ground vehicles impose a greater difficulty due to high speeds and fast movements. This thesis aims to estimate the scale of monocular vision data by using an inertial sensor in addition to the camera. It is shown that the simultaneous estimation of pose and scale in autonomous ground vehicles is possible by the fusion of visual and inertial sensors in an Extended Kalman Filter (EKF) framework. However, the convergence of scale is sensitive to several factors including the initialization error. An accurate estimation of scale allows the accurate estimation of pose. This facilitates the localization of ground vehicles in the absence of GNSS, providing a reliable fall-back option.Monokulära kameror används ofta vid rörelseestimering av obemannade flygande farkoster. Med det ökade intresset för autonoma fordon har även användningen av monokulära kameror i fordon ökat. Detta är fram för allt fördelaktigt i situationer där satellitnavigering (Global Navigation Satellite System (GNSS)) äropålitlig, exempelvis i dagbrott. De flesta system som använder sig av monokulära kameror har problem med att estimera skalan. Denna estimering blir ännu svårare på grund av ett fordons större hastigheter och snabbare rörelser. Syftet med detta exjobb är att försöka estimera skalan baserat på bild data från en monokulär kamera, genom att komplettera med data från tröghetssensorer. Det visas att simultan estimering av position och skala för ett fordon är möjligt genom fusion av bild- och tröghetsdata från sensorer med hjälp av ett utökat Kalmanfilter (EKF). Estimeringens konvergens beror på flera faktorer, inklusive initialiseringsfel. En noggrann estimering av skalan möjliggör också en noggrann estimering av positionen. Detta möjliggör lokalisering av fordon vid avsaknad av GNSS och erbjuder därmed en ökad redundans.
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Azmat, Muhammad. "Impact of autonomous vehicles on urban mobility." Institut für Transportwirtschaft und Logistik, WU Wien, 2015. http://epub.wu.ac.at/4633/1/WU_MSc_SCM_Master_Thesis.pdf.
Full textAbstract:
The urban population is growing at an exponential rate throughout the world leading to the problems related to swift and speedy mobility or issues caused by convectional mobility options. This study illustrates and explores the new ways to transport people specially taking into account the self-driving cars concept and discusses the concept of mobility 4.0 (smart / intelligent mobility) and briefly highlights the technological aspects of autonomous vehicles, adaptation advantages and progress in laws and legislations of autonomous vehicle. The study is primarily qualitative and relies on the work of previous researcher, technical reports and blogs but the part of this study is quantitative where empirical data was collected from the experts in a conference held by BBG Austria. The result of the studies shows adaptation readiness of Austrian professional market and business prospects associated with autonomous vehicles Moreover, different business models are suggested, which could be adopted to incorporate the driverless vehicles in day-to-day life of an individual living in urban environment. The models basically suggest that the adaptation of the technology would help curbing transport externalities especially external cost associated to transportation of each individual; which includes congestion, accident, infrastructure costs and environmental costs which are incurred by least efficient conventional cars and would also help shrinking the diseases like premature mortality, aggravation of respiratory as well as cardiovascular disease and sleep disturbance which are the result of city level congestion and pollution. (author's abstract)Series: Schriftenreihe des Instituts für Transportwirtschaft und Logistik - Verkehr