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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Real-Time Computational Scheduling with Path Planning for Autonomous Mobile Robots

Chen, David Xitai 05 June 2024 (has links)
With the advancement in technology, modern autonomous vehicles are required to perform more complex tasks and navigate through challenging terrains. Thus, the amount of computation resources to accurately accomplish those tasks have exponentially grown in the last decade. With growing computational intensity and limited computational resources on embedded devices, schedulers are necessary to manage and fully optimize computational loads between the GPU and CPU as well as reducing the power consumption to maximize time in the field. Thus far, it has been proven the effectiveness of schedulers and path planners on computational load on embedded devices through numerous bench testing and simulated environments. However, there have not been any significant data collection in the real-world with all hardware and software combined. This thesis focuses on the implementation of various computational loads (i.e. scheduler, path planner, RGB-D camera, object detection, depth estimation, etc.) on the NVIDIA Jetson AGX Xavier and real-world experimentation on the Clearpath Robotics Jackal. We compare the computation response time and effectiveness of all systems tested in the real-world versus the same software and hardware architecture on the bench. / Master of Science / Modern autonomous vehicles are required to perform more complex tasks with limited computational resources, power and operating frequency. In recent past, the research around autonomous vehicles have been focused on proving the effectiveness of using software-based programming on embedded devices with integrated GPU to improve the overall performance by speeding up task completion. Our goal is to perform real-world data collection and experimentation with both hardware and software frameworks onboard the Clearpath Robotics Jackal. This will validate the efficiency and computational load of the software framework under multiple varying environments.
332

Le texte comme partition dans le slam de poésie : l'exemple québécois suivi de Gris écarlate

Sylvain, Ann 06 January 2023 (has links)
La pratique du slam de poésie, dont les débuts remontent à une cinquantaine d'années tout au plus, gagne en popularité. C'est un art de la brièveté et, surtout, fortement ancré dans l'oralité, ce qui lui confère sa singularité. Ainsi, il est nécessaire de s'imprégner de l'essence du slam de poésie afin de s'assurer de sa pleine réception. La nature orale du slam de poésie l'exigeant, la partie critique de ce mémoire précède la partie création puisqu'il est essentiel de comprendre l'orientation de cette pratique particulière et de saisir quel état d'esprit est requis à la lecture. Nous nous intéressons donc, dans la première partie, à l'origine du slam de poésie, à son évolution en contexte québécois, aux particularités propres à sa pratique dans la ville de Québec ainsi qu'aux détails de sa pratique. Nous étudions les textes de slam de poésie sous l'angle de leur oralité, c’est-à-dire en considérant le texte comme une partition et chercherons à comprendre les traces d'oralité sous un aspect rhétorique pour ensuite écouter les performances enregistrées et ainsi valider nos observations. Une fois l'univers du slam de poésie mis en perspective, la partie création propose d'explorer les possibilités qu'offre le slam dans des textes de création que nous proposons de lire comme des partitions.
333

Multistage Localization for High Precision Mobile Manipulation Tasks

Mobley, Christopher James 03 March 2017 (has links)
This paper will present a multistage localization approach for an autonomous industrial mobile manipulator (AIMM). This approach allows tasks with an operational scope outside the range of the robot's manipulator to be completed without having to recalibrate the position of the end-effector each time the robot's mobile base moves to another position. This is achieved by localizing the AIMM within its area of operation (AO) using adaptive Monte Carlo localization (AMCL), which relies on the fused odometry and sensor messages published by the robot, as well as a 2-D map of the AO, which is generated using an optimization-based smoothing simultaneous localization and mapping (SLAM) technique. The robot navigates to a predefined start location in the map incorporating obstacle avoidance through the use of a technique called trajectory rollout. Once there, the robot uses its RGB-D sensor to localize an augmented reality (AR) tag in the map frame. Once localized, the identity and the 3-D position and orientation, collectively known as pose, of the tag are used to generate a list of initial feature points and their locations based on a priori knowledge. After the end-effector moves to the approximate location of a feature point provided by the AR tag localization, the feature point's location, as well as the end-effector's pose are refined to within a user specified tolerance through the use of a control loop, which utilizes images from a calibrated machine vision camera and a laser pointer, simulating stereo vision, to localize the feature point in 3-D space using computer vision techniques and basic geometry. This approach was implemented on two different ROS enabled robots, the Clearpath Robotics' Husky and the Fetch Robotics' Fetch, in order to show the utility of the multistage localization approach in executing two tasks which are prevalent in both manufacturing and construction: drilling and sealant application. The proposed approach was able to achieve an average accuracy of ± 1 mm in these operations, verifying its efficacy for tasks which have a larger operational scope than that of the range of the AIMM's manipulator and its robustness to general applications in manufacturing. / Master of Science
334

Real Time SLAM Using Compressed Occupancy Grids For a Low Cost Autonomous Underwater Vehicle

Cain, Christopher Hawthorn 07 May 2014 (has links)
The research presented in this dissertation pertains to the development of a real time SLAM solution that can be performed by a low cost autonomous underwater vehicle equipped with low cost and memory constrained computing resources. The design of a custom rangefinder for underwater applications is presented. The rangefinder makes use of two laser line generators and a camera to measure the unknown distance to objects in an underwater environment. A visual odometry algorithm is introduced that makes use of a downward facing camera to provide our underwater vehicle with localization information. The sensor suite composed of the laser rangefinder, downward facing camera, and a digital compass are verified, using the Extended Kalman Filter based solution to the SLAM problem along with the particle filter based solution known as FastSLAM, to ensure that they provide in- formation that is accurate enough to solve the SLAM problem for out low cost underwater vehicle. Next, an extension of the FastSLAM algorithm is presented that stores the map of the environment using an occupancy grid is introduced. The use of occupancy grids greatly increases the amount of memory required to perform the algorithm so a version of the Fast- SLAM algorithm that stores the occupancy grids using the Haar wavelet representation is presented. Finally, a form of the FastSLAM algorithm is presented that stores the occupancy grid in compressed form to reduce the amount memory required to perform the algorithm. It is shown in experimental results that the same result can be achieved, as that produced by the algorithm that stores the complete occupancy grid, using only 40% of the memory required to store the complete occupancy grid. / Ph. D.
335

A Hardware-Minimal Unscented Kalman Filter Framework for Visual-Inertial Navigation of Small Unmanned Aircraft

Eddy, Joshua Galen 06 June 2017 (has links)
This thesis presents the development and implementation of a software framework for estimating the position of a drone during flight. This framework is based on an algorithm known as the Unscented Kalman Filter (UKF), a recursive method of estimating the state of a highly nonlinear system, such as an aircraft. In this thesis, we present a UKF formulation specially designed for a quadcopter carrying an Inertial Measurement Unit (IMU) and a downward-facing camera. The UKF fuses data from each of these sensors to track the position of the quadcopter over time. This work supports a number of similar efforts in the robotics and aerospace communities to navigate in GPS-denied environments with minimal hardware and minimal computational complexity. The software framework explored in this thesis provides a means for roboticists to easily implement similar UKF-based state estimators for a wide variety of systems, including surface vessels, undersea vehicles, and automobiles. We test the system's effectiveness by comparing its position estimates to those of a commercial motion capture system and then discuss possible applications. / Master of Science
336

SLAM-as-a-Service : An explorative study for outdoor AR applications

Ström, Felix, Fallberg, Filip January 2024 (has links)
This study investigates the feasibility and performance of SLAM (Simultaneous Localization and Mapping) as a service (SLAM-as-a-Service) for outdoor augmented reality (AR) applications. Given the rapid advancements in AR technology, integrating lightweight AR glasses with real-time SLAM capabilities poses significant challenges, particularly due to the computational demands of SLAM algorithms and the limited hardware capacity of AR devices. This study proposes a scalable SLAM-as-a-Service framework that offloads intensive computational tasks to remote servers, leveraging cloud and edge computing resources. The ORB-SLAM3 algorithm, known for its robustness and real-time processing capabilities, was adapted and implemented in a service-oriented architecture. The framework was evaluated using the EuRoC dataset to benchmark processing speed, accuracy, and round trip time. The results indicate that while the proposed SLAM-as-a-Service model shows promise in handling high computational loads, several obstacles need to be addressed to achieve minimal round trip time and ensure a seamless AR experience. This thesis contributes to the development of scalable and efficient AR solutions by addressing the limitations of on device processing and highlighting the potential of cloud-based services in enhancing the performance and feasibility of AR applications in dynamic outdoor environments.
337

A rapid approach to the digital documentation of Bradford's rich industrial heritage

Moore, Joseph, Gaffney, Christopher F., Sparrow, Thomas, Irving, H., Ali, S., Middleton, R., Campbell, S., Ackroyd, J., Walker, A., Simpson, S., Ritchings, J., Wilson, Andrew S. 19 August 2022 (has links)
No / The industrial heritage for the City of Bradford Metropolitan District is of international significance, with the city formerly being the centre of the world’s worsted trade during the nineteenth century. The intensification of textile production during the industrial revolution resulted in exponential growth of all aspects of the city, the legacy seen in the townscape heritage of the city today. The structures from this period have played a key role in defining the city’s identity. Since the decline of the textile industry the fabric of many of these buildings from the city’s golden age are under threat and at high risk of loss due to weathering, vandalism and fire. Given the varied nature and condition of these structures, a rapid approach has been applied that complements initiatives in train with Bradford Council to regenerate the ‘Top of Town’; that are reflective of Historic England’s ‘Engines of Prosperity’ report into the regeneration of Industrial Heritage; and with the Management of Saltaire World Heritage site. This chapter focuses on the digital documentation of a conservation area which is highly vulnerable, producing a dataset to aid conservation, management, interpretation and promotion of Bradford’s rich heritage.
338

Towards Dense Visual SLAM

Pietzsch, Tobias 05 December 2011 (has links) (PDF)
Visual Simultaneous Localisation and Mapping (SLAM) is concerned with simultaneously estimating the pose of a camera and a map of the environment from a sequence of images. Traditionally, sparse maps comprising isolated point features have been employed, which facilitate robust localisation but are not well suited to advanced applications. In this thesis, we present map representations that allow a more dense description of the environment. In one approach, planar features are used to represent textured planar surfaces in the scene. This model is applied within a visual SLAM framework based on the Extended Kalman Filter. We presents solutions to several challenges which arise from this approach.
339

Towards Dense Visual SLAM

Pietzsch, Tobias 07 June 2011 (has links)
Visual Simultaneous Localisation and Mapping (SLAM) is concerned with simultaneously estimating the pose of a camera and a map of the environment from a sequence of images. Traditionally, sparse maps comprising isolated point features have been employed, which facilitate robust localisation but are not well suited to advanced applications. In this thesis, we present map representations that allow a more dense description of the environment. In one approach, planar features are used to represent textured planar surfaces in the scene. This model is applied within a visual SLAM framework based on the Extended Kalman Filter. We presents solutions to several challenges which arise from this approach.
340

Architectures pour des systèmes de localisation et de cartographie simultanées / Architectures for simultaneous localization and mapping systems

Vincke, Bastien 03 December 2012 (has links)
La robotique mobile est un domaine en plein essor. L'un des domaines de recherche consiste à permettre à un robot de cartographier son environnement tout en se localisant dans l'espace. Les techniques couramment employées de SLAM (Simultaneous Localization And Mapping) restent généralement coûteuses en termes de puissance de calcul. La tendance actuelle vers la miniaturisation des systèmes impose de restreindre les ressources embarquées. L'ensemble de ces constatations nous ont guidés vers l'intégration d'algorithmes de SLAM sur des architectures adéquates dédiées pour l’embarqué.Les premiers travaux ont consisté à définir une architecture permettant à un robot mobile de se localiser. Cette architecture doit respecter certaines contraintes, notamment celle du temps réel, des dimensions réduites et de la faible consommation énergétique.L’implantation optimisée d’un algorithme (EKF-SLAM), en utilisant au mieux les spécificités architecturales du système (capacités des processeurs, implantation multi-cœurs, calcul vectoriel ou parallélisation sur architecture hétérogène), a permis de démontrer la possibilité de concevoir des systèmes embarqués pour les applications SLAM dans un contexte d’adéquation algorithme architecture. Une seconde approche a été explorée ayant pour objectif la définition d’un système à base d’une architecture reconfigurable (à base de FPGA) permettant la conception d'une architecture fortement parallèle dédiée au SLAM. L'architecture définie a été évaluée en utilisant une méthodologie HIL (Hardware in the Loop).Les principaux algorithmes de SLAM sont conçus autour de la théorie des probabilités, ils ne garantissent en aucun cas les résultats de localisation. Un algorithme de SLAM basé sur la théorie ensembliste a été défini garantissant l'ensemble des résultats obtenus. Plusieurs améliorations algorithmiques sont ensuite proposées. Une comparaison avec les algorithmes probabilistes a mis en avant la robustesse de l’approche ensembliste.Ces travaux de thèse mettent en avant deux contributions principales. La première consiste à affirmer l'importance d'une conception algorithme-architecture pour résoudre la problématique du SLAM. La seconde est la définition d’une méthode ensembliste permettant de garantir les résultats de localisation et de cartographie. / Mobile robotics is a growing field. One important research area is Simultaneous Localization And Mapping (SLAM). Algorithms commonly used in SLAM are generally expensive in terms of computing power. The current trend towards miniaturization imposes to restrict the embedded processing units. All these observations lead us to integrate SLAM algorithms on dedicated architectures suitable for embedded systems.The first work was to define an architecture for a mobile robot to localize itself. This architecture must satisfy some constraints, including the real-time, small dimensions and low power consumption. The optimized implementation of a SLAM algorithm, using the best architectural characteristics of the system (capacity of processors, multi-core implementation, SIMD instructions or parallelization on heterogeneous architecture), has demonstrated the ability to design embedded systems for SLAM applications in the context of Hardware-Software codesign.A second approach has been explored with the aim of designing a system based on a reconfigurable architecture (FPGA-based) for a highly parallel architecture dedicated to SLAM. The defined architecture was evaluated using a HIL (Hardware in the Loop) methodology.The main SLAM algorithms use the probabilistic theories, they do not guarantee their localization results. A SLAM algorithm based on interval analysis is defined to guarantee the overall results. Several algorithmic improvements are then proposed. A comparison with probabilistic algorithms highlighted the robustness of the approach.This thesis put forward two main contributions. The first is to affirm the importance of the hardware software codesign to solve the problem of SLAM with real-time constraint. The second is the definition of a new algorithm to ensure the results of localization and mapping.

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