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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.
191

Where My Girls At? A Critical Discourse Analysis of Gender, Race, Sexuality, Voice and Activism in Ottawa’s Capital Slam Poetry Scene

Tenn-Yuk, Jenna January 2014 (has links)
Ottawa’s Capital Slam poetry scene has transformed over the past decade, marking a shift in the identities, discourses and performance styles of local poets. This thesis investigates these changes and trends within the time periods of 2008-2010 and 2012- 2014. This thesis demonstrates the shift from male poets of colour in 2008-2010 to female voices in 2012-2014 at Capital Slam, through an examination of Ottawa’s history and a multimodal critical discourse analysis of online performances. In particular, the creation of local alternative poetry shows over the past five years has increased the representation of female poets and transformed the racial dynamics of the scene. During the period 2008-2010 and 2012-2014, poets used key historical elements of slam poetry such as storytelling and speaking through personal experiences to effectively demonstrate how marginalized individuals can speak counter-narratives to dominant culture. The use of storytelling allowed these poets to engage, connect and dialogue with the audience, as well as demonstrate their different identities, discourses and performance styles.
192

SLAM collaboratif dans des environnements extérieurs / Collaborative SLAM for outdoor environments

Contreras Samamé, Luis Federico 10 April 2019 (has links)
Cette thèse propose des modèles cartographiques à grande échelle d'environnements urbains et ruraux à l'aide de données en 3D acquises par plusieurs robots. La mémoire contribue de deux manières principales au domaine de recherche de la cartographie. La première contribution est la création d'une nouvelle structure, CoMapping, qui permet de générer des cartes 3D de façon collaborative. Cette structure s’applique aux environnements extérieurs en ayant une approche décentralisée. La fonctionnalité de CoMapping comprend les éléments suivants : Tout d’abord, chaque robot réalise la construction d'une carte de son environnement sous forme de nuage de points.Pour cela, le système de cartographie a été mis en place sur des ordinateurs dédiés à chaque voiture, en traitant les mesures de distance à partir d'un LiDAR 3D se déplaçant en six degrés de liberté (6-DOF). Ensuite, les robots partagent leurs cartes locales et fusionnent individuellement les nuages de points afin d'améliorer leur estimation de leur cartographie locale. La deuxième contribution clé est le groupe de métriques qui permettent d'analyser les processus de fusion et de partage de cartes entre les robots. Nous présentons des résultats expérimentaux en vue de valider la structure CoMapping et ses métriques. Tous les tests ont été réalisés dans des environnements extérieurs urbains du campus de l’École Centrale de Nantes ainsi que dans des milieux ruraux. / This thesis proposes large-scale mapping model of urban and rural environments using 3D data acquired by several robots. The work contributes in two main ways to the research field of mapping. The first contribution is the creation of a new framework, CoMapping, which allows to generate 3D maps in a cooperative way. This framework applies to outdoor environments with a decentralized approach. The CoMapping's functionality includes the following elements: First of all, each robot builds a map of its environment in point cloud format.To do this, the mapping system was set up on computers dedicated to each vehicle, processing distance measurements from a 3D LiDAR moving in six degrees of freedom (6-DOF). Then, the robots share their local maps and merge the point clouds individually to improve their local map estimation. The second key contribution is the group of metrics that allow to analyze the merging and card sharing processes between robots. We present experimental results to validate the CoMapping framework with their respective metrics. All tests were carried out in urban outdoor environments on the surrounding campus of the École Centrale de Nantes as well as in rural areas.
193

Studie av mätosäkerhet hos punktmoln skapade med Matterport Pro2 3D-kamera vid IR-skanning i olika ljusförhållanden

Belander West, Markus January 2020 (has links)
Med den tekniska utvecklingen inom 3D-skanning det senaste decenniet har användningen av punkmolnsdata ökat signifikant. För att skapa dessa punkmoln används en mängd olika metoder och instrument. Bland annat används ofta fotogrammetri, terrester laserskanning eller mobil laserskanning. Med de nyare mobila skannrarna används oftast en SLAM-algoritm för att kunna korrekt skanna omgivningen samtidigt som skannern förflyttas. Till detta används oftast en IMU som positionerar skannern genom tröghetsnavigering eller kameror för att med triangulering bestämma positionen. Med nya förbättrade algoritmer och utrustning blir systemen hela tiden noggrannare och det utvecklas fler och fler nya system, ofta för specifika användningsområden. Matterport Pro2 3D-kamera som testades i detta projekt är ett sådant system som huvudsakligen utvecklats för att genom skanning, RGB-D och 360°- bilder visualisera och skapa digitala modeller av bostäder. Dessa modeller skapas både i form av punktmoln och meshmodeller. I projektet undersöks hur olika ljusförhållanden påverkar resultatet vid skapande av 3D-modeller med Matterport Pro2 kameran. Uppmätta längder mellan signaler utplacerade i testrummet användes för att kontrollera punktmolnen. Totalt skannades rummet fem gånger vid olika ljussättning varierande från 1 till 800 lux. Avvikelserna i längderna från punktmolnen jämfördes för att avgöra vilket punktmoln som avvek minst från de uppmätta längderna i rummet. Resultatet tyder på att bästa ljussättningen är runt 30 - 60 lux. Ingen skillnad i mätosäkerhet mellan övriga ljusnivåer kunde ses. Utöver det visar avvikelserna också tecken på påtagliga systematiskt fel vilket inte är helt oväntat och har påvisats av en tidigare studie av samma kamera. Detta betyder att kameran behöver kalibreras innan den används för skanning som kräver låg mätosäkerhet. / Due to the technological development within 3D-scanning the last decade usage of pointcloud data has increased significantly. To generate these pointclouds a plethora of methods and instrument are used. Among other photogrammetry, terrestrial laser scanning and mobile laser scanning are commonly used. With the newer mobile scanning systems a SLAM algorithm is usually used for the scanner to correctly scan the surroundings while being moved at the same time. To achieve this a IMU is usually used for positioning or cameras using triangulation. With new algorithms and equipment scanning systems keeps improving. This leads to more and more systems being developed, usually for a specific area of usage. Matterport Pro2 3D-camera which was tested in this project is such a system developed mainly for visualising and creating 3D-models of housing through scanning, RGB-D and 360°-images. These models generated are pointclouds aswell as meshmodels. In this project the effect of different illuminance has on the results when creating 3D-models with the Pro2 camera is tested. Measured distances between targets placed around the testing room were used for checking the point clouds for errors. In total five scans were performed at different illuminance varying from 1 – 800 lux. Deviations between measured distances and point cloud distances were compared to determine which point cloud deviated the least. Results show that an illuminance of about 30 - 60 lux gave the best result. Any significant differences between the other light conditions could not be determined. Furthermore, the results imply there is a systematic error which is not completely unexpected and has been shown in a previous study with the same camera. This means the camera needs a calibration before being used to scan where higher accuracy is needed.
194

Guaranteed Localization and Mapping for Autonomous Vehicles / Localisation et cartographie garanties pour les véhicules autonomes

Wang, Zhan 19 October 2018 (has links)
Avec le développement rapide et les applications étendues de la technologie de robot, la recherche sur le robot mobile intelligent a été programmée dans le plan de développement de haute technologie dans beaucoup de pays. La navigation autonome joue un rôle de plus en plus important dans le domaine de recherche du robot mobile intelligent. La localisation et la construction de cartes sont les principaux problèmes à résoudre par le robot pour réaliser une navigation autonome. Les techniques probabilistes (telles que le filtre étendu de Kalman et le filtre de particules) ont longtemps été utilisées pour résoudre le problème de localisation et de cartographie robotisées. Malgré leurs bonnes performances dans les applications pratiques, ils pourraient souffrir du problème d'incohérence dans les scénarios non linéaires, non gaussiens. Cette thèse se concentre sur l'étude des méthodes basées sur l'analyse par intervalles appliquées pour résoudre le problème de localisation et de cartographie robotisées. Au lieu de faire des hypothèses sur la distribution de probabilité, tous les bruits de capteurs sont supposés être bornés dans des limites connues. Sur la base d'une telle base, cette thèse formule le problème de localisation et de cartographie dans le cadre du problème de satisfaction de contraintes d'intervalle et applique des techniques d'intervalles cohérentes pour les résoudre de manière garantie. Pour traiter le problème du "lacet non corrigé" rencontré par les approches de localisation par ICP (Interval Constraint Propagation), cette thèse propose un nouvel algorithme ICP traitant de la localisation en temps réel du véhicule. L'algorithme proposé utilise un algorithme de cohérence de bas niveau et est capable de diriger la correction d'incertitude. Par la suite, la thèse présente un algorithme SLAM basé sur l'analyse d'intervalle (IA-SLAM) dédié à la caméra monoculaire. Une paramétrisation d'erreur liée et une initialisation non retardée pour un point de repère naturel sont proposées. Le problème SLAM est formé comme ICSP et résolu par des techniques de propagation par contrainte d'intervalle. Une méthode de rasage pour la contraction de l'incertitude historique et une méthode d'optimisation basée sur un graphique ICSP sont proposées pour améliorer le résultat obtenu. L'analyse théorique de la cohérence de la cartographie est également fournie pour illustrer la force de IA-SLAM. De plus, sur la base de l'algorithme IA-SLAM proposé, la thèse présente une approche cohérente et peu coûteuse pour la localisation de véhicules en extérieur. Il fonctionne dans un cadre en deux étapes (enseignement visuel et répétition) et est validé avec un véhicule de type voiture équipé de capteurs de navigation à l'estime et d'une caméra monoculaire. / With the rapid development and extensive applications of robot technology, the research on intelligent mobile robot has been scheduled in high technology development plan in many countries. Autonomous navigation plays a more and more important role in the research field of intelligent mobile robot. Localization and map building are the core problems to be solved by the robot to realize autonomous navigation. Probabilistic techniques (such as Extented Kalman Filter and Particle Filter) have long been used to solve the robotic localization and mapping problem. Despite their good performance in practical applications, they could suffer the inconsistency problem in the non linear, non Gaussian scenarios. This thesis focus on study the interval analysis based methods applied to solve the robotic localization and mapping problem. Instead of making hypothesis on the probability distribution, all the sensor noises are assumed to be bounded within known limits. Based on such foundation, this thesis formulates the localization and mapping problem in the framework of Interval Constraint Satisfaction Problem and applied consistent interval techniques to solve them in a guaranteed way. To deal with the “uncorrected yaw” problem encountered by Interval Constraint Propagation (ICP) based localization approaches, this thesis proposes a new ICP algorithm dealing with the real-time vehicle localization. The proposed algorithm employs a low-level consistency algorithm and is capable of heading uncertainty correction. Afterwards, the thesis presents an interval analysis based SLAM algorithm (IA-SLAM) dedicates for monocular camera. Bound-error parameterization and undelayed initialization for nature landmark are proposed. The SLAM problem is formed as ICSP and solved via interval constraint propagation techniques. A shaving method for landmark uncertainty contraction and an ICSP graph based optimization method are put forward to improve the obtaining result. Theoretical analysis of mapping consistency is also provided to illustrated the strength of IA-SLAM. Moreover, based on the proposed IA-SLAM algorithm, the thesis presents a low cost and consistent approach for outdoor vehicle localization. It works in a two-stage framework (visual teach and repeat) and is validated with a car-like vehicle equipped with dead reckoning sensors and monocular camera.
195

Observation missions with UAVs : defining and learning models for active perception and proposition of an architecture enabling repeatable distributed simulations / Missions d'observations pour des drones : définition et apprentissage de modèles pour la perception active, et proposition d'une architecture permettant des simulations distribuées répétables

Reymann, Christophe 08 July 2019 (has links)
Cette thèse se focalise sur des tâches de perceptions pour des drones à voilures fixes (UAV). Lorsque la perception est la finalité, un bon modèle d'environnement couplé à la capacité de prédire l'impact de futures observations sur celui-ci est crucial. La perception active traite de l'intégration forte entre modèles de perception et processus de raisonnement, permettant au robot d'acquérir des informations pertinentes à propos du statut de la mission et de replanifier sa trajectoire de mesure en réaction à des évènements et résultats imprévisibles. Ce manuscrit décrit deux approches pour des tâches de perception active, dans deux scénarios radicalement différents. Le premier est celui de la cartographie des phénomènes météorologiques de petite échelle et fortement dynamiques, en particulier de nuages de type cumulus. L'approche présentée utilise la régression par processus Gaussien pour construire un modèle d'environnement, les hyper-paramètres étant appris en ligne. Des métriques de gain d'information sont introduites pour évaluer la qualité de futures trajectoires d'observation. Un algorithme de planification stochastique est utilisé pour optimiser une fonction d'utilité équilibrant maximisation du gain d'information avec des buts de minimisation du coût énergétique. Dans le second scénario, un UAV cartographie des champs de grandes cultures pour les besoins de l'agriculture de précision. Utilisant le résultat d'un algorithme de localisation et cartographie simultanée (SLAM), une approche nouvelle pour la construction d'un modèle d'erreurs relatives est proposée. Ce modèle est appris à partir d'attributs provenant des structures de données du SLAM, ainsi que de la topologie sous-jacente du graphe de covisibilité formé par les observations. Tous les développement ont été testés en simulation. Se focalisant sur la problématique de gestion de l'avancement tu temps et de la synchronisation de simulateurs hétérogènes dans une architecture distribuée, une solution originale basée sur une architecture décentralisée est proposée. / This thesis focuses on perception tasks for an unmanned aerial vehicle (UAV). When sensing is the finality, having a good environment model as well as being capable of predicting the impacts of future observations is crucial. Active perception deals with integrating tightly perception models in the reasoning process, enabling the robot to gain knowledge about the status of its mission and to replan its sensing trajectory to react to unforeseen events and results. This manuscript describes two approaches for active perception tasks, in two radically different settings. The first one deals with mapping highly dynamic and small scale meteorological phenomena such as cumulus clouds. The presented approach uses Gaussian Process Regression to build environment models, learning its hyperparameters online. Normalized marginal information metrics are introduced to compute the quality of future observation trajectories. A stochastic planning algorithm is used to optimize an utility measure balancing maximization of theses metrics with energetic minimization goals. The second setting revolves around mapping crop fields for precision agriculture purposes. Using the output of a monocular graph Simultaneous Localization and Mapping (SLAM) algorithm, a novel approach to building a relative error model is proposed. This model is learned both from features extracted from the SLAM algorithm’s data structures, as well as the underlying topology of the covisibility graph of the observations. All developments have been tested using realistic, distributed simulations. An analysis of the simulation issue in robotics is proposed. Focusing on the problem of managing time advancement of multiple interconnected simulators, a novel solution based on a decentralized scheme is presented.
196

Une solution opérationnelle de localisation pour des véhicules autonomes basée sur le SLAM / An operational localization solution based on SLAM for autonomous vehicles

Roussillon, Cyril 21 October 2013 (has links)
Les applications de la robotique mobile autonome en environnements extérieurs sont nombreuses : surveillance de site à la recherche d’anomalies, campagne d’acquisition de données,exploration, recherche de victimes sur des lieux de catastrophes, etc, et l’intérêt de la robotique pour ces applications est d’autant plus grand que les environnements peuvent être dangereux ou risqués pour l’homme. La localisation des robots est une fonction clé dans ces contextes car elle est indispensable à de nombreuses autres fonctions, particulièrement la construction de modèles d’environnement, l’exécution des trajectoires, ou la supervision des missions. Ces travaux présentent la construction d’une solution de localisation pour des robots autonomes,conçue pour être à la fois un outil générique de recherche et un outil opérationnel pour localiser nos robots lors de leurs missions de navigation autonome, capable de gérer de fortes dynamiques de mouvement. En partant d’une solution de localisation et cartographie simultanées (SLAM) basée sur l’utilisation d’une simple caméra, différentes solutions sont successivement construites en ajoutant progressivement des capteurs afin de pallier les difficultés rencontrées lors des évaluations, et ce jusqu’à obtenir un système robuste et précis combinant plusieurs caméras, une centrale inertielle et l’odométrie, et ayant en outre la possibilité d’intégrer des estimations de positions absolues quand elles peuvent être produites (par un récepteur GPS ou un algorithme exploitant une carte initiale). Une analyse profonde des capacités et limitations des différents systèmes est systématiquement effectuée, en considérant notamment l’intérêt d’estimer enligne les calibrages extrinsèques et biais des capteurs. Un accent particulier est mis sur l’exécution temps réel des algorithmes à bord du robot et sur leur robustesse : cela implique la résolution de nombreux problèmes, portant notamment sur les aspects temporels de la gestion des données. Une large évaluation sur différents jeux de données réalistes permet d’évaluer et de valider les différents développements proposés tout au long du manuscrit. / There are numerous applications of outdoor autonomous mobile robots : surveillance of areas to detect anomalies, data acquisition campaigns, exploration, search of victims in disaster areas, etc. Robot localization is a key function in these contexts because it is necessary fora lot of essential robotics tasks, in particular to build environment models, follow paths or supervise the execution of the missions.This work presents the development of a localization solution for autonomous robots, designedto be both a generic research tool and an effective tool to localize robots navigating with highlydynamic movements.Starting with a simultaneous localization and mapping (SLAM) solution using a single camera,several solutions are successively built by gradually adding sensors, until obtaining a robust and precise system combining several cameras, an inertial sensor and odometry, which is inaddition able to integrate absolute position measures when available (e.g. as provided byGPS or a map-based localization scheme). A in-depth analysis of the abilities and limitations of the different systems is systematically made, in particular considering the advantages of estimating online extrinsic calibration parameters and sensor biases. A particular emphasisis set on real time execution of the algorithms on board the robots and on their robustness,requiring to address various problems related to temporal aspects of data management.Thorough evaluations using different realistic datasets allows to evaluate and validate the proposed work throughout the manuscript.
197

[en] ANOTHER BLACK WOMAN DIDN T SMILE: THE EXPERIENCE OF BLACK DIASPORA IN THE POEMS OF CAROL DALL FARRA AND PORSHA OLAYIWOLA / [pt] OUTRA PRETA QUE NÃO SORRIU: A EXPERIÊNCIA DA DIÁSPORA NEGRA NOS POEMAS DE CAROL DALL FARRA E PORSHA OLAYIWOLA

STEFFANY DIAS DA SILVA 19 June 2023 (has links)
[pt] A dissertação apresenta uma incursão pelos poemas de duas poetas da diáspora negra, Carol Dall Farra, do Brasil, e Porsha Olayiwola, dos Estados Unidos, numa investigação sobre processos do sentimento de não pertencimento na constituição de subjetividades de mulheres negras a partir de reflexões acerca de elementos de diferenciação, como raça, gênero, classe, religião e orientação sexual. Em formato de ensaios, pretende-se discutir economia onomástica, assim como a influência da cultura negra nas línguas coloniais, a heterossexualidade compulsória e outras experiências relacionadas à diáspora negra, cuja resistência, aqui, desponta nas performances poéticas das autoras no slam poetry, que, nesse sentido, funciona como uma ferramenta de construção de identidades e da partilha do sensível, formulação de Jacques Rancière, em que os interlocutores dos poemas são muitas vezes as mulheres negras, que, assim como as poetas, constroem suas subjetividades com os poemas declamados. Sob a luz dos escritos de intelectuais como bell hooks, Audre Lorde e Lélia Gonzalez, discute-se as disputas que as poetas escolhidas escolhem travar para forjar subjetividades e criar vínculos. / [en] The dissertation presents an excursion into the poems of two poets from the African diaspora: Carol Dall Farra, from Brazil, and Porsha Olayiwola, from the United States, in an investigation into processes of the feeling of non-belonging in the constitution of subjectivities of black women upon reflections on elements of differentiation, such as race, gender, class, religion and sexual orientation. These essays discuss onomastic economics, as well as the influence of Black culture on colonial languages, compulsory heterosexuality and various experiences related to the African diaspora, whose resistance, in this case, emerges in the poetic performances of the authors in slam poetry , which, in this sense, function as tools for building identities and partage du sensible, formulation by Jacques Rancière, in which the interlocutors of the poems are often black women, who, such as the poets, assemble their identities in virtue of the recited poems. In the light of the writings of intellectuals such as bell hooks, Audre Lorde and Lélia Gonzalez, the disputes that these poets choose to wage to forge subjectivities and create bonds are discussed.
198

Impact of Vehicle Dynamics Modelling on Feature Based SLAM for Autonomous Racing. / Fordonsmodelleringens påverkan på SLAM för autonom racing.

Skeppström Lehto, Hugo, Hedlund, Richard January 2019 (has links)
In autonomous racing there is a need to accurately localize the vehicle while simultaneously creating a map of the track. This information can be delivered to planning and control layers in order to achieve fully autonomous racing. The kinematic model is a commonly used motion model in feature-based SLAM. However, it is a poor representation of the vehicle when considering high lateral accelerations since the model is only based on trigonometric relationships. This Master’s Thesis investigates the consequence of using the kinematic model when undertaking demanding maneuvers; and if by switching to a dynamic model, which takes the tire forces into account, can improve the localization performance. An EKF-SLAM algorithm comprising the kinematic and dynamic model was implemented on a development platform. The pose estimation accuracy was compared using either model when subject to typical maneuvers in racing-scenarios. The results showed that the pose estimation accuracy was in general similar when using either of the vehicle models. When exposed to large slip angles, the implications of switching from a kinematic model to a dynamic model resulted in a significantly better pose estimation accuracy when driving in an unknown environment. However, switching to a dynamic model had little effect when driving in a known environment. The implications of the study suggest that, during the first lap of a racing track, the kinematic model should be switched to a dynamic model when subject to high lateral accelerations. For the consecutive laps, the choice of vehicle model has less impact. Keywords: SLAM, EKF-SLAM, Localization, Estimation, Vehicle Dynamics, Kinematic Model, Dynamic Model, Autonomous Racing / I autonom racing är det viktigt att kunna lokalisera fordonet med hög noggrannhet samtidigt som en karta över banan skapas. Den här informationen kan vidare bli hanterad av planerings- och reglersystem för att uppfylla autonom racing fullt ut. Den kinematiska modellen är en vanligt förekommande rörelsemodell i SLAM. Den är däremot en bristande representation av fordonet vid höga laterala accelerationer eftersom modellen enbart är baserad på trigonometriska samband. Det här masterarbetet undersöker den kinematiska modellens påverkan vid olika manövrar och huruvida den dynamiska modellen, som modellerar däckkrafterna, kan förbättra prestandan. En EKF-SLAM algorithm innehållande den kinematiska- och dynamiska modellen implementerades på en utvecklingsplattform. Estimeringsnoggrannheten av positionen och orienteringen jämfördes vid typiska manövrar för racingscenarier. Resultatet visade att estimeringsnoggrannheten av positionen och orienteringen var generellt sett lika vid användandet av antingen den kinematiska eller den dynamiska modellen. Implikationerna av att byta från den kinematiska modellen till den dynamiska modellen vid höga glidvinklar, resulterade i en signifikant bättre estimeringsnoggrannhet av positionen och orienteringen vid körning i en okänd miljö. Emellertid så var effekterna av att byta till en dynamisk modell insignifikanta vid körning i en känd miljö. Implikationerna av denna studie föreslår att under det första varvet av racingbanan byta från den kinematiska modellen till den dynamiska vid höga laterala accelerationer. Under kommande varv har valet av fordonsmodell mindre effekt. Nyckelord: SLAM, EKF-SLAM, lokalisering, estimering, fordonsmodellering, kinematisk modell, dynamisk modell, autonom racing.
199

Localisation and mapping in smoke filled environments : A study of robot perception in harsh conditionsusing practical experiments

Zakardissnehf, Martin, Jernström, Agnes January 2017 (has links)
Det här examensarbetet är utfört i samarbete med Realisator Robotics, vilka förtillfället utvecklar en robot, FUMO, som ska hjälpa till vid brandbekämpning. Målet med examensarbetet är att implementera autonom navigering från en punkt till en annan samt SLAM (Simultaneous Localisation and Mapping, simultan lokaliseringoch kartläggning) funktionalitet. Dessa funktioners färmåga att hantera rök ska även testas. Efter en inledande litteraturstudie på olika sätt att lösa en robots perception i rök så blev det bestämt att använda en så kallad ”multi-echo LIDAR” som huvudsensor. Alla implementationer är gjorda i robotoperativsystemet ROS och öppenkällkod har använts för vissa funktioner. De första testerna av systemet gjordes i en simulerad miljö. I den så approximerades röken utav Gaussiskt brus. Det blev dock senare fastställt att detta inte lyckas representera alla effekter utav riktig rök. De delar dock vissa beteenden. De slutgiltiga testerna utfördes i en testanläggning för rökdykare, där algoritmerna testades i olika nivåer av rök. Dessa tester visade att multi-echo LIDAR:n klarade av att se igenom lätt till mediumtjock rök, det vill säga rök som kan ses igenom upp till ett par meter med blotta ögat. SLAMalgoritmen kunde i dessa fall generera användbara kartor. När det kontinuerligt lades till ny rök till testområdet så blev kartorna fragmenterade och oläsliga. Den autonoma navigeringen testades inte i rök på grund av säkerhetsrisker. Däremot så testades lokaliseringen som den bygger på genom att manuellt köra roboten genom röken. Resultaten från detta tyder på att det är möjligt att använda den autonoma navigeringen under rökfyllda förhållanden. / This thesis is carried out together with Realisator Robotics who is currently developinga fire-fighting assistant robot, FUMO. The aim of the thesis is to implementautonomous path planning and SLAM (Simultaneous Localisation and Mapping) functionality on the existing FUMO prototype as well as to test how robust these are to smoke. After an initial literature study on different ways of robot perception in smokeit was decided to use a multi-echo LIDAR as the main sensor for these tasks. All implementations were done in ROS (Robot Operating System) and open sourcecode was used for some functions. Testing of the system was first performed in asimulated environment. In this environment smoke was approximated using Gaussiannoise. However it was later concluded that this did not accurately portrayall effects of real smoke. It does however share some similarities. The final tests were performed at a testing facility for smoke divers where the algorithms were tested in different levels of smoke. The tests showed that the multi-echo LIDARmanaged to see through light to medium smoke, in other words smoke which you could see through with your bare eyes to up to a few meters. In those conditions the SLAM algorithm was able to create usable maps. When new smoke was continuously added to the already smoke filled environment the maps became fragmented and unreadable. The autonomous path planning was not tested in smoke due to safety concerns. However the localisation which the path planning is based onwas tested when driving the robot manually through the smoke. The result fromthis hints at a possibility of successfully using the path planning in these conditions.
200

Outlier Robustness in Server-Assisted Collaborative SLAM : Evaluating Outlier Impact and Improving Robustness / Robusthet mot outliers i serverassisterad, samarbetande SLAM : En utvärdering utav outliers påverkan och hur robustheten kan ökas

Miguel de Almeida Pedro, José January 2023 (has links)
In order to be able to perform many tasks, autonomous devices need to understand their environment and know where they are in this environment. Simultaneous Localisation and Mapping (SLAM) is a solution to this problem. When several devices attempt to jointly solve this problem they use Collaborative SLAM (C-SLAM), but this is a very resource-demanding process. In order to enable resource-constrained devices, like small mobile robots or eXtended Reality (XR) devices, to run C-SLAM we look towards a Server-Assisted C-SLAM architecture to lift the computational burden from these devices. In a real-world scenario, sensors might fail, the devices might process sensor data wrongly or a malicious actor might inject wrong data into the system. In order for these solutions to be reliable, they must be able to deal with these \emph{outliers}. This thesis looks into the impact of outliers in Server-Assisted C-SLAM algorithms and presents two novel solutions for a robust algorithm, based on robust estimation of the initial device poses. We show the novel solutions outperform the state of the art both in estimation accuracy, yielding better estimates of the real device trajectories, and computational performance, making it suitable for device-constrained devices. / För att kunna utföra flertalet uppgifter måste autonoma enheter förstå sin miljö och veta var de befinner sig i den här miljön. Simultaneous Localization and Mapping (SLAM) är en lösning på detta problem. När flera enheter försöker lösa detta problem tillsammans använder de Samarbetande SLAM (C-SLAM), men detta är en mycket resurskrävande process. För att möjliggöra att resursbegränsade enheter, så som exempelvis små mobila robotar eller eXtended Reality (XR)-enheter, ska kunna köra C-SLAM föreslås en serverassisterar C-SLAM-arkitektur beräkningsbördan kan lyftas från dessa enheter till servern. I ett verkligt scenario kan sensorer vara felaktiga, enheter behandla sensordata felaktigt eller illvilliga aktörer injicera felaktig data i systemet. Därför undersöker detta arbete effekten av \emph{outliers} i Serverassisterade C-SLAM-algoritmer och presenterar två nya lösningar för en robust algoritm, baserad på robusta uppskattningar av enhetens initiala positioner. Denna lösning visar sig överträffa likartade lösningar i litteraturen både vad gäller uppskattningsnoggrannhet, vilket ger bättre uppskattningar av den verkliga enhetsbanor och beräkningsprestanda, vilket gör den lämplig för enheter med begränsade resurser.

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