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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.
121

Co-projeto de hardware/software do filtro de partículas para localização em tempo real de robôs móveis / Hardware/Software codesign of particle filter for real time localization of mobile robots

Bruno Franciscon Mazzotti 11 February 2010 (has links)
Sofisticadas técnicas para estimação de modelos baseadas em simulação, os filtros de partículas ou métodos de Monte Carlo Seqüenciais, foram empregadas recentemente para solucionar diversos problemas difícieis no campo da robótica móvel. No entanto, o sucesso dos fitros de partículas limitou-se à computação de parâmetros em espaços de baixa dimensionalidade. Os atuais esforços de pesquisa em robótica móvel têm comecado a explorar certas propriedades estruturais de seus domnios de aplicação que envolvem a utilização de filtros de partculas em espacos de maior dimensão, aumentando consideravelmente a complexidade da simulação envolvida. Simulações estatsticas dessa natureza requerem uma grande quantidade de numeros pseudo-aleatorios que possam ser gerados eficientemente e atendam a certos criterios de qualidade. O processo de geração de numeros pseudo-aleatorios torna-se o ponto crtico de tais aplicações em termos de desempenho. Neste contexto, a computação reconguravel insere-se como uma tecnologia capaz de satisfazer a demanda por alto desempenho das grandes simulações estatsticas pois sistemas baseados em arquiteturas reconguraveis possuem o potencial de mapear computação em hardware visando aumento de eficiência sem comprometer seriamente sua exibilidade. Tecnologias reconguraveis também possui o atrativo de um baixo consumo de energia, uma caracterstica essencial para os futuros robôs moveis embarcados. Esta dissertação apresenta a implementação um sistema embarcado baseado em FPGA e projetado para solucionar o problema de localização de robôs por meio de tecnicas probabilsticas. A parte fundamental de todo este sistema e um veloz gerador de numeros aleatorios mapeado ao hardware reconguravel que foi capaz de atender rígidos criterios estatsticos de qualidade / Sophisticated techniques for estimation of models based on simulation, particle filters or Sequential Monte Carlo Methods, were recently used to solve many difficult problems in the field of mobile robotics. However, the success of particle filters was limited to the computation of parameters in low dimensionality spaces. The current research efforts in mobile robotics have begun to explore some structural properties of their application\'s domain involving the use of particle filters in spaces of a higher dimension, greatly increasing the complexity of the involved simulation. Statistical simulations of this nature require a lot of pseudorandom numbers that can be generated efficiently and meet certain quality criteria. The process of generating pseudorandom number becomes the critical point of such applications in terms of performance. In this context, reconfigurable computing is a technology capable of meeting the demand for high performance of large statistical simulations because systems based on reconfigurable architectures have the potential to map computation to hardware aiming to increase eficiency without a serious drawback in exibility. Reconfigurable technologies are also attractive because of their low energy consume, a essential feature for the future mobile robots. This dissertation presents an implementation of a FPGA based embedded system designed to solve the robot localization problem by the means of probabilistic technics. The fundamental part from the whole system is a fast random number generator mapped to reconfigurable hardware wich atends a rigid quality criteria
122

Využití nástroje ROS pro řízení autonomního mobilního robotu / ROS framework utilization for autonomous mobile robot control system

Vávra, Patrik January 2019 (has links)
Tato práce se zabývá vytvořením lokalizačního a navigačního systému mobilního robota pro vnitřní prostředí pomocí frameworku ROS. Stručně je zde představen projekt, v rámci kterého diplomová práce vznikla, a jeho cíle. V rešeršní části je v krátkosti popsán ROS framework, simulační prostředí Gazebo a senzory, kterými robot disponuje. Následuje vytvoření modelu robota a simulačního prostředí, v němž jsou vyzkoušeny lokalizační, navigační a další rutiny. V experimentální části je provedeno testování senzorů a popsáno využití jejich výstupů. Následně jsou upraveny a otestovány algoritmy ze simulace na reálném robotovi. V závěru jsou popsány vytvořené vzdělávací minihry. Hlavním výstupem této práce je funkční stavový automat, který umožňuje manuální ovládání, zadávání cílů pro navigaci a v případě potřeby zajistí autonomní nabití robota.
123

Systém pro autonomní mapování závodní dráhy / System for autonomous racetrack mapping

Soboňa, Tomáš January 2021 (has links)
The focus of this thesis is to theoretically design, describe, implement and verify thefunctionality of the selected concept for race track mapping. The theoretical part ofthe thesis describes the ORB-SLAM2 algorithm for vehicle localization. It then furtherdescribes the format of the map - occupancy grid and the method of its creation. Suchmap should be in a suitable format for use by other trajectory planning systems. Severalcameras, as well as computer units, are described in this part, and based on parametersand tests, the most suitable ones are selected. The thesis also proposes the architectureof the mapping system, it describes the individual units that make up the system, aswell as what is exchanged between the units, and in what format the system output issent. The individual parts of the system are first tested separately and subsequently thesystem is tested as a whole. Finally, the achieved results are evaluated as well as thepossibilities for further expansion.
124

Čtyřnohý kráčejicí robot / Four legged walking robot

Veleba, Tomáš January 2008 (has links)
The diploma paper deal with control problems of a four legged walking robot. They endeavour to establish and partly implement the walking and control algorithms. They are divided into six parts. Individual chassis types and their advantages and drawbacks are analysed in introduction. Next part describes mechanical design of the robot and also all realised electronics facilities. The third part describes in detail sensors that are used by the robot. Following part deals with description of robot's walking. It explains individual walking phases and analyses both static and dynamic stability. Next part contains description of the robot's software facility. The software facility of the control micro-controller and the algorithm that generates walking are explained in this part. It also describes software facility of control application in computer. Exploration of the possibilities for wireless control is carried out in the last part.
125

Průběžná lokalizace a mapování pomocí mobilního robotu / Simultaneous Localization and Mapping Using Mobile Robot

Neužil, Tomáš January 2008 (has links)
This work presents an overview of the simultaneous localisation and mapping (SLAM) problem in the mobile robotics. The Extended Kalman filter (EKF) based algorithm for localisation and mapping is proposed. For EKF algorithm the models of the skid steering mobile robot and the laser scanner are presented. The EKF algortihm is feature based algorithm, therefore the method for the landmark position determination was developed. This segmentation method is based on the clustering of the Radon transform space. Proposed SLAM algorithm was tested with real data measured with UTAR mobile platform. Achievments of the work are summarized in the conclusion of the proposed work and possible improvements of the components are suggested.
126

Fault Detection in Mobile Robotics using Autoencoder and Mahalanobis Distance

Mortensen, Christian January 2021 (has links)
Intelligent fault detection systems using machine learning can be applied to learn to spot anomalies in signals sampled directly from machinery. As a result, expensive repair costs due to mechanical breakdowns and potential harm to humans due to malfunctioning equipment can be prevented. In recent years, Autoencoders have been applied for fault detection in areas such as industrial manufacturing. It has been shown that they are well suited for the purpose as such models can learn to recognize healthy signals that facilitate the detection of anomalies. The content of this thesis is an investigation into the applicability of Autoencoders for fault detection in mobile robotics by assigning anomaly scores to sampled torque signals based on the Autoencoder reconstruction errors and the Mahalanobis distance to a known distribution of healthy errors. An experiment was carried out by training a model with signals recorded from a four-wheeled mobile robot executing a pre-defined diagnostics routine to stress the motors, and datasets of healthy samples along with three different injected faults were created. The model produced overall greater anomaly scores for one of the fault cases in comparison to the healthy data. However, the two other cases did not yield any difference in anomaly scores due to the faults not impacting the pattern of the signals. Additionally, the Autoencoders ability to isolate a fault to a location was studied by examining the reconstruction errors faulty samples determine whether the errors of signals originating from the faulty component could be used for this purpose. Although we could not confirm this based on the results, fault isolation with Autoencoders could still be possible given more representative signals.
127

Intrinsic motivation mecanisms for incremental learning of visual saliency / Apprentissage incrémental de la saillance visuelle par des mécanismes de motivation intrinsèque

Craye, Céline 03 April 2017 (has links)
La conception de systèmes de perception autonomes, tels que des robots capables d’accomplir un ensemble de tâches de manière sûre et sans assistance humaine, est l’un des grands défis de notre siècle. Pour ce faire, la robotique développementale propose de concevoir des robots qui, comme des enfants, auraient la faculté d’apprendre directement par interaction avec leur environnement. Nous avons dans cette thèse exploré de telles possibilités en se limitant à l’apprentissage de la localisation des objets d’intérêt (ou objets saillants) dans l’environnement du robot.Pour ce faire, nous présentons dans ces travaux un mécanisme capable d’apprendre la saillance visuelle directement sur un robot, puis d’utiliser le modèle appris de la sorte pour localiser des objets saillants dans son environnement. Cette méthode a l’avantage de permettre la création de modèles spécialisés pour l’environnement du robot et les tâches qu’il doit accomplir, tout en restant flexible à d’éventuelles nouveautés ou modifications de l’environnement.De plus, afin de permettre un apprentissage efficace et de qualité, nous avons développé des stratégies d’explorations basées sur les motivations intrinsèques, très utilisées en robotique développementale. Nous avons notamment adapté l’algorithme IAC à l’apprentissage de la saillance visuelle, et en avons conçu une extension, RL-IAC, pour permettre une exploration efficace sur un robot mobile. Afin de vérifier et d’analyser les performances de nos algorithmes, nous avons réalisé des évaluations sur plusieurs plateformes robotiques dont une plateforme fovéale et un robot mobile, ainsi que sur des bases de données publiques. / Conceiving autonomous perceptual systems, such as robots able to accomplish a set of tasks in a safe way, without any human assistance, is one of the biggest challenge of the century. To this end, the developmental robotics suggests to conceive robots able to learn by interacting directly with their environment, just like children would. This thesis is exploring such possibility while restricting the problem to the one of localizing objects of interest (or salient objects) within the robot’s environment.For that, we present in this work a mechanism able to learn visual saliency directly on a robot, then to use the learned model so as to localize salient objects within their environment. The advantage of this method is the creation of models dedicated to the robot’s environment and tasks it should be asked to accomplish, while remaining flexible to any change or novelty in the environment.Furthermore, we have developed exploration strategies based on intrinsic motivations, widely used in developmental robotics, to enable efficient learning of good quality. In particular, we adapted the IAC algorithm to visual saliency leanring, and proposed an extension, RL-IAC to allow an efficient exploration on mobile robots.In order to verify and analyze the performance of our algorithms, we have carried out various experiments on several robotics platforms, including a foveated system and a mobile robot, as well as publicly available datasets.
128

Edge Orchestrator for Mobile Robotics to provide on-demand run-time support

El Yaacoub, Ahmed January 2020 (has links)
Edge computing emerged as an attractive method of distributing computational resources in a network. When compared with cloud computing, edge computing presents a number of key benefits which include improved response times, scalability, privacy, and redundancy. This makes edge computing desirable for use in mobile robotics, in which low response times and redundancy are key issues. This thesis work will cover the design and implementation of a general-purpose edge orchestrator, that can support a wide range of domains due to being built around the concept of modularity. An edge orchestrator is a program that manages an edge network by analyzing the edge network and the requirements of devices within that network, then optimizing how the computational resources are distributed within the devices in the network. Modules have been designed and implemented on top of the orchestrator that allow for optimizations specific to mobile robotics. A proof of concept module was designed to optimize for latency which was compared with an external algorithm that seeks to optimize for latency as well. Both were implemented on the orchestrator and an evaluation was performed to compare both approaches. It was found that the module designed in this thesis is better suited for optimizing for latency. LXD was chosen to be used for software packaging which is a container-based software packaging solution. A software packaging solution is used to package software which would be deployed by the orchestrator. The choice of LXD is analyzed through an evaluation procedure that compares it with Docker, which is another container-based software packaging solution. It was found that LXD produces containers of smaller size but required more time to generate those containers, when compared with Docker. It was also found that LXD container images exhibited better performance than the Docker ones for software which is not I/O heavy. It was decided through this evaluation that LXD was a better choice for the orchestrator. / Edge computing är en attraktiv metod för distribution av beräkningsresurser i ett nätverk. Jämfört med molnberäkningar har edge computing ett antal viktiga fördelar som inkluderar förbättrade svarstider, skalbarhet, integritet och redundans. Detta gör edge computing önskvärt för användning i mobil robotik, där låga svarstider och redundans är viktiga frågor. Detta examensarbete täcker min design och implementering av en generell edge-orkestrerare, som kan stödja ett brett spektrum av domäner eftersom den är byggd på ett modulärt sätt. En edge-orkestrerare är ett program som hanterar ett edge-nätverk genom att analysera edge-nätverket och kraven på enheter inom det nätverket, för att sedan optimera hur beräkningsresurserna fördelas över enheterna i nätverket. Jag har utformat och implementerat moduler ovanpå orkestratorn som möjliggör optimeringar specifika för mobil robotik. Jag designade också en koncepttest-modul för att optimera för latens, vilken jag jämförde med en extern algoritm som även den försöker optimera för latens. Jag implementerade båda på orkestratorn och utförde en utvärdering för att jämföra båda metoderna. Resultaten visar att modulen utformad i detta examensarbete är bättre lämpad för att optimera för latens. För mjukvarupaketering valde jag att använda LXD, vilket är en containerbaserad mjukvarupaketeringslösning. Dess syfte är att paketera programvara som ska distribueras av orkestratorn. Jag analyserade valet av LXD genom ett utvärderingsförfarande som jämför det med Docker, som är en annan containerbaserad mjukvarupaketeringslösning. Jag fann att LXD producerar mindre containrar, men krävde mer tid för att generera dessa containrar jämfört med Docker. Jag fann också att LXD-containerbilder visade bättre prestanda än Docker-bilderna för programvara som inte är I/O-intensiv. Jag fann genom denna utvärdering att LXD var ett bättre val för orkestratorn.
129

DEVELOPMENT OF PASSIVE VISION BASED RELATIVE STATION KEEPING FOR UNMANNED SURFACE VEHICLES

Ajinkya Avinash Chaudhary (18430029) 26 April 2024 (has links)
<p dir="ltr">Unmanned surface vehicles (USVs) offer a versatile platform for various maritime applications, including research, surveillance, and search-and-rescue operations. A critical capability for USVs is maintaining position (station keeping) in dynamic environments and coordinating movement with other USVs (formation control) for collaborative missions. This thesis investigates control strategies for USVs operating in challenging conditions. </p><p dir="ltr">The initial focus is on evaluating traditional control methods like Backstepping and Sliding Mode controllers for station keeping in simulated environments with disturbances. The results from these tests pointed towards the need for a more robust control technique, like deep-learning based control for enhanced performance. </p><p dir="ltr">The thesis then explores formation control, a crucial aspect of cooperative USV missions. A vision-based passive control strategy utilizing a virtual leader concept is proposed. This approach leverages onboard cameras to detect markers on other USVs, eliminating the need for direct communication and potentially improving scalability and resilience. </p><p dir="ltr">Then the thesis presents vision-based formation control architecture and the station keeping controller evaluations. Simulation results are presented, analyzed, and used to draw conclusions about the effectiveness of the proposed approaches. Finally, the thesis discusses the implications of the findings and proposes potential future research directions</p>
130

Object detection and classication in outdoor environments for autonomous passenger vehicle navigation based on Data Fusion of Articial Vision System and LiDAR sensor / Detecção e classificação de objetos em ambientes externos para navegação de um veículo de passeio autônomo utilizando fusão de dados de visão artificial e sensor laser

Roncancio Velandia, Henry 30 May 2014 (has links)
This research project took part in the SENA project (Autonomous Embedded Navigation System), which was developed at the Mobile Robotics Lab of the Mechatronics Group at the Engineering School of São Carlos, University of São Paulo (EESC - USP) in collaboration with the São Carlos Institute of Physics. Aiming for an autonomous behavior in the prototype vehicle this dissertation focused on deploying some machine learning algorithms to support its perception. These algorithms enabled the vehicle to execute articial-intelligence tasks, such as prediction and memory retrieval for object classication. Even though in autonomous navigation there are several perception, cognition and actuation tasks, this dissertation focused only on perception, which provides the vehicle control system with information about the environment around it. The most basic information to be provided is the existence of objects (obstacles) around the vehicle. In formation about the sort of object it is also provided, i.e., its classication among cars, pedestrians, stakes, the road, as well as the scale of such an object and its position in front of the vehicle. The environmental data was acquired by using a camera and a Velodyne LiDAR. A ceiling analysis of the object detection pipeline was used to simulate the proposed methodology. As a result, this analysis estimated that processing specic regions in the PDF Compressor Pro xii image (i.e., Regions of Interest, or RoIs), where it is more likely to nd an object, would be the best way of improving our recognition system, a process called image normalization. Consequently, experimental results in a data-fusion approach using laser data and images, in which RoIs were found using the LiDAR data, showed that the fusion approach can provide better object detection and classication compared with the use of either camera or LiDAR alone. Deploying a data-fusion classication using RoI method can be executed at 6 Hz and with 100% precision in pedestrians and 92.3% in cars. The fusion also enabled road estimation even when there were shadows and colored road markers in the image. Vision-based classier supported by LiDAR data provided a good solution for multi-scale object detection and even for the non-uniform illumination problem. / Este projeto de pesquisa fez parte do projeto SENA (Sistema Embarcado de Navegação Autônoma), ele foi realizado no Laboratório de Robótica Móvel do Grupo de Mecatrônica da Escola de Engenharia de São Carlos (EESC), em colaboração com o Instituto de Física de São Carlos (IFSC). A grande motivação do projeto SENA é o desenvolvimento de tecnologias assistidas e autônomas que possam atender às necessidades de diferentes tipos de motoristas (inexperientes, idosos, portadores de limitações, etc.). Vislumbra-se que a aplicação em larga escala desse tipo de tecnologia, em um futuro próximo, certamente reduzirá drasticamente a quantidade de pessoas feridas e mortas em acidentes automobilísticos em estradas e em ambientes urbanos. Nesse contexto, este projeto de pesquisa teve como objetivo proporcionar informações relativas ao ambiente ao redor do veículo, ao sistema de controle e de tomada de decisão embarcado no veículo autônomo. As informações mais básicas fornecidas são as posições dos objetos (obstáculos) ao redor do veículo; além disso, informações como o tipo de objeto (ou seja, sua classificação em carros, pedestres, postes e a própria rua mesma), assim como o tamanho deles. Os dados do ambiente são adquiridos através do emprego de uma câmera e um Velodyne LiDAR. Um estudo do tipo ceiling foi usado para simular a metodologia da detecção dos obstáculos. Estima-se que , após realizar o estudo, que analisar regiões especificas da imagem, chamadas de regiões de interesse, onde é mais provável encontrar um obstáculo, é o melhor jeito de melhorar o sistema de reconhecimento. Observou-se na implementação da fusão dos sensores que encontrar regiões de interesse usando LiDAR, e classificá-las usando visão artificial fornece um melhor resultado na hora de compará-lo com os resultados ao usar apenas câmera ou LiDAR. Obteve-se uma classificação com precisão de 100% para pedestres e 92,3% para carros, rodando em uma frequência de 6 Hz. A fusão dos sensores também forneceu um método para estimar a estrada mesmo quando esta tinha sombra ou faixas de cor. Em geral, a classificação baseada em visão artificial e LiDAR mostrou uma solução para detecção de objetos em várias escalas e mesmo para o problema da iluminação não uniforme do ambiente.

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