In order to improve the comfort of power wheelchair users, it is proposed in this dissertation the implementation of a position and orientation control system which allow the users to travel the desired trajectories safely, without the need for constant interaction with the device command system. To reach this objective, it is proposed a methodology for the implementation of a control system, able to drive the vehicle from an initial position to the desired one or make it follow a specified trajectory, from commands received in the system. The proposed control system is based on a cascade control law, composed by a nonlinear pose controller and a velocity tracking controller. Two velocity control strategies are proposed. The first one uses a velocity controller composed of two joint-independent Proportional-Integral controllers while the second one uses a velocity controller based on the dynamic model, which is linearized by a state-feedback. The methods are implemented using the ros_control package, provided by the framework Robot Operating System (ROS). The evaluation of the proposed methods is done with a differential-drive mobile robot, which has the same kinematic configuration as the majority of commercial power wheelchairs. The results of dynamic-model parameter identification, as well as the convergence of the controlled variables by using the proposed control methods, are presented. The results demonstrate that the methods achieve the proposed control objectives.

In order to improve the comfort of power wheelchair users, it is proposed in this dissertation the implementation of a position and orientation control system which allow the users to travel the desired trajectories safely, without the need for constant interaction with the device command system. To reach this objective, it is proposed a methodology for the implementation of a control system, able to drive the vehicle from an initial position to the desired one or make it follow a specified trajectory, from commands received in the system. The proposed control system is based on a cascade control law, composed by a nonlinear pose controller and a velocity tracking controller. Two velocity control strategies are proposed. The first one uses a velocity controller composed of two joint-independent Proportional-Integral controllers while the second one uses a velocity controller based on the dynamic model, which is linearized by a state-feedback. The methods are implemented using the ros_control package, provided by the framework Robot Operating System (ROS). The evaluation of the proposed methods is done with a differential-drive mobile robot, which has the same kinematic configuration as the majority of commercial power wheelchairs. The results of dynamic-model parameter identification, as well as the convergence of the controlled variables by using the proposed control methods, are presented. The results demonstrate that the methods achieve the proposed control objectives.

Orientador: Prof. Dr. Luiz de Siqueira Martins-Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, 2017. / Esta dissertação trata do problema de navegação e orientação do robô móvel, que são considerados como as principais tarefas dele. Diferentes sistemas sensoriais, como o visual, ultra-som e infravermelho, executam com êxito a tarefa de navegação. No entanto, o desempenho desses sensores depende estritamente da neblina ambiente, neblina densa, condições subaquáticas. Um robô extremamente simples será apresentado com a qual a navegação ainda é possível. Para conseguir isso, replicar exatamente o que a natureza está fazendo não é obrigatório. É necessário apenas obter princípios envolvidos, por exemplo, em como um homem cego encontra o caminho ou mesmo como as baratas, ratos ou selos navegam. Toda a idéia é utilizar o robô móvel para que ele possa explorar um ambiente interno e encontrar a porta de saída por requisitos mínimos de detecção com a tentativa de fazer o robô mais simples com apenas informações de contato navegar. Portanto, uma antena é anexada a um robô de rodas comercialmente disponível. A antena faz o robô detectar o seu ambiente e não permite que o robô se guie muito perto da parede. Uma estratégia de navegação para um robô móvel é introduzida com base no mecanismo do homem cego encontrando sua maneira de usar a informação interativa obtida através de contatos e informações do próprio braço para entender a posição relativa dos objetos contatados ou sua própria posição e explorar em uma sala sem o mapa. O método apresentado para um robô equipado com uma antena de 1 DOF como um efetor final onde a variação de ângulo entre o braço do robô móvel DaNI e a parede vem de um codificador. Este robô simples escolhe uma direção de movimento e se move naquela direção na medida do possível. Finalmente, a viabilidade e a confiabilidade deste estudo são verificadas pelos resultados da simulação no LabVIEW. / This dissertation deals with the Navigation and orientation problem of mobile robot, which are considered as the main tasks of it. Different sensory systems such as visual, ultrasonic and infrared successfully perform navigation task. However, the performance of these sensors strictly depends on the ambient dark, dense fog, underwater conditions. An extremely simple robot will be presented with which navigation is still possible. To achieve this replicating exactly what nature is doing is not obligatory. It is necessary to just get principles involved in for instance how a blind man find its way or even how cockroaches, rats or seals navigate. The whole idea is to utilize the mobile robot so that it could explore an indoor environment and find the exit door by minimum sensing requirements with the attempt to make simplest robot with only contact information navigate. Therefore an antenna is attached to a commercially available wheeled robot. The antenna makes the robot sense its environment and does not allow the robot to steer too close to the wall. A navigation strategy for a mobile robot is introduced based on the mechanism of blind man finding their way using the interactive information obtained through contacts and own arm information to understand the relative position of the objects contacted or its own position and to explore in a room without the map. The method presented for a robot equipped with a 1-DOF antenna as an end effector where the angle variation between DaNI mobile robot arm and wall comes from an encoder. This simple robot chooses a motion direction and moves in that direction as far as possible. Finally, the feasibility and reliability of this study are verified by the simulation results in LabVIEW.

abstract: Toward the ambitious long-term goal of a fleet of cooperating Flexible Autonomous Machines operating in an uncertain Environment (FAME), this thesis addresses several critical modeling, design and control objectives for ground vehicles. One central objective was to show how off-the-shelf (low-cost) remote-control (RC) “toy” vehicles can be converted into intelligent multi-capability robotic-platforms for conducting FAME research. This is shown for two vehicle classes: (1) six differential-drive (DD) RC vehicles called Thunder Tumbler (DDTT) and (2) one rear-wheel drive (RWD) RC car called Ford F-150 (1:14 scale). Each DDTT-vehicle was augmented to provide a substantive suite of capabilities as summarized below (It should be noted, however, that only one DDTT-vehicle was augmented with an inertial measurement unit (IMU) and 2.4 GHz RC capability): (1) magnetic wheel-encoders/IMU for(dead-reckoning-based) inner-loop speed-control and outer-loop position-directional-control, (2) Arduino Uno microcontroller-board for encoder-based inner-loop speed-control and encoder-IMU-ultrasound-based outer-loop cruise-position-directional-separation-control, (3) Arduino motor-shield for inner-loop motor-speed-control, (4)Raspberry Pi II computer-board for demanding outer-loop vision-based cruise- position-directional-control, (5) Raspberry Pi 5MP camera for outer-loop cruise-position-directional-control (exploiting WiFi to send video back to laptop), (6) forward-pointing ultrasonic distance/rangefinder sensor for outer-loop separation-control, and (7) 2.4 GHz spread-spectrum RC capability to replace original 27/49 MHz RC. Each “enhanced”/ augmented DDTT-vehicle costs less than 􀀀175 but offers the capability of commercially available vehicles costing over 􀀀500. Both the Arduino and Raspberry are low-cost, well-supported (software wise) and easy-to-use. For the vehicle classes considered (i.e. DD, RWD), both kinematic and dynamical (planar xy) models are examined. Suitable nonlinear/linear-models are used to develop inner/outer-loopcontrol laws. All demonstrations presented involve enhanced DDTT-vehicles; one the F-150; one a quadrotor. The following summarizes key hardware demonstrations: (1) cruise-control along line, (2) position-control along line (3) position-control along curve (4) planar (xy) Cartesian stabilization, (5) cruise-control along jagged line/curve, (6) vehicle-target spacing-control, (7) multi-robot spacing-control along line/curve, (8) tracking slowly-moving remote-controlled quadrotor, (9) avoiding obstacle while moving toward target, (10) RC F-150 followed by DDTT-vehicle. Hardware data/video is compared with, and corroborated by, model-based simulations. In short, many capabilities that are critical for reaching the longer-term FAME goal are demonstrated. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

Submitted by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-16T12:39:19Z No. of bitstreams: 1 arquivototal.pdf: 6585826 bytes, checksum: 7c4b9710f530b142defafd4f6be7d1a8 (MD5) / Made available in DSpace on 2017-08-16T12:39:19Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 6585826 bytes, checksum: 7c4b9710f530b142defafd4f6be7d1a8 (MD5) Previous issue date: 2016-02-19 / Abstract This paper aims to present a novel approach in planar RGB-D SLAM, here called Object Subtraction SLAM (OS-SLAM), using only low-cost RGB-D sensors such as the Microsoft Kinect. Our approach subtracts objects from the 3D environment and creates a clean 3D map projecting estimated planes without identified objects encountered along the mapping procedure aiming to increase accuracy. To validate our approach we performed four experiments, three in a real environment and one with an open dataset comparing them with other state-of-the-art algorithms. The algorithms were applied to a TurtleBot 2 platform which has a RGB-D sensor as its main sensor. The results demonstrated the efficiency on generated a clean and accurate map using the OS-SLAM algorithm. / Resumo Este trabalho tem como objetivo apresentar uma nova abordagem em RGB-D Planar SLAM, aqui chamada SLAM Baseado em Subtração de Objetos (OS-SLAM), utilizando apenas sensores RGB-D de baixo custo, como o Microsoft Kinect. Essa abordagem subtrai objetos do ambiente 3D e cria um mapa 3D limpo, projetando planos estimados sem os objetos identificados e encontrados ao longo do procedimento de mapeamento. Para validar esta abordagem, foram realizados quatro experimentos. Três deles em um ambiente real e um com um conjunto de dados abertos comparando-os com outros algoritmos do estado-da-arte. Os algoritmos foram aplicados a uma plataforma turtlebot 2, que tem um sensor RGB-D como seu sensor principal. Os resultados demonstraram a eficiência na geração de mapas limpos e precisos utilizando o algoritmo OS-SLAM

Made available in DSpace on 2015-05-14T12:36:49Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3512497 bytes, checksum: 22606000aee179c4fa5e12daeebccb2c (MD5) Previous issue date: 2014-02-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The development of algorithms oriented to robotic systems, in simulation environments, supports the identification and prediction of many problems before their tests in real environments. However, there is still not a process to ensure that an algorithm evaluated in a simulation platform will similarly work when migrated to real robots. The interference of several factors, such as engine and sensors properties, as well as the lack of a methodology that supports the interaction simulation/reality is considered as one of the main problems in this transition, so that there is a large conceptual development gap between real and simulated environments. This work aims to contribute with the formalization of a conceptual model to assist in the transition process, in which it is possible to highlight the peculiarities that require further attention from developers.. For that end, as a case study, it was developed an anti-collision algorithm, which involves several characteristics of a robotic system. Its implementation was carried out in both Unity3D simulator and real robots developed in the Arduino platform. The results were obtained and compared by a quantitative analysis of graphs using MATLAB. All necessary changes were classified and evaluated, raising up an initial idea of the transition model, which formalizes the main particulars of the project / O desenvolvimento de algoritmos voltados para sistemas robóticos, em ambientes de simulação, auxilia na identificação e antecipação de muitos problemas antes mesmo de serem testados em ambientes reais. Porém, nada garante que um algoritmo avaliado em uma plataforma de simulação funcione quando migrado para robôs reais. A interferência de diversos fatores, como propriedades dos motores e sensores, bem como a falta de uma metodologia necessária para interação simulação/realidade, se caracteriza como um dos principais problemas desta transição, de modo que, existe um grande gap conceitual entre o desenvolvimento para ambientes reais e simulados. Este trabalho tem o objetivo de contribuir com a formalização de um modelo conceitual que auxilie no processo de transição, no qual é possível destacar as peculiaridades que carecem de uma maior atenção por parte dos desenvolvedores. Para isso, como estudo de casos, foi desenvolvido um algoritmo de anticolisão, que engloba diversas características de um sistema robótico, sendo realizada sua implementação tanto no simulador Unity3D, quanto em robôs reais desenvolvidos na plataforma Arduino. Os resultados foram obtidos e comparados através de uma análise quantitativa de gráficos originados pelo MATLAB. Todas as alterações necessárias foram classificadas e avaliadas, de forma que possamos ter uma ideia do modelo de transição inicial, o qual formalize as principais particularidades do projeto

Made available in DSpace on 2014-12-17T14:55:32Z (GMT). No. of bitstreams: 1 VivianeAA_pag47_ate_pag74.pdf: 8458101 bytes, checksum: b6838ee89eafca0ef9837da1230e9148 (MD5) Previous issue date: 2004-12-22 / In this work, we propose methodologies and computer tools to insert robots in cultural environments. The basic idea is to have a robot in a real context (a cultural space) that can represent an user connected to the system through Internet (visitor avatar in the real space) and that the robot also have its representation in a Mixed Reality space (robot avatar in the virtual space). In this way, robot and avatar are not simply real and virtual objects. They play a more important role in the scenery, interfering in the process and taking decisions. In order to have this service running, we developed a module composed by a robot, communication tools and ways to provide integration of these with the virtual environment. As welI we implemented a set of behaviors with the purpose of controlling the robot in the real space. We studied available software and hardware tools for the robotics platform used in the experiments, as welI we developed test routines to determine their potentialities. Finally, we studied the behavior-based control model, we planned and implemented alI the necessary behaviors for the robot integration to the real and virtual cultural spaces. Several experiments were conducted, in order to validate the developed methodologies and tools / Neste trabalho, propomos metodologias e ferramentas computacionais visando inserir rob?s em ambientes culturais. O objetivo ? que um rob? localizado em um contexto real (espa?o cultural) possa representar tanto um usu?rio conectado ao sistema via Internet (avatar real para o visitante virtual), como tamb?m ter seu avatar em um ambiente de Realidade Mista (avatar para o rob? no ambiente virtual). Nesse sentido, o rob? e seu avatar deixam de ser meros objetos, real e virtual, e passam a ter uma fun??o mais importante no cen?rio, podendo interferir no processo e tomar decis?es. Para que esse servi?o possa ser disponibilizado, desenvolvemos um m?dulo composto por um rob?, ferramentas de comunica??o e provemos maneiras de realizar a integra??o entre este e o ambiente virtual, bem como implementamos um conjunto de comportamentos com a finalidade de controle do prot?tipo no seu ambiente real. Estudamos ferramentas de software e Hardware dispon?veis para a plataforma rob?tica usada nos experimentos, bem como desenvolvemos rotinas de testes para determinar suas potencialidades. Ainda, estudamos o modelo de controle baseado em comportamentos, planejamos e implementamos todos os comportamentos necess?rios ? integra??o do rob? aos ambientes real e virtual. V?rios experimentos foram realizados para valida??o das metodologias e ferramentas desenvolvidas, permitindo concluir que as mesmas atendem de forma satisfat?ria ao prop?sito inicial para o qual foram desenvolvidas

Made available in DSpace on 2014-12-17T14:56:02Z (GMT). No. of bitstreams: 1 FredericoCV.pdf: 1331103 bytes, checksum: ada41c7da2fcc7a89d6ae45f8758a676 (MD5) Previous issue date: 2006-02-03 / This work addresses the dynamic control problem of two-wheeled differentially driven non-holonomic mobile robot. Strategies for robot positioning control and robot orientating control are presented. Such strategies just require information about the robot con?guration (x, y and teta), which can be collected by an absolute positioning system. The strategies development is related to a change on the controlled variables for such systems, from x, y and teta to s (denoting the robot linear displacement) and teta, and makes use of the polar coordinates representation for the robot kinematic model. Thus, it is possible to obtain a linear representation for the mobile robot dynamic model and to develop such strategies. It is also presented that such strategies allow the use of linear controllers to solve the control problem. It is shown that there is flexibility to choice the linear controller (P, PI, PID, Model Matching techniques, others) to be implemented. This work presents an introduction to mobile robotics and their characteristics followed by the control strategies development and controllers design. Finally, simulated and experimental results are presented and commented / Esta disserta??o trata do problema de controle din?mico de rob?s m?veis n?o-holon?micos com duas rodas e acionamento diferencial. S?o apresentadas estrat?gias para controle de posi??o e de orienta??o de rob?s com as caracter?sticas citadas, baseadas apenas em informa??es de configura??o do rob? (posi??o e orienta??o no espa?o cartesiano x, y e teta), coletadas a partir de um sistema de posicionamento absoluto. O desenvolvimento da estrat?gia est? associado a uma mudan?a nas vari?veis controladas do rob?, de x, y e teta para s (representando o deslocamento linear do rob?) e teta, e na representa??o em coordenadas polares do modelo cinem?tico do rob?. Desta forma, consegue-se uma representa??o linear para o modelo din?mico do rob?, a partir da qual s?o propostas as estrat?gias de controle. Com as estrat?gias definidas, mostra-se que ? poss?vel implementar controladores din?micos lineares para permitir a estabiliza??o do sistema rob?tico. As estrat?gias apresentadas tamb?m fornecem flexibilidade com rela??o ? escolha do tipo de controlador din?mico (P, PI, PID, t?cnica Model Matching, entre outros) a ser utilizado. Esta disserta??o apresenta uma introdu??o ? rob?tica m?vel e ?s caracter?sticas do tipo de sistema abordado, seguindo para uma revis?o bibliogr?fica, desenvolvimento das estrat?gias de controle e projeto dos controladores. Finalmente, s?o apresentados e discutidos resultados obtidos atrav?s de simula??es e resultados experimentais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this work is to present the development of a robotic leg, based on a four-bar 4R spatial mechanism, named as Bennett s mechanism. Using an adequate configuration of this mechanism, it is possible to describe a spatial curve, which is similar to the profile of a gait, using only one degree of freedom. Due to its simplicity, the modeled leg is simpler than the legs which are currently used on the mobile robots. To make easy the obstacles transposition, another two degrees of freedom had been added to the leg, allowing it a higher mobility. These aditional degrees of freedom don t compromise the performance of the structure because they are used just during the crossing of the obstacle, where the robot normally moves at lower speeds. The modeled leg, although not to have its configuration optimized, it has presented good results, being capable of crossing obstacles of considerable dimensions, comparing to its own dimensions. Graphical simulations have shown that the physical dimensions of the structure influence the dimensions of the obstacle that the leg can transpose. / O objetivo desse trabalho é apresentar o desenvolvimento de uma perna robótica, modelada com base em um mecanismo espacial de quatro barras do tipo 4R, denominado mecanismo de Bennett. Sabe-se que com uma configuração adequada desse mecanismo é possível descrever uma trajetória espacial, com perfil similar ao perfil de um passo, utilizando apenas um grau de liberdade. Em função disso, a perna modelada é bem mais simples do que a grande maioria das pernas que são utilizadas atualmente nos robôs móveis. Em função da necessidade de se transpor obstáculos, foram adicionados à perna dois graus de liberdade, dando a ela uma maior mobilidade. Esses graus de liberdade adicionais não comprometem o desempenho da estrutura, pois são utilizados apenas durante a transposição de obstáculos, que é uma situação na qual o robô normalmente se movimenta a velocidades mais baixas. A perna modelada, apesar de não ter tido sua configuração otimizada, apresentou resultados satisfatórios, sendo capaz de transpor obstáculos de dimensões comparativas às dimensões da perna. As simulações gráficas confirmam que as dimensões físicas da estrutura exercem grande influência sobre as dimensões de obstáculos que a perna pode transpor. / Mestre em Engenharia Mecânica

The upcoming new generation of autonomous vehicles for transporting materials in industrial environments will be more versatile, flexible and efficient than traditional Automatic Guided Vehicles (AGV), which simply follow pre-defined paths. However, freely navigating vehicles can appear unpredictable to human workers and thus cause stress and render joint use of the available space inefficient. This work addresses the problem of providing information regarding a service robot’s intention to humans co-populating the environment. The overall goal is to make humans feel safer and more comfortable, even when they are in close vicinity of the robot. A spatial Augmented Reality (AR) system for robot intention communication by means of projecting proxemic information onto shared floor space is developed on a robotic fork-lift by equipping it with a LED projector. This helps in visualizing internal state information and intents on the shared floors spaces. The robot’s ability to communicate its intentions is evaluated in realistic situations where test subjects meet the robotic forklift. A Likert scalebased evaluation which also includes comparisons to human-human intention communication was performed. The results show that already adding simple information, such as the trajectory and the space to be occupied by the robot in the near future, is able to effectively improve human response to the robot. This kind of synergistic human-robot interaction in a work environment is expected to increase the robot’s acceptability in the industry.