Shared control is a technique to provide interactive autonomy in a telerobotic task, replacing the requirement for pure teleoperation where the operator's intervention is unnecessary or even undesirable. In this thesis, a geometrically correct theory of shared control for teleoperation is developed using differential geometry. The autonomous function proposed is force control. In shared control, the workspace is commonly partitioned into a "position domain" and a "force domain". This computational process requires the use of a metric. In the context of manifolds, these are known as Riemannian metrics. The switching matrix is shown to be equivalent to a filter which embodies a Riemannian metric form. However, since the metric form is non-invariant, it is shown that the metric form must undergo a transformation if the measurement reference frame is moved. If the transformation is not made, then the switching matrix fails to produce correct results in the new measurement frame. Alternatively, the switching matrix can be viewed as a misinterpretation of a projection operator. Again, the projection operator needs to be transformed correctly if the measurement reference frame is moved. Many robot control architectures preclude the implementation of robust force control. However, a compliant device mounted between the robot wrist and the workpiece can be a good alternative in lieu of explicit force control. In this form of shared control, force and displacement are regulated by control of displacement only. The geometry of compliant devices is examined in the context of shared control and a geometrically correct scheme for shared control is derived. This scheme follows naturally from a theoretical analysis of stiffness and potential energy. This thesis unifies some recent results formulated for robotic hybrid position / force control under the modern framework of differential geometry and Lie groups.

La conception d'architectures opérationnelles d'un système de contrôle-commande est une phase très importante lors de la conception de systèmes de production d'énergie. Cette phase consiste à projeter l'architecture fonctionnelle sur l'architecture organique tout en respectant des contraintes de capacité et de sûreté, c'est-à-dire à allouer les fonctions de commande à un ensemble de contrôleurs tout en respectant ces contraintes. Les travaux présentés dans cette thèse proposent : i)une formalisation des données et contraintes du problème d'allocation de fonctions - ii)une méthode d'allocation, par recherche d'atteignabilité, basée sur un mécanisme d'appel/réponse dans un réseau d'automates communicants à variables entières - iii)la comparaison de cette méthode à une méthode de résolution par programmation linéaire en nombres entiers. Les résultats de ces travaux ont été validés sur des exemples de taille réelle et ouvrent la voie à des couplages entre recherche d'atteignabilité et programmation linéaire en nombres entiers pour la résolution de problèmes de satisfaction de systèmes de contraintes non linéaires. / The design of operational control architectures is a very important step of the design of energy production systems. This step consists in mapping the functional architecture of the system onto its hardware architecture while respecting capacity and safety constraints, i.e. in allocating control functions to a set of controllers while respecting these constraints. The work presented in this thesis presents: i) a formalization of the data and constraints of the function allocation problem- ii) a mapping method, by reachability analysis, based on a request/response mechanism in a network of communicating automata with integer variables- iii) a comparison between this method and a resolution method by integer linear programming. The results of this work have been validated on examples of actual size and open the way to the coupling between reachability analysis and integer linear programming for the resolution of satisfaction problems for non-linear constraint systems.

Devido à grande importância do ambiente aquático sobre a vida humana e às dificuldades inerentes ao seu estudo e exploração, a aplicação de AUVs tem se mostrado bastante benéfica e seu uso vem crescendo ao longo dos anos. Este trabalho apresenta um estudo sobre o desenvolvimento de veículos autônomos submarinos para realização de missões oceanográficas, com foco nas características de seus sistemas embarcados que permitam atender melhor os requisitos desta aplicação. Analisando trabalhos publicados nos últimos anos pode-se notar uma grande quantidade de AUVs desenvolvidos ou adaptados para aplicações em oceanografia, com uma grande variedade de soluções aplicadas em seus diversos sistemas, visando a realização de diversos tipos de missões necessárias para tais estudos. Como estudo de caso, foi apresentada a adaptação do AUV Pirajuba, desenvolvido inicialmente como uma plataforma de testes hidrodinâmicos, para aplicação em missões de levantamento de dados para estudos oceanográficos. Para tal, foi necessário realizar uma série de modificações em seus subsistemas, permitindo a instalação de novos sensores e equipamentos para aumento da segurança nas operações em mar aberto. As modificações necessárias envolveram tanto o sistema hidromecânico do veículo, com instalação de novos módulos no casco, quanto no seu sistema embarcado, implicando no desenvolvimento de uma nova versão do sistema de hardware e uma atualização no software de controle. Tendo em vista esta necessidade, foi proposto um estudo dos requisitos da aplicação oceanográfica de AUVs e os impactos no seu desenvolvimento. Para isso, foi realizado um levantamento dos requisitos das principais aplicações oceanográficas e seus impactos no desenvolvimento dos veículos, envolvendo os sistemas hidromecânico, energia, navegação, comunicação e controle. Foi realizado também um estudo da arquitetura de controle CANARMES, desenvolvida para o AUV Pirajuba, envolvendo os requisitos de seu projeto e as principais características da arquitetura de controle, que serviu como base para a atualização do veículo para as novas aplicações. São apresentados os resultados obtidos em testes de campo realizados no litoral de Ubatuba - SP, nos quais foram feitas manobras com movimentação vertical com a aquisição de dados de diversos sensores oceanográficos, utilizados para o estudo de detecção de camadas finas. / Due to the great importance of the aquatic environment on human life and the inherent difficulties of its study and exploration, the application of AUVs has been shown to be very beneficial and its use has been growing over the years. This work presents a study on the development of autonomous submarine vehicles for the accomplishment of oceanographic missions, focusing on the characteristics of the embedded systems of these vehicles in order to better meet the application requirements. Analyzing published works in the last five years, it can be noticed a great amount of AUVs developed or adapted for applications in oceanography, with a great variety of solutions applied in their embedded systems, involving both hardware and software, aiming at the accomplishment of several types of missions necessary for such studies. As a case study, the adaptation of the AUV Pirajuba, initially developed as a platform for hydrodynamic tests, was presented for application in data collection missions for oceanographic studies. For this, it was necessary to make a series of modifications in its subsystems, allowing the installation of new sensors and equipment to increase the safety in the operations in the open sea. The necessary modifications involved both the vehicle\'s hydromechanical system, with the installation of new modules in the hull, and in its embedded system, requiring the development of a new version of the hardware system and an update in the control software. Due to this necessities, a study was proposed to better understand the requirements of AUVs for oceanographic application and the impacts on their development. For that, a survey was made of the requirements of the main oceanographic applications and their impacts on the development of the vehicles, involving the hydromechanical, energy, navigation, communication and control systems. A study of the CANARMES control architecture, developed for the Pirajuba AUV, was carried out, involving the requirements of its design and the main characteristics of the control architecture, which served as a basis for updating the vehicle for new applications. We present the results obtained in field tests conducted in the coastal area of Ubatuba - SP, Brazil, in which maneuvers were performed with vertical movement, while acquiring data from several oceanographic sensors, used for the study of thin layer detection.

This thesis focuses on the development of a system in which a team of heterogeneous mobile robots can cooperate to perform a wide range of tasks. In order that a group of heterogeneous robots can cooperate among them, one of the most important parts to develop is the creation of an architecture which gives support for the cooperation. This architecture is developed by means of embedding agents and interfacing agent code with native low-level code. It also addresses the implementation of resource sharing among the whole group of robots, that is, the robots can borrow capabilities from each-other.In order to validate this architecture, some cooperative applications have been implemented. The first one is an application where a group of robots must cooperate in order to safely navigate through an unknown environment. One robot with camera calculates the optical flow values from the images, and from these values calculates the "time to contact" values. This information is shared among the team so that any robot can navigate without colliding with the obstacles.The second cooperative application consists of enabling the team of heterogeneous robots to create a certain formation and navigate maintaining this formation. The application consists of two parts or stages. The first one is the creation of the formation, where a robot with the camera can detect where the rest of the robots are in the environment and indicates to them which is their initial position in the formation. In the second stage the robots must be able to navigate through an environment following the path that the robot with the laser indicates. Due to the odometry errors of the robots, the camera of one of the robots is used so that robots which lose their correct position in the formation can re-align themselves. Finally, in an attempt to facilitate access to the robots of the team and to the information that their accessories provide, a system for the teleoperation of the team has been implemented. This system can be used for teaching robotics or to facilitate the tasks of programming and debugging in the research tasks.

The presented work focuses on the theoretical and practical aspects concerning the design and development of a formal method to build a mission control system for autonomous underwater vehicles bringing systematic design principles for the formal description of missions using Petri nets. The proposed methodology compounds Petri net building blocks within it to de_ne a mission plan for which it is proved that formal properties, such as reachability and reusability, hold as long as these same properties are also guaranteed by each Petri net building block. To simplify the de_nition of these Petri net blocks as well as their composition, a high level language called Mission Control Language has been developed. Moreover, a methodology to ensure coordination constraints for teams of multiple robots as well as the de_nition of an interface between the proposed system and an on-board planner able to plan/replan sequences of prede_ned mission plans is included as well. Results of experiments with several real underwater vehicles and simulations involving an autonomous surface craft and an autonomous underwater vehicles are presented to show the system's capabilities. / El treball presentat en aquesta tesi està centrat en el disseny i desenvolupament d'un mètode formal per a construir un sistema de control de missió per a vehicles submarins autònoms, que aporta principis sistemàtics de disseny per a la descripció formal de missions. La metodologia proposada parteix d'uns blocs elementals de construcció, descrits mitjançant xarxes de Petri. La composició d'aquests blocs entre si genera un pla de missió per el qual diverses propietats, com ara accessibilitat o reutilització, són garantides sempre i quan aquestes mateixes propietats siguin també garantides per a cada un dels blocs elementals de construcció. Per simplificar la definició d'aquests blocs, així com per simplificar-ne la seva composició, s'ha desenvolupat un llenguatge d'alt nivell anomenat Mission Control Language. A més, s'ha inclòs una metodologia per assegurar la coordinació de restriccions entre equips de múltiples robots. També s'ha establert una interfície entre el sistema proposat i un planificador a bord del vehicle capaç de planificar/replanificar seqü_encies de plans de missió prèviament definits. Per tal de demostrar les capacitats del sistema, s'han presentat resultats d'experiments amb diversos vehicles submarins reals, així com simulacions amb vehicles autònoms submarins i en superfície.

Devido à grande importância do ambiente aquático sobre a vida humana e às dificuldades inerentes ao seu estudo e exploração, a aplicação de AUVs tem se mostrado bastante benéfica e seu uso vem crescendo ao longo dos anos. Este trabalho apresenta um estudo sobre o desenvolvimento de veículos autônomos submarinos para realização de missões oceanográficas, com foco nas características de seus sistemas embarcados que permitam atender melhor os requisitos desta aplicação. Analisando trabalhos publicados nos últimos anos pode-se notar uma grande quantidade de AUVs desenvolvidos ou adaptados para aplicações em oceanografia, com uma grande variedade de soluções aplicadas em seus diversos sistemas, visando a realização de diversos tipos de missões necessárias para tais estudos. Como estudo de caso, foi apresentada a adaptação do AUV Pirajuba, desenvolvido inicialmente como uma plataforma de testes hidrodinâmicos, para aplicação em missões de levantamento de dados para estudos oceanográficos. Para tal, foi necessário realizar uma série de modificações em seus subsistemas, permitindo a instalação de novos sensores e equipamentos para aumento da segurança nas operações em mar aberto. As modificações necessárias envolveram tanto o sistema hidromecânico do veículo, com instalação de novos módulos no casco, quanto no seu sistema embarcado, implicando no desenvolvimento de uma nova versão do sistema de hardware e uma atualização no software de controle. Tendo em vista esta necessidade, foi proposto um estudo dos requisitos da aplicação oceanográfica de AUVs e os impactos no seu desenvolvimento. Para isso, foi realizado um levantamento dos requisitos das principais aplicações oceanográficas e seus impactos no desenvolvimento dos veículos, envolvendo os sistemas hidromecânico, energia, navegação, comunicação e controle. Foi realizado também um estudo da arquitetura de controle CANARMES, desenvolvida para o AUV Pirajuba, envolvendo os requisitos de seu projeto e as principais características da arquitetura de controle, que serviu como base para a atualização do veículo para as novas aplicações. São apresentados os resultados obtidos em testes de campo realizados no litoral de Ubatuba - SP, nos quais foram feitas manobras com movimentação vertical com a aquisição de dados de diversos sensores oceanográficos, utilizados para o estudo de detecção de camadas finas. / Due to the great importance of the aquatic environment on human life and the inherent difficulties of its study and exploration, the application of AUVs has been shown to be very beneficial and its use has been growing over the years. This work presents a study on the development of autonomous submarine vehicles for the accomplishment of oceanographic missions, focusing on the characteristics of the embedded systems of these vehicles in order to better meet the application requirements. Analyzing published works in the last five years, it can be noticed a great amount of AUVs developed or adapted for applications in oceanography, with a great variety of solutions applied in their embedded systems, involving both hardware and software, aiming at the accomplishment of several types of missions necessary for such studies. As a case study, the adaptation of the AUV Pirajuba, initially developed as a platform for hydrodynamic tests, was presented for application in data collection missions for oceanographic studies. For this, it was necessary to make a series of modifications in its subsystems, allowing the installation of new sensors and equipment to increase the safety in the operations in the open sea. The necessary modifications involved both the vehicle\'s hydromechanical system, with the installation of new modules in the hull, and in its embedded system, requiring the development of a new version of the hardware system and an update in the control software. Due to this necessities, a study was proposed to better understand the requirements of AUVs for oceanographic application and the impacts on their development. For that, a survey was made of the requirements of the main oceanographic applications and their impacts on the development of the vehicles, involving the hydromechanical, energy, navigation, communication and control systems. A study of the CANARMES control architecture, developed for the Pirajuba AUV, was carried out, involving the requirements of its design and the main characteristics of the control architecture, which served as a basis for updating the vehicle for new applications. We present the results obtained in field tests conducted in the coastal area of Ubatuba - SP, Brazil, in which maneuvers were performed with vertical movement, while acquiring data from several oceanographic sensors, used for the study of thin layer detection.

<p> Cooperative haptics enables multiple users to manipulate computer simulated objects in a shared virtual environment and to feel the presence of other users. Prior research in the literature has mainly addressed single user haptic interaction. This thesis is concerned with haptic simulation in multi-user virtual environments in which the users can interact in a shared virtual world from separate workstations over Ethernet-based Local Area Networks (LANs) or Metropolitan Area Networks (MANs). In practice, the achievable real-time communication rate using a typical implementation of network protocols such as the UDP and TCP/IP can be well below the 1kHz update rate that is suggested in the literature for high fidelity haptic rendering. However by adopting a multi-rate control strategy as proposed in this work, the local control loops can be executed at 1kHz while the data packet transmission between the user workstations occur at a lower rate. Within such a framework, two control architectures, namely centralized and distributed are presented. In the centralized controller a central workstation simulates the virtual environment, whereas in the distributed controller each user workstation simulates its own copy of the virtual environment. Two different approaches have been proposed for mathematical modeling of the controllers and have been used in a comparative analysis of their stability and performance. The results of such analysis demonstrate that the distributed control architecture has greater stability margins and outperforms the centralized controller. They also reveal that the limited network transmission rate can degrade the haptic fidelity by introducing viscous damping into the virtual object perceived impedance. This extra damping is compensated by active control based on the damping values obtained from the analytical results. Experimental results conducted with a dual-user/dual-finger haptic platform are presented for each of the proposed controller under various scenarios in which the user workstations communicate with UDP protocol subjected to a limited transmission rate. The results demonstrate the effectiveness of the proposed distributed architecture in providing a stable and transparent haptic simulation in free motion and in contact with rigid environments.</p> / Thesis / Master of Applied Science (MASc)

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: RoboCup promotes research in robotics and multi-robot systems (MRS). The RoboCup Small Size League (SSL), in particular, offers an entry level opportunity to take part in this field of study. This thesis presents a starting phase for research in robotics and MRS at Stellenbosch University. It includes the full documentation of the mechanical, electronic and software design of an omni-directional soccer robot for RoboCup SSL. The robot is also meant to operate as a hardware and software development platform for research in MRS. The platform was therefore designed with high-level programming language compatibility, a wide range of connectivity, and modularity in mind. The robot uses a single board computer (SBC) running a Linux operating system to accomplish these objectives. Moreover, a driver class library was written in C++ as a software application interface (API) for future development on the robot platform. The robot was also developed with a particular focus on a distributed control architecture. "Player" was implemented as the middleware, which can be used for communication between multiple robots in a distributed environment. Additionally, three tests were performed to demonstrate the functionality of the prototype: a PI speed control test, a direction accuracy test and a static communication test using the middleware. Recommendations for possible future work are also given. / AFRIKAANSE OPSOMMING: RoboCup bevorder navorsing in robotika en multi-robot-stelsels (MRS). Die RoboCup Klein Liga (KL) bied in die besonder die geleentheid om op intreevlak navorsing te doen in hierdie veld. Hierdie tesis verteenwoordig die eerste fase van navorsing in robotika en MRS by Stellenbosch Universiteit. Dit sluit die volledige dokumentasie van die meganiese, elektroniese en sagteware-ontwerp van ’n omnidireksionele sokker-robot vir die KL in. Die robot is ook veronderstel om te dien as ’n hardeware- en sagteware-ontwikkelingsplatform vir navorsing in MRS. Die platform is dus ontwerp met ’n verskeidenheid van uitbreingsmoontlikhede en modulariteit in gedagte asook die moontlikheid om gebruik te maak van ’n hoë-vlak programmeertaal. Om hierdie doelwitte te bereik, maak die robot gebruik van ’n enkel-bord-rekenaar met ’n Linux bedryfstelsel. Verder was ’n sagteware drywer in C++ geskryf om te dien as ’n sagteware-koppelvlak vir toekomstige ontwikkeling op die robot platform. Die robot is ook ontwikkel met die besondere fokus op ’n gedesentraliseerde beheerstels. Player was geïmplementeer as die middelware, wat gebruik kan word vir kommunikasie tussen verskeie robotte in ’n gedesentralliseerde beheerstelsel. Daar is drie toetse uitgevoer om die funksionaliteit van die prototipe te demonstreer, ’n PI spoed beheer toets, ’n rigting akkuraatheidstoets en ’n statiese kommunikasie toets deur van die middelware gebruik te maak. Aanbevelings vir moontlike toekomstige werk word ook verskaf.

Made available in DSpace on 2016-06-02T19:05:49Z (GMT). No. of bitstreams: 1 3569.pdf: 2552721 bytes, checksum: b67cadf34336e157d59bd554dfc7534e (MD5) Previous issue date: 2006-05-29 / An Automated Manufacturing System (AMS) is a production system where a discrete number of raws is processed and assembled by controlled machines and/or robots. Controlling AMS is a complex task, due to the several sub-systems that compose it and the need for attending strategic production issues and market. The AMS control complexity increases with the necessity of production and technologic resources. The studies related to AMS control normally consider specific features of the system. Some authors propose solutions considering architecture, some others consider approaches by modular nets, others consider mathematic analysis; and so, each study has its contribution in a specific point. This work considers a wider set of features related to the problem of modeling AMS control. It is presented different options of architecture, different ways to concern hierarchically about the problem, the use of Petri Nets as a way to represent graphically the problem conserving the mathematic formalisms, simulation, and the use of a graphic software that treat all the options before. The proposal of this work is indicate a modeling method for AMS control that considers all features related to its control. This method proposes eight elaboration stages of the model. The stands consider the elements in a specification level more generic and, gradually, they are more detailed. In some stands, simulations are applied with the objective of validate what has been modeled. The work ends with the application of the method to a hypothetic FMS. It is considered a production planning for five types of products in determined quantities. The method application is considered effective, since trough the simulation of the model, it can be verified that all the products are produced according to the production plan proposed and that eventual deadlocks and conflicts can be avoided. / Um sistema automático de manufatura (AMS) é um sistema de produção onde um número discreto de matérias-primas é processado e montado por máquinas controladas e/ou robôs. Fazer o controle de um AMS é uma tarefa complexa pela existência de vários subsistemas e elementos que o compõem, e também pela necessidade de responder a questões estratégicas de produção e mercado. A complexidade de controle de AMS aumenta com as necessidades de produção e recursos tecnológicos. Os trabalhos relativos a controle de AMS normalmente consideram características específicas do sistema. Alguns autores propõem soluções considerando a arquitetura, outros consideram abordagens por redes modulares, alguns consideram análise matemática; e assim, cada trabalho faz sua contribuição em um ponto mais especifico. Este trabalho busca considerar um conjunto mais abrangente de características inerentes ao problema de modelagem de controle de AMS. Nele são apresentadas várias abordagens inerentes às diversas características encontradas em um AMS. São mostradas diferentes opções de arquiteturas, formas diferentes de abordar hierarquicamente o problema, o uso de redes de Petri como forma de representar graficamente o problema conservando o formalismo matemático, simulação, e o uso de um software gráfico que contemple todas as opções anteriores. A proposta do trabalho é indicar um método de modelagem de AMS que considere as características inerentes ao seu controle. Este método propõe oito etapas de elaboração do modelo. As etapas consideram os elementos em um nível de especificação mais genérico e que, gradualmente, vão sendo mais detalhados. Em algumas etapas são feitas simulações no intuito de validar o que já tenha sido modelado. O trabalho chega ao fim com a aplicação do método de modelagem sobre um FMS hipotético. É considerado um planejamento da produção para cinco tipos de produtos em quantidades determinadas. A aplicação do método se mostra eficaz uma vez que, através da simulação do modelo, pode-se verificar que todos os produtos são fabricados conforme o plano de produção proposto e que eventuais deadlocks e conflitos podem ser evitados.

Cette thèse présente l’étude d’une stratégie de coordination hybride d’un groupe de robots sous-marins pour la recherche d’objets de petites dimensions ou de singularités sur les fonds marins. Chaque robot est équipé d’un module de perception utilisant la librairie de traitement d’image OpenCV qui lui permet d’apercevoir les autres éléments de la meute ainsi que l’environnement d’évolution de la mission.Cette stratégie hybride est constituée de deux phases : une phase de mise en formation géométrique et une phase d’acquisition des données vidéo. La première phase s’appuie sur des algorithmes de type "essaims" alors que la seconde se fonde sur une méthode hiérarchique de coordination. En cas de perte de la formation, le groupe de robots quitte le mode hiérarchique et reprend le mode essaim pour se reformer. Ces changements de modes sont contrôlés par une machine à états finis. Avant d’entamer une expérimentation en grandeur nature, la méthodologie et les algorithmes de coordination doivent être testés et validés par simulation.Dans ce contexte, un simulateur basé sur le logiciel Blender a été conçu de façon à ce qu’il tienne compte des différentes contraintes liées à l’évolution des robots dans l’environnement sous-marin. Les résultats de simulation d’une meute de 3 AUVs montrent la capacité de notre stratégie à optimiser l’exécution d’une mission d’acquisition vidéo par un groupe de robots autonomes contrôlés par la vision et coordonnés par une stratégie hybride. / In the underwater environment, the needs of data acquisition have significantly increased over the last decades. As electromagnetic waves show poor propagation in sea water, acoustical sensing is generally preferred. However, the emergence of small and low cost autonomous underwater vehicles (AUV) allow for rethinking the underwater use of optical sensors as their small coverage can be significantly improved by using a fleet of coordinated underwater robots.This paper presents a strategy to coordinate the group of robots in order to systematically survey the seabed to detect small objects or singularities. The proposed hybrid coordination strategy is defined by two main modes. The first mode relies on a swarm algorithm to organize the team in geometrical formation. In the second mode, the robot formation is maintained using a hierarchical coordination. A finite state machine controls the high level hybrid strategy by defining the appropriate coordination mode according to the evolution of the mission. Before sea validation, the behavior and the performance of the hybrid coordination strategy are first assessed in simulation. The control of individual robots relies on visual servoing, implemented with the OpenCV library, and the simulation tool is based on Blender software.The dynamics of the robots has been implemented in a realistic way in Blender by using the Bullet solver and the hydrodynamic coeficcients estimated on the actual robot. First results of the hybrid coordination strategy applied on a fleet of 3 AUV’s, show execution of a video acquisition task by a group of autonomous robots controlled by vision and coordinated by a hybrid strategy.