Navigation and guidance of mobile robots towards steady or maneuvering objects (targets) is one of the most important areas of robotics that has attracted a lot of attention in recent decades. However, in most of the existing methods, both the line-of-sight angle (bearing) and the relative distance (range) are assumed to be available for navigation and guidance algorithms. There is also a relatively large body of research on navigation and guidance with bearings-only measurements. In contrast, only a few results on navigation and guidance towards an unknown target using range-only measurements have been published. Various problems of navigation, guidance, location estimation and target tracking based on range-only measurements often arise in new wireless networks related applications. Recent advances in these applications allow us to use inexpensive transponders and receivers for range-only measurements which provide information in dynamic and noisy environments without the necessity of line-of-sight. To take advantage of these sensors, algorithms must be developed for range-only navigation. The main part of this thesis is concerned with the problem of real-time navigation and guidance of Wheeled Mobile Robots (WMRs) towards an unknown stationary or moving target using range-only measurements. The range can be estimated using the signal strength and the robust extended Kalman filtering. Several similar algorithms for navigation and guidance termed Equiangular Navigation and Guidance (ENG) laws are proposed and mathematically rigorous proofs of convergence and stability of the proposed guidance laws are given. The experimental investigation into the use of range data for a WMR navigation is documented and the results and discussions on the performance of the proposed guidance strategies are presented, where a wheeled robot successfully approach a stationary or follow a maneuvering target. In order to safely navigate and reliably operate in populated environments, ENG is then modified into Augmented-ENG (AENG), which enables the robot to approach a stationary target or follow an unpredictable maneuvering object in an unknown environment, while keeping a safe distance from the target, and simultaneously preserving a safety margin from the obstacles. Furthermore, we propose and experimentally investigate a new biologically inspired method for local obstacle avoidance and give the mathematically rigorous proof of the idea. In order for the robot to avoid collision and bypass the enroute obstacles in this method, the angle between the instantaneous moving direction of the robot and a reference point on the surface of the obstacle is kept constant. The proposed idea is combined with the ENG law, which leads to a reliable and fast long-range navigation. The performance of both navigation strategy and local obstacle avoidance techniques are confirmed with computer simulations and several experiments with ActivMedia Pioneer 3-DX wheeled robots. The second part of the thesis investigates some challenging problems in the area of wheeled robot navigation. We first address the problem of bearing-only guidance of an autonomous vehicle following a moving target with smaller minimum turning radius compared to that of the follower and propose a simple and constructive navigation law. In compliance with the increasing research on decentralized control laws for groups of mobile autonomous robots, we consider the problems of decentralized navigation of network of WMRs with limited communication and decentralized stabilization of formation of WMRs. New control laws are presented and simulation results are provided to illustrate the control laws and their applications.

This thesis is concerned with algorithms for finding natural features that are then used for simultaneous localisation and mapping, commonly known as SLAM in navigation theory. The task involves capturing raw sensory inputs, extracting features from these inputs and using the features for mapping and localising during navigation. The ability to extract natural features allows automatons such as robots to be sent to environments where no human beings have previously explored working in a way that is similar to how human beings understand and remember where they have been. In extracting natural features using images, the way that features are represented and matched is a critical issue in that the computation involved could be wasted if the wrong method is chosen. While there are many techniques capable of matching pre-defined objects correctly, few of them can be used for real-time navigation in an unexplored environment, intelligently deciding on what is a relevant feature in the images. Normally, feature analysis that extracts relevant features from an image is a 2-step process, the steps being firstly to select interest points and then to represent these points based on the local region properties. A novel technique is presented in this thesis for extracting a small enough set of natural features robust enough for navigation purposes. The technique involves a 3-step approach. The first step involves an interest point selection method based on extrema of difference of Gaussians (DOG). The second step applies Textural Feature Analysis (TFA) on the local regions of the interest points. The third step selects the distinctive features using Distinctness Analysis (DA) based mainly on the probability of occurrence of the features extracted. The additional step of DA has shown that a significant improvement on the processing speed is attained over previous methods. Moreover, TFA / DA has been applied in a SLAM configuration that is looking at an underwater environment where texture can be rich in natural features. The results demonstrated that an improvement in loop closure ability is attained compared to traditional SLAM methods. This suggests that real-time navigation in unexplored environments using natural features could now be a more plausible option.

The first part of this thesis documents experimental investigation into the use of vision for wheeled robot navigation problems. Specifically, using a video camera as a source of feedback to control a wheeled robot toward a static and a moving object in an environment in real-time. The wheeled robot control algorithms are dependent on information from a vision system and an estimator. The vision system design consists of a pan video camera and a visual gaze algorithm which attempts to search and continuously maintain an object of interest within limited camera field of view. Several vision-based algorithms are presented to recognize simple objects of interest in an environment and to calculate relevant parameters required by the control algorithms. An estimator is designed for state estimation of the motion of an object using visual measurements. The estimator uses noisy measurements of relative bearing to an object and object's size on an image plane formed by perspective projection. These measurements can be obtained from the vision system. A set of algorithms have been designed and experimentally investigated using a pan video camera and two wheeled robots in real-time in a laboratory setting. Experimental results and discussion are presented on the performance of the vision-based control algorithms where a wheeled robot successfully approached an object in various motions. The second part of this thesis investigates the coordination problem of flocking in multi-robot system using concepts from graph theory. New control laws are presented for flocking motion of groups of mobile robots based on several leaders. Simulation results are provided to illustrate the control laws and its applications.

Estimer le mouvement d'un robot et construire en même temps une représentation de l'environnement (problème SLAM: Simultaneous Localisation And Mapping) est souvent considéré comme un problème essentiel pour développer des robots pleinement autonomes qui ne nécessitent pas de connaissances à priori de l'environnement pour réaliser leurs tâches. L'évolution du SLAM est très liée aux capteurs utilisés. Les sonars couplés avec l'odométrie sont souvent présentés comme les premiers capteurs ayant fourni des résultats convaincants. Depuis, les lasers 2D ont souvent remplacés ces capteurs pour des raisons de précision et de rapport signal/bruit. Néanmoins les lasers 2D permettent uniquement d'estimer des mouvements planaires et ne donnent pas des informations perceptuelles suffisantes pour identifier de manière fiable des régions précédemment explorées. Ces observations nous ont amenés à explorer à travers cette thèse comment combiner un capteur omnidirectionnel avec un télémètre laser pour effectuer la localisation et cartographie simultanée dans des environnements complexes et de grandes tailles. Les contributions de cette thèse concernent l'étalonnage des capteurs centraux catadioptriques (avec le développement d'un logiciel open source disponible sur le site internet de l'auteur) et la recherche de la position relative entre un capteur omnidirectionnel et un télémètre laser. Des approches efficaces pour estimer le mouvement 3D du capteur en utilisant des droites et des plans sont détaillées. Enfin deux méthodes sont proposées combinant laser et vision pour effectuer du SLAM planaire mais aussi pour estimer la position 3D du robot ainsi que la structure de l'environnement.

Le sujet traité dans cette thèse concerne la localisation précise et intègre de robots mobiles ( de véhicules routiers en l'occurence) dans un environnement routier cartographié. Pour ceci, nous proposons une approche multisensorielle hybridant les capteurs classiquement utilisés dans ce genre d'application (un GPS naturel, un odomètre et un gyromètre) avec un système de vision. Ce dernier, en outre, est capable de déterminer très précisement la pose locale du véhicule sur la chaussée en détectant les marquages signalétiques au sol. Il peut donc par l'intermèdiaire de la carte de l'environnement routier, fournir des informations à la fois redondantes et complémentaires à celles fournies par le GPS. Ainsi, cette combinaison d'informations doit garantir la précision et l'intégrité du système de localisation et ce notamment dans les zones urbaines denses où les informations du GPS ne sont pas forcément fiables. La mise en oeuvre de ce système a été menée dans deux études distinctes. Dans la première, la fusion de données est effectuée par un filtre de Kalman étendu . Dans ce cas, la précision obtenue est quasi-décimétrique, cependant la gestion d'hypothèses multiples dans le cadre autoroutier ou des fortes non-linéarités introduites par le système de vision nuisent fortement à l'intégrité des résultats de localisation. C'est donc tout naturellement, que dans la seconde étude, le filtre de Kalman est remplacé par un filtre particulaire et plus particulièrement par un filtre particulaire génétique. La précision obtenue est ici similaire à la première étude et l'intégrité des résultats de la localisation assurée. En revanche, cette méthode est gourmande en temps de calcul et ne peut être utilisée en temps réel sur les ordinateurs actuels

<p>Att kunna äta själv, utan hjälp från omgivningen är en egenskap många ser som självklar. Tyvärr är det inte så för alla, och de som har problem med att kunna äta själva har hittills behövt förlita sig på att en vänlig människa i närheten har möjlighet kunna mata honom eller henne.</p><p>Det finns få alternativ till att bli matad av en människa och detta examensarbete bestod i att formge och konstruera samt att bygga en "demonstrator" som kan användas för att äta med på egen hand.</p><p>Den blivande produkten kallas för Bestic och skall då alltså vara en ett äthjälpmedel som med en sked eller en tång kan plocka upp mat från en tallrik och lyfta upp det till munnen på användaren.</p><p>Krav som ställdes var att den färdiga produkten skulle vara enkel att tillverka, montera och gärna billig inom vissa ramar, och dessutom vara attraktiv för målgruppen.</p><p>I denna rapport kommer du att kunna läsa om hur idéprocessen, konceptutvärderingarna, skissarbetet, materialvalen, konstruktionerna, cad-arbetet och modellbyggandet gick till.</p><p>Resultatet av detta arbete blev en CAD-modell över samtliga delar som måste tillverkas, och samtidigt en lista över komponenter som behövs för att montera ihop en färdig produkt. Utöver CAD-filerna tillverkades det också en "demonstrator", en till så stor utsträckning som möjligt fungerande prototyp och samtidigt utställningsmodell.</p><p>Demonstratorn visade att det fanns brister i konstruktionen ifrån CAD-filerna och en analys gav en lista på problem som måste lösas innan en serietillverkning kunde påbörjas.</p>

Notre sujet de recherche est : “ comment obtenir la suite des reconfigurations que le système robotique doit faire pour qu'il se déplace globalement vers une destination ? ”. Comme nous le montrerons ce problème est très complexe. Nous verrons que ce travail qui a vite donné de bons résultats nous a permis de tester plusieurs méthodes : algorithmes réactifs, apprentissage supervisé et apprentissage à partir d'exemple. Nous montrerons également qu'au cours de ces simulations des problèmes inattendus sont apparus. Des blocages nous ont montré que la méthode utilisée pour faire les simulations était à discuter. C'est grâce à un grand nombre simulations que nous avons vu émerger deux types de problèmes. L'un lié à la nature de l'attracteur utilisé, l'autre lié à l'ordonnancement et à la dynamique des interactions. Nous définirons ces problèmes et expliquerons comment et pourquoi ils émergent. Deux axes seront proposés pour résoudre ces problèmes liés à l'émergence. L'un s'intéressera au type d'attracteur utilisé et proposera un système d'attraction aux propriétés différentes pour garantir un ordre sur l'espace. L'autre proposera une méthode pour permettre de garantir une politique d'ordonnancement quelque soit l'ordre dans lequel les calculs sont effectués dans les différents modules. L'ensemble de ces deux propriétés nous permettra de prouver la convergence du système robotique reconfigurable quelque soit la position de l'attracteur et quelque soit la configuration initiale du robot.

<p>The purpose of this work is to providing a general set of base classes for building simulators, for example a robot system. Instead of every time building a new simulator from the beginning, you get the already completed components from a library. The library should in that way act as a springboard for development.</p><p>To do this work, there’s a lot of knowledge required in how a general robot system could look like. Therefore it was necessary to gather some information about robotics. </p><p>On the basis of what the information gave, two different user cases were built. From these user cases, the components were fetched, which was supposed to be included in the library. </p><p>The result of this work leads to a number of classes, which describes the components. A simple test program is also done, which handles the components. To get the classes more useful, the com-ponents must be broken down in much smaller parts. The operations on the classes should also be more realistic than what has been achieved in this work.</p>

<p>Industrial robots have been used for a long time in the industry. Despite this thedevelopment of advanced force control system using industrial robots is relativelylimited. Using force controlled robot systems expands the possibility of what canbe done with industrial robots.Previously a force feedback system for a standard industrial robot from ABBhas been developed. The system is developed towards the aircraft industry, where amounted drill machine on the robot has to fulfill the requirements in robot drillingin aircraft structures. This thesis presents experimental results and improvementsof this industrial robot system. Mechanical modifications and tests of a new endeffector are analyzed.</p>

<p>In the assembly process of airframe structures there are many drilled holes and on some parts the holes are mainly drilled manually with pneumatic handheld drilling machines. During conventional drilling in metal, burrs appear. To remove these burrs the parts of the structure must be separated and deburred before they can be put together for fastening. This is a time consuming measure and therefore expensive. To facilitate this process and lower production costs some parts of the process needs to be automated.</p><p>A part of this thesis was a project in co-operation with Saab, Novator, Specma Automation and the University of Linköping. The purpose of this project was to investigate the ability of an industrial robot to drill holes in aeroplane structures using orbital drilling.</p><p>How the project tests were carried out and the results of these tests are presented in the first part of this thesis. The tests showed that slip-stick appeared when a force was applied on the working object by the robot. Because of the movement of the pressure foot the drilled hole will be in the wrong position and if the movement appears during drilling the quality of the hole is being poor.</p><p>Several different tests were performed using different amounts of forces and different pressure feet trying to prevent slip-stick from appearing. Finally tests were performed with good results concerning the quality of the holes.</p><p>In the second part of this thesis the proceeding tests that were carried out are presented. The purpose of these tests was to find out how the robot acts when a static pressure is applied on a work object by the robot and try to find out what the cause of the slip-stick was. Several tests were done where the robot applied a force on several different points on the fixture and the slip-stick was measured.</p><p>The tests that were carried out during this thesis showed that an industrial robot can be used to drill holes in aeroplane structures. To make sure that the quality of the drilled holes is sufficient for the high demands of the aeroplane industry the working area of the robot is limited to a small area in front of the robot. The slip-stick that appears when the robot is extended into a position on the far side of the robot is too large for the robot to drill the hole in an accurate position.</p> / <p>Vid flygplansmontering borras det många olika hål och på vissa delar borras större delen av dessa hål manuellt med pneumatiska handborrmaskiner. Vid konventionell borrning i metall bildas oönskade grader. Strukturen plockas därför isär så att graderna kan tas bort innan strukturens delar kan passas samman igen för att sammanfogas. Detta är en tidskrävande åtgärd och därmed dyr och i ett steg att förenkla denna process och få en billigare produktion vill man automatisera vissa steg i denna process.</p><p>En del av detta examensarbete var ett projekt i samarbete med Saab, Novator, Specma Automation och Linköpings Universitet vars syfte var att klargöra en robots förmåga att borra hål i flygplansmaterial med orbitalborrningsteknik.</p><p>I första delen av detta examensarbete redovisas genomförande och resultat av projektets tester. Testerna visade att tryckfoten gled på testmaterialets yta när roboten lade en tryckkraft på testplåten, så kallad slip-stick uppkom. Denna glidning gör att det borrade hålet inte hamnar på rätt position och sker glidningen under borroperationen så försämras hålets kvalité. Flera olika tester gjordes med varierad tryckkraft och med olika tryckfötter för att försöka förhindra att slip-stick uppkom. Tester genomfördes där hål borrades med bra kvalité.</p><p>I den andra delen av denna rapport redovisas fortsättningen på examensarbetet som var en vidareundersökning av de tidigare genomförda testerna. Syftet med denna del var att undersöka hur en industrirobot beter sig när den används för att lägga på en tryckkraft mot ett material samt att försöka ta reda på vad som är orsaken till slip-sticken. Fler tester gjordes där roboten tryckte på olika punkter på en fixtur och de uppkomna slip-sticken mättes upp.</p><p>Testerna under detta examensarbete har visat att det går att använda en industrirobot till att borra hål i flyglansmaterial. För att kvaliteten på de borrade hålen ska klara de höga krav som ställs inom flygplansindustrin är robotens arbetsområde begränsat till ett litet fönster mitt framför roboten. De glidningar som uppkommer när robotarmen är utsträckt långt åt sidan om roboten är alldeles för stora för de positioneringskrav som är på hålens placering på flygplansstrukturen.</p>