A robótica móvel é uma área de pesquisa que está obtendo grande atenção da comunidade científica. O desenvolvimento de robôs móveis autônomos, que sejam capazes de interagir com o ambiente, aprender e tomar decisões corretas para que suas tarefas sejam executadas com êxito é o maior desafio em robótica móvel. O desenvolvimento destes sistemas inteligentes e autônomos consiste em uma área de pesquisa multidisciplinar considerada recente e extremamente promissora que envolve; por exemplo, inteligência artificial, aprendizado de máquina, estimação estatística e sistemas embarcados. Dentro desse contexto, esse trabalho aborda o problema de navegação e monitoramento de ambientes utilizando robôs móveis. Dada uma representação do ambiente (mapa topológico) e uma lista com urgências de cada uma das regiões do mapa, o robô deve estimar qual o percurso mais eficiente para monitorar esse ambiente. Uma vez que a urgência de cada região não visitada aumenta com o tempo, o trajeto do robô deve se adaptar a essas alterações. Entre as diversas aplicações práticas desse tipo de algoritmo, destaca-se o desenvolvimento de sistemas de segurança móveis inteligentes / The mobile robotics is a research area that has started to get some serious attention from the scientific community. The development of robots able to interact with the environment - to learn and make correct decisions so their tasks are successfully completed - is the biggest challenge in mobile robotics. The development of these intelligent and autonomous systems consists of a multidisciplinary research area considered recent and very promising that involves, for example, artificial intelligence, machine learning, statistical estimation and embedded systems. Within this context, this paper addresses the problem of navigation in dynamic environments with priorities using mobile robots. Given a representation of the environment (topological map) and a list of priorities for each region of the map, the robot must estimate what is the most efficient way to monitor this environment. As the dynamic priority of each region increases with time since the last visit of the robot, its trajectory must adapt to these changes. This approach is similar to the traveling salesman, but a solution that specifically addresses the problem described in this dissertation was not found in the literature. Among the many practical applications of this type of algorithm, we highlight the development of smart mobile security systems

Denna studie har undersökt hur en spelares spelupplevelse påverkas av tillgången eller frånvaron av diskreta navigationshjälpmedel i en stor, öppen, virtuell 3D-värld. För att undersöka detta har en spelmodifikation skapats till spelet The Elder Scrolls: Skyrim, som två grupper av testdeltagare har fått spela med olika tillgång till navigationshjälpmedel. 8 personer har deltagit i testet och blivit intervjuade angående sin upplevda spelupplevelse. Resultatet har därefter analyserats och jämförts med hjälp av Grounded Theory. Resultatet har varit oklart men tyder inte på att frånvaron av diskreta navigationshjälpmedel markant förbättrade spelupplevelsen. Vidare undersökning skulle kunna ske med bredare målgrupper under en längre tidsperiod. I framtiden skulle detta kunna leda till mera skräddarsydda spelupplevelser där spelarna själva bestämmer sin nivå av utmaning genom att manipulera de diskreta navigationshjälpmedlen.

D.Ing. / Aerial Vehicle (UAV)-based observation system, by using the principles of strapdown inertial measurement and navigation systems. Effort is concentrated around the mathematical implementation thereof and analysis and proof of the concept in a computer simulation environment. Although the principles of the strapdown system approach to camera-to-target vector estimation are universal to any type of airborne platform that can carry the observation payload, the application thereof is specifically tailored for a UAV system. More specifically, the operational scenario and UAV parameters of a typical close-range UAV system that is used for artillery observation, is used in the derivation of the models and equations. The secondary objective of this research is to derive a realizable mathematical implementation for this strapdown system based camera-to-target vector estimation methodology, by performing a systematic tradeoff between the use of Euler angles and quaternions for describing the camera-to-target vector, and by incorporating the principles of Kalman filtering. This dissertation fully describes the approach that was followed in the derivation of the strapdown system equations for the camera-to-target vector estimation. The mathematical models and principles used are universal for any airborne targeting application with a real-time video down-link. The results as presented in this dissertation, prove that the methodology provides satisfactory results in both a pure digital computer simulation environment, as well as in a digital computer simulation that is hybridized with experimentally determined sensor outputs. It has led to a realizable and workable implementation that could form the basis of practical implementation thereof in operational targeting systems. It further proves that the slant range between a camera and a stationary target on the ground, can be estimated effectively without the use of a laser rangefinder.

M.Ing. / Please refer to full text to view abstract

The work discussed in this thesis is the product of investigation on information and coding theoretic properties of colluding populations of navigationally relevant mammalian neurons. For brevity and completeness, that work is presented chronologically in the order in which it was investigated. This thesis details coding theoretic properties of (and develop a model for communication between) colluding populations of spatially responsive neurons in the hippocampus (HC) and medial entorhinal cortex (MEC) through a hypothetical layer of interneurons (each of which posesses exclusively excitatory or inhibitory synapses). This work presents analysis of the changes in network structure induced by an anti-Hebbian learning process and translate these analyses into biologically testable hypotheses. Further, it is demonstrated that for appropriately parameterized codes (i.e. populations of grid and place cells in MEC and HC, respectively), this network is able to learn the code and correct for errors introduced by neural noise, potentially explaining the results of a correlational study: Place cell variability sharply decreases at a time that coincides with the maturation of the grid cell network in developing mice. Further, this work predicts that disruption of the grid cell network (e.g. via optogenetic inactivation and lesioning) should increase the variability of place cell firing, and impair decoding from these place cells' activities. Continuing down this avenue, we consider how the inclusion of a population of the somewhat controversial time cells (purportedly residing in HC and MEC) impacts de-noising network structure, coding properties of the population of populations of all three classes of navigatory neuron, and denoisability. These results are translated to testable neurobiological predictions. Additionally, to ensure realistic stimulus statistics, locations and times are taken from real rat paths recorded from navigating rats in the Computational and Experimental Neuroscience Laboratory at the University of Arizona. Interestingly, while time cells exhibit some of the coding and information theoretic trends described in chapter 4, in certain cases, they admit surprising connectivity trends. Most surprisingly, after including time cells in this framework it was discovered that some classes of neural noise appear to improve decoding accuracy over the entire path while simultaneously impairing accuracy of decoding position and time independently.

Please read the abstract in the front pages of the file named 00dissertation / Dissertation (MEng (Mechanical))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

Cette thèse s'inscrit dans la démarche de l'entreprise nke, visant à améliorer la qualité de la mesure du vent apparent et réel de ses centrales de navigations. Ces améliorations doivent profiter à ses utilisateurs mais également contribuer à la performance du pilote automatique. Dans un premier temps, est décrit le contexte spécifique à la mesure du vent depuis un voilier, et ses problématiques inhérentes. Suite à cette étude, deux types de verrous scientifiques ont été identifiés, à savoir : la mesure du vent sur le bateau par le senseur (lié à son design et à son modèle de réponse) et la chaîne de reconstruction du triangle de vent.Cette thèse propose donc, dans un premier temps, une nouvelle méthodologie pour le design de la girouette permettant de mettre en adéquation le profil du capteur avec les caractéristiques du bateau et son programme de navigation. Les contributions à l’amélioration de ce capteur aérien ont permis, d’une part, de diviser son temps de réponse par deux via l’optimisation de la forme de ses senseurs, et d’autre part, de fournir un signal utile 12 fois plus réactif, en appliquant des techniques de traitement du signal prédictif, intégrant la dynamique du capteur.Les travaux liés aux problématiques de reconstruction du vent réel en trois dimensions sont ensuite détaillés. Tout d'abord en s'intéressant aux normes et définitions des métriques qui lui sont associées, puis, en exposant les solutions permettant de prendre en compte les perturbations qui s'appliquent au vent apparent et réel dans la couche basse de l’atmosphère. Dans un second temps, les méthodes actuelles de reconstruction du vent réel sont étudiées. Cette analyse met en exergue le fait que ces corrections ne s’appliquent pas dans les bons référentiels. Pour pallier à ces problèmes, nous proposons une nouvelle approche de reconstruction du vent réel, mettant en œuvre les méthodes de corrections précédemment décrites.Ce manuscrit se termine par les apports au pilotage automatique. Ceux-ci prennent la forme d'un nouveau concept de "Mode Super", s’appliquant en sur-couche des modes de pilotage classiques. Leur rôle est d'améliorer la sécurité du pilotage pour le mode rafale et la performance pour le mode surf. Ces nouveautés ont été validées par des victoires en course, ont reçu un prix de l'innovation et a fait l'objet d'un dépôt de brevet pour le mode surf. Le pilote étant maintenant capable de barrer comme un humain dans les surfs. La dernière contribution apportée au pilote automatique concerne l'intégration d'un nouveau type de capteur : les penons électroniques.Enfin, le manuscrit contribue à l'appréhension de la globalité des problématiques et subtilités à prendre en compte, lorsque l'on développe ou utilise une centrale de navigation et un pilote automatique.Ces travaux ont mis en avant la forte corrélation entre les différents capteurs et données calculées par la centrale de navigation. Une avancée significative sur la précision de l'ensemble pourra être obtenue lorsque le concept du filtrage prédictif sera étendu et appliqué à la centrale de navigation dans sa globalité. / This thesis is part of NKE Marine’s attempts to improve the quality of apparent and real wind measurementsprovided by its navigation unit. These improvements are expected to benefit both users and improve autopilot performance. The first part describes the specific context of wind measurement on a sailboat, and the inherent issues. This study identified two knotty scientific problems: on-board wind measurements recorded by the sensor (linked to its design and response model) and how the wind triangle is reconstructed. The first objective of this thesis is therefore to propose a new methodology for the design of the wind vane that can match the sensor’s profile with the boat’s characteristics and its route planning. Improvements to this aerial sensor make it possible, on the one hand, to divide the response time by two (via the optimization of the shape of the sensors) and, on the other hand, to provide a useful signal that is twelve times more sensitive (via the application of predictive signal processing techniques that take account of sensor dynamics). Next, previous work on the problem of reconstructing three-dimensional true wind is described in detail. This part begins with a presentation of the relevant standards and definitions of metrics, before examining some solutions that can take account of perturbations in apparent and true wind in the lower layer of the atmosphere. The following part examines current methods for reconstructing true wind. This analysis highlights the fact that these corrections are not applied in the correct frames. To overcome these problems, we propose a new approach to the reconstruction of the true wind, which implements the corrections described above. This manuscript ends with a presentation of the contribution to auto piloting. Specifically, it takes the form of a new concept, termed Super Mode, which can be overlaid onto classical modes of piloting. The aim is to improve safety in gusty conditions (Gust mode), and performance when surfing (Surf mode). The value of this innovation has been proven by competition victories; it has received an innovation award, and Surf mode is the subject of a patent application. The pilot is now able to glide like a human surfer. The final contribution to the autopilot concerns the integration of a new type of sensor: electronic telltales. Finally, this manuscript contributes to our overall understanding of the problems and nuances that must be taken into account when developing or using a navigation unit and an autopilot. The work highlights the close correlation between the various sensors and the data calculated by the navigation unit. Significant improvements to the accuracy of both elements can be obtained when the concept of predictive filtering is extended and appliedto the navigation unit as a whole.

The use of potential field based navigation schemes in robotics has been limited by inherent local minima issues. Local minima traps, small passages, unstable motion, and targets positioned near objects all pose major concerns when using potential fields for local vehicle control. This work proposes a new algorithm, "Re-Active Vector Equilibrium" (RAVE) that mitigates many of these issues. The vehicle representation model is expanded to use multiple points subject to potential calculation and the addition of two forces, a velocity dependent "risk force" (F_rsk) and a velocity and direction dependent "tangential force" (F_tan). The vehicle representation model is also expanded from a single reactive point to a series of points that define the vehicle body, providing better and simpler vehicle control. This has the effect of simplifying the required calculations at the cost of increasing the calculation count. The risk force, F_rsk, allows for dynamic adaptation to the immediate environment by acting in opposition to the net obstacle force, and is inversely proportional to the vehicle speed. The tangential force, F_tan, encourages better wall-following behaviour and provides a biasing mechanism to resolve obstacle aligned with target local minima issues.

This thesis presents contributions to applied robotic control and manipulation in the areas of motion algorithm design, hardware, and software robotic system design. Mobile robotic systems are widely used in several applications. Control of such systems poses many challenges caused by system modeling uncertainty. Complex physics phenomena and environmental effects are usually neglected to simplify analysis and control design. In motion planning, this thesis introduces an algorithm for navigation learning in mobile robots that aims to reduce the effect of modeling uncertainties on control performance. Starting from an initial feasible state and input trajectories, the objective is to reduce navigation time through iterative trials. A nominal model of the actual system and the experimental system output are used to update the control input in every iteration for incremental improvement. The navigation problem is formulated as an optimal control problem that is solved after each trial to generate a vector of input deviations for the next trial. The formulation of the approach, simulation, and experimental results shows the effectiveness of the presented method. The design part focuses on developing hardware and software systems for manipulation and aerial robots. A software tool for automated generation of multirotor simulation models is developed utilizing CAD software API and Matlab. In the area of human-robot interaction, a human-supervised UAV inspection system has been developed and tested. The UAV is guided by a human operator using a handheld laser pointing device that is designed and fabricated in-house. In the field of robotic manipulation, a novel gripper mechanism is designed and implemented. The proposed mechanism targets applications where a grasped object lies in areas with limited surrounding clearance and where external torques affect the grasped object. This design was implemented on a mobile manipulation platform and tested during an international robotics competition.

Nach einer Betrachtung der bestehenden Ansätze zur automatischen Graphgenerierung wurde eine Möglichkeit entwickelt, auf der Grundlage von OpenStreetMap-Innenraumkarten mit Hilfe einer bereits existierenden Implementierung des Straight Skeleton in Python automatisch Wege zu berechnen und diese wieder ins OpenStreetMap-Format zu überführen.:1. Einleitung 2. Überblick zur aktuellen Forschung 3. Anwendung des Straight Skeleton auf OpenStreetMap-Daten 3.1. Polyskel 3.2. Einlesen der Daten und Extrahieren der Türen und Räume 3.3. Kombination von Türen und Räumen 3.4. Generierung von Wegen mit Hilfe von polyskel 3.5. Kurze Wege zu längeren zusammenfassen 3.6. Wege vereinfachen 3.7. Wege im OpenStreetMap-Format speichern 4. Fazit und Ausblick Literaturverzeichnis Anhang