El siguiente trabajo busca desarrollar y testear un controlador para un robot móvil con fines agrícolas. Enmarcado en un proyecto más grande, que actualmente desarrolla un prototipo de robot móvil con desplazamiento autónomo para colaborar en las tareas agropecuarias, este trabajo parte de las ecuaciones cinemáticas desarrolladas para este prototipo y desarrolla una estrategia de control mediante torque computado para el desplazamiento autónomo del vehículo en el medio y se realizan simulaciones de las mismas. Realizado este trabajo y obteniendo resultados certeros se deja todo pronto para continuar con la instancia experimental en el prototipo. / The following dissertation tries to develop and test a movil robot controller for agricultural purposes. Framed in a bigger proyect that is currently developing a mobile robot prototype with autonomous movement to help with agricultural work, this work starts in the kinematic equations developed for the prototype and develops a control strategy through computed torque control for the autonomous movement of the vehicle and simulations are performed of such computation. With this work finished and with the results obtained is ready to continue with the experimental instance in the prototype.

Dans ce travail de thèse, on s’intéresse au problème de déplacement et de la localisation d'un robot mobile autonome dans son environnement local. La première partie du manuscrit les deux tâches de mouvement de base : c'est-à-dire, la stabilisation et le suivi de trajectoire. Deux stratégies de commande ont été traitées: le mode de glissement intégral, et la méthode dite «Immersion et Invariance». La deuxième partie porte sur l'asservissement visuel, les deux techniques 2D et 3D d'asservissement visuel ont été appliquées. Les moments d'image ont été choisis comme indices visuels car ils sont moins sensibles au bruit d'image et autres erreurs de mesure. Une nouvelle approche de l'asservissement visuel qui repose sur l'image est ici proposée. Elle est basée sur la génération de trajectoires sur le plan de l'image directement (calcul des valeurs des primitives d’image correspondantes à une trajectoire cartésienne donnée). Cette approche garantit que la robustesse et la stabilité bien connues de l'asservissement 2D ont été étendues en raison du fait que les emplacements initial et désiré de la caméra sont proches. Les trajectoires obtenues garantissent aussi que la cible reste dans le champ de vue de la caméra et que le mouvement du robot correspondant est physiquement réalisable. Des tests expérimentaux ont été effectués et des résultats satisfaisants ont été obtenus à partir des implémentations des stratégies de commande et d'asservissement visuel. Bien qu'ils soient développés et expérimentés dans le cadre spécifique d'un robot de type unicycle, ces travaux sont assez génériques pour être appliqués sur autres types de véhicules. / This thesis focuses on the problem of moving and localizing an autonomous mobile robot in its local environments. The first part of the manuscript concerns two basic motion tasks, namely the stabilization and trajectory tracking. Two control strategies were discussed: the integral sliding mode, and the method known as “Immersion and Invariance” for nonlinear control. The second part focuses on both 2D and 3D visual servoing techniques. Image moments were chosen as visual features as they provide a more geometric and intuitive meaning than other features, and they are less sensitive to image noise and other measurement errors. A new approach to visual servoing based on image is herein proposed. It is based on the generation of trajectories directly on the image plane (Calculation of the image features corresponding to a given Cartesian path). This approach ensures that the robustness and stability are extended due to the fact that the initial and desired locations of the camera are close. The trajectories obtained guarantee that the target remains in the field of view of the camera and the corresponding movement of the robot is physically feasible. Experimental tests have been conducted, and satisfactory results have been obtained from both implementations regarding motion control and visual servoing strategies. Although developed and tested in the specific context of a unicycle type robot, this work is generic enough to be applied to other types of vehicles.

Norteado pela necessidade de evolução do mercado agrícola, o desenvolvimento da agricultura de precisão atinge o nível de gerenciamento escalar de uma única planta, utilizando robôs agrícolas autônomos, os quais deverão trabalhar por longos períodos, ser ambientalmente corretos, atender às necessidades dos clientes, e ainda, com qualidade, confiabilidade e segurança. Este trabalho tem como objetivos pesquisar, discutir e apresentar os requisitos da qualidade em robôs agrícolas, focando a satisfação do usuário final. Tais objetivos serão atingidos por meio do detalhamento da aplicação de ferramentas utilizadas durante o desenvolvimento do produto, e da avaliação de um robô existente, quanto ao atendimento dos requisitos definidos pelo usuário final. O estudo conclui que, a melhor metodologia a ser utilizada para satisfazer as necessidades do usuário final de um robô agrícola, é aplicação da ferramenta QFD durante o desenvolvimento do projeto do produto. Quanto à avaliação do robô existente, a conclusão foi de que, por se tratar de um robô desenvolvido com finalidade experimental para execução de pequenas atividades e com recursos financeiros limitados, sua nota média obtida pode ser considerada apropriada. / Guided by agricultural market evolution demand, precision agriculture development reaches scalar management level of one only plant, through the usage of autonomous agricultural robots, which must work in long shifts, environmentally friendly, meet customer requirements, all this with quality, reliability and safety. This work aims the research, discussion and presentation of quality requirements of agricultural robots, focusing on the satisfaction of final user. These objectives are reached through the tools application detailing used during the product development and evaluation of an existent robot on the requirements defined by the final user. The study concludes that the best methodology to be used to satisfy agricultural robots final user needs is through the application of QFD tool during the product design. As for the evaluation on the existent robot, the conclusion was that, as a robot developed for an experimental execution of small activities and with limited budget, his average score may be considered appropriated.

The use of teams of coordinated mobile robots in industrial settings such as underground mining, toxic waste cleanup and material storage and handling, is a viable and reliable approach to solving such problems that require or involve automation. In this thesis, abilities a team of mobile robots should demonstrate in order to successfully perform a mission in industrial settings are identified as a set of functional components. These components are related to navigation and obstacle avoidance, localization, task achieving behaviors and mission planning. The thesis focuses on designing and developing functional components applicable to diverse missions involving teams of mobile robots; in detail, the following are presented: 1. A navigation and obstacle avoidance technique to safely navigate the robot in an unknown environment. The technique relies on information retrieved by the robot's vision system and sonar sensors to identify and avoid surrounding obstacles. 2. A localization method based on Kalman filtering and Fuzzy logic to estimate the robot's position. The method uses information derived by multiple robot sensors such as vision system, odometer, laser range finder, GPS and IMU. 3. A target tracking and collision avoidance technique based on information derived by a vision system and a laser range finder. The technique is applicable in scenarios where an intruder is identified in the patrolling area. 4. A limited lookahead control methodology responsible for mission planning. The methodology is based on supervisory control theory and it is responsible for task allocation between the robots of the team. The control methodology considers situations where a robot may fail during operation. The performance of each functional component has been verified through extensive experimentation in indoor and outdoor environments. As a case study, a warehouse patrolling application is considered to demonstrate the effectiveness of the mission planning component.

<p>In this thesis, semantic mapping is understood to be the process of putting a tag or label on objects or regions in a map. This label should be interpretable by and have a meaning for a human. The use of semantic information has several application areas in mobile robotics. The largest area is in human-robot interaction where the semantics is necessary for a common understanding between robot and human of the operational environment. Other areas include localization through connection of human spatial concepts to particular locations, improving 3D models of indoor and outdoor environments, and model validation.</p><p>This thesis investigates the extraction of semantic information for mobile robots in outdoor environments and the use of semantic information to link ground-level occupancy maps and aerial images. The thesis concentrates on three related issues: i) recognition of human spatial concepts in a scene, ii) the ability to incorporate semantic knowledge in a map, and iii) the ability to connect information collected by a mobile robot with information extracted from an aerial image.</p><p>The first issue deals with a vision-based virtual sensor for classification of views (images). The images are fed into a set of learned virtual sensors, where each virtual sensor is trained for classification of a particular type of human spatial concept. The virtual sensors are evaluated with images from both ordinary cameras and an omni-directional camera, showing robust properties that can cope with variations such as changing season.</p><p>In the second part a probabilistic semantic map is computed based on an occupancy grid map and the output from a virtual sensor. A local semantic map is built around the robot for each position where images have been acquired. This map is a grid map augmented with semantic information in the form of probabilities that the occupied grid cells belong to a particular class. The local maps are fused into a global probabilistic semantic map covering the area along the trajectory of the mobile robot.</p><p>In the third part information extracted from an aerial image is used to improve the mapping process. Region and object boundaries taken from the probabilistic semantic map are used to initialize segmentation of the aerial image. Algorithms for both local segmentation related to the borders and global segmentation of the entire aerial image, exemplified with the two classes ground and buildings, are presented. Ground-level semantic information allows focusing of the segmentation of the aerial image to desired classes and generation of a semantic map that covers a larger area than can be built using only the onboard sensors.</p>

This paper describes a method by which range data from a sonar or other type of rangefinder can be used to determine the 2-dimensional position and orientation of a mobile robot inside a room. The plan of the room is modeled as a list of segments indicating the positions of walls. The method works by extracting straight segments from the range data and examining all hypotheses about pairings between the segments and walls in the model of the room. Inconsistent pairings are discarded efficiently by using local constraints based on distances between walls, angles between walls, and ranges between walls along their normal vectors. These constraints are used to obtain a small set of possible positions, which is further pruned using a test for physical consistency. The approach is extremely tolerant of noise and clutter. Transient objects such as furniture and people need not be included in the room model, and very noisy, low-resolution sensors can be used. The algorithm's performance is demonstrated using Polaroid Ultrasonic Rangefinder, which is a low-resolution, high-noise sensor.

Mobile robots are commonly used to achieve tasks involving tracking a desired trajectory and following a predefined path in different types of terrains that have different surface characteristics. A mobile robot can perform the same navigation task task over different surfaces if the tracking performance and accuracy are not essential. However, if the tracking performance is the main objective, due to changing the characteristics of wheel-ground interaction, a single set of controller parameters or an equation of motion might be easily failing to guarantee a desired performance and accuracy. The interaction occurring between the wheels and ground can be integrated into the system model so that the performance of the mobile robot can be enhanced on various surfaces. This modeling approach related to wheel-ground interaction can also be incorporated into the motion controller. In this thesis study, modeling studies for a two wheeled differential drive mobile robot and a steerable four-wheeled robot vehicle are carried out. A strategy to achieve better tracking performance for a differential drive mobile robot is developed by introducing a procedure including the effects of external wheel forces / i.e, traction, rolling and lateral. A new methodology to represent the effects of lateral wheel force is proposed. An estimation procedure to estimate the parameters of external wheel forces is also introduced. Moreover, a modeling study that is related to show the effects of surface inclination on tracking performance is performed and the system model of the differential drive mobile robot is updated accordingly. In order to accomplish better trajectory tracking performance and accuracy for a steerable four-wheeled mobile robot, a modeling work that includes a desired trajectory generator and trajectory tracking controller is implemented. The slippage is defined via the slip velocities of steerable front and motorized rear wheels of the mobile robot. These slip velocities are obtained by using the proposed slippage estimation procedure. The estimated slippage information is then comprised into the system model so as to increase the performance and accuracy of the trajectory tracking tasks. All the modeling studies proposed in this study are tested by using simulations and verified on experimental platforms.

Controlling systems with multiple robots is quickly becoming the next large hurdle that must be overcome for groups of robots to successfully function as a team. An agent oriented approach for this problem is presented in this thesis. By using an agent oriented method, the robots can act independently yet still work together. To be able to establish communities of robots, a basic agent oriented control system for each robot must first be implemented. This thesis introduces a novel method to create Physical Robot Agents, promoting a separation of cognitive and reactive behaviours into a two layer system. These layers are further abstracted into key subsections that are required for the Physical Robot Agents to function. To test this architecture, experiments are performed with physical robots to determine the feasibility of this approach. <br /><br /> A real-time implementation of a Physical Robot Agent would greatly expand its field of use. The speed of internal communication is analyzed to validate the application of this architecture to real-time tasks. <br /><br /> It is concluded that the Physical Robot Agents are well suited for multiple robot systems and that real-time applications are feasible.

We propose and solve a synchronized path following problem for a differential drive robot modeled as a dynamic unicycle and an Euler-Lagrange system. Each system is assigned a simple closed curve in its output space. The outputs of systems must approach and traverse their assigned curves while synchronizing their motions along the paths. The synchronization problems we study in this thesis include velocity synchronization and position synchronization. Velocity synchronization aims to force the velocities of the systems be equal on the desired paths. Position synchronization entails enforcing a positional constraint between the systems modeled as a constraint function on the paths. After characterizing feasible positional constraints, a finite-time stabilizing control law is used to enforce the position constraint.

During last decades, the Internet teleobotics has been growing at an enormous ratedue to the rapid improvement of Internet technology. This paper presents theinternet-based remote control of mobile robot. To face unpredictable Internet delaysand possible connection rupture, a direct continuous control based teleoperationarchitecture with “Speed Limit Module” (SLM) and “Delay Approximator” (DA) isproposed. This direct continuous control architecture guarantees the path error of therobot motion is restricted within the path error tolerance of the application.Experiment results show the feasibility and effectiveness of this direct Internet controlarchitecture in the real Internet environment.