A Comparative Analysis of Weed Images Classification Approaches in Vegetables Crops

This paper exposes a comparative analysis of three weed classification strategies based on area and texture features over images of vegetable crops, focus on provide a technological tool to support farmers in their maintenance tasks. The classification alternatives embrace a basic approach which defines an umbral according to scene features, indeed, a detection with a certain degree of uncertainty on the decision region is purposed and a rigid boundary decision arrangement are exposed. A first mode carry out an unsupervised learning, it uses area and color features with a practical thresholding classifier to differentiate between weed and vegetable classes, the following two, extracts statistical measures of autocorrelation, contrast, correlation and others, from grey level co-occurrence matrices to calculate texture features, next, a principal component analysis is made for dimensionality reduction. These patterns serve as basis for training K-Nearest Neighbor and Support Vector Machine classifiers. The algorithms performance is measured calculating sensitivity (SN), specificity (SP), positive and negative predicted values (PPV and NPV), also, the execution time is stored and tabulated in order to evaluate the proposed methods. Finally, the results show a similar performance of correct classification over 90 and 80% on SN and SP indices respectively, however, approaches present a clear difference in execution time respect of train an evaluation stages.This paper exposes a comparative analysis of three weed classification strategies based on area and texture features over images of vegetable crops, focus on provide a technological tool to support farmers in their maintenance tasks. The classification alternatives embrace a basic approach which defines an umbral according to scene features, indeed, a detection with a certain degree of uncertainty on the decision region is purposed and a rigid boundary decision arrangement are exposed. A first mode carry out an unsupervised learning, it uses area and color features with a practical thresholding classifier to differentiate between weed and vegetable classes, the following two, extracts statistical measures of autocorrelation, contrast, correlation and others, from grey level co-occurrence matrices to calculate texture features, next, a principal component analysis is made for dimensionality reduction. These patterns serve as basis for training K-Nearest Neighbor and Support Vector Machine classifiers. The algorithms performance is measured calculating sensitivity (SN), specificity (SP), positive and negative predicted values (PPV and NPV), also, the execution time is stored and tabulated in order to evaluate the proposed methods. Finally, the results show a similar performance of correct classification over 90 and 80% on SN and SP indices respectively, however, approaches present a clear difference in execution time respect of train an evaluation stages

Controlador PI2 para las velocidades de un robot agrícola evaluado usando Hardware en el lazo (HIL)

Agriculture is considered as one of the most essential activities for human beings, mainly because food is obtained through it. With the aim of increasing production and improving the state of food and even the health of farmers, different robots have started to be used, in what is currently known as precision agriculture. With this purpose the Ceres agricultural robot was designed and built to mainly assist vegetable crops. In this document, the different steps that were developed to achieve the tracking of linear and angular velocities by the robot using a dynamic controller are shown. First, the mathematical modeling of the robot and the identification of the model parameters are shown. Subsequently, the linearization of the model is found, and given the coupling between linear and angular velocities, the design of dynamic decouplers at an operating point determined by the references to follow. Finally, a PI controller with an integral double action is used and it is programmed in an embedded system in order to verify the controller performance using hardware in the loop (HIL) tests. The results show stabilization times and an adequate input following for future integrations with the real plant and trajectory controllers.La agricultura es considerada como una de las actividades más esenciales para el ser humano debido a que por medio de esta se obtienen los alimentos. Con el objetivo de aumentar la producción y de mejorar el estado de los alimentos se han empezado a usar diferentes robots, en la agricultura de precisión. Con este fin se desarrolló el robot para agricultura Ceres, diseñado y construido para asistir cultivos de hortalizas. En este documento, se el desarrollo para lograr el seguimiento de las velocidades lineales y angulares por parte del robot mediante el uso de un controlador dinámico. En primer lugar, se muestra la modelación matemática del robot y la identificación de los diferentes parámetros del modelo. Posteriormente, se encuentra la linealización el modelo y dado el acoplamiento entre velocidad lineal y angular, el diseño de desacopladores dinámicos en un punto de operación determinado por las referencias a seguir. Finalmente, se utiliza un controlador PI con doble acción integral y se programa en un sistema embebido verificando su desempeño mediante pruebas de hardware en el lazo (HIL). Los resultados muestran tiempos de estabilización y seguimientos adecuados para futuras integraciones con la planta real y controladores de trayectoria

Conducción segura de una plataforma móvil en configuración diferencial, basado en técnica de control predictivo.

Within the safe driving process, particularly in the field of agriculture where a robotic platform intervenes, it is necessary to safeguard both the structure and its environment. In the literature, applications oriented to “self-driving” can be found, where the objective is to achieve strategies that guide and control systems such as cars or robots immersed in dynamic environments. The present work proposes an option for a robot in differential configuration (specifically the CERES platform) to move safely in a crop, preventing collisions or damage to it and its environment. In this way, the result is the implementation of a control based on a predictive control technique, where the dynamic restrictions and saturations of the control signals are integrated within the objective function to be solved. The control developed consider the maximum and minimum speed restrictions provided by the electric motors used. The mean square error and its variance were the statistical criteria used as metrics when verifying the behavior of the system when following a reference trajectory.Dentro del proceso de conducción segura, particularmente en el campo del agro donde interviene una plataforma robótica, se hace necesario salvaguardar tanto la estructura como su entorno. En la literatura se pueden encuentran aplicaciones orientadas a ‘’self-driving’’, donde el objetivo es conseguir estrategias que guíen y controlen sistemas como automóviles o robots inmersos en ambientes dinámicos. El presente trabajo plantea una opción para que un robot en configuración diferencial (específicamente la plataforma CERES) se desplace de manera segura en un cultivo, previniendo colisiones o daños a ella y su entorno. De esta manera, se tiene como resultado la implementación de un control basado en una técnica de control predictivo, donde se integran las restricciones dinámicas y las saturaciones de las señales de control dentro de la función objetivo a solucionar. El control desarrollado considerar las restricciones de velocidad máximas y mínimas proporcionadas por los motores eléctricos utilizados. El error cuadrático medio y su varianza fueron los criterios estadísticos usados como métricas a la hora de verificar el comportamiento del sistema al seguir una trayectoria referencia

Implementación de ROS en sistema de control para un seguidor de personas usando robot Pioneer 3-DX

Robot Operating System(ROS) proporciona algoritmos y servicios para el control de diferentes tipos de robots. ROS es una herramienta útil en muchos problemas en el campo de los robots autónomos, especialmente en aplicaciones como la cartografía, localización y navegación autónoma en un ambiente interior. La navegación autónoma en un entorno dinámico contempla muchos factores ambientales que afectan el proceso de navegación. El enfoque de este trabajo es desarrollar un sistema modular para llegar a un seguidor humano utilizando un robot PIONEER 3-DX y un sensor Carmine PrimeSense,con el apoyo de hilos por cada pasode procesamiento a través de paquetes desarrollados enROS. Estas etapas se dividen en: búsqueda y ubicacióndel usuario a seguir, estimación de la dinámica del robot, control de velocidades y por último, un módulo de seguridad de evasión de obstáculos.Robot operating system (ROS) provides algorithms and services to control different kind of robots. ROS is a useful tool in many issues in the field of autonomous robots, especially in applications as mapping, localization and autonomous navigation in an indoor environment.  Autonomous navigation in a dynamic environment is not only challenging, but also uncovers many indoor environmental factors which affect the navigation process. The presented work describes how a ROS-Based control system is used with a Pioneer 3-DX robot for a human leader and robot follower system. The approach for this work is develop a modular system to reach a human follower using PIONEER 3-DX and Carmine Prime sense Sensor supported by threads for each processing steps  through ROS packages, these stages are divided in: coordinate human acquisition, robot´s pose estimation,  angular and linear speed control and obstacles security module

Implementación de ROS en sistema de control para un seguidor de personas usando robot Pioneer 3-DX

Robot Operating System(ROS) proporciona algoritmos y servicios para el control de diferentes tipos de robots. ROS es una herramienta útil en muchos problemas en el campo de los robots autónomos, especialmente en aplicaciones como la cartografía, localización y navegación autónoma en un ambiente interior. La navegación autónoma en un entorno dinámico contempla muchos factores ambientales que afectan el proceso de navegación. El enfoque de este trabajo es desarrollar un sistema modular para llegar a un seguidor humano utilizando un robot PIONEER 3-DX y un sensor Carmine PrimeSense,con el apoyo de hilos por cada pasode procesamiento a través de paquetes desarrollados enROS. Estas etapas se dividen en: búsqueda y ubicacióndel usuario a seguir, estimación de la dinámica del robot, control de velocidades y por último, un módulo de seguridad de evasión de obstáculos.Robot operating system (ROS) provides algorithms and services to control different kind of robots. ROS is a useful tool in many issues in the field of autonomous robots, especially in applications as mapping, localization and autonomous navigation in an indoor environment.  Autonomous navigation in a dynamic environment is not only challenging, but also uncovers many indoor environmental factors which affect the navigation process. The presented work describes how a ROS-Based control system is used with a Pioneer 3-DX robot for a human leader and robot follower system. The approach for this work is develop a modular system to reach a human follower using PIONEER 3-DX and Carmine Prime sense Sensor supported by threads for each processing steps  through ROS packages, these stages are divided in: coordinate human acquisition, robot´s pose estimation,  angular and linear speed control and obstacles security module

Modelado, control y navegacion para el vuelo autonomo de dirigibles

The aims of this thesis are the development of a dynamic model for the LAAS's Karma and los Andes University's UrAn airships, the elaboration of a set of base control laws of speed, altitude and heading in cruise flight, and optimal path planning and its pursuit. This work has been done within the framework of cooperation between the INSA of Toulouse and De los Andes University - Colombia. On the INSA side, this work has been made principally in the Robotic and Artificial Intelligent group of LAAS/CNRS, within the COMETS project. The LAAS robot was already equipped with sensors, an onboard CPU and radiofrequency links as FM and Ethernet whereas a radio-operated airship has been bought by De los Andes University to the Minizzep society. Then, instrumentation and on board CPU with Ethernet radio link have been installed. The first part of the document presents a mathematical model of the blimp dynamics. The analytic description of the model has been deduced from a dynamic and aerodynamic study. In a first time, the model parameters have been taken from precedent work based on wind tunnel experiments. Next to that, an identification of aerodynamic parameters of the grand model and also simplified models (called control model) were made with classical techniques and the Kalman filter as parametric estimator. A third part is devoted to the formulation of control strategies (PID, GPC and non-linear control by extended linearization principally), based on the decoupling of the velocity, the longitudinal and lateral dynamics. When this base controls are formulated, an approach to optimal planning based on the optimal control theory is presented. Two extensions to the initial model of path planning are proposed and their solutions are computed with numerical methods. A control for the following of the generated trajectory has been developed and is presented in the fourth chapter. These different control strategies have been validated by numerous simulation tests with and wit hout wind. The speed and altitude controllers have been tested in the real airship structure (UrAn).Cette thèse concerne l'élaboration d'un modèle dynamique pour des ballons dirigeables, la conception de lois de commande pour l'asservissement de la vitesse, de l'altitude et du cap dans le vol de croisière, et la planification de chemins optimaux ainsi que leur contrôle de leur exécution. Ce travail a été réalisé dans le cadre d'une convention de cotutelle entre l'INSA de Toulouse - France et l'Université de los Andes à Bogotá - Colombie. La première partie du travail concerne la détermination du modèle mathématique de la dynamique du dirigeable. Le modèle analytique a été obtenu à partir d'une étude mécanique et aérodynamique. Les paramètres du modèle ont été repris dans un première temps d'un travail précèdent, basé sur des expérimentations effectuées en soufflerie. Ensuite, l'identification des coefficients aérodynamiques du modèle complet et des modèles réduits (sous-modèles de commande), a été réalisée avec des techniques classiques et le filtre de Kalman comme estimateur paramétrique. Dans une deuxième partie, des stratégies de commandes ont été étudiés (principalement PID, GPC et commande non-linéaire de type premier ordre) basées sur un découplage de la vitesse de déplacement et des dynamiques relatives aux plans de navigation latéral et longitudinal. Ensuite, les asservissements de bas niveau ont été établis et une approche de la planification de chemins optimaux a été effectuée avec la théorie de la commande optimale et le géométrie. Deux extensions du modèle initial pour la planification ont aussi été proposées et résolues par des méthodes numériques. Une boucle de haut niveau assurant l'asservissement de la trajectoire planifiée a été développée. Ces différents résultats ont été validés par de nombreux tests en simulation, avec et sans vent, et les asservissements en vitesse, cap et altitude on été évalués sur les ballons UrAn à Bogotá et Karma à Toulouse

Modelado, control y navegación para el vuelo autónomo de dirigibles

Cette thèse concerne l'élaboration d'un modèle dynamique pour des ballons dirigeables, la conception de lois de commande pour l'asservissement de la vitesse, de l'altitude et du cap dans le vol de croisière, et la planification de chemins optimaux ainsi que leur contrôle de leur exécution. Ce travail a été réalisé dans le cadre d'une convention de cotutelle entre l'INSA de Toulouse - France et l'Université de los Andes à Bogotá - Colombie. La première partie du travail concerne la détermination du modèle mathématique de la dynamique du dirigeable. Le modèle analytique a été obtenu à partir d'une étude mécanique et aérodynamique. Les paramètres du modèle ont été repris dans un première temps d'un travail précèdent, basé sur des expérimentations effectuées en soufflerie. Ensuite, l'identification des coefficients aérodynamiques du modèle complet et des modèles réduits (sous-modèles de commande), a été réalisée avec des techniques classiques et le filtre de Kalman comme estimateur paramétrique. Dans une deuxième partie, des stratégies de commandes ont été étudiés (principalement PID, GPC et commande non-linéaire de type premier ordre) basées sur un découplage de la vitesse de déplacement et des dynamiques relatives aux plans de navigation latéral et longitudinal. Ensuite, les asservissements de bas niveau ont été établis et une approche de la planification de chemins optimaux a été effectuée avec la théorie de la commande optimale et le géométrie. Deux extensions du modèle initial pour la planification ont aussi été proposées et résolues par des méthodes numériques. Une boucle de haut niveau assurant l'asservissement de la trajectoire planifiée a été développée. Ces différents résultats ont été validés par de nombreux tests en simulation, avec et sans vent, et les asservissements en vitesse, cap et altitude on été évalués sur les ballons UrAn à Bogotá et Karma à ToulouseThe aims of this thesis are the development of a dynamic model for the LAAS's Karma and los Andes University's UrAn airships, the elaboration of a set of base control laws of speed, altitude and heading in cruise flight, and optimal path planning and its pursuit. This work has been done within the framework of cooperation between the INSA of Toulouse and De los Andes University - Colombia. On the INSA side, this work has been made principally in the Robotic and Artificial Intelligent group of LAAS/CNRS, within the COMETS project. The LAAS robot was already equipped with sensors, an onboard CPU and radiofrequency links as FM and Ethernet whereas a radio-operated airship has been bought by De los Andes University to the Minizzep society. Then, instrumentation and on board CPU with Ethernet radio link have been installed. The first part of the document presents a mathematical model of the blimp dynamics. The analytic description of the model has been deduced from a dynamic and aerodynamic study. In a first time, the model parameters have been taken from precedent work based on wind tunnel experiments. Next to that, an identification of aerodynamic parameters of the grand model and also simplified models (called control model) were made with classical techniques and the Kalman filter as parametric estimator. A third part is devoted to the formulation of control strategies (PID, GPC and non-linear control by extended linearization principally), based on the decoupling of the velocity, the longitudinal and lateral dynamics. When this base controls are formulated, an approach to optimal planning based on the optimal control theory is presented. Two extensions to the initial model of path planning are proposed and their solutions are computed with numerical methods. A control for the following of the generated trajectory has been developed and is presented in the fourth chapter. These different control strategies have been validated by numerous simulation tests with and without wind. The speed and altitude controllers have been tested in the real airship structure (UrAn)INIST-CNRS (INIST), under shelf-number: RP 17272 / SudocSudocFranceF