233 publications from this institution
Industrial and service robots deal with the complex task of grasping objects that have different shapes and which are seen from diverse points of view. In order to autonomously perform grasps, the robot must calculate where to place its robotic hand to ensure that the grasp is stable. We propose a method to find the best pair of grasping points given a three-dimensional point cloud with the partial view of an unknown object. We use a set of straightforward geometric rules to explore the cloud and propose grasping points on the surface of the object. We then adapt the pair of contacts to a multi-fingered hand used in experimentation. We prove that, after performing 500 grasps of different objects, our approach is fast, taking an average of 17.5 ms to propose contacts, while attaining a grasp success rate of 85.5%. Moreover, the method is sufficiently flexible and stable to work with objects in changing environments, such as those confronted by industrial or service robots.
Calibration techniques allow the estimation of the intrinsic parameters of a camera. This paper describes an adaptive visual servoing scheme which employs the visual data measured during the task to determine the camera intrinsic parameters. This approach is based on the virtual visual servoing approach. However, in order to increase the robustness of the calibration several aspects have been introduced in this approach with respect to the previous developed virtual visual servoing systems. Furthermore, the system is able to determine the value of the intrinsic parameters when they vary during the task. This approach has been tested using an eye-in-hand robotic system.
Resumen – En este articulo se presenta un enfoque practico para la ensenanza de la vision artificial en la asignatura de “Robots y Sistemas Sensoriales” impartida por el area de Ingenieria de Sistemas y Automatica en la Universidad de Alicante. En primer lugar, se describe la herramienta VISUAL que ha sido desarrollada por miembros del grupo de Automatico, Robotica y Vision Artificial y que permite al alumno especificar un algoritmo de procesamiento de imagenes mediante un esquema grafico formado por un conjunto de diferentes modulos basicos de procesamiento. Asi, la herramienta VISUAL proporciona un interfaz para la vision artificial de manejo intuitivo, al mismo tiempo que permite desarrollos de algoritmos facilmente comprensibles gracias a su escalabilidad y modularidad, posibilitando realizar etapas de procesamiento claramente definidas. Ademas, se comentan algunos de los experimentos practicos propuestos y desarrollados haciendo uso de VISUAL y destinados al reconocimiento y localizacion de objetos para su posterior manipulacion con un robot.
This paper presents a new dynamic visual control system for redundant robots with chaos compensation. In order to implement the visual servoing system, a new architecture is proposed that improves the system maintainability and traceability. Furthermore, high performance is obtained as a result of parallel execution of the different tasks that compose the architecture. The control component of the architecture implements a new visual servoing technique for resolving the redundancy at the acceleration level in order to guarantee the correct motion of both end-effector and joints. The controller generates the required torques for the tracking of image trajectories. However, in order to guarantee the applicability of this technique, a repetitive path tracked by the robot-end must produce a periodic joint motion. A chaos controller is integrated in the visual servoing system and the correct performance is observed in low and high velocities. Furthermore, a method to adjust the chaos controller is proposed and validated using a real three-link robot.
Este trabajo ha sido financiado por el proyecto MCYT (DPI2008-02647) “Manipulacion inteligente mediante percepcion haptica y control visual empleando una estructura articular ubicada en el robot manipulador”.
Reseña del libro “Familias fragilizadas en Chile: propuestas para las políticas públicas y la formación de profesionales”Baeza, Jorge; Donoso, María de la Paz y Rojas, Paola (2013).Editorial UCSH, Santiago, Chile.
This paper describes a method to detect changes in given surfaces tracked by the robot end-effector. To do so, first an approach to combine visual and force information is described. By filtering the interaction forces, a parameter which provides the probability of a change in the tracking surface is obtained. In order to obtain a more accurate determination of the change in the surface, information from a laser located at the robot end-effector is also employed. Therefore, a robust method for detecting surface discontinuities which employs force and visual information jointly with structured light is presented
