Suchergebnisse

The camera-Lidar sensor fusion plays an important role in autonomous navigation research. Nowadays, the automatic calibration of these sensors remains a significant challenge in mobile robotics. In this article, we present a novel calibration method that achieves an accurate six-degree-of-freedom (6-DOF) rigid-body transformation estimation (aka extrinsic parameters) between the camera and LiDAR sensors. This method consists of a novel co-registration approach that uses local edge features in arbitrary environments to get 3D-to-2D errors between the data of both, camera and LiDAR. Once we have 3D-to-2D errors, we estimate the relative transform, i.e., the extrinsic parameters, that minimizes these errors. In order to find the best transform solution, we use the perspective-three-point (P3P) algorithm. To refine the final calibration, we use a Kalman Filter, which gives the system high stability against noise disturbances. The presented method does not require, in any case, an artificial target, or a structured environment, and therefore, it is a target-less calibration. Furthermore, the method we present in this article does not require to achieve a dense point cloud, which holds the advantage of not needing a scan accumulation. To test our approach, we use the state-of-the-art Kitti dataset, taking the calibration provided by the dataset as the ground truth. In this way, we achieve accuracy results, and we demonstrate the robustness of the system against very noisy observations. ; This work was supported by the Regional Valencian Community Government and the European Regional Development Fund (ERDF) through the grants ACIF/2019/088 and AICO/2019/020.

Tactile sensors play an important role in robotics manipulation to perform dexterous and complex tasks. This paper presents a novel control framework to perform dexterous manipulation with multi-fingered robotic hands using feedback data from tactile and visual sensors. This control framework permits the definition of new visual controllers which allow the path tracking of the object motion taking into account both the dynamics model of the robot hand and the grasping force of the fingertips under a hybrid control scheme. In addition, the proposed general method employs optimal control to obtain the desired behaviour in the joint space of the fingers based on an indicated cost function which determines how the control effort is distributed over the joints of the robotic hand. Finally, authors show experimental verifications on a real robotic manipulation system for some of the controllers derived from the control framework. ; This work was funded by the Spanish Ministry of Economy, the European FEDER funds and the Valencia Regional Government, through the research projects DPI2012-32390 and PROMETEO/2013/085.

The exponential spread of the World Wide Web has had an enormous impact on educational institutions. New technologies, such as virtual and remote laboratories, have improved learning and training in the academic community, mainly in the field of technical and science subjects. They allow students to acquire methods, skills and experience related to real equipment in an intuitive and cost-effective way. The purpose of this paper is to present the last improvements of an e-learning environment, based on a Java applet, in the field of Robotics. This application allows students the simulation and teleoperation of a robotic arm by means of an interface with augmented reality support. Other main features of this system are its realistic graphical interface and its portability, which have been possible thanks to Easy Java Simulations, a Java-based tool which has been used to create this application. ; Supported by the "Ministerio de Educación y Ciencia" of the Spanish Government through research project DPI2005-06222.

Research in mobile robotics requires fully operative autonomous systems to test and compare algorithms in real-world conditions. However, the implementation of such systems remains to be a highly time-consuming process. In this work, we present an robot operating system (ROS)-based navigation framework that allows the generation of new autonomous navigation applications in a fast and simple way. Our framework provides a powerful basic structure based on abstraction levels that ease the implementation of minimal solutions with all the functionalities required to implement a whole autonomous system. This approach helps to keep the focus in any sub-problem of interest (i.g. localization or control) while permitting to carry out experimental tests in the context of a complete application. To show the validity of the proposed framework we implement an autonomous navigation system for a ground robot using a localization module that fuses global navigation satellite system (GNSS) positioning and Monte Carlo localization by means of a Kalman filter. Experimental tests are performed in two different outdoor environments, over more than twenty kilometers. All the developed software is available in a GitHub repository. ; This work has been supported by InterregV Sudoe and FEDER programs of European Commission through the COMMANDIA project SOE2/P1/F0638, and by the Spanish Government through the FPU grant FPU15/04446 and the research project RTI2018-094279-B-I00.

This paper presents a system that combines computer vision and surface electromyography techniques to perform grasping tasks with a robotic hand. In order to achieve a reliable grasping action, the vision-driven system is used to compute pre-grasping poses of the robotic system based on the analysis of tridimensional object features. Then, the human operator can correct the pre-grasping pose of the robot using surface electromyographic signals from the forearm during wrist flexion and extension. Weak wrist flexions and extensions allow a fine adjustment of the robotic system to grasp the object and finally, when the operator considers that the grasping position is optimal, a strong flexion is performed to initiate the grasping of the object. The system has been tested with several subjects to check its performance showing a grasping accuracy of around 95% of the attempted grasps which increases in more than a 13% the grasping accuracy of previous experiments in which electromyographic control was not implemented. ; This work was funded by the Spanish Government's Ministry of Economy, Industry and Competitiveness through the DPI2015-68087-R, by the European Commission's and FEDER funds through the COMMANDIA (SOE2/P1/F0638) action supported by Interreg-V Sudoe and by University of Alicante through project GRE16-20, Control Platform for a Robotic Hand based on Electromyographic Signals.

A fully integrated development tool for computer vision systems has been built in the framework of this paper. There are many applications that helps the user in the design of such systems, using graphical interfaces and function libraries. Even in some cases, the find source code can be generated by these applications.This paper goes a step beyond;it allows the development of computer vision systems from a distributed environment. Besides, and as distinctive characteristic with regard to other similar utilities, the system is able to automatically optimize task scheduling and assignment, depending on the available hardware. ; This work was supported by the Spanish Government through CICYT in the framework of project TAP-96-0629-C04-01.

Virtual and remote laboratories (VRLs) are e-learning resources that enhance the accessibility of experimental setups providing a distance teaching framework which meets the student's hands-on learning needs. In addition, online collaborative communication represents a practical and a constructivist method to transmit the knowledge and experience from the teacher to students, overcoming physical distance and isolation. This paper describes the extension of two open source tools: (1) the learning management system Moodle, and (2) the tool to create VRLs Easy Java Simulations (EJS). Our extension provides: (1) synchronous collaborative support to any VRL developed with EJS (i.e., any existing VRL written in EJS can be automatically converted into a collaborative lab with no cost), and (2) support to deploy synchronous collaborative VRLs into Moodle. Using our approach students and/or teachers can invite other users enrolled in a Moodle course to a real-time collaborative experimental session, sharing and/or supervising experiences at the same time they practice and explore experiments using VRLs. ; This work was supported by the Spanish Government under the CICYT Project DPI2007-61068 and the GITE grant of the Technology and Educational Innovation Vice-President Office of the University of Alicante.