1,425 research outputs found

    A STUDY OF WAYPOINT NAVIGATION FOR OUTDOOR MOBILE ROBOTS BY FUSING AERIAL PHOTOGRAPHS AND ELECTRONIC MAPS

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    Waypoint navigation for autonomous mobile robots allows navigation safely and smoothly to the destination point by following predetermined waypoints that serve as route points. To assign waypoints, environmental maps are needed to accurately determine the current location and the moving direction of the mobile robot. In this paper, we propose a new waypoint navigation method using both aerial photographs and electronic maps. By fusing aerial photographs and electronic map data, waypoint navigation environmental maps can be generated without prior acquisition of environmental data by traveling. The effectiveness of the proposed system was demonstrated by using an actual autonomous mobile robot and generated environmental maps of outdoor environments to confirm the validity of the proposed waypoint navigation

    The Revisiting Problem in Simultaneous Localization and Mapping: A Survey on Visual Loop Closure Detection

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    Where am I? This is one of the most critical questions that any intelligent system should answer to decide whether it navigates to a previously visited area. This problem has long been acknowledged for its challenging nature in simultaneous localization and mapping (SLAM), wherein the robot needs to correctly associate the incoming sensory data to the database allowing consistent map generation. The significant advances in computer vision achieved over the last 20 years, the increased computational power, and the growing demand for long-term exploration contributed to efficiently performing such a complex task with inexpensive perception sensors. In this article, visual loop closure detection, which formulates a solution based solely on appearance input data, is surveyed. We start by briefly introducing place recognition and SLAM concepts in robotics. Then, we describe a loop closure detection system's structure, covering an extensive collection of topics, including the feature extraction, the environment representation, the decision-making step, and the evaluation process. We conclude by discussing open and new research challenges, particularly concerning the robustness in dynamic environments, the computational complexity, and scalability in long-term operations. The article aims to serve as a tutorial and a position paper for newcomers to visual loop closure detection.Comment: 25 pages, 15 figure

    Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

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    This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

    A Survey on Aerial Swarm Robotics

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    The use of aerial swarms to solve real-world problems has been increasing steadily, accompanied by falling prices and improving performance of communication, sensing, and processing hardware. The commoditization of hardware has reduced unit costs, thereby lowering the barriers to entry to the field of aerial swarm robotics. A key enabling technology for swarms is the family of algorithms that allow the individual members of the swarm to communicate and allocate tasks amongst themselves, plan their trajectories, and coordinate their flight in such a way that the overall objectives of the swarm are achieved efficiently. These algorithms, often organized in a hierarchical fashion, endow the swarm with autonomy at every level, and the role of a human operator can be reduced, in principle, to interactions at a higher level without direct intervention. This technology depends on the clever and innovative application of theoretical tools from control and estimation. This paper reviews the state of the art of these theoretical tools, specifically focusing on how they have been developed for, and applied to, aerial swarms. Aerial swarms differ from swarms of ground-based vehicles in two respects: they operate in a three-dimensional space and the dynamics of individual vehicles adds an extra layer of complexity. We review dynamic modeling and conditions for stability and controllability that are essential in order to achieve cooperative flight and distributed sensing. The main sections of this paper focus on major results covering trajectory generation, task allocation, adversarial control, distributed sensing, monitoring, and mapping. Wherever possible, we indicate how the physics and subsystem technologies of aerial robots are brought to bear on these individual areas

    Autonomous Drones for Trail Navigation using DNNs

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    Στην παρούσα διπλωματική εργασία, προτείνεται ο σχεδιασμός και η υλοποίηση ενός πρότυπου drone που έχει τη δυνατότητα αυτόνομης πλοήγησης σε δασικό μονοπάτι χωρίς πρότερη γνώση του περιβάλλοντα χώρου. Χρησιμοποιεί σύστημα τεχνητής όρασης τριών επιπέδων: (i) ένα νευρωνικό δίκτυο βάθους (DNN) για εκτίμηση πλευρικής μετατόπισης και προσανατολισμού ως προς το κέντρο του μονοπατιού, (ii) ένα DNN για αναγνώριση αντικειμένων, και (iii) ένα σύστημα αποφυγής εμποδίων. Η σύνθεση του μικρού εναέριου σκάφους (MAV) έγινε από διαθέσιμα εξαρτήματα (hardware) του εργαστηρίου. Για τον αλγόριθμο ακολουθίας δασικών μονοπατιών, ως βάση νευρωνικού δικτύου χρησιμοποιήθηκε το TrailNet. Στη συνέχεια επανεκπαιδεύτηκε και εμπλουτίστηκε με σύνολο δεδομένων που δημιουργήθηκε από την δασική περιοχή της Πανεπιστημιούπολης Ιλισίων, προσαρμόζοντάς το στην τοπική βλάστηση. Για την επιλογή των βέλτιστων αλγορίθμων αναγνώρισης αντικειμένων, έγινε δοκιμή και αξιολόγηση από αντίστοιχους της τελευταίας γενιάς στην πλακέτα επεξεργασίας Jetson TX2 της NVIDIA. Τέλος δίνεται πρόταση πειραματικής πτήσης με συγκεκριμένες παραμέτρους για την αξιολόγηση της ορθής λειτουργίας.This thesis proposes the design and implementation of a prototype drone stack that is able to autonomously navigate through a forest trail path without having prior knowledge of the surrounding area. It uses a 3 level vision system: (i) a deep neural network (DNN) for estimating the view orientation and lateral offset of the vehicle with respect to the trail center, (ii) a DNN for object detection and (iii) a Guidance system for obstacle avoidance. Hardware synthesis of the Micro Aerial Vehicle (MAV) was built upon hardware parts, available from the lab. Trail following algorithm makes use of TrailNet’s neural network. It was also retrained and enriched by a newly created dataset, formed with footage from the nearby forest canopy of Ilisia Univesity Campus. This also made the model more adaptive to local vegetation characteristics. For object detection service, a comparison between well-known algorithms was made and an evaluation was done in terms of accuracy and efficiency. These were tested on NVIDIA’s Jetson TX2 Dev Kit board. At last, a suggestion of an experimental flight is given with particular parameters, for the evaluation of the proper operation

    Initialization Requirement in Developing of Mobile Learning 'Molearn' for Biology Students Using Inquiry-based learning

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    Inquiry-based learning is kind of learning activities that involves students’ entire capabilities in exploring and investigating particular objects or phenomenon using critical thinking skills. Recently, information technology tangibly contributes in any education aspects, including the existence of e-learning, a widely spreading learning model in the 21st century education. This study aims at initializing needs of developing mobile learning ‘Molearn’ based on inquiry-based method. By cooperating with Biology teacher community in senior high school, ‘Molearn’ provides IT-based medium in Biology learning process

    Model-driven engineering for mobile robotic systems: a systematic mapping study

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    Mobile robots operate in various environments (e.g. aquatic, aerial, or terrestrial), they come in many diverse shapes and they are increasingly becoming parts of our lives. The successful engineering of mobile robotics systems demands the interdisciplinary collaboration of experts from different domains, such as mechanical and electrical engineering, artificial intelligence, and systems engineering. Research and industry have tried to tackle this heterogeneity by proposing a multitude of model-driven solutions to engineer the software of mobile robotics systems. However, there is no systematic study of the state of the art in model-driven engineering (MDE) for mobile robotics systems that could guide research or practitioners in finding model-driven solutions and tools to efficiently engineer mobile robotics systems. The paper is contributing to this direction by providing a map of software engineering research in MDE that investigates (1) which types of robots are supported by existing MDE approaches, (2) the types and characteristics of MRSs that are engineered using MDE approaches, (3) a description of how MDE approaches support the engineering of MRSs, (4) how existing MDE approaches are validated, and (5) how tools support existing MDE approaches. We also provide a replication package to assess, extend, and/or replicate the study. The results of this work and the highlighted challenges can guide researchers and practitioners from robotics and software engineering through the research landscape

    Outdoor operations of multiple quadrotors in windy environment

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    Coordinated multiple small unmanned aerial vehicles (sUAVs) offer several advantages over a single sUAV platform. These advantages include improved task efficiency, reduced task completion time, improved fault tolerance, and higher task flexibility. However, their deployment in an outdoor environment is challenging due to the presence of wind gusts. The coordinated motion of a multi-sUAV system in the presence of wind disturbances is a challenging problem when considering collision avoidance (safety), scalability, and communication connectivity. Performing wind-agnostic motion planning for sUAVs may produce a sizeable cross-track error if the wind on the planned route leads to actuator saturation. In a multi-sUAV system, each sUAV has to locally counter the wind disturbance while maintaining the safety of the system. Such continuous manipulation of the control effort for multiple sUAVs under uncertain environmental conditions is computationally taxing and can lead to reduced efficiency and safety concerns. Additionally, modern day sUAV systems are susceptible to cyberattacks due to their use of commercial wireless communication infrastructure. This dissertation aims to address these multi-faceted challenges related to the operation of outdoor rotor-based multi-sUAV systems. A comprehensive review of four representative techniques to measure and estimate wind speed and direction using rotor-based sUAVs is discussed. After developing a clear understanding of the role wind gusts play in quadrotor motion, two decentralized motion planners for a multi-quadrotor system are implemented and experimentally evaluated in the presence of wind disturbances. The first planner is rooted in the reinforcement learning (RL) technique of state-action-reward-state-action (SARSA) to provide generalized path plans in the presence of wind disturbances. While this planner provides feasible trajectories for the quadrotors, it does not provide guarantees of collision avoidance. The second planner implements a receding horizon (RH) mixed-integer nonlinear programming (MINLP) model that is integrated with control barrier functions (CBFs) to guarantee collision-free transit of the multiple quadrotors in the presence of wind disturbances. Finally, a novel communication protocol using Ethereum blockchain-based smart contracts is presented to address the challenge of secure wireless communication. The U.S. sUAV market is expected to be worth $92 Billion by 2030. The Association for Unmanned Vehicle Systems International (AUVSI) noted in its seminal economic report that UAVs would be responsible for creating 100,000 jobs by 2025 in the U.S. The rapid proliferation of drone technology in various applications has led to an increasing need for professionals skilled in sUAV piloting, designing, fabricating, repairing, and programming. Engineering educators have recognized this demand for certified sUAV professionals. This dissertation aims to address this growing sUAV-market need by evaluating two active learning-based instructional approaches designed for undergraduate sUAV education. The two approaches leverages the interactive-constructive-active-passive (ICAP) framework of engagement and explores the use of Competition based Learning (CBL) and Project based Learning (PBL). The CBL approach is implemented through a drone building and piloting competition that featured 97 students from undergraduate and graduate programs at NJIT. The competition focused on 1) drone assembly, testing, and validation using commercial off-the-shelf (COTS) parts, 2) simulation of drone flight missions, and 3) manual and semi-autonomous drone piloting were implemented. The effective student learning experience from this competition served as the basis of a new undergraduate course on drone science fundamentals at NJIT. This undergraduate course focused on the three foundational pillars of drone careers: 1) drone programming using Python, 2) designing and fabricating drones using Computer-Aided Design (CAD) and rapid prototyping, and 3) the US Federal Aviation Administration (FAA) Part 107 Commercial small Unmanned Aerial Vehicles (sUAVs) pilot test. Multiple assessment methods are applied to examine the students’ gains in sUAV skills and knowledge and student attitudes towards an active learning-based approach for sUAV education. The use of active learning techniques to address these challenges lead to meaningful student engagement and positive gains in the learning outcomes as indicated by quantitative and qualitative assessments
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