65 research outputs found
Predictive QoS for cellular connected UAV payload communication
Unmanned aerial vehicles (UAVs), or drones, are revolutionizing industries due to their versatility, affordability and applicability. Reliable communication links are essential for UAV operations, especially for beyond visual line of sight scenarios where drones are flown beyond the operator’s line of sight. Cellular networks, particularly in the context of 5G and beyond, offer potential solutions to meet the data-intensive demands of UAV applications. This study explores the feasibility of predictive quality of service for forecasting uplink (UL) throughput quality of service (QoS) parameter in UAV payload communication links. Comprehensive field tests were conducted to ensure accurate real-world results, as simulations may not fully capture real-world complexities. Field trial measurements were conducted in a sub-urban area to evaluate drone performance at various altitudes and bands. This sheds light on potential challenges and trade-offs for cellular-connected drones and their coexistence with terrestrial users. Drones flying at high altitudes often experience line of sight propagation, causing them to undergo frequent handovers between multiple base stations. Field trials demonstrated that drones connected to a 700 MHz signal encountered minimal interference and no handovers. Conversely, drones connected to the 3500 MHz frequency band faced multiple handovers, highlighting the complexities of UAV-cellular integration and emphasizing the significance of frequency band selection in drone applications. By harnessing machine learning (ML) models and comparative analysis of centralized and federated learning methods, this research investigates ML model performances in forecasting UL throughput based on prediction accuracy. The findings emphasize the importance of diverse training data and highlight the impact of frequency bands on UAV communication. These insights lay the groundwork for addressing UAV communication complexities and advancing the integration of machine learning and network dynamics for improving UAV operations
Locomotion system for ground mobile robots in uneven and unstructured environments
One of the technology domains with the greatest growth rates nowadays is service robots. The extensive use of ground mobile robots in environments that are unstructured or structured for humans is a promising challenge for the coming years, even though Automated Guided Vehicles (AGV) moving on flat and compact grounds are already commercially available and widely utilized to move components and products inside indoor industrial buildings. Agriculture, planetary exploration, military operations, demining, intervention in case of terrorist attacks, surveillance, and reconnaissance in hazardous conditions are important application domains.
Due to the fact that it integrates the disciplines of locomotion, vision, cognition, and navigation, the design of a ground mobile robot is extremely interdisciplinary. In terms of mechanics, ground mobile robots, with the exception of those designed for particular surroundings and surfaces (such as slithering or sticky robots), can move on wheels (W), legs (L), tracks (T), or hybrids of these concepts (LW, LT, WT, LWT). In terms of maximum speed, obstacle crossing ability, step/stair climbing ability, slope climbing ability, walking capability on soft terrain, walking capability on uneven terrain, energy efficiency, mechanical complexity, control complexity, and technology readiness, a systematic comparison of these locomotion systems is provided in [1].
Based on the above-mentioned classification, in this thesis, we first introduce a small-scale hybrid locomotion robot for surveillance and inspection, WheTLHLoc, with two tracks, two revolving legs, two active wheels, and two passive omni wheels. The robot can move in several different ways, including using wheels on the flat, compact ground,[1] tracks on soft, yielding terrain, and a combination of tracks, legs, and wheels to navigate obstacles. In particular, static stability and non-slipping characteristics are considered while analyzing the process of climbing steps and stairs. The experimental test on the first prototype has proven the planned climbing maneuver’s efficacy and the WheTLHLoc robot's operational flexibility. Later we present another development of WheTLHLoc and introduce WheTLHLoc 2.0 with newly designed legs, enabling the robot to deal with bigger obstacles.
Subsequently, a single-track bio-inspired ground mobile robot's conceptual and embodiment designs are presented. This robot is called SnakeTrack. It is designed for surveillance and inspection activities in unstructured environments with constrained areas. The vertebral column has two end modules and a variable number of vertebrae linked by compliant joints, and the surrounding track is its essential component. Four motors drive the robot: two control the track motion and two regulate the lateral flexion of the vertebral column for steering. The compliant joints enable limited passive torsion and retroflection of the vertebral column, which the robot can use to adapt to uneven terrain and increase traction. Eventually, the new version of SnakeTrack, called 'Porcospino', is introduced with the aim of allowing the robot to move in a wider variety of terrains.
The novelty of this thesis lies in the development and presentation of three novel designs of small-scale mobile robots for surveillance and inspection in unstructured environments, and they employ hybrid locomotion systems that allow them to traverse a variety of terrains, including soft, yielding terrain and high obstacles.
This thesis contributes to the field of mobile robotics by introducing new design concepts for hybrid locomotion systems that enable robots to navigate challenging environments. The robots presented in this thesis employ modular designs that allow their lengths to be adapted to suit specific tasks, and they are capable of restoring their correct position after falling over, making them highly adaptable and versatile.
Furthermore, this thesis presents a detailed analysis of the robots' capabilities, including their step-climbing and motion planning abilities. In this thesis we also discuss possible refinements for the robots' designs to improve their performance and reliability.
Overall, this thesis's contributions lie in the design and development of innovative mobile robots that address the challenges of surveillance and inspection in unstructured environments, and the analysis and evaluation of these robots' capabilities. The research presented in this thesis provides a foundation for further work in this field, and it may be of interest to researchers and practitioners in the areas of robotics, automation, and inspection.
As a general note, the first robot, WheTLHLoc, is a hybrid locomotion robot capable of combining tracked locomotion on soft terrains, wheeled locomotion on flat and compact grounds, and high obstacle crossing capability. The second robot, SnakeTrack, is a small-size mono-track robot with a modular structure composed of a vertebral column and a single peripherical track revolving around it. The third robot, Porcospino, is an evolution of SnakeTrack and includes flexible spines on the track modules for improved traction on uneven but firm terrains, and refinements of the shape of the track guidance system. This thesis provides detailed descriptions of the design and prototyping of these robots and presents analytical and experimental results to verify their capabilities
Collaborative autonomy in heterogeneous multi-robot systems
As autonomous mobile robots become increasingly connected and widely deployed in different domains, managing multiple robots and their interaction is key to the future of ubiquitous autonomous systems. Indeed, robots are not individual entities anymore. Instead, many robots today are deployed as part of larger fleets or in teams. The benefits of multirobot collaboration, specially in heterogeneous groups, are multiple. Significantly higher degrees of situational awareness and understanding of their environment can be achieved when robots with different operational capabilities are deployed together. Examples of this include the Perseverance rover and the Ingenuity helicopter that NASA has deployed in Mars, or the highly heterogeneous robot teams that explored caves and other complex environments during the last DARPA Sub-T competition.
This thesis delves into the wide topic of collaborative autonomy in multi-robot systems, encompassing some of the key elements required for achieving robust collaboration: solving collaborative decision-making problems; securing their operation, management and interaction; providing means for autonomous coordination in space and accurate global or relative state estimation; and achieving collaborative situational awareness through distributed perception and cooperative planning. The thesis covers novel formation control algorithms, and new ways to achieve accurate absolute or relative localization within multi-robot systems. It also explores the potential of distributed ledger technologies as an underlying framework to achieve collaborative decision-making in distributed robotic systems.
Throughout the thesis, I introduce novel approaches to utilizing cryptographic elements and blockchain technology for securing the operation of autonomous robots, showing that sensor data and mission instructions can be validated in an end-to-end manner. I then shift the focus to localization and coordination, studying ultra-wideband (UWB) radios and their potential. I show how UWB-based ranging and localization can enable aerial robots to operate in GNSS-denied environments, with a study of the constraints and limitations. I also study the potential of UWB-based relative localization between aerial and ground robots for more accurate positioning in areas where GNSS signals degrade. In terms of coordination, I introduce two new algorithms for formation control that require zero to minimal communication, if enough degree of awareness of neighbor robots is available. These algorithms are validated in simulation and real-world experiments. The thesis concludes with the integration of a new approach to cooperative path planning algorithms and UWB-based relative localization for dense scene reconstruction using lidar and vision sensors in ground and aerial robots
Recent Advances in Multi Robot Systems
To design a team of robots which is able to perform given tasks is a great concern of many members of robotics community. There are many problems left to be solved in order to have the fully functional robot team. Robotics community is trying hard to solve such problems (navigation, task allocation, communication, adaptation, control, ...). This book represents the contributions of the top researchers in this field and will serve as a valuable tool for professionals in this interdisciplinary field. It is focused on the challenging issues of team architectures, vehicle learning and adaptation, heterogeneous group control and cooperation, task selection, dynamic autonomy, mixed initiative, and human and robot team interaction. The book consists of 16 chapters introducing both basic research and advanced developments. Topics covered include kinematics, dynamic analysis, accuracy, optimization design, modelling, simulation and control of multi robot systems
Mobile Robots Navigation
Mobile robots navigation includes different interrelated activities: (i) perception, as obtaining and interpreting sensory information; (ii) exploration, as the strategy that guides the robot to select the next direction to go; (iii) mapping, involving the construction of a spatial representation by using the sensory information perceived; (iv) localization, as the strategy to estimate the robot position within the spatial map; (v) path planning, as the strategy to find a path towards a goal location being optimal or not; and (vi) path execution, where motor actions are determined and adapted to environmental changes. The book addresses those activities by integrating results from the research work of several authors all over the world. Research cases are documented in 32 chapters organized within 7 categories next described
Framework for autonomous navigation through MS HoloLenses
Τα τελευταία χρόνια, η τεράστια ανάπτυξη των τεχνολογιών εικονικής πραγματικότητας
φαίνεται να κατακλύζει την τεχνολογική κοινότητα. Οι δυνατότητες που η οικογένεια της
εικονικής πραγματικότητας φέρνει στο τραπέζι, αποτελούν μια εμπειρία που αλλάζει τόσο
την καθημερινή όσο και τη βιομηχανική ζωή. Πιο συγκεκριμένα, η Επαυξημένη
Πραγματικότητα (AR) θεωρείται από ένα μεγάλο μέρος της επιστημονικής κοινότητας, η
κυρίαρχη τεχνολογία των Διεπαφών Χρήστη (UI). Το βασικό χαρακτηριστικό του AR είναι ότι
προσθέτει ψηφιακό περιεχόμενο στο πραγματικό περιβάλλον χωρίς να απομονώνει το
χρήστη από αυτό, παρέχοντας μια πολύ ρεαλιστική αλληλεπίδραση κοντά στην αντίληψη
του χρήστη. Λαμβάνοντας υπόψη αυτά τα χαρακτηριστικά, η τεχνολογία AR μπορεί να
χρησιμοποιηθεί για παράδειγμα σε περιπτώσεις βελτιωμένης μάθησης, ελέγχου μηχανής,
πλοήγησης ανθρώπου / οχήματος. Για παράδειγμα, ένα AR UI ανεπτυγμένο σε γυαλιά AR
μπορεί να βοηθήσει τον χειριστή να ελέγξει ένα μηχάνημα εύκολα και χωρίς κίνδυνο από
απόσταση.
Επιπλέον, αυτή η λειτουργικότητα μπορεί να εμπλουτιστεί χρησιμοποιώντας ένα μη
επανδρωμένο όχημα, ένα ρομπότ, ως το μηχάνημα που θα ελέγχεται. Η ρομποτική είναι
ένας τομέας της τεχνολογίας, του οποίου η παρέμβαση στη ζωή των ανθρώπων φαίνεται
ασταμάτητη σε όλο και περισσότερες πτυχές. Σήμερα, τα μη επανδρωμένα οχήματα
χρησιμοποιούνται στην πλειονότητα των βιομηχανικών δραστηριοτήτων και των
καθημερινών συνηθειών. Ας εξετάσουμε μια κατάσταση κατά την οποία επιβλαβή απόβλητα
πρέπει να εξαχθούν από μια συγκεκριμένη περιοχή. Η χρήση μη επανδρωμένου οχήματος
είναι υποχρεωτική για τη συλλογή και την απομάκρυνση των αποβλήτων. Επιπλέον, ένα UI
επαυξημένης πραγματικότητας για το τηλεχειριστήριο του UV, προσφέρει τη δυνατότητα
στον χειριστή να αξιοποιήσει στο έπακρο τις δεξιότητές του χωρίς να διακινδυνεύσει τη ζωή
του. Το AR UI προσφέρει έναν πολύ φυσικό και οικείο έλεγχο στον χρήστη.
Σε αυτήν την πτυχιακή εργασία, εξετάζουμε το σενάριο όπου ο χρήστης ελέγχει / πλοηγεί
ένα μη επανδρωμένο όχημα εδάφους με τη βοήθεια AR γυαλιών. Τα γυαλιά AR προβάλλουν
μία ειδικά σχεδιασμένη διεπαφή χρήστη για τον έλεγχο κίνησης του ρομπότ. Η πλοήγηση
του οχήματος εξαρτάται αποκλειστικά από την αντίληψη και την εμπειρία του χρήστη. Εκεί η
τεχνολογία AR γίνεται πρακτική καθώς δεν επηρεάζει την όραση και την αντίληψη του
περιβάλλοντος για τον χρήστη και το περιβάλλον του. Πιο συγκεκριμένα, πραγματοποιείται
μια σειρά πειραμάτων, όπου ο χρήστης φορά τα AR γυαλιά και πλοηγεί το ρομπότ δίνοντας
μια σειρά εντολών κίνησης. Φυσικά, το ρομπότ πρέπει να παραμένει πάντα στο οπτικό του
πεδίο.
Τα πειράματα εκτελέστηκαν τόσο σε προσομοιωμένο όσο και σε πραγματικό κόσμο. Για την
προσομοίωση, χρησιμοποιήθηκε ο προσομοιωτής Gazebo με ένα εικονικό Turtlebot 2 με
λειτουργικό σύστημα ROS και ο προσομοιωτής Unity για τα AR γυαλιά. Τα πειράματα του
πραγματικού κόσμου εκτελέστηκαν με ένα Turtlebot2 που εκτελεί ROS και τα γυαλιά
Microsoft HoloLens AR όπου αναπτύχθηκε η εφαρμογή AR.In recent years, the immense development of the virtual reality technologies seems to
overwhelm the technological community. The possibilities which the virtual reality family
brings to the table, pose a life changing experience for both daily and industrial life. More
particular, Augmented Reality (AR) in considered by a large portion of the scientific
community, the reign technology of User Interfaces (UI). The key feature of AR is that adds
digital content to the real environment without isolating the user from it, providing a very
realistic interaction, close to the user’s perception. Considering these features, AR
technology can be used for instance in cases of enhanced learning, machine control,
human/vehicle navigation. For example, an AR UI deployed in AR glasses can help the actor
control a machine easily and without risk from distance.
In addition, this functionality can be enriched by using an unmanned vehicle, a robot, as the
machine that will be controlled. Robotics is a field of technology, whose intervention in
people’s lives seems unstoppable in more and more aspects. Nowadays, unmanned
vehicles are used in the majority of industrial operations and daily habits. Let us consider a
situation where harmful waste should be extracted from a specific area. The use of an
unmanned vehicle is mandatory for the collection and the removal of the waste. On top of
this, an Augmented Reality UI for the remote control of the UV, offers the ability to the actor
to make the most out of his skills without risking his life. The AR UI offers a very natural an
intimate control to the user.
In this Thesis, we examine the scenario where the user controls/navigates an unmanned
ground vehicle with the aid of an AR headset. The AR headset projects a specially designed
UI for the robot’s movement control. The vehicle’s navigation depends solely on the user’s
perception and experience. That’s where the AR technology comes in handy as is does not
affects the vision and the environment perception of the user and his surroundings. More
specifically, a series of experiments are carried out, where the user wears the AR headset
and navigates the robot by giving a series of movement commands. Of course, the robot
should always remain on his field of view.
Experiments were executed both in simulated and real world. For the simulation Gazebo
simulator was used with a virtual Turtlebot 2 running ROS operating system and the Unity
simulator for the AR headset. The real - world experiments were executed with a Turtlebot2
running ROS and the Microsoft HoloLens AR headset where our AR application was
deployed
Naval Research Program 2021 Annual Report
NPS NRP Annual ReportThe Naval Postgraduate School (NPS) Naval Research Program (NRP) is funded by the Chief of Naval Operations and supports research projects for the Navy and Marine Corps. The NPS NRP serves as a launch-point for new initiatives which posture naval forces to meet current and future operational warfighter challenges. NRP research projects are led by individual research teams that conduct research and through which NPS expertise is developed and maintained. The primary mechanism for obtaining NPS NRP support is through participation at NPS Naval Research Working Group (NRWG) meetings that bring together fleet topic sponsors, NPS faculty members, and students to discuss potential research topics and initiatives.Chief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.
Underwater Vehicles
For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties
Factories of the Future
Engineering; Industrial engineering; Production engineerin
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