12 research outputs found

    Autonomous homing and docking tasks for an underwater vehicle

    No full text
    This paper briefly introduces a strategy for autonomous homing and docking tasks using an autonomous underwater vehicle. The control and guidance based path following for those tasks are described in this work. A standard sliding mode for controller design is briefly given. The method provides robust motion control efforts for an underwater vehicle’s decoupled system whilst minimising chattering effects. In a guidance system, the vector field based on a conventional artificial potential field method gives a desired trajectory with a use of existing information from sensors in the network. A well structured Line-of-Sight method is used for an AUV to follow the path. It provides guidance for an AUV to follow the predefined trajectory to a required position with the final desired orientation at the dock. Integration of a control and guidance system provides a complete system for this application. Simulation studies are illustrated in the paper

    Multi-robot behaviors with bearing-only sensors and scale-free coordinates

    Get PDF
    This thesis presents a low-cost multi-robot system for large populations of robots, a new coordinate system for the robot based on angles between robots and a series of experiments validating robot performance. The new robot platform, the r-one will serve as an educational, outreach and research platform for robotics. I consider the robot's bearing-only sensor model, where each robot is capable of measuring the bearing, but not the distance, to each of its neighbors. This work also includes behaviors demonstrating the efficiency of this approach with this bearing-only sensor model. The new local coordinate systems based on angular information is introduced as scale-free coordinate system . Each robot produces its own local scale-free coordinates to determine the relative positions of its neighbors up to an unknown scaling factor. The computation of scale-free coordinates is analyzed with hardware and simulation validation. For hardware, the scale-free algorithm is tailored to low-cost systems with limited communication bandwidth and sensor resolution. The algorithm also uses a noise sensitivity model to reduce the impact of noise on the computed scale-free coordinates. I validate the algorithm with static and dynamic motion experiments

    Adaptive Formation Control of Cooperative Multi-Vehicle Systems

    Get PDF
    The literature comprises many approaches and results for the formation control of multi-vehicle systems; however, the results established for the cases where the vehicles contain parametric uncertainties are limited. Motivated by the need for explicit characterization of the effects of uncertainties on multi-vehicle formation motions, we study distributed adaptive formation control of multi-vehicle systems in this thesis, focusing on different interrelated sub-objectives. We first examine the cohesive motion control problem of minimally persistent formations of autonomous vehicles. Later, we consider parametric uncertainties in vehicle dynamics in such autonomous vehicle formations. Following an indirect adaptive control approach and exploiting the features of the certainty equivalence principle, we propose control laws to solve maneuvering problem of the formations, robust to parametric modeling uncertainties. Next, as a formation acquisition/closing ranks problem, we study the adaptive station keeping problem, which is defined as positioning an autonomous mobile vehicle AA inside a multi-vehicle network, having specified distances from the existing vehicles of the network. In this setting, a single-integrator model is assumed for the kinematics for the vehicle AA, and AA is assumed to have access to only its own position and its continuous distance measurements to the vehicles of the network. We partition the problem into two sub-problems; localization of the existing vehicles of the network using range-only measurements and motion control of AA to its desired location within the network with respect to other vehicles. We design an indirect adaptive control scheme, provide formal stability and convergence analysis and numerical simulation results, demonstrating the characteristics and performance of the design. Finally, we study re-design of the proposed station keeping scheme for the more challenging case where the vehicle AA has non-holonomic motion dynamics and does not have access to its self-location information. Overall, the thesis comprises methods and solutions to four correlated formation control problems in the direction of achieving a unified distributed adaptive formation control framework for multi-vehicle systems

    Navigation autonome sans collision pour robots mobiles nonholonomes

    Get PDF
    Cette thèse traite de la navigation autonome en environnement encombré pour des véhicules à roues soumis à des contraintes cinématiques de type nonholonome. Les applications de ces travaux sont par exemple l'automatisation de véhicules ou l'assistance au parking. Notre contribution porte sur le développement de méthodes qui réalisent certaines des fonctionnalités de la navigation autonome et sur l'intégration de ces différentes fonctionnalités au sein d'une architecture générique, en tenant compte des spécificités des systèmes considérés. Nous présentons une méthode d'évitement réactif d'obstacles pour systèmes nonholonomes et nous proposons une méthode de parking référencé sur des amers pour de tels systèmes. Ensuite nous présentons une architecture générique pour l'intégration des fonctionnalités de localisation, d'évitement d'obstacles et de suivi de trajectoire. Enfin nous illustrons l'ensemble de ces travaux par des résultatsexpérimentaux obtenus avec plusieurs robots. ABSTRACT : This work deals with autonomous navigation in cluttered environments for wheeled mobile robots subject to nonholonomic kinematic constraints. The potential applications of this work are for instance the development of autonomous cars and of parking assistance systems. Our contribution lies in the development of original methods to solve some of the functionalities of autonomous navigation and in their integration into a generic software architecture, while taking into account the specificities of the systems we deal with. We present an obstacle avoidance method for nonholonomic systems and we propose a landmark-based parking method for such systems. Then, we present a generic architecture for the integration of the functionalities of localisation, obstacle avoidance and trajectory following. Eventually, we illustrate this work with some experimental results obtained with several robots

    Transportation Statistics Annual Report 2022

    Get PDF
    Recognizing the importance of transportation and the importance of objective statistics for transportation decision-making, Congress requires the Director of the Bureau of Transportation Statistics (BTS) of the U.S. Department of Transportation (USDOT) to provide the Transportation Statistics Annual Report (TSAR) each year to Congress and the President.1 BTS published the first TSAR in 1994. This 28th TSAR edition documents the conduct of the duties of BTS as called out in the statute. This edition also includes new content focusing on "Passenger Travel and Equity," and the safety of automated vehicles; e-scooters, e-bikes, and hoverboards; and, harassment of passengers and operators

    Town of Bucksport Maine Ordinances

    Get PDF
    Ordinances Cover: General Provisions; Personnel; Animals; Boards; Buildings; Business Licensing; Fire Protection; Offenses; Sewers; Roads; Silver Lake; Traffic and Safety; Charter; Council Rules; Subdivision; Floodplain; Cable Television; HazWaste; Harbor Master; Signs; Solid Waste Flow; Junkyards; Land Use; Street Names & Numbers; General Assistance; PACE; Food Sovereignt

    Labour in a Single Shot

    Get PDF
    This collection of essays offers a critical assessment of Labour in a Single Shot, a groundbreaking documentary video workshop. From 2011 to 2014, curator Antje Ehmann and film- and videomaker Harun Farocki produced an art project of truly global proportions. They travelled to fifteen cities around the world to conduct workshops inspired by cinema history’s first film, Workers Leaving the Lumière Factory, shot in 1895 by the Lumière brothers in France. While the workshop videos are in colour and the camera was not required to remain static, Ehmann and Farocki’s students were tasked with honouring the original Lumière film’s basic parameters of theme and style. The fascinating result is a collection of more than 550 short videos that have appeared in international exhibitions and on an open-access website, offering the widest possible audience the opportunity to ponder contemporary labour in multiple contexts around the world

    Towards a Legal end Ethical Framework for Personal Care Robots. Analysis of Person Carrier, Physical Assistant and Mobile Servant Robots.

    Get PDF
    Technology is rapidly developing, and regulators and robot creators inevitably have to come to terms with new and unexpected scenarios. A thorough analysis of this new and continuosuly evolving reality could be useful to better understand the current situation and pave the way to the future creation of a legal and ethical framework. This is clearly a wide and complex goal, considering the variety of new technologies available today and those under development. Therefore, this thesis focuses on the evaluation of the impacts of personal care robots. In particular, it analyzes how roboticists adjust their creations to the existing regulatory framework for legal compliance purposes. By carrying out an impact assessment analysis, existing regulatory gaps and lack of regulatory clarity can be highlighted. These gaps should of course be considered further on by lawmakers for a future legal framework for personal care robot. This assessment should be made first against regulations. If the creators of the robot do not encounter any limitations, they can then proceed with its development. On the contrary, if there are some limitations, robot creators will either (1) adjust the robot to comply with the existing regulatory framework; (2) start a negotiation with the regulators to change the law; or (3) carry out the original plan and risk to be non-compliant. The regulator can discuss existing (or lacking) regulations with robot developers and give a legal response accordingly. In an ideal world, robots are clear of impacts and therefore threats can be responded in terms of prevention and opportunities in form of facilitation. In reality, the impacts of robots are often uncertain and less clear, especially when they are inserted in care applications. Therefore, regulators will have to address uncertain risks, ambiguous impacts and yet unkown effects

    Intelligence, Creativity and Fantasy

    Get PDF
    UID/HIS/04666/2019 This is the 2nd volume of PHI series, published by CRC Press, the 4th published by CRC Press and the 5th volume of PHI proceedings.The texts presented in Proportion Harmonies and Identities (PHI) - INTELLIGENCE, CREATIVITY AND FANTASY were compiled with the intent to establish a multidisciplinary platform for the presentation, interaction and dissemination of research. The aim is also to foster the awareness and discussion on the topics of Harmony and Proportion with a focus on different visions relevant to Architecture, Arts and Humanities, Design, Engineering, Social and Natural Sciences, and their importance and benefits for the sense of both individual and community identity. The idea of modernity has been a significant motor for development since the Western Early Modern Age. Its theoretical and practical foundations have become the working tools of scientists, philosophers, and artists, who seek strategies and policies to accelerate the development process in different contexts.authorsversionpublishe

    A Bearing-Only Control Law for Stable Docking of Unicycles

    No full text
    This paper proposes a new control method for stabilising control design for docking unicycle-like vehicles based on bearing-only information. An omni-directional panoramic camera is used to detect visual targets around the docking station and provides bearing (or heading) data for each observed landmark. The convergence of the controlled system is fully analysed and simulations are provided to demonstrate the ideal behaviour of the system. A robust and computationally cheap blob detection algorithm is proposed and results are provided to demonstrate its performance in extracting targets from cluttered scenes. Experimental results are presented demonstrating the performance of the algorithm on the ANU Nomadic Technologies Nomad XR4000 robot
    corecore