115 research outputs found

    Cooperative control of multi-robot system with force reflecting via internet

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    Lo Wang Tai.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 58-63).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.iiiTables of Content --- p.ivList of Figures --- p.viiList of Tables --- p.viiiChapter Chapter1 --- Introduction --- p.1Chapter 1.1 --- Internet-based Tele-cooperation --- p.1Chapter 1.1.1 --- Cooperative Control of Multiple Robot --- p.1Chapter 1.1.2 --- Internet-based Teleoperation --- p.3Chapter 1.1.3 --- Time Delay of Internet Communication --- p.4Chapter 1.2 --- Related Work --- p.5Chapter 1.3 --- Motivation and Contribution --- p.6Chapter 1.3.1 --- Motivation --- p.6Chapter 1.3.2 --- Contribution --- p.7Chapter 1.4 --- Outline of the thesis --- p.8Chapter Chapter2 --- The Internet Robotic System --- p.9Chapter 2.1 --- System Architecture --- p.9Chapter 2.2 --- The Hardware --- p.12Chapter 2.2.1 --- Operator System --- p.12Chapter 2.2.2 --- Mobile Robot System --- p.13Chapter 2.2.3 --- Multi-fingered Robot Hand System --- p.17Chapter 2.2.4 --- Visual Tracking System --- p.19Chapter 2.3 --- Software Design --- p.21Chapter 2.3.1 --- Robot Client and Arm Client --- p.22Chapter 2.3.2 --- Robot Server --- p.23Chapter 2.3.3 --- Image Server --- p.25Chapter 2.3.4 --- Arm Server --- p.75Chapter 2.3.5 --- Arm Controller --- p.27Chapter 2.3.6 --- Finger Server --- p.27Chapter 2.3.7 --- Finger Controller --- p.27Chapter 2.3.8 --- Robot Tracker --- p.28Chapter 2.3.9 --- Interaction Forwarder --- p.28Chapter Chapter3 --- Event-based Control for Force Reflecting Teleoperation --- p.29Chapter 3.1 --- Modeling and Control --- p.29Chapter 3.1.1 --- Model of Operator System --- p.31Chapter 3.1.2 --- Model of Mobile Robot System --- p.33Chapter 3.1.3 --- Model of Multi-fingered Hand System --- p.34Chapter 3.2 --- Force Feedback Generation --- p.35Chapter 3.2.1 --- Obstacle Avoidance --- p.35Chapter 3.2.2 --- Singularity Avoidance --- p.38Chapter 3.2.3 --- Interaction Rendering --- p.40Chapter Chapter4 --- Experiments --- p.42Chapter 4.1 --- Experiment1 --- p.42Chapter 4.2 --- Experiment2 --- p.47Chapter 4.3 --- Experiment3 --- p.52Chapter Chapter5 --- Future Wok --- p.54Chapter Chapter6 --- Conclusions --- p.56Bibliography --- p.5

    Optimized route selection for logging trucks

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    The forestry sector is playing an important role in the transition to a bioeconomy.In the supply chain of forest raw material, logging transport is a crucial component. The forestry sector must improve transport efficiency to mitigate its impact on the environment, to reduce costs and road safety risks,and to remain competitive. Forestry transport in Sweden is paid according to payload and distance travelled. The forestry sector has developed a system for distance measurement, Calibrated Route Finder (CRF), which balances quantitative factors, such as distance, functional road class and road width, with qualitative factors, such as stress and traffic safety. An inverse optimization process is used to translate best-practice routes into a weighted objective that is used when new routes are generated. The objectives of this thesis have been to improve CRF, by including features describing road curvature and hilliness, and addressing illegal or impossible turns in intersections. Methods have been developed to calculate curvature and hilliness using available data in the national road data base. The study has proposed an augmentation of the road data network so that illegal, non-logical and undesirable turns and short-cuts can be considered. The augmented network also enables detailed descriptions of increased time and fuel consumption in relation to intersections, which provides opportunities to generate routing with a focus on minimizing cost or greenhouse emissions. Two of the major cost elements in logging transport are time and fuel consumption, and this study has shown that fuel consumption is mainly affected by road gradient and truck weight, while operating speed is mainly affected by horizontal curvature and surface roughness. A new variable was introduced, integrated gradient, which describes the vertical work performed by the truck on undulating road sections better than the gradient variable

    New Challenges in Quality of Services Control Architectures in Next Generation Networks

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    A mesura que Internet i les xarxes IP s'han anat integrant dins la societat i les corporacions, han anat creixent les expectatives de nous serveis convergents així com les expectatives de qualitat en les comunicacions. Les Next Generation Networks (NGN) donen resposta a les noves necessitats i representen el nou paradigma d'Internet a partir de la convergència IP. Un dels aspectes menys desenvolupats de les NGN és el control de la Qualitat del Servei (QoS), especialment crític en les comunicacions multimèdia a través de xarxes heterogènies i/o de diferents operadors. A més a més, les NGN incorporen nativament el protocol IPv6 que, malgrat les deficiències i esgotament d'adreces IPv4, encara no ha tingut l'impuls definitiu.Aquesta tesi està enfocada des d'un punt de vista pràctic. Així doncs, per tal de poder fer recerca sobre xarxes de proves (o testbeds) que suportin IPv6 amb garanties de funcionament, es fa un estudi en profunditat del protocol IPv6, del seu grau d'implementació i dels tests de conformància i interoperabilitat existents que avaluen la qualitat d'aquestes implementacions. A continuació s'avalua la qualitat de cinc sistemes operatius que suporten IPv6 mitjançant un test de conformància i s'implementa el testbed IPv6 bàsic, a partir del qual es farà la recerca, amb la implementació que ofereix més garanties.El QoS Broker és l'aportació principal d'aquesta tesi: un marc integrat que inclou un sistema automatitzat per gestionar el control de la QoS a través de sistemes multi-domini/multi-operador seguint les recomanacions de les NGN. El sistema automatitza els mecanismes associats a la configuració de la QoS dins d'un mateix domini (sistema autònom) mitjançant la gestió basada en polítiques de QoS i automatitza la negociació dinàmica de QoS entre QoS Brokers de diferents dominis, de forma que permet garantir QoS extrem-extrem sense fissures. Aquesta arquitectura es valida sobre un testbed de proves multi-domini que utilitza el mecanisme DiffServ de QoS i suporta IPv6.L'arquitectura definida en les NGN permet gestionar la QoS tant a nivell 3 (IP) com a nivell 2 (Ethernet, WiFi, etc.) de forma que permet gestionar també xarxes PLC. Aquesta tesi proposa una aproximació teòrica per aplicar aquesta arquitectura de control, mitjançant un QoS Broker, a les noves xarxes PLC que s'estan acabant d'estandarditzar, i discuteix les possibilitats d'aplicació sobre les futures xarxes de comunicació de les Smart Grids.Finalment, s'integra en el QoS Broker un mòdul per gestionar l'enginyeria del tràfic optimitzant els dominis mitjançant tècniques de intel·ligència artificial. La validació en simulacions i sobre un testbed amb routers Cisco demostra que els algorismes genètics híbrids són una opció eficaç en aquest camp.En general, les observacions i avenços assolits en aquesta tesi contribueixen a augmentar la comprensió del funcionament de la QoS en les NGN i a preparar aquests sistemes per afrontar problemes del món real de gran complexitat.A medida que Internet y las redes IP se han ido integrando dentro de la sociedad y las corporaciones, han ido creciendo las expectativas de nuevos servicios convergentes así como las expectativas de calidad en las comunicaciones. Las Next Generation Networks (NGN) dan respuesta a las nuevas necesidades y representan el nuevo paradigma de Internet a partir de la convergencia IP. Uno de los aspectos menos desarrollados de las NGN es el control de la Calidad del Servicio (QoS), especialmente crítico en las comunicaciones multimedia a través de redes heterogéneas y/o de diferentes operadores. Además, las NGN incorporan nativamente el protocolo IPv6 que, a pesar de las deficiencias y agotamiento de direcciones IPv4, aún no ha tenido el impulso definitivo.Esta tesis está enfocada desde un punto de vista práctico. Así pues, con tal de poder hacer investigación sobre redes de prueba (o testbeds) que suporten IPv6 con garantías de funcionamiento, se hace un estudio en profundidad del protocolo IPv6, de su grado de implementación y de los tests de conformancia e interoperabilidad existentes que evalúan la calidad de estas implementaciones. A continuación se evalua la calidad de cinco sistemas operativos que soportan IPv6 mediante un test de conformancia y se implementa el testbed IPv6 básico, a partir del cual se realizará la investigación, con la implementación que ofrece más garantías.El QoS Broker es la aportación principal de esta tesis: un marco integrado que incluye un sistema automatitzado para gestionar el control de la QoS a través de sistemas multi-dominio/multi-operador siguiendo las recomendaciones de las NGN. El sistema automatiza los mecanismos asociados a la configuración de la QoS dentro de un mismo dominio (sistema autónomo) mediante la gestión basada en políticas de QoS y automatiza la negociación dinámica de QoS entre QoS brokers de diferentes dominios, de forma que permite garantizar QoS extremo-extremo sin fisuras. Esta arquitectura se valida sobre un testbed de pruebas multi-dominio que utiliza el mecanismo DiffServ de QoS y soporta IPv6. La arquitectura definida en las NGN permite gestionar la QoS tanto a nivel 3 (IP) o como a nivel 2 (Ethernet, WiFi, etc.) de forma que permite gestionar también redes PLC. Esta tesis propone una aproximación teórica para aplicar esta arquitectura de control, mediante un QoS Broker, a las noves redes PLC que se están acabando de estandardizar, y discute las posibilidades de aplicación sobre las futuras redes de comunicación de las Smart Grids.Finalmente, se integra en el QoS Broker un módulo para gestionar la ingeniería del tráfico optimizando los dominios mediante técnicas de inteligencia artificial. La validación en simulaciones y sobre un testbed con routers Cisco demuestra que los algoritmos genéticos híbridos son una opción eficaz en este campo.En general, las observaciones y avances i avances alcanzados en esta tesis contribuyen a augmentar la comprensión del funcionamiento de la QoS en las NGN y en preparar estos sistemas para afrontar problemas del mundo real de gran complejidad.The steady growth of Internet along with the IP networks and their integration into society and corporations has brought with it increased expectations of new converged services as well as greater demands on quality in communications. The Next Generation Networks (NGNs) respond to these new needs and represent the new Internet paradigm from the IP convergence. One of the least developed aspects in the NGNs is the Quality of Service (QoS) control, which is especially critical in the multimedia communication through heterogeneous networks and/or different operators. Furthermore, the NGNs natively incorporate the IPv6 protocol which, despite its shortcomings and the depletion of IPv4 addresses has not been boosted yet.This thesis has been developed with a practical focus. Therefore, with the aim of carrying out research over testbeds supporting the IPv6 with performance guarantees, an in-depth study of the IPv6 protocol development has been conducted and its degree of implementation and the existing conformance and interoperability tests that evaluate these implementations have been studied. Next, the quality of five implementations has been evaluated through a conformance test and the basic IPv6 testbed has been implemented, from which the research will be carried out. The QoS Broker is the main contribution to this thesis: an integrated framework including an automated system for QoS control management through multi-domain/multi-operator systems according to NGN recommendations. The system automates the mechanisms associated to the QoS configuration inside the same domain (autonomous system) through policy-based management and automates the QoS dynamic negotiation between peer QoS Brokers belonging to different domains, so it allows the guarantee of seamless end-to-end QoS. This architecture is validated over a multi-domain testbed which uses the QoS DiffServ mechanism and supports IPv6.The architecture defined in the NGN allows QoS management at level 3 (IP) as well as at level 2 (e.g. Ethernet, WiFi) so it also facilitates the management of PLC networks. Through the use of a QoS Broker, this thesis proposes a theoretical approach for applying this control architecture to the newly standardized PLC networks, and discusses the possibilities of applying it over the future communication networks of the Smart Grids.Finally, a module for managing traffic engineering which optimizes the network domains through artificial intelligence techniques is integrated in the QoS Broker. The validations by simulations and over a Cisco router testbed demonstrate that hybrid genetic algorithms are an effective option in this area.Overall, the advances and key insights provided in this thesis help advance our understanding of QoS functioning in the NGNs and prepare these systems to face increasingly complex problems, which abound in current industrial and scientific applications

    Network Structures of Cargo Airlines - An Empirical and a Modelling Approach

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    The development of efficient air freight networks is an upcoming challenge. The present book approaches this problem for cargo airlines by characterising and classifying their network structures and by developing a model for an airline\u27s strategic network design. The book provides results which are of value for airline professionals (network efficiency analysis), policy makers (policy impact assessment) and researchers (cargo airline network design model)

    Human adaptive mechatronics methods for mobile working machines

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    Despite the trend of increasing automation degree in control systems, human operators are still needed in applications such as aviation and surgery, or machines used in remote mining, forestry, construction, and agriculture, just to name a few. Although there are research results showing that the performance between the operators of working machines differ significantly, there are currently no means to improve the performance of the human-machine system automatically based on the skill and working differences of the operators. Traditionally the human-machine systems are designed so that the machine is "constant" for every operator. On the contrary, the Human Adaptive Mechatronics (HAM) approach focuses on individual design, taking into account the skill differences and preferences of the operators. This thesis proposes a new type of a HAM system for mobile working machines called Human Adaptive Mechatronics and Coaching (HAMC) system that is designed to account for the challenges regarding to the measurement capability and the work complexity in the real-life machines. Moreover, the related subproblems including intent recognition, skill evaluation, human operator modeling, intelligent coaching and skill adaptivity are described. The intent recognition is solved using a Hidden Markov model (HMM) based work cycle modeling method, which is a basis for the skill evaluation. The methods are implemented in three industrial applications. The human operator modeling problem is studied from the structural models' perspective. The structural models can be used to describe a continuum of human operator models with respect to the operating points of the controlled machine. Several extensions and new approaches which enable more efficient parameter estimation using the experimental data are described for the conventional Modified Optimal Control Model (MOCM) of human operator. The human operator modeling methods are implemented to model a human operator controlling a trolley crane simulator. Finally, the concept of human adaptive Human-Machine Interface (HMI) is described. The analytic and knowledge-based approaches for realizing the HMI adaptation are presented and implemented for trolley crane simulator control

    Optimization models and solution methods for intermodal transportation

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    Self-organizing Fast Routing Protocols for Underwater Acoustic Communications Networks

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    To address this problem, in this thesis we propose a cross-layer proactive routing initialization mechanism that does not require additional measurements and, at the same time, is energy efficient. Two routing protocols are proposed: Self-Organized Fast Routing Protocol for Radial Underwater Networks (SOFRP) for radial topology and Self-organized Proactive Routing Protocol for Non-uniformly Deployed Underwater Networks (SPRINT) for a randomly deployed network. SOFRP is based on the algorithm to recreate a radial topology with a gateway node, such that packets always use the shortest possible path from source to sink, thus minimizing consumed energy. Collisions are avoided as much as possible during the path initialization. The algorithm is suitable for 2D or 3D areas, and automatically adapts to a varying number of nodes. In SPRINT the routing path to the gateway is formed on the basis of the distance, measured by the signal strength received. The data sending node prefers to choose the neighbor node which is closest to it. It is designed to achieve high data throughput and low energy consumption of the nodes. There is a tradeoff between the throughput and the energy consumption: more distance needs more transmission energy, and more relay nodes (hops) to the destination node affects the throughput. Each hop increases the packet delay and decreases the throughput. Hence, energy consumption requires nearest nodes to be chosen as forwarding node whereas the throughput requires farthest node to be selected to minimize the number of hops. Fecha de lectura de Tesis Doctoral: 11 mayo 2020Underwater Wireless Sensor Networks (UWSNs) constitute an emerging technology for marine surveillance, natural disaster alert and environmental monitoring. Unlike terrestrial Wireless Sensor Networks (WSNs), electromagnetic waves cannot propagate more than few meters in water (high absorption rate). However, acoustic waves can travel long distances in underwater. Therefore, acoustic waves are preferred for underwater communications, but they travel very slow compare to EM waves (typical speed in water is 1500 m/s against 2x10^8 m/s for EM waves). This physical effect makes a high propagation delay and cannot be avoided, but the end-to-end packet delay it can be reduced. Routing delay is one of the major factors in end-to-end packet delay. In reactive routing protocols, when a packet arrives to a node, the node takes some time to select the node to which the data packet would be forwarded. We may reduce the routing delay for time-critical applications by using proactive routing protocols. Other two critical issues in UWSNs are determining the position of the nodes and time synchronization. Wireless sensor nodes need to determine the position of the surrounding nodes to select the next node in the path to reach the sink node. A Global Navigation Satellite System (GNSS) cannot be used because of the very short underwater range of the GNSS signal. Timestamping to estimate the distance is possible but the limited mobility of the UWSN nodes and variation in the propagation speed of the acoustic waves make the time synchronization a challenging task. For these reasons, terrestrial WSN protocols cannot be readily used for underwater acoustic networks

    Reinforcement and deep reinforcement learning for wireless Internet of Things: A survey

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    International audienceNowadays, many research studies and industrial investigations have allowed the integration of the Internet of Things (IoT) in current and future networking applications by deploying a diversity of wireless-enabled devices ranging from smartphones, wearables, to sensors, drones, and connected vehicles. The growing number of IoT devices, the increasing complexity of IoT systems, and the large volume of generated data have made the monitoring and management of these networks extremely difficult. Numerous research papers have applied Reinforcement Learning (RL) and Deep Reinforcement Learning (DRL) techniques to overcome these difficulties by building IoT systems with effective and dynamic decision-making mechanisms, dealing with incomplete information related to their environments. The paper first reviews pre-existing surveys covering the application of RL and DRL techniques in IoT communication technologies and networking. The paper then analyzes the research papers that apply these techniques in wireless IoT to resolve issues related to routing, scheduling, resource allocation, dynamic spectrum access, energy, mobility, and caching. Finally, a discussion of the proposed approaches and their limits is followed by the identification of open issues to establish grounds for future research directions proposal

    Highly reliable, low-latency communication in low-power wireless networks

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    Low-power wireless networks consist of spatially distributed, resource-constrained devices – also referred to as nodes – that are typically equipped with integrated or external sensors and actuators. Nodes communicate with each other using wireless transceivers, and thus, relay data – e. g., collected sensor values or commands for actuators – cooperatively through the network. This way, low-power wireless networks can support a plethora of different applications, including, e. g., monitoring the air quality in urban areas or controlling the heating, ventilation and cooling of large buildings. The use of wireless communication in such monitoring and actuating applications allows for a higher flexibility and ease of deployment – and thus, overall lower costs – compared to wired solutions. However, wireless communication is notoriously error-prone. Message losses happen often and unpredictably, making it challenging to support applications requiring both high reliability and low latency. Highly reliable, low-latency communication – along with high energy-efficiency – are, however, key requirements to support several important application scenarios and most notably the open-/closed-loop control functions found in e. g., industry and factory automation applications. Communication protocols that rely on synchronous transmissions have been shown to be able to overcome this limitation. These protocols depart from traditional single-link transmissions and do not attempt to avoid concurrent transmissions from different nodes to prevent collisions. On the contrary, they make nodes send the same message at the same time over several paths. Phenomena like constructive interference and capture then ensure that messages are received correctly with high probability. While many approaches relying on synchronous transmissions have been presented in the literature, two important aspects received only little consideration: (i) reliable operation in harsh environments and (ii) support for event-based data traffic. This thesis addresses these two open challenges and proposes novel communication protocols to overcome them
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