6,704 research outputs found

    Methodology to assess safety effects of future Intelligent Transport Systems on railway level crossings

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    There is consistent evidence showing that driver behaviour contributes to crashes and near miss incidents at railway level crossings (RLXs). The development of emerging Vehicle-to-Vehicle and Vehicle-to-Infrastructure technologies is a highly promising approach to improve RLX safety. To date, research has not evaluated comprehensively the potential effects of such technologies on driving behaviour at RLXs. This paper presents an on-going research programme assessing the impacts of such new technologies on human factors and drivers’ situational awareness at RLX. Additionally, requirements for the design of such promising technologies and ways to display safety information to drivers were systematically reviewed. Finally, a methodology which comprehensively assesses the effects of in-vehicle and road-based interventions warning the driver of incoming trains at RLXs is discussed, with a focus on both benefits and potential negative behavioural adaptations. The methodology is designed for implementation in a driving simulator and covers compliance, control of the vehicle, distraction, mental workload and drivers’ acceptance. This study has the potential to provide a broad understanding of the effects of deploying new in-vehicle and road-based technologies at RLXs and hence inform policy makers on safety improvements planning for RLX

    A Learning-Based Framework for Two-Dimensional Vehicle Maneuver Prediction over V2V Networks

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    Situational awareness in vehicular networks could be substantially improved utilizing reliable trajectory prediction methods. More precise situational awareness, in turn, results in notably better performance of critical safety applications, such as Forward Collision Warning (FCW), as well as comfort applications like Cooperative Adaptive Cruise Control (CACC). Therefore, vehicle trajectory prediction problem needs to be deeply investigated in order to come up with an end to end framework with enough precision required by the safety applications' controllers. This problem has been tackled in the literature using different methods. However, machine learning, which is a promising and emerging field with remarkable potential for time series prediction, has not been explored enough for this purpose. In this paper, a two-layer neural network-based system is developed which predicts the future values of vehicle parameters, such as velocity, acceleration, and yaw rate, in the first layer and then predicts the two-dimensional, i.e. longitudinal and lateral, trajectory points based on the first layer's outputs. The performance of the proposed framework has been evaluated in realistic cut-in scenarios from Safety Pilot Model Deployment (SPMD) dataset and the results show a noticeable improvement in the prediction accuracy in comparison with the kinematics model which is the dominant employed model by the automotive industry. Both ideal and nonideal communication circumstances have been investigated for our system evaluation. For non-ideal case, an estimation step is included in the framework before the parameter prediction block to handle the drawbacks of packet drops or sensor failures and reconstruct the time series of vehicle parameters at a desirable frequency

    A Distributed Approach for Collision Avoidance between Multirotor UAVs Following Planned Missions

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    [EN] As the number of potential applications for Unmanned Aerial Vehicles (UAVs) keeps rising steadily, the chances that these devices get close to each other during their flights also increases, causing concerns regarding potential collisions. This paper proposed the Mission Based Collision Avoidance Protocol (MBCAP), a novel UAV collision avoidance protocol applicable to all types of multicopters flying autonomously. It relies on wireless communications in order to detect nearby UAVs, and to negotiate the procedure to avoid any potential collision. Experimental and simulation results demonstrated the validity and effectiveness of the proposed solution, which typically introduces a small overhead in the range of 15 to 42 s for each risky situation successfully handled.This work was partially supported by the "Ministerio de Ciencia, Innovacion y Universidades, Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad, Proyectos I+D+I 2018", Spain, under Grant RTI2018-096384-B-I00, and the Universitat Politecnica de Valencia (UPV) under grant number FPI-2017-S1 for the training of PhD researchers.Fabra Collado, FJ.; Zamora-Mero, WJ.; Sangüesa-Escorihuela, JA.; Tavares De Araujo Cesariny Calafate, CM.; Cano, J.; Manzoni, P. (2019). A Distributed Approach for Collision Avoidance between Multirotor UAVs Following Planned Missions. Sensors. 19(10):1-25. https://doi.org/10.3390/s19102404S1251910Mohamed, N., Al-Jaroodi, J., Jawhar, I., Idries, A., & Mohammed, F. (2020). Unmanned aerial vehicles applications in future smart cities. Technological Forecasting and Social Change, 153, 119293. doi:10.1016/j.techfore.2018.05.004SESAR Joint Undertakinghttps://www.sesarju.eu/Fabra, F., T. Calafate, C., Cano, J.-C., & Manzoni, P. (2018). MBCAP: Mission Based Collision Avoidance Protocol for UAVs. 2018 IEEE 32nd International Conference on Advanced Information Networking and Applications (AINA). doi:10.1109/aina.2018.00090Drone Collision Avoidancehttps://create.arduino.cc/projecthub/anshulsingh163/drone-collision-avoidance-system-0b6002Liu, Z., & Foina, A. G. (2016). Feature article: an autonomous quadrotor avoiding a helicopter in low-altitude flights. IEEE Aerospace and Electronic Systems Magazine, 31(9), 30-39. doi:10.1109/maes.2016.150131Xiang, J., Liu, Y., & Luo, Z. (2016). Flight safety measurements of UAVs in congested airspace. Chinese Journal of Aeronautics, 29(5), 1355-1366. doi:10.1016/j.cja.2016.08.017Lin, Q., Wang, X., & Wang, Y. (2018). Cooperative Formation and Obstacle Avoidance Algorithm for Multi-UAV System in 3D Environment. 2018 37th Chinese Control Conference (CCC). doi:10.23919/chicc.2018.8483113Zhou, X., Yu, X., & Peng, X. (2019). UAV Collision Avoidance Based on Varying Cells Strategy. IEEE Transactions on Aerospace and Electronic Systems, 55(4), 1743-1755. doi:10.1109/taes.2018.2875556Kim, H., & Ben-Othman, J. (2018). A Collision-Free Surveillance System Using Smart UAVs in Multi Domain IoT. IEEE Communications Letters, 22(12), 2587-2590. doi:10.1109/lcomm.2018.2875477Wang, M., Voos, H., & Su, D. (2018). Robust Online Obstacle Detection and Tracking for Collision-Free Navigation of Multirotor UAVs in Complex Environments. 2018 15th International Conference on Control, Automation, Robotics and Vision (ICARCV). doi:10.1109/icarcv.2018.8581330Ma, L. (2018). Cooperative Target Tracking using a Fleet of UAVs with Collision and Obstacle Avoidance. 2018 22nd International Conference on System Theory, Control and Computing (ICSTCC). doi:10.1109/icstcc.2018.8540717Chen, P.-H., & Lee, C.-Y. (2018). UAVNet: An Efficient Obstacel Detection Model for UAV with Autonomous Flight. 2018 International Conference on Intelligent Autonomous Systems (ICoIAS). doi:10.1109/icoias.2018.8494201Fabra, F., Calafate, C. T., Cano, J. C., & Manzoni, P. (2018). ArduSim: Accurate and real-time multicopter simulation. Simulation Modelling Practice and Theory, 87, 170-190. doi:10.1016/j.simpat.2018.06.009Accurate and real-time multi-UAV simulationhttps://bitbucket.org/frafabco/ardusim/src/master/MAVLink Micro Air Vehicle Communication Protocolhttp://qgroundcontrol.org/mavlink/startGorelick, N., Hancher, M., Dixon, M., Ilyushchenko, S., Thau, D., & Moore, R. (2017). Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sensing of Environment, 202, 18-27. doi:10.1016/j.rse.2017.06.031NS-2 The Network Simulatorhttp://nsnam.sourceforge.net/wiki/index.php/Main_PageOMNeT++ Discrete Event Simulatorhttps://omnetpp.org/Quaternium, Home of the Longest Flight Time Hybrid Dronehttp://www.quaternium.com/Gauss-Markov Mobilityhttps://doc.omnetpp.org/inet/api-current/neddoc/inet.mobility.single.GaussMarkovMobility.htmlFerrera, E., Alcántara, A., Capitán, J., Castaño, A., Marrón, P., & Ollero, A. (2018). Decentralized 3D Collision Avoidance for Multiple UAVs in Outdoor Environments. Sensors, 18(12), 4101. doi:10.3390/s1812410

    Throughput optimization strategies for large-scale wireless LANs

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    Thanks to the active development of IEEE 802.11, the performance of wireless local area networks (WLANs) is improving by every new edition of the standard facilitating large enterprises to rely on Wi-Fi for more demanding applications. The limited number of channels in the unlicensed industrial scientific medical frequency band however is one of the key bottlenecks of Wi-Fi when scalability and robustness are points of concern. In this paper we propose two strategies for the optimization of throughput in wireless LANs: a heuristic derived from a theoretical model and a surrogate model based decision engine

    Long-lasting virtual motorcycle-riding trainer effectiveness

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    This work aimed to test the long-lasting effects of learning acquired with a virtual motorcycle-riding trainer as a tool to improve hazard perception. During the simulation, the rider can interact with other road actors and experience the most common potential accident situations in order to learn to modify his or her behavior to anticipate hazards and avoid crashes. We compared performance to the riding simulator of the two groups of participants: the experimental group, which was trained with the same simulator one year prior, and the control group that had not received any type of training with a riding or driving simulator. All of the participants had ridden a moped in the previous 12 months. The experimental group showed greater abilities to avoid accidents and recognize hazards in comparison to their performance observed a year before, whereas the performance of the control group was similar to that of the experimental group 1 year before in the first two sessions, and even better in the third. We interpreted this latter result as a consequence of their prior on-road experience. Also, the fact that the performance of the experimental group at the beginning of the follow-up is better than that recorded at the end of the training 1 year before is in line with the idea of a transfer from the on-road experience to the simulator. The present data confirm our main expectation that the effectiveness of the riding training simulator on the ability to cope with potentially dangerous situations persists over time and provides additional evidence in favor of the idea that simulators may be considered useful tools for training the ability to detect and react to hazards, leading to an improvement of this higher-order cognitive skill that persists over time. Implications for the reciprocal influence of the training with the simulator and the on-the road experience are discussed as well

    A planned approach to high collision risk area

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    Submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2020.This thesis examines the transition of a vessel from the open ocean, where collisions are rare, to a high risk and heavy traffic area such as a Traffic Separation Scheme (TSS). Previous autonomy approaches generally view path planning and collision avoidance as two separate functions, i.e. a vessel will follow the planned path until conditions are met for collision avoidance algorithms to take over. Here an intermediate phase is proposed with the goal of adjusting the time of arrival to a high vessel density area so that the risk of collision is reduced. A general algorithm that calculates maximum future traffic density for all choices in the speed domain is proposed and implemented as a MOOS-IvP behavior. This behavior gives the vessel awareness of future collision risks and aids the collision avoidance process. This new approach improves the safety of the vessel by reducing the number of risky encounters that will likely require the vessel to maneuver for safety

    Numerical approach of collision avoidance and optimal control on robotic manipulators

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    Collision-free optimal motion and trajectory planning for robotic manipulators are solved by a method of sequential gradient restoration algorithm. Numerical examples of a two degree-of-freedom (DOF) robotic manipulator are demonstrated to show the excellence of the optimization technique and obstacle avoidance scheme. The obstacle is put on the midway, or even further inward on purpose, of the previous no-obstacle optimal trajectory. For the minimum-time purpose, the trajectory grazes by the obstacle and the minimum-time motion successfully avoids the obstacle. The minimum-time is longer for the obstacle avoidance cases than the one without obstacle. The obstacle avoidance scheme can deal with multiple obstacles in any ellipsoid forms by using artificial potential fields as penalty functions via distance functions. The method is promising in solving collision-free optimal control problems for robotics and can be applied to any DOF robotic manipulators with any performance indices and mobile robots as well. Since this method generates optimum solution based on Pontryagin Extremum Principle, rather than based on assumptions, the results provide a benchmark against which any optimization techniques can be measured

    Haptic Feedback to Assist Bus Drivers for Pedestrian Safety at Low Speed

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    Buses and coaches are massive Passenger Transportation Systems (PTS), because they represent more than half of land PTS in the European Union. Despite of that, bus accident figures are lower than other means of transport, but its size and weight increase the severity of accidents in which buses are involved, even at low speed. In urban scenarios, turnings and manoeuvres around bus stops are the main causes of accidents, mostly due to low visibility, blind spots or driver s distractions. Therefore, there is an increasing interest in developing driving assistance systems to avoid these situations, among others. However, even though there are some solutions on the market, they are not meant to work in urban areas at low speed and with the sole purpose of preventing collisions with pedestrians. In this sense, the paper proposes an active safety system for buses in manoeuvres at low speed. The safety system consists of haptic feedback devices together with collision avoidance and risk evaluation systems based on detected people nearby the bus. The performance of the active safety system has been validated in a simulated urban scenario. Our results show that driver s reaction time is reduced and time to collision increased due to the proposed low-speed active safety system. In particular, it is shown that there is a reduction in the number of high risk cases and collisions, which implies a considerable improvement in safety terms. In addition to this, a brief discussion about current regulations for innovative safety systems on a real vehicles is carried out.This paper has been funded by Ministerio de Ciencia e Innovacion (Spain) through the projects "Sistemas Avanzados de Seguridad Integral en Autobuses (SAFEBUS)" (IPT-2011-1165-370000) and "Sistemas de Conduccion Segura de Vehiculos de Transporte de Pasajeros y Materiales con Asistencia Haptica/Audiovisual e Interfaces Biomedicas (SAFETRANS)" (DPI2013-42302-R). This work was also supported by Programa VALi+d (Generalitat Valenciana). The authors wish to thank Jose Luis Sanchez Carrascosa for his dedication and commitment to the project and thank to Ana Isabel Sanchez Galdon for her valuable help regarding ANOVA analysis.Girbés, V.; Armesto Ángel, L.; Dols Ruiz, JF.; Tornero Montserrat, J. (2016). Haptic Feedback to Assist Bus Drivers for Pedestrian Safety at Low Speed. IEEE Transactions on Haptics. 9(3):345-357. https://doi.org/10.1109/TOH.2016.2531686S3453579
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