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Bai, Chengchao (author), Yan, Peng (author), Piao, Haiyin (author), Pan, W. (author), Guo, Jifeng (author)This article explores deep reinforcement learning (DRL) for the flocking control of unmanned aerial vehicle (UAV) swarms. The flocking control policy is trained using a centralized-learning-decentralized-execution (CTDE) paradigm, where a centralized critic network augmented with additional information about the entire UAV swarm is utilized...journal article 2024
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Wang, X. (author), Li, Zirui (author), Alonso-Mora, J. (author), Wang, Meng (author)Risk assessment is a crucial component of collision warning and avoidance systems for intelligent vehicles. Reachability-based formal approaches have been developed to ensure driving safety to accurately detect potential vehicle collisions. However, they suffer from over-conservatism, potentially resulting in false–positive risk events in...journal article 2024
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Xin, Jianbin (author), Meng, Chuang (author), D'Ariano, Andrea (author), Schulte, F. (author), Peng, Jinzhu (author), Negenborn, R.R. (author)This paper investigates a novel routing problem of a multi-robot station in a manufacturing cell. In the existing literature, the objective is to minimize the cycle time or energy consumption separately. The routing problem considered in this paper aims to reduce the cycle time and energy consumption jointly for each robot while avoiding...journal article 2023
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Ferranti, L. (author), Lyons, L. (author), Negenborn, R.R. (author), Keviczky, T. (author), Alonso-Mora, J. (author)This work presents a method for multi-robot coordination based on a novel distributed nonlinear model predictive control (NMPC) formulation for trajectory optimization and its modified version to mitigate the effects of packet losses and delays in the communication among the robots. Our algorithms consider that each robot is equipped with an...journal article 2023
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Li, M. (author), Mou, Junmin (author), Chen, Pengfei (author), Chen, Linying (author), van Gelder, P.H.A.J.M. (author)Regional risk analysis and management of maritime accidents is one of the fundamental tasks for maritime safety management. With the heavy and complicated maritime traffic in the ports and waterways, accidents, especially ship collision accidents, have been continuously posing threats to the maritime transportation system. To achieve effective...journal article 2023
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Zhang, Lei (author), Liu, Wenjie (author), Du, Zhe (author), Du, Lei (author), Li, Xiaobin (author)Collision avoidance is a priority task for ensuring the safety of a maritime transportation system. However, for a ship towing system, which is characterized by multiple vessels and physical connections, the research works about collision avoidance is limited. Thus, this paper proposes a speed and heading control-based conflict resolution of...journal article 2023
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Liu, Xinjie (author), Peters, L. (author), Alonso-Mora, J. (author)Many autonomous agents, such as intelligent vehicles, are inherently required to interact with one another. Game theory provides a natural mathematical tool for robot motion planning in such interactive settings. However, tractable algorithms for such problems usually rely on a strong assumption, namely that the objectives of all players in...journal article 2023
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Angelini, Franco (author), Angelini, Pierangela (author), Angiolini, Claudia (author), Bagella, Simonetta (author), Caccianiga, Marco (author), Della Santina, C. (author), Gigante, Daniela (author), Hutter, Marco (author), Nanayakkara, Thrishantha (author)In this paper, we first discuss the challenges related to habitat monitoring and review possible robotic solutions. Then, we propose a framework to perform terrestrial habitat monitoring exploiting the mobility of legged robotic systems. The idea is to provide the robot with the Natural Intelligence introduced as the combination of the...journal article 2023
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Serra Gomez, A. (author), Zhu, H. (author), Ferreira de Brito, B.F. (author), Böhmer, J.W. (author), Alonso-Mora, J. (author)Decentralized multi-robot systems typically perform coordinated motion planning by constantly broadcasting their intentions to avoid collisions. However, the risk of collision between robots varies as they move and communication may not always be needed. This paper presents an efficient communication method that addresses the problem of “when...journal article 2023
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Bai, X. (author), Fielbaum, Andres (author), Kronmüller, M. (author), Knödler, L. (author), Alonso-Mora, J. (author)This paper studies the multi-robot task assignment problem in which a fleet of dispersed robots needs to efficiently transport a set of dynamically appearing packages from their initial locations to corresponding destinations within prescribed time-windows. Each robot can carry multiple packages simultaneously within its capacity. Given a...journal article 2023
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Cheng, Gang (author), Wu, S. (author), Shi, M. (author), Dong, W. (author), Zhu, H. (author), Alonso-Mora, J. (author)Autonomous navigation of Micro Aerial Vehicles (MAVs) in dynamic and unknown environments is a complex and challenging task. Current works rely on assumptions to solve the problem. The MAV's pose is precisely known, the dynamic obstacles can be explicitly segmented from static ones, their number is known and fixed, or they can be modeled with...journal article 2023
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Liu, Kezhong (author), Wu, Xiaolie (author), Zhou, Y. (author), Yuan, Zhitao (author), Yang, Xing (author), Xin, Xuri (author), Zhuang, Sujie (author)During the process of collision avoidance, especially in a multi-ship encounter situation, the dynamic interactions among individual ships impose a significant impact on collision avoidance decision-making. It is imperative, therefore, that collision avoidance decisions are formulated with a comprehensive consideration of not only the current...journal article 2023
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Chen, Gang (author), Dong, Wei (author), Peng, Peng (author), Alonso-Mora, J. (author), Zhu, Xiangyang (author)Particle-based dynamic occupancy maps were proposed in recent years to model the obstacles in dynamic environments. Current particle-based maps describe the occupancy status in discrete grid form and suffer from the grid size problem, wherein a large grid size is unfavorable for motion planning while a small grid size lowers efficiency and...journal article 2023
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Roth, M. (author), Stapel, J.C.J. (author), Happee, R. (author), Gavrila, D. (author)We present a novel method for vehicle-pedestrian path prediction that takes into account the awareness of the driver and the pedestrian towards each other. The method jointly models the paths of vehicle and pedestrian within a single Dynamic Bayesian Network (DBN). In this DBN, sub-graphs model the environment and entity-specific context cues...journal article 2022
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Raju, Narayana (author), Arkatkar, Shriniwas (author), Antoniou, Constantinos (author)Using vehicle trajectory datasets developed over a study section for three traffic flow levels, a rectangular hyperbolic relation between time-to-collision and relative speeds in vehicle-following behavior were observed. A new methodology for estimating the probable rear-end collisions in the given traffic stream is developed based on this...journal article 2022
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Mauro, F. (author), Vassalos, Dracos (author), Paterson, Donald (author), Boulougouris, Evangelos (author)A more contemporary damaged stability assessment of a passenger ship can be addressed with a non-zonal approach, assessing multiple damage types and environmental conditions and employing dynamic analysis for ship survivability. This direct method necessitates the generation and simulation of many damage scenarios. However, the probabilistic...journal article 2022
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Raju, Narayana (author), Arkatkar, Shriniwas S. (author), Easa, Said (author), Joshi, Gaurang (author)Road safety is one of the major concerns in the ever-growing traffic network. In addressing this, surrogate safety measures play a critical role in identifying collision instincts. Besides the added advantage of quantifying collision instincts in advance, surrogate safety measures have their limitations. For example, in some instances, those...journal article 2022
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Wang, X. (author), Alonso-Mora, J. (author), Wang, M. (author)Road traffic safety has attracted increasing research attention, in particular in the current transition from human-driven vehicles to autonomous vehicles. Surrogate measures of safety are widely used to assess traffic safety but they typically ignore motion uncertainties and are inflexible in dealing with two-dimensional motion. Meanwhile,...journal article 2022
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He, Zhibo (author), Liu, Chenguang (author), Chu, Xiumin (author), Negenborn, R.R. (author), Wu, Qing (author)For the complex multi-ship encounter scenarios, this article proposes a dynamic collision avoidance path planning algorithm based on the A-star algorithm and ship navigation rules, namely Dynamic Anti-collision A-star (DAA-star) algorithm. A dynamic search mechanism of the DAA-star algorithm considering time factors is designed to enable the...journal article 2022
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Zhu, H. (author), Ferreira de Brito, B.F. (author), Alonso-Mora, J. (author)In this paper, we present a decentralized and communication-free collision avoidance approach for multi-robot systems that accounts for both robot localization and sensing uncertainties. The approach relies on the computation of an uncertainty-aware safe region for each robot to navigate among other robots and static obstacles in the...journal article 2022