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2006 IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Siyao Fu Weiming Li Yunchu Zhang Zize Liang Zengguang Hou Min Tan Wenbo Ye Bo Lian Qi Zuo Key laboratory of complex systems and intelligence science Institute of Automation Chinese Academy and Sciences Beijing China National laboratory of pattern recognition Institute of Automation Chinese Academy and Sciences Beijing China Faculty of Information and Electrical Engineering Shandong University of Architecture and Engineering Jinan China Zunyi Power Supply Bureau Guizhou Power Grid Corporation Zunyi China Department of Automation North-China University of Technology Beijing China

Inspection robot must plan its behavior to detect the obstacles from the complex background according to their types when it is crawling along the power transmission line in order to negotiate reliably. However, in most instances, detecting the obstacles from the complex background is a hard task. For this purpose, a novel and fast visual obstacle recognition algorithm is designed based on the structure of the 220 KV power transmission line. Basic principle and architecture of the algorithm are given. By this approach, three typical obstacles on the power transmission line such as insulator strings, counterweights and suspension clamps can be recognized with high accuracy. Experiments in the real power transmission line show its effectiveness. This method can contribute to the process of the mobile robot negotiating obstacles

关键词： Power transmission lines Inspection Mobile robots Robotics and automation Sensor arrays Robot sensing systems Intelligent robots Insulation Power system reliability Laboratories

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Connecting Disconnected Agents in Multiagent systems via Federated Control

Connecting Disconnected Agents in Multiagent Systems via Fed...

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European Control Conference (ECC)

作者： Rongrong Qian Zhisheng Duan Yuan Qi Tao Peng Wenbo Wang School of Artificial Intelligence Beijing University of Posts and Telecommunications (BUPT) Beijing China State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University Beijing China School of Electronic Engineering Beijing University of Posts and Telecommunications (BUPT) Beijing China Wireless Signal Processing and Network Lab (Key Lab. of Universal Wireless Communication Ministry of Education) Beijing University of Posts and Telecommunications (BUPT) Beijing China

ISBN: (数字)9783907144107

ISBN: (纸本)9798331540920

This study develops a control technique, called federated control, to connect disconnected agents in multiagent systems aided by control stations. Specifically, we first use a federated architecture to model multiagent systems with control stations. Based on this architecture, a federated-control procedure is proposed for the task of connecting disconnected agents, together with an initialization procedure. Then, how the federated-control procedure connects disconnected agents by incorporating simple global coordination (i.e., global averaging) is analyzed. We derive the close-form expression of the time sufficient to connect disconnected agents, which possesses interesting properties including early computability and delay independence. The convergence of the formation of multiagent systems and the velocities of all agents can also be proved.

关键词： Robot kinematics Oceans Computer architecture Control systems Space-air-ground integrated networks Path planning Delays

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Open-jet facility for bio-inspired micro-air-vehicle flight experiment at low speed and high turbulence intensity

Advances in Aerodynamics

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Advances in Aerodynamics 2024年第3期 93-111页

作者： Zhifeng Liu Yue Yang State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University HEDPS-CAPT Peking University

Bio-inspired micro-air-vehicles(MAVs) usually operate in the atmospheric boundary layer at a low Reynolds number and complex wind conditions including large-scale turbulence, strong shear, and gusts. We develop an open jet facility(OJF) to meet the requirements of MAV flight experiments at very low speed and high turbulence intensity. Powered by a stage-driven fan, the OJF is capable of generating wind speeds covering 0.1 – 16.8 m/s, with a velocity ratio of 100:1. The contraction section of the OJF is designed using an adjoint-driven optimization method, resulting in a contraction ratio of 3:1 and a length-to-diameter ratio of 0.75. A modularized design of the jet nozzle can produce laminar or high-turbulence wind conditions. Flow field calibration results demonstrate that the OJF is capable of producing a high-quality baseline flow with steady airspeed as low as 0.1 m/s, uniform region around 80% of the cross-sectional test area, and turbulence intensity around 0.5%. Equipped with an optimized active grid(AG), the OJF can reproduce controllable, fully-developed turbulent wind conditions with the turbulence intensity up to 24%, energy spectrum satisfying the five-thirds power law, and the uniform region close to 70% of the crosssectional area of the test section. The turbulence intensity, integral length scale, Kolmogorov length scale, and mean energy dissipation rate of the generated flow can be adjusted by varying the area of the triangular through-hole in the wings of the AG.

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Preparation and tribological properties of NiCr/Cr3C2 -BaF2·CaF2

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Mocaxue Xuebao/Tribology 2009年第1期29卷 68-74页

作者： Huang, Chuan-Bing Du, Ling-Zhong Zhang, Wei-Gang State Key Laboratory of Multi-Phase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Graduate University Chinese Academy of Sciences Beijing 100049 China

BaF2·CaF2 eutectic and Cr3C2 composite powders coated with NiCr alloy were prepared with the technology of hydrogen reduction hydrothermal process combined with a solid state alloying. NiCr/Cr3C2 -BaF2·CaF2 coating was produced by atmospheric plasma spray (APS) using the prepared powders. The microstructure and phase compositions of the powders as well as the deposited coating were analyzed by SEM and XRD, while the friction and wear behavior of the coatings from room temperature to 500C were evaluated using a SRV high temperature tribometer. The NiCr/Cr3C2 -BaF2·CaF2 composite coating exhibited excellent wear-resistant performance by high temperature self-lubrication with high microhardness and cohesive strength. Oxidation, decarburization and ablation of Cr3C2-BaF2·CaF2 during spray were avoided due to the protection by NiCr layer. The friction coefficient of the coating, 0.740.02 at room temperature, gradually decreased with the increase of temperature, a small value of 0.380.03 was achieved as temperature up to 500C, which led to a significant decrease of wear rates of both of the coating and the Si3N4 ball. BaF2·CaF2 eutectic underwent a transition with decrease of shear strength at high temperature from brittle to plastic state, which resulted in the formation on a continuous lubricating layer in the wear track at 500C.

关键词： Binary alloys

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SGNet: Salient Geometric Network for Point Cloud Registration

SGNet: Salient Geometric Network for Point Cloud Registratio...

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IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Qianliang Wu Yaqing Ding Lei Luo Haobo Jiang Shuo Gu Chuanwei Zhou Jin Xie Jian Yang PCA Lab Key Lab of Intelligent Perception and Systems for High-Dimensional Information of Ministry of Education Jiangsu Key Lab of Image and Video Understanding for Social Security School of Computer Science and Engineering Nanjing University of Science and Technology Visual Recognition Group Faculty of Electrical Engineering Czech Technical University in Prague Prague Czech Republic State Key Laboratory for Novel Software Technology Nanjing University Nanjing China School of Intelligence Science and Technology Nanjing University Suzhou China

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

Point Cloud Registration (PCR) is a critical and challenging task in computer vision and robotics. One of the primary difficulties in PCR is identifying salient and meaningful points that exhibit consistent semantic and geometric properties across different scans. Previous methods have encountered challenges with ambiguous matching due to the similarity among patch blocks throughout the entire point cloud and the lack of consideration for efficient global geometric consistency. To address these issues, we propose a new framework that includes several novel techniques. Firstly, we introduce a semantic-aware geometric encoder that combines object-level and patch-level semantic information. This encoder significantly improves registration recall by reducing ambiguity in patch-level superpoint matching. Additionally, we incorporate a prior knowledge approach that utilizes an intrinsic shape signature to identify salient points. This enables us to extract the most salient super points and meaningful dense points in the scene. Secondly, we introduce an innovative transformer that encodes High-Order (HO) geometric features. These features are crucial for identifying salient points within initial overlap regions while considering global high-order geometric consistency. We introduce an anchor node selection strategy to optimize this high-order transformer further. By encoding inter-frame triangle or polyhedron consistency features based on these anchor nodes, we can effectively learn high-order geometric features of salient super points. These high-order features are then propagated to dense points and utilized by a Sinkhorn matching module to identify critical correspondences for successful registration. The experiments conducted on the 3DMatch/3DLoMatch and KITTI datasets demonstrate the effectiveness of our method.

关键词： Point cloud compression Computer vision Accuracy Shape Semantics Transformers Feature extraction Encoding Intelligent robots

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Three-dimensional dynamic modeling and motion analysis for an active-tail-actuated robotic fish with barycentre regulating mechanism

arXiv

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arXiv 2020年

作者： Zheng, Xingwen Xiong, Minglei Zheng, Junzheng Wang, Manyi Tian, Runyu Xie, Guangming The State Key Laboratory for Turbulence and Complex Systems Intelligent Biomimetic Design Lab College of Engineering Peking University Beijing100871 China Robot Technology Co. Ltd. Beijing100084 China The China Aerodynamics Research and Development Center Sichuan Mianyang621000 China Laboratory Shenzhen518055 China The Institute of Ocean Research Peking University Beijing100871 China

Dynamic modeling has been capturing attention for its fundamentality in precise locomotion analyses and control of underwater robots. However, the existing researches have mainly focused on investigating two-dimensional motion of underwater robots, and little attention has been paid to three-dimensional dynamic modeling, which is just what we focus on. In this article, a three-dimensional dynamic model of an active-tail-actuated robotic fish with a barycentre regulating mechanism is built by combining Newton’s second law for linear motion and Euler’s equation for angular motion. The model parameters are determined by three-dimensional computer-aided design (CAD) software SolidWorks, HyperFlow-based computational fluid dynamics (CFD) simulation, and grey-box model estimation method. Both kinematic experiments with a prototype and numerical simulations are applied to validate the accuracy of the dynamic model mutually. Based on the dynamic model, multiple three-dimensional motions, including rectilinear motion, turning motion, gliding motion, and spiral motion, are analyzed. The experimental and simulation results demonstrate the effectiveness of the proposed model in evaluating the trajectory, attitude, and motion parameters, including the velocity, turning radius, angular velocity, etc., of the robotic fish. Copyright © 2020, The Authors. All rights reserved.

关键词： Dynamic models

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Concept, Principle, and Modeling of Driving Risk Entropy Based on Human-Vehicle-Road Coupling Model for Autonomous Vehicle

SSRN

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SSRN 2024年

作者： Gao, Hongbo Yang, Hanqing Zhu, Juping Su, Huiping Wang, Ning Xie, Liping Li, Keqiang Department of Automation University of Science and Technology of China Hefei230026 China Institute of Advanced Technology University of Science and Technology of China Hefei230088 China School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore Chongqing College of Mobile Communication Chongqing400044 China Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of Education School of Automation Southeast University Nanjing210096 China State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing100084 China

Driving risk entropy, based on entropy law, is an innovative concept proposed for intelligent driving systems. The concept deals with the driving risks caused by the human-vehicle-road system from the driving information obtained;however, driving risks are difficult to assess due to many influencing factors and great uncertainty. The risk entropy model of vehicles is visualized by introducing the concept of basic isotropic risk elliptic line (BIREL). Further incorporating the concept of information entropy, risk entropy models for vehicle interaction and vulnerable participants are established, and the risk entropy model for roads is developed using raster coordinates. Ultimately, a three-dimensional driving risk entropy model is constructed based on the human-vehicle-road coupling model, with appropriate weights assigned to each parameter through the DDPG algorithm. Experimental results demonstrate the effectiveness of the driving risk entropy model. © 2024, The Authors. All rights reserved.

关键词： Autonomous vehicles

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Animal Shapes, Modal Analysis, and Visualization of Motion (III): Giraffe, Duck, Goose, T-Rex Dinosaur, and the Flying Modes of Eagle

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Journal of Geometric Analysis 2023年第10期33卷 1-28页

作者： Yang, Jing Chen, Goong Wei, Chunqiu Sergeev, Alexey Huang, Jingtong Scully, Matthew M. Krantz, Steven G. Yao, Pengfei Guo, Tiexin Wang, Junmin Chen, Ming-Chieh Corti, Darrell School of Mathematics and Statistics Beijing Institute of Technology Beijing 102488 China Department of Mathematics Texas A &M University College Station 77843 TX United States Institute for Quantum Science and Engineering Texas A &M University College Station 77843 TX United States Hsinchu Branch National Center for Theoretical Sciences National Tsing Hua University Hsinchu Taiwan Department of Mathematics and Data Science Beijing University of Civil Engineering and Architecture Beijing 100044 China Department of Mathematics Washington University at St. Louis St. Louis 63130 MO United States Key Laboratory of Complex Systems and Data Science of Ministry of Education School of Mathematics Shanxi University Shanxi Taiyuan 030006 China Institute of Systems Science Academy of Mathematics and Systems Science Academia Sinica Beijing 100190 China School of Mathematics and Statistice Central South University Hunan Changsha 410075 China Department of Mechanical Engineering Cheng Shiu University Kaohsiung Taiwan Corti Brothers 5810 Folsom Blvd. Sacramento 95819 CA United States

This paper contains more varieties of animals, including the giraffe, bird species duck, goose and eagle, and the T-Rex dinosaur. They range across mammals, birds and reptiles. For each of them, we present their first one hundred modes of motion. Three objectives of this paper are as follows: (i)To see more different types of modes of motion from a larger varieties of animals so as to make visual comparisons between interspecies behavioral patterns.(ii)To illustrate the wing-flapping flying modes of an eagle.(iii)To show the modes of motions of an extinct animal, the T-Rex dinosaur. © 2023, Mathematica Josephina, Inc.

关键词： Animal shapes Duck, Goose, Dinosaur, and the flying modes of an eagle Motion patterns

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Magnetic dipoles at topological defects in the Meissner state of a nanostructured superconductor

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Physical Review B 2016年第22期93卷 224502-224502页

作者： Jun-Yi Ge Vladimir N. Gladilin Cun Xue Jacques Tempere Jozef T. Devreese Joris Van de Vondel Youhe Zhou Victor V. Moshchalkov INPAC–Institute for Nanoscale Physics and Chemistry KU Leuven Celestijnenlaan 200D B–3001 Leuven Belgium TQC–Theory of Quantum and Complex Systems Universiteit Antwerpen Universiteitsplein 1 B–2610 Antwerpen Belgium Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China Department of Mechanics and Engineering Sciences School of Civil Engineering and Mechanics Lanzhou University Lanzhou Gansu 730000 China

In a magnetic field, superconductivity is manifested by total magnetic field expulsion (Meissner effect) or by the penetration of integer multiples of the flux quantum Φ0. Here we present experimental results revealing magnetic dipoles formed by Meissner current flowing around artificially introduced topological defects (lattice of antidots). By using scanning Hall probe microscopy, we have detected ordered magnetic dipole lattice generated at spatially periodic antidots in a Pb superconducting film. While the conventional homogeneous Meissner state breaks down, the total magnetic flux of the magnetic dipoles remains quantized and is equal to zero. The observed magnetic dipoles strongly depend on the intensity and direction of the locally flowing Meissner current, making the magnetic dipoles an effective way to monitor the local supercurrent. We have also investigated the first step of the vortex depinning process, where, due to the generation of magnetic dipoles, the pinned Abrikosov vortices are deformed and shifted from their original pinning sites.

关键词： Magnetic texture Meissner effect Vortices in superconductors Thin films Type-II superconductors Superconducting devices

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Large-scale pedestrian flow experiments under high-density conditions

arXiv

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arXiv 2017年

作者： Jin, Cheng-Jie Jiang, Rui Wong, S.C. Li, Dawei Guo, Ning Wang, Wei Jiangsu Key Laboratory of Urban Its Southeast University of China Nanjing Jiangsu210096 China Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic Technologies Nanjing Jiangsu210096 Moe Key Laboratory for Urban Transportation Complex Systems Theory and Technology Beijing Jiaotong University Beijing100044 Department of Civil Engineering University of Hong Kong Hong Kong Island Hong Kong School of Engineering Science University of Science and Technology of China Hefei Anhui230026 China

Despite the vast amount of studies on pedestrian flow, the data concerning high densities are still very inadequate. We organize one large-scale pedestrian flow experiment on a ring corridor. With 278 participants, the density as high as 9 m"2is reached. In the uni-directional flow, four different states are observed, including the free flow, congested state, over-congested state and hyper-congested state. The features of the hyper-congested state are similar to the "crowd turbulence" reported in the empirical data of Helbing et al., and the transition between the stopped state and the moving state can be found. The flow rates in the over-congested state are nearly constant, due to the downstream propagation of pedestrian clusters. In the bi-directional flow, three different types of lane formations are observed in the experiment: (1) three lanes are directly formed;(2) two lanes are directly formed;(3) firstly three lanes are formed, and then they transit into two lanes. After the lane formation, some interesting phenomena have been observed, including the inhomogeneous distribution of pedestrians across the lanes, and the formation and dissipation of localized crowd. Our study is expected to help for better understanding and modeling the dynamics of high density pedestrian flow. Copyright © 2017, The Authors. All rights reserved.

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