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第40届中国控制会议

作者： Chen Yan Chuan-Ke Zhang Xi-Zi Zhou School of Automation China University of Geosciences Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems Engineering Research Center of Intelligent Technology for Geo-Exploration Ministry of Education School of Art and Design Wuhan University of Technology

This paper investigates the stability of linear systems with two additive time-varying delays. Firstly, an augmented Lyapunov-Krasovskii functional(LKF) is constructed by introducing a novel augmented term which contains the derivative of state vector into integral terms. Then the extended reciprocally convex matrix inequality together with the Wirtinger integral inequality is used to estimate the derivative of the proposed LKF. As a result, a stability criterion with less conservatism is established. Finally, the advantage of the stability criterion is demonstrated through a numerical example and the application of the stability criterion to stability analysis of load frequency control is illustrated.

关键词： linear system additive time-varying delays stability analysis reciprocally convex matrix inequality

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Step-length optimization based on genetic algorithm for a parallel mobile robot 7

Step-length optimization based on genetic algorithm for a pa...

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7th International Conference on Information Science and Control Engineering, ICISCE 2020

作者： Liu, Shuang Chen, Wei Wu, Hang Zhang, Wenchang Tianjin University of Technology Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Tianjin China Institute of Medical Support Technology Academy of Military Sciences of Chinese PLA Tianjin China

ISBN: (纸本)9781728164069

With the development of technology, parallel mobile robots have been paid more attention in various industries due to the strong load capacity, high running stability and rapid response speed. However, step-length optimization is an important but challenging task for this kind of mobile robot. Step length has dramatic effect on the stability of robot and the performance of electric cylinder. Balancing the speed characteristics and stability margin, we propose a genetic algorithm to solve this problem and design a novel fitness function that can measure the motion characteristics of parallel mobile robot. Effectiveness of our method is verified by experiments. © 2020 IEEE.

关键词： Mobile robots

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Application of Digital Twin Technology in the Teaching of Engineering Drawing Course

Application of Digital Twin Technology in the Teaching of En...

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Information Science and Education (ICISE-IE), International Conference on

作者： Runfeng Zhang Yuxin Tang Zhenzhong Liu Yanfang Sun Jianguo Wu Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China School of Language and Culture Tianjin University of Technology Tianjin China Tianjin Hanhailanfan Marine Technology Co. Ltd. Tianjin China

As an advanced technology that integrates virtuality and reality, digital twin technology has shown a wide range of application prospects in various fields. This paper aims to explore the potential application of digital twin technology in the teaching of engineering drawing courses, to improve students' theoretical knowledge and practical ability. By combining digital twin technology with traditional engineering drawing teaching, students can carry out practical operations and simulations in a virtual environment to better understand and apply drawing concepts and principles. Besides, taking the assembly drawing of thread connection as an actual teaching case, the specific application of digital twin technology in theoretical and experimental teaching is explained, respectively. The results show that digital twin technology is conducive to improving students' interest in engineering drawing courses and training students' spatial imagination ability, which is of great significance to reforming drawing courses.

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Individual Dynamic Graduation Requirements Achievements of Students 2020

Individual Dynamic Graduation Requirements Achievements of S...

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5th International Conference on Distance Education and Learning, ICDEL 2020

作者： Zhao, Yalu Hao, Shuying Yang, Lu Xia, Guofeng Hu, Wenhua Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China Chongqing Engineering Research Center for Advanced Intelligent Manufacturing Technology Chongqing China

ISBN: (纸本)9781450377546

In the engineering education accreditation system, it is clearly required that the major applying for certification should prove the achievement of graduation requirements with appraisal. The common appraisal methods of graduation requirements achievements (GRAs) focus on the whole situation of graduates, which lacks personalized guidance for students at school. Based on the analytical method of exam scores in the common methods, the paper presents the achievement of individual graduation requirements and designs algorithms to dynamically appraise every student with real examples, which may provide detailed data and immediate guidance for the major and its own students. The dynamic appraisal method can improve the GRAs of the major, and also can strengthen the core concepts of engineering education accreditation. © 2020 ACM.

关键词： Students

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Networked Integrated Sensing and Communications for 6G Wireless Systems

arXiv

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arXiv 2024年

作者： Li, Jiapeng Shao, Xiaodan Chen, Feng Wan, Shaohua Liu, Chang Wei, Zhiqiang Ng, Derrick Wing Kwan The College of Artificial Intelligence Southwest University Chongqing400715 China The Brain-Inspired Computing and Intelligent Control Key Laboratory Southwest University Chongqing400715 China The Key Laboratory of Luminescence Analysis and Molecular Sensing Southwest University Chongqing400715 China The Shenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen518110 China The School of Mathematics and Statistics Xi'an Jiaotong University Xi'An710049 China The Peng Cheng Laboratory Guangdong Shenzhen518055 China Guangdong Guangzhou510555 China The Department of Computer Science and Information Technology La Trobe University MelbourneVIC3150 Australia The School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW2052 Australia

Integrated sensing and communication (ISAC) is envisioned as a key pillar for enabling the upcoming sixth generation (6G) communication systems, requiring not only reliable communication functionalities but also highly accurate environmental sensing capabilities. In this paper, we design a novel networked ISAC framework to explore the collaboration among multiple users for environmental sensing. Specifically, multiple users can serve as powerful sensors, capturing back scattered signals from a target at various angles to facilitate reliable computational imaging. Centralized sensing approaches are extremely sensitive to the capability of the leader node because it requires the leader node to process the signals sent by all the users. To this end, we propose a two-step distributed cooperative sensing algorithm that allows low-dimensional intermediate estimate exchange among neighboring users, thus eliminating the reliance on the centralized leader node and improving the robustness of sensing. This way, multiple users can cooperatively sense a target by exploiting the block-wise environment sparsity and the interference cancellation technique. Furthermore, we analyze the mean square error of the proposed distributed algorithm as a networked sensing performance metric and propose a beamforming design for the proposed network ISAC scheme to maximize the networked sensing accuracy and communication performance subject to a transmit power constraint. Simulation results validate the effectiveness of the proposed algorithm compared with the state-of-the-art algorithms. Copyright © 2024, The Authors. All rights reserved.

关键词： Beamforming

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Spatial Heterogeneity of Microstructure and Mechanical Properties in Large Thin-Walled High-Pressure Die-Cast Aluminum Alloys

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Journal of Alloys and Compounds 2025年

作者： Zhanwei Su Jinping Xie Zhenyu Xiao College of Mechanical and Intelligent Manufacturing Central South University of Forestry and Technology Changsha 410004 China State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Changsha 410082 China

This study systematically investigates the microstructural heterogeneity, mechanical property gradients, and defect formation mechanisms in large thin-walled AlSi 10 MnMg alloy components produced via high-pressure die casting (HPDC). Through experimental characterization and numerical simulations, the spatial variations in microstructure comprising fine-grained skin layers, externally solidified crystals (ESCs) in sub-skin regions, and eutectic-Si-dominated segregation bands. Results reveal that rapid solidification and thin-walled geometry promote a single central segregation band (~300 µm), contrasting with prior reports of dual symmetric zones. Mold-filling simulations demonstrate flow bifurcation and gas entrapment at structural reinforcements, leading to defect clusters in thick-walled regions. Mechanical testing highlights significant spatial heterogeneity: yield strength (200±51 MPa), ultimate tensile strength (348±68 MPa), and elongation (8.78±3.81%) vary across the casting, driven by ESC distribution and eutectic phase concentration. Fractography identifies ductile failure in skin/sub-skin regions and ductile-brittle hybrid fracture in segregation zones, with eutectic Si particles acting as crack nucleation sites. In-situ EBSD tensile characterization demonstrates that interfacial stresses are generated at the boundaries of ESCs under shear stresses imposed by the molten alloy during mold filling. Dendritic ESCs with well-developed morphologies promote stress concentration, while fragmented ESCs exhibit enhanced strain accommodation via dislocation-mediated strain hardening synergizing with refined microstructures, countering their conventional role as mechanically weak phases reported in prior studies. These findings provide critical insights for optimizing HPDC processes to mitigate microstructure-property inhomogeneity in automotive structural components.

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Decentralized Nonconvex Robust Optimization over Unsafe Multiagent Systems: System Modeling, Utility, Resilience, and Privacy Analysis

arXiv

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arXiv 2024年

作者： Hu, Jinhui Chen, Guo Li, Huaqing Cheng, Huqiang Guo, Xiaoyu Huang, Tingwen School of Automation Central South University Changsha410083 China Department of Biomedical Engineering City University of Hong Kong Kowloon Hong Kong School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW2052 Australia Chongqing Key Laboratory of Nonlinear Circuits and Intelligent Information Processing College of Electronic and Information Engineering Southwest University Chongqing400715 China Key Laboratory of Dependable Services Computing in Cyber Physical Society Ministry of Education College of Computer Science Chongqing University Chongqing400044 China Faculty of Computer Science and Control Engineering Shenzhen University of Advanced Technology Shenzhen518055 China

Privacy leakage and Byzantine failures are two adverse factors to the intelligent decision-making process of multiagent systems (MASs). Considering an unsafe MAS with these two issues, this paper targets the resolution of a class of nonconvex optimization problems under the Polyak-Lojasiewicz (P-L) condition. To address this problem, we first identify and construct the unsafe MAS model. Under this kind of unfavorable MASs, we mask the local gradients with Gaussian noises and adopt a resilient aggregation method self-centered clipping (SCC) to design a differentially private (DP) decentralized Byzantine-resilient algorithm, namely DP-SCC-PL, which simultaneously achieves differential privacy and Byzantine resilience. The convergence analysis of DP-SCC-PL is challenging since the convergence error can be contributed jointly by privacy-preserving and Byzantine-resilient mechanisms, as well as the nonconvex relaxation, which is addressed via seeking the contraction relationships among the disagreement measure of reliable agents before and after SCC aggregation, together with the optimal gap. Theoretical results reveal that DP-SCC-PL achieves consensus among all reliable agents and sublinear (inexact) convergence with well-designed step-sizes. It has also been proved that if there are no privacy issues and Byzantine agents, then the asymptotic exact convergence can be recovered. Numerical experiments verify the utility, resilience, and differential privacy of DP-SCC-PL by tackling a nonconvex optimization problem satisfying the P-L condition under various Byzantine attacks. Copyright © 2024, The Authors. All rights reserved.

关键词： Differential privacy

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A new ultra-wideband MIMO antenna based on metamaterials for 5G

A new ultra-wideband MIMO antenna based on metamaterials for...

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International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)

作者： Yaqin Li Shijie Huang Liang Zhang Xianliang Wu Key Laboratory of Intelligent Computing & Signal Processing Anhui University Hefei China AnHui Province Key Laboratory of simulation and design for Electronic informationKey Laboratory of Intelligent Computing & Signal Processing Hefei Normal university Hefei China

ISBN: (数字)9781728169668

ISBN: (纸本)9781728169675

An improved ultra-wideband low-coupling MIMO antenna based on a metamaterial periodic structure frequency-selective surface wide slot antenna is derived from the basic -shaped resonant ring. The antenna can be implemented without loading any parasitic branches low coupling and high gain, the relative bandwidth exceeds the international standard of ultra-wideband (20%), and at the same time uses metamaterials whose electromagnetic characteristics can be artificially changed as a medium, the element antennas are arranged in a 9 × 9 array and processed at 90° In order to achieve the goal of miniaturization, the structure is more compact. The 37 GHz MIMO antenna with a structure size of 108 mm × 104 mm × 1 mm working in the 5G millimeter wave band is simulated. The results show that the peak gain of the unit antenna bandwidth is 10 dB, the impedance bandwidth is 21%, and the isolation is less than 20 dB. It meets the expected performance requirements of ultra-wideband, low coupling, miniaturization and other performances, and will have important applications in the area of 5G mobile communications.

关键词： Slot antennas Bandwidth Ultra wideband antennas Metamaterials Loaded antennas Antenna arrays Periodic structures

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Effects of Wall Emissivity on Aerodynamic Heating in Scramjets

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Fluid Dynamics & Materials Processing 2020年第6期16卷 206-216页

作者： Yue Zhou Pengfei Ju School of Aeronautical Science and Technology Beihang UniversityBeijing100191China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education(Tianjin University of Technology) Tianjin300384China

The effects of the wall emissivity on aerodynamic heating in a scramjet are *** supersonic turbulent combustion flow including radiation is solved in the framework of a decoupled strategy where the flow field is determined first and the radiation field *** particular,a finite difference method is used for solving the flow while a DOM(iscrete ordinates method)approach combined with a WSGGM(weighted sum of gray gases)model is implemented for radiative *** nonreactive turbulent channel flows are examined for a DLR hydrogen fueled scramjet changing parametrically the wall *** results indicate that the wall radiative heating rises greatly with increasing the wall *** the wall emissivity rises,the radiative source and total absorption increase,while the incident radiation decreases ***,although the radiative heating can reach a significant level,its contribution to the total aerodynamic heating is relatively limited.

关键词： Scramjet aerodynamic heating wall emissivity radiation

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Hamiltonian Dynamics and Targeted Energy Transfer of a Grounded Bistable Nonlinear Energy Sink

SSRN

引用

SSRN 2022年

作者： Li, Shuangbao Zhou, Xinxing Chen, Jianen Research Institute of Science and Technology Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A two-degree-of-freedom nonlinear mechanical system describing a damped linear oscillator weakly coupled to a lightweight grounded bistable nonlinear energy sink is proposed to investigate the targeted energy transfer (TET) under asymmetric local nonlinear potentials. The Bogdanov-Takens bifurcations of equilibria are discussed to reflect the bistable and asymmetric characteristics of the system. Through projections of isoenergetic manifolds, the topological features of the Hamiltonian dynamics under $1:1$ internal resonance have been investigated, which induces conditions for energy localization and exchange. In the general case, the topological features of the Hamiltonian dynamics related to the nonlinear normal modes (NNMs) are classified by the Poincare map, the relations between the NNMs and the Hamiltonian dynamics have been interpreted through the frequency energy plots. The results show that introducing the asymmetric characteristics may enhance the TET and realize the complete TET. © 2022, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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