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2023 china Automation Congress, CAC 2023

作者： Tang, Wentao Fan, Junfang Ji, Yi Li, Yafeng Xu, Xiaobin Zang, Luyao Beijing Information Science and Technology University Beijing Key Laboratory of High Dynamic Navigation Technology Beijing China School of Automation Beijing Information Science and Technology University Beijing China The System Design Institute of Mechan-ical-Electrical Engineering Beijing China

ISBN: (纸本)9798350303759

A super-twisting control strategy is proposed to tackle the complex problem of attitude stabilization control for rigid-elastic coupled hypersonic vehicles experiencing significant aerodynamic perturbations. Initially, the elastic modes are treated as uncertain factors, leading to the construction of a control-oriented dynamic model. To design the attitude subsystem, a combination of a super-twisting algorithm and a non-singular terminal sliding mode is proposed. A first-order differentiator is introduced to address the 'derivative explosion' issue commonly found in traditional control methods, thus eliminating the need for intricate differential computations. Moreover, a switching control strategy is integrated into the nonlinear feedback control law design, ensuring robust velocity tracking. Simulation results validate that the proposed control method surpasses conventional methods in both tracking performance and robustness. © 2023 IEEE.

关键词： Sliding mode control

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Electrical and optical properties of three BaTiO3 crystal phases by the first-principles study 6

Electrical and optical properties of three BaTiO3 crystal ph...

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6th International Conference on Optoelectronic science and Materials, ICOSM 2024

作者： Ma, Xinguo Liu, Zhiwen Guo, Youyou Ren, Yijing State Key Laboratory of Advanced Technology for Float Glass Bengbu Glass Industrial Design and Research Institute Bengbu233030 China School of Science Hubei University of Technology Wuhan430068 China Hubei Engineering Technology Research Center of Energy Photoelectric Device and System Hubei University of Technology Wuhan430068 China

ISBN: (数字)9781510686823

ISBN: (纸本)9781510686816

The study on the properties of barium carbonate in different crystal systems is play an important role for the evolution of electronic products requiring miniaturization and high performance. Here, the electrical and optical properties of BaTiO3 crystal structures with three space groups (Pm 3 m, P4mm, and P4/mmm) were systematically studied using the first-principles method. The structural are confirmed to be stable by the Born criterion The evolution energy band structures under HSE06 functional were more consistent with other theoretical and experimental results compared to the PBE functional. The band gaps of BaTiO3 for Pm 3 m, P4mm, and P4/mmm space groups up to 3.42, 3.24, and 3.26 eV and exhibit indirect semiconductor behavior. The optical parameters show that the light absorption rate and loss function of all three BaTiO3 were almost zero in the lower energy range. However, the tetragonal phase BaTiO3 with P4/mmm space group has a lower light reflection rate and higher light refractive index compared to the tetragonal phase BaTiO3 with P4/mmm and the cubic phase BaTiO3 with Pm 3 m space group, indicating its potential application value in electro-optic modulation. © 2024 SPIE.

关键词： Refractive index

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Experimental Research about Corrosion Effect on Boiling Heat Transfer Performance of Plate-type Samples with Micro-structures 20

Experimental Research about Corrosion Effect on Boiling Heat...

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20th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2023

作者： Xu, Wei Liu, Xiaojing Ouyang, Kun He, Xiaoqiang College of Smart Engineering Shanghai Jiao Tong University Shanghai200240 China School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9780894487934

Enormous studies have demonstrated that suitable modification methods, such as micro-structures machining, are adopted to enhance boiling heat transfer performance, especially critical heat flux (CHF) value. This significant improvement can lead to broader application prospect of micro-structured surface in the nuclear power plant scenario. However, little attention has been paid to research the durability of micro-structured surface, and whether strengthening effect can be maintained after a long time of harsh corrosive environment within reactor. In this paper, experimental studies are conducted to research the corrosion effect on boiling heat transfer capability of heating plates with micro-structures. To be specific, microgrooves, pores and columns are machined on metal plate-type samples by laser processing. These samples are placed in autoclave of high temperature and high pressure to simulate the actual conditions, with the corrosion span up to 300 days. After then, saturated pool boiling tests are carried out and high-speed camera is also utilized to quantitatively illustrate the boiling heat transfer characteristics. The experimental results show that the CHF values of different micro-structured samples increase initially and then decreases with increasing corrosion time. In addition, the samples with micro-pores have the largest bubble departure frequency at the beginning of nucleate boiling and those with micro-grooves have the highest CHF value instead. © 2023 Proceedings of the 20th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2023. All rights reserved.

关键词： High speed cameras

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Anomaly Detection of Logistics Packages Based on CNN and Image Recognition technology 4

Anomaly Detection of Logistics Packages Based on CNN and Ima...

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4th IEEE International Conference on Data science and Computer Application, ICDSCA 2024

作者： Liang, Kun Zhang, Hang School of Management Tianjin University of Technology Tianjin China 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

ISBN: (纸本)9798350368239

To address abnormal situations such as packaging damage, liquid leakage, and item displacement during logistics package transportation, this paper introduces Convolutional Neural Network (CNN) and image recognition technology to achieve real-time anomaly detection and alarm, improving the response speed and accuracy of the logistics system. First, by designing multiple layers of convolution and pooling layers, adding Batch Normalization layers and Dropout layers to prevent overfitting, a CNN deep learning model suitable for logistics package anomaly detection is constructed. key features are extracted through image preprocessing methods such as normalization and data enhancement to ensure that the model has high recognition adaptability to various abnormal situations such as damage and leakage. Secondly, through data enhancement methods such as rotation, scaling, brightness adjustment, and transfer learning using pre-trained models, the model's adaptability in different lighting, angles, and occlusion conditions is improved. Finally, the model is applied to actual monitoring, and real-time alarms are issued for abnormalities such as damage and leakage, which are then fed back to the system closed-loop management. This method is significantly better than traditional methods in terms of detection accuracy and response speed. Under natural light environment, the model detection accuracy is as high as 98.4%, reducing false positives and false negatives. Combining CNN's anomaly detection technology effectively improves the accuracy and efficiency of logistics monitoring and provides technical support for intelligent logistics management. ©2024 IEEE.

关键词： Convolutional neural networks

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Research on data assimilation strategy of turbulent separated flow over airfoil

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Applied Mathematics and Mechanics(English Edition) 2022年第4期43卷 571-586页

作者： Ying ZHANG Lin DU Weiwei ZHANG Zichen DENG National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Complex System Dynamics and Control Academic Exchange Center School of Mathematics and StatisticsNorthwestern Polytechnical UniversityXi'an 710119China Rotor Aerodynamics Key Laboratory China Aerodynamics Research and Development CenterMianyang 621000Sichuan ProvinceChina

In order to increase the accuracy of turbulence field reconstruction,this paper combines experimental observation and numerical simulation to develop and establish a data assimilation framework,and apply it to the study of S809 low-speed and high-angle airfoil *** method is based on the ensemble transform Kalman filter(ETKF)algorithm,which improves the disturbance strategy of the ensemble members and enhances the richness of the initial members by screening high flow field sensitivity constants,increasing the constant disturbance dimensions and designing a fine disturbance *** results show that the pressure distribution on the airfoil surface after assimilation is closer to the experimental value than that of the standard Spalart-Allmaras(S-A)*** separated vortex estimated by filtering is fuller,and the eddy viscosity field information is more abundant,which is physically consistent with the observation ***,the data assimilation method based on the improved ensemble strategy can more accurately and effectively describe complex turbulence phenomena.

关键词： turbulence data assimilation ensemble disturbance strategy large angle of attack separation ensemble transform Kalman filter(ETKF)

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Joint Trajectory and Power Optimization for Securing UAV Communications Against Active Eavesdropping

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china Communications 2021年第1期18卷 88-99页

作者： Bin Duo Junsong Luo Yilian Li Hao Hu Zibin Wang College of Information Science and Technology Chengdu University of TechnologyChengdu 610059China National Key Laboratory of Science and Technology on Information System Security Beijing 100093China

Due to both of jamming and eavesdropping,active eavesdroppers can induce more serious security threats to unmanned aerial vehicle(UAV)-enabled *** paper considers a secure UAV communication system including both the downlink(DL)and uplink(UL)transmissions,where the confidential information is transmitted between a UAV and a ground node in the presence of an active *** aim to maximize the average secrecy rates of the DL and UL communications,respectively,by jointly optimizing the UAV trajectory and the UAV/ground node’s transmit power control over a given flight *** to the non-convexity of the formulated problems,it is difficult to obtain globally optimal ***,we propose efficient iterative algorithms to obtain high-quality suboptimal solutions by applying the block coordinate descent and successive convex optimization *** results show that the joint optimization algorithms can effectively improve the secrecy rate performance for both the DL and UL communications,as compared with other baseline *** proposed schemes can be considered as special cases of UAV-assisted non-orthogonal multiple access(NOMA)networks.

关键词： UAV communications active eavesdropping physical-layer security secrecy rate maximization power control trajectory design

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Effect of rotationally accelerated shot peening on the microstructure and mechanical behavior of a metastableβtitanium alloy

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Journal of Materials science & technology 2021年第16期75卷 27-38页

作者： Xinkai Ma Zhuo Chen Dongling Zhong SNLuo Lei Xiao Wenjie Lu Shanglin Zhang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China National Key Laboratory of Reactor System Design Technology Nuclear Power Institute of ChinaChengdu 610041China

Microstructural evolution and deformation mechanism of a metastableβalloy(Ti-10 V-2 Fe-3 Al)processed by rotationally accelerated shot peening(RASP)were systematically investigated with optical microscopy,X-ray diffraction,electron backscatter diffraction and transmission electron *** gradient hierarchical microstructures(gradients inα″martensite andβphase,and hierarchical twins range from the nanoscale to microscale)can be fabricated by RASP via changing the shot peening *** hardening behavior and tensile mechanical properties of gradient hierarchical microstructure were systematically *** deformation twinning systems of{112}α″and{130}<310>α″in the kinkedα″martensite were revealed during the tensile *** was found that stress-induced martensitic transformation,twinnedα″martensite and the related dynamic grain refinement contribute to hardness and work hardening *** improvement of strength and ductility of the metastableα″titanium alloy can be achieved by introducing a gradient hierarchical microstructure.

关键词： Titanium alloys Gradient hierarchical microstructure α″martensite Rotationally accelerated shot peening Mechanical behavior

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Analysis and Optimization of Medium Frequency Noise in Vehicle Cabin Based on FE-SEA Hybrid Method 2nd

Analysis and Optimization of Medium Frequency Noise in Vehic...

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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Zhang, Dongye Gu, Junjie Zhang, Yanni Institute of Launch Dynamics Nanjing University of Science and Technology Jiangsu Province Nanjing210094 China National Key Laboratory of Complex Multibody System Dynamics Jiangsu Province Nanjing210094 China

ISBN: (纸本)9789819980475

This paper demonstrates the coupling relationship between Finite Element (FE) models and Statistical Energy Analysis (SEA) models based on wave theory and modal theory. A vehicle hybrid FE-SEA model is established by considering points, lines, surfaces, and loads. The VA One software is utilized to construct material and acoustic packages for the mixed model materials and acoustic media, and to perform vehicle cabin noise simulation analysis. This study investigates the effects of acoustic materials and damping materials on vehicle cabin noise under different working conditions, obtaining sound pressure level curves at the driver’s head under various conditions. By adding different structures of sound-absorbing materials to the model, the vibration and sound radiation performance of the cabin body panels are compared. Considering the comprehensive factors such as weight and driver’s comfort, an optimized design scheme for vehicle cabin noise reduction and vibration damping is proposed. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Damping

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Parametric Study on Performance of Parallel Asymmetric Nonlinear Energy Sinks

Parametric Study on Performance of Parallel Asymmetric Nonli...

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International Conference on Applied Nonlinear Dynamics, Vibration, and Control, ICANDVC 2023

作者： Li, Huiyang Chen, Jianen Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9789819705535

The complexification-averaging method is utilized to study the amplitude-frequency response of a system connected to a parallel asymmetric nonlinear energy sink (NES) under harmonic excitation, and the Runge-Kutta method is used to analyze the change law of the frequency band of the higher branches of response and the strongly modulated responses with the assistance of the complexification-averaging method. Under shock loading, the effect of parallel asymmetric NES parameters on its vibration absorption efficiency is investigated. The results demonstrate that the frequency band of higher branches of response is widened by reducing the stiffness ratio, mass ratio, and damping ratio of the two NES, emphasizing the fact that the frequency band of the strongly modulated response can be widened or narrowed with the reduction of these parameters. Moreover, reducing the mass ratio and damping ratio of the two NESs decreases the vibration absorption efficiency when the system is subjected to a shock load. However, the vibration absorption efficiency increases by reducing the stiffness ratio. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Energy dissipation

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A human-sensitive frequency band vibration isolator for heavy-duty truck seats

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1733-1748页

作者： Qingqing LIU Shenlong WANG Ge YAN Hu DING Haihua WANG Qiang SHI Xiaohong DING Huijie YU School of Mechanical Engineering University of Shanghai for Science and TechnologyShanghai 200093China State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Yanfeng Adient Seating Co. Ltd.Shanghai 201315China College of Mechanical and Electrical Engineering Jiaxing Nanhu UniversityJiaxing 314001Zhejiang ProvinceChina

In this study,a human-sensitive frequency band vibration isolator(HFBVI)with quasi-zero stiffness(QZS)characteristics for heavy-duty truck seats is designed to improve the comfort of heavy-duty truck drivers on uneven ***,the analytical expressions for the force and displacement of the HFBVI are derived with the Lagrange equation and d'Alembert's principle,and are validated through the prototype restoring force ***,the harmonic balance method(HBM)is used to obtain the dynamic responses under harmonic excitation,and further the influence of pre-stretching on the dynamic characteristics and transmissibility is ***,the experimental prototype of the HFBVI is fabricated,and vibration experiments are conducted under harmonic excitation to verify the vibration isolation performance(VIP)of the proposed vibration *** experimental results indicate that the HFBVI can effectively suppress the frequency band(4-8 Hz)to which the human body is sensitive to vertical *** addition,under real random road spectrum excitation,the HFBVI can achieve low-frequency vibration isolation close to 2 Hz,providing new prospects for ensuring the health of heavy-duty truck drivers.

关键词： human-sensitive frequency band quasi-zero stiffness(QZS) heavy-duty truck seat real random road spectrum low-frequency vibration isolation

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