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Cooperative interception with fast multiple model adaptive estimation

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Defence technology（防务技术） 2021年第6期17卷 1905-1917页

作者： Shao-bo Wang Yang Guo Shi-cheng Wang Zhi-guo Liu Shuai Zhang xi’an research institution of Hi-technology China xi’an research institution of Hi-technology Northwestern Polytechnical UniversityChina

For the case that two pursuers intercept an evasive target,the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target,which performs a bang For the case that two pursuers intercept an evasive target,the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target,which performs a bang-bang evasive maneuver with a random switching time.Combined Fast multiple model adaptive estimation(Fast MMAE)algorithm,the cooperative guidance law takes detection configuration affecting the accuracy of interception into consideration.Introduced the detection error model related to the line-of-sight(LOS)separation angle of two interceptors,an optimal cooperative guidance law solving the optimization problem is designed to modulate the LOS separation angle to reduce the estimation error and improve the interception performance.Due to the uncertainty of the target bang-bang maneuver switching time and the effective fitting of its multi-modal motion,Fast MMAE is introduced to identify its maneuver switching time and estimate the acceleration of the target to track and intercept the target accurately.The designed cooperative optimal guidance law with Fast MMAE has better estimation ability and interception performance than the traditional guidance law and estimation method via Monte Carlo simulation.

关键词： Cooperative guidance Optimal control Fast multiple model adaptive estimation (fast MMAE) Bang-bang maneuver Switch time Detection configuration Estimation error

Real-time interactive motion control of virtual human in virtual maintenance based on limited information

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International Journal of Modeling, Simulation, and Scientific Computing 2015年第2期6卷 16-39页

作者： xiangyang Li Zhili Zhang Feng Liang Zhao Tong Xi’an Research Institution of High Technology Xi’an People’s Republic of China

In order to provide a simple and efficient approach to perform the real-time interactive motion control of virtual human in virtual maintenance environment(VME),the motion control method of virtual human based on limited input information is proposed.With the space position tracking system with only one sensor the action sequences and motion models of virtual human,the human motions and hand actions in VME are driven by the sensor data in stages and in real time through the transmission condition control in the process of maintenance operation.And the input data and information is processed based on the method of Kalman filtering and wavelet transforming to improve the control effects.An experimental VME is also established to validate the control efficiency,and the experiment results show that the space motion control of virtual human in VME can be performed based on limited information with proposed control strategy.

关键词： Real-time interactive motion control virtual human virtual maintenance virtual maintenance environment limited information

A Review of research on Galvanic Corrosion of Aluminum Alloys

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1907-1923页

作者： Huixin Zhu Mingzhe Leng Guofeng Jin Heyang Miao xi’an Institute of high technology Xi’an710038China

When aluminum alloys are coupled with dissimilar materials,they often act as corrosion anodes and are suscepted to accelerated corrosion.Therefore,deepening our knowledge of such corrosion phenomena,related mechanisms,and elaborating new prediction model is of great theoretical and practical significance.In this paper,such mechanisms are explained from both macroscopic and microscopic points of view by considering several aspects such as the second phase particle type,grain size,and environmental ions.More specifically,different perspectives on such a problem are elaborated,which take into account:the properties of the coupling pair materials,geometrical characteristics,environmental media characteristics,the corrosion regularity of different types of aluminum alloys,the influence of area ratio on anode corrosion current density,the interference of the solution primary ions represented by Cl-and the accompanying ions represented by Al3+.A review is also conducted of the standard test methods used in the study of aluminum alloys galvanic corrosion and of research methods such as the Wire Beam Electrodes technology(WBE),the Scanning Kelvin Probe Force Microscopy(SKPFM)technology.Finally,three kinds of inhibition technologies are discussed,including the anodic oxidation treatment,the corrosion inhibitor treatment and the coating protection method.

关键词： Aluminum alloy microgalvanic corrosion influencing factors first principles calculations

Effect of deposition temperature on SrFe12O19@carbonyl iron core–shell composites as high-performance microwave absorbers

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Chinese Physics B 2020年第6期29卷 505-511页

作者：刘渊李茸贾瑛何祯鑫 xi’an research Institute of high technology Xi’an 710025China

The SrFe12O19@carbonyl iron(CI) core–shell composites used in microwave absorption are prepared by the metal–organic chemical vapor deposition(MOCVD). The x-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, and vector network analyzer are used to characterize the structural, electromagnetic, and absorption properties of the composites. The results show that the SrFe12O19@CI composites with a core–shell structure could be successfully prepared under the condition: deposition temperatures above 180℃, deposition time 30 min, and gas flow rate 30 m L/min.The electromagnetic properties of the composites change significantly, and their absorption capacities are improved. Of the obtained samples, those samples prepared at a deposition temperature of 180℃ exhibit the best absorption performance.The reflection loss of SrFe12O19@CI(180℃) with 1.5 mm–2.5 mm in thickness is less than-10 dB in a frequency range of 8 GHz–18 GHz, which covers the whole X band and Ku band.

关键词： SrFe12O19 carbonyl iron electromagnetic properties microwave absorption

First-principles study of co-adsorption behavior of O_(2)and CO_(2)molecules onδ-Pu(100)surface

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Chinese Physics B 2021年第2期30卷 431-441页

作者：戚春保王涛李如松王金涛秦铭澳陶思昊 xi'an research Institute of high technology Xi'an 710025China xi'an Jiaotong University Xi'an 710049China

First principles calculation is performed to study the co-adsorption behaviors of O_(2)and CO_(2)onδ-Pu(100)surface by using a slab model within the framework of density functional theory(DFT).The results demonstrate that the most favorable co-adsorption configurations are T_(v)-C_(4)O_(7)and T_(p1)-C_(2)O_(8),with adsorption energy of-17.296 e V and-23.131 e V for CO_(2)-based and O_(2)-based system,respectively.The C and O atoms mainly interact with the Pu surface atoms.Furthermore,the chemical bonding between C/O and Pu atom is mainly of ionic state,and the reaction mechanism is that C 2 s,C 2 p,O 2s,and O 2p orbitals overlap and hybridize with Pu 6 p,Pu 6 d,and Pu 5 f orbital,resulting in the occurrence of new band structure.The adsorption and dissociation of CO_(2)molecule are obviously promoted by preferentially occupying adsorbed O atoms,therefore,a potential CO_(2)protection mechanism for plutonium-based materials is that in CO_(2)molecule there occurs complete dissociation of CO_(2)→C+O+O,then the dissociated C atom combines with O atom from O_(2)dissociation and produces CO,which will inhibit the O_(2)from further oxidizing Pu surface,and slow down the corrosion rate of plutoniumbased materials.

关键词： adsorption energy density functional theory electron density reaction mechanism

Directional Analysis of the Chaotic Superlattice around the Equilibrium Point in the Phase Space

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Chinese Physics Letters 2018年第4期35卷 82-85页

作者：刘延飞杨东东汪立新李琪 xi'an research Institute of high technology Xi'an 710025

The recently proposed method of our research group named as directional Lyapunov exponents（DLEs） is presented. Then, DLEs are used to analyze the eigenstructure of the output phase space around the equilibrium points. Finally, the impacts of the superlattice parameter changes on the characteristics of the output chaotic signal are analyzed. The experimental results show that parameter changes of the superlattice will affect the eigenstructure around the equilibrium points in the output phase space, and DLEs are sensitive to these changes.

关键词： DLE Directional Analysis of the Chaotic Superlattice around the Equilibrium Point in the Phase Space

Impact point prediction guidance of ballistic missile in high maneuver penetration condition

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Defence technology（防务技术） 2023年第8期26卷 213-230页

作者： Yong xian Le-liang Ren Ya-jie Xu Shao-peng Li Wei Wu Da-qiao Zhang xi'an research Institute of high technology Xi'an710025China Department of Automation Tsinghua UniversityBeijing100084China

An impact point prediction(IPP) guidance based on supervised learning is proposed to address the problem of precise guidance for the ballistic missile in high maneuver penetration condition.An accurate ballistic trajectory model is applied to generate training samples,and ablation experiments are conducted to determine the mapping relationship between the flight state and the impact point.At the same time,the impact point coordinates are decoupled to improve the prediction accuracy,and the sigmoid activation function is improved to ameliorate the prediction efficiency.Therefore,an IPP neural network model,which solves the contradiction between the accuracy and the speed of the IPP,is established.In view of the performance deviation of the divert control system,the mapping relationship between the guidance parameters and the impact deviation is analysed based on the variational principle.In addition,a fast iterative model of guidance parameters is designed for reference to the Newton iteration method,which solves the nonlinear strong coupling problem of the guidance parameter solution.Monte Carlo simulation results show that the prediction accuracy of the impact point is high,with a 3 σ prediction error of 4.5 m,and the guidance method is robust,with a 3 σ error of 7.5 m.On the STM32F407 singlechip microcomputer,a single IPP takes about 2.374 ms,and a single guidance solution takes about9.936 ms,which has a good real-time performance and a certain engineering application value.

关键词： Ballistic missile high maneuver penetration Impact point prediction Supervised learning Online guidance Activation function

超声热成像检测中预紧力对疲劳裂纹生热的影响

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Journal of Central South University 2022年第6期29卷 1906-1915页

作者：杨正伟寇光杰周伟张炜王震刘俊立李胤 School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China xi’an research Institute of high technology Xi’an 710025China China Aerodynamics research and Development Center(CARDC) Mianyang 621000China

结合数值仿真和试验,深入研究了不同预紧力作用下的疲劳裂纹生热行为。首先,建立了一个多接触模型来模拟裂纹面接触和变幅杆-试件表面的接触效应。而后,通过超声热成像检测和显微镜观测,分析不同预紧力作用下裂纹区域的生热和塑变行为... 详细信息

结合数值仿真和试验,深入研究了不同预紧力作用下的疲劳裂纹生热行为。首先,建立了一个多接触模型来模拟裂纹面接触和变幅杆-试件表面的接触效应。而后,通过超声热成像检测和显微镜观测,分析不同预紧力作用下裂纹区域的生热和塑变行为。基于此,提出基于斑点分布的间接观察法来评估裂纹接触面的塑性变形。结果表明:当预紧力小于250 N时,裂纹区域温升随预紧力的增大而增大;当预紧力为280 N时,由于振动抑制效应和裂纹接触面塑性变形而导致温升减小。塑性变形并未导致裂纹扩展,但降低了疲劳裂纹的检测重复率。研究提供了一种优化实际检测条件的一种有效方法,对超声热成像检测中建立不同对象的体系化检测标准具有重要促进作用。

关键词：超声热成像预紧力生热疲劳裂纹斑点分布

Synergistic Effect and Electrochromic Mechanism of Nanoflake Li-doped NiO in LiOH Electrolyte

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Energy & Environmental Materials 2023年第3期6卷 66-73页

作者： Kejun Xu Liuying Wang Gu Liu Chaoqun Ge Long Wang Weichao Wang Mengzhou Chen xi’an research Institute of high technology Xi’an 710025China

Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display applications.Therefore,the development of electrochromic films with good cycling stabilities,fast color-change response times,and high coloring efficiencies has attracted considerable attention.In this study,nanoflake Li-doped NiO electrochromic films were prepared using a hydrothermal method,and the films exhibited superior electrochromic performances in the LiOH electrolyte.Li^(+)ions doping increased the ion transmission rates of the NiO films,and effectively promoted the transportation of ions from the electrolyte into NiO films.Meanwhile,the nanoflake microstructure caused the NiO films to have larger specific surface areas,providing more active sites for electrochemical reactions.It was determined that the NiO-Li20%film exhibited an ultra-fast response in the LiOH electrolyte(coloring and bleaching times reached 3 and 1.5 s,respectively).Additionally,the coloration efficiency was 62.1 cm^(2)C^(−1),and good cycling stability was maintained beyond 1500 cycles.Finally,the simulation calculation results showed that Li doping weakened the adsorption strengths of the NiO films to OH^(−),which reduced the generation and decomposition of NiOOH and helped to improve the cycling stabilities of the films.Therefore,the research presented in this article provides a strategy for designing electrochromic materials in the future.

关键词： electrochromic materials Li-doped NiO films LiOH electrolyte nanoflake