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Satellite fault diagnosis method based on predictive filter and empirical mode decomposition

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Journal of Systems Engineering and Electronics 2011年第1期22卷 83-87页

作者： Yi Shen yingchun zhang Zhenhua Wang School of Astronautics Harbin Institute of Technology Harbin 150001 E R. China

A novel satellite fault diagnosis scheme is presented based on the predictive filter and empirical mode composition（EMD）.First,the predictive filter is utilized to obtain the fault estimation,which is corrupted by *** the EMD method is introduced to decompose the fault estimation into a finite number of intrinsic mode functions and extract the trend of faults for fault *** proposed scheme has the ability of diagnosing both abrupt and incipient faults of the actuator in a satellite attitude control subsystem.A mathematical simulation is given to illustrate the effectiveness of the proposed scheme.

关键词： satellite fault diagnosis predictive filter empirical mode decomposition(EMD).

Deformation behavior of dispersion-strengthened copper at high temperature

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Rare Metals 2006年第6期25卷 687-692页

作者： WANG Mengjun zhang yingchun LUO Yun LIU Xinyu School of Material Science and Engineering Central South University Changsha 410083 China Guilin College of Electronic Technology Guangxi 541004 China

The deformation behavior of dispersion-strengthened copper with different compositions was investigated by hot compression simulation tests on a Gleeble-1500 thermal-mechanical simulator. The microstructure during deformation at high temperature was also studied. The result shows that at the beginning of hot compression simulation, the flowing stress of the dispersion-strengthened copper quickly attains a peak value and the stress shows a greater decrease when the temperature is higher and the strain rate is lower. The dispersion particles lead to an obvious increase in the recrystallization temperature. Under experimental conditions, dynamic recovery is the main softening method. The constitutive equation at high temperature of 1.2%Al2O3-0.4%WC/Cu is obtained.

关键词： dispersion-strengthened copper thermal simulation flowing stress microstructure constitutive equation

Fault-tolerant control of linear uncertain systems using H∞ robust predictive control

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Journal of Systems Engineering and Electronics 2008年第3期19卷 571-577页

作者： Chen Xueqin Geng Yunhai zhang yingchun Wang Feng Research Center of Satellite Technology Harbin Inst. of Technology Harbin 150080 P. R. China

The robust fault-tolerant control problem of linear uncertain systems is studied. It is shown that a solution for this problem can be obtained from a H∞ robust predictive controller （RMPC） by the method of linear matrix inequality （LMI）. This approach has the advantages of both H∞ control and MPC： the robustness and ability to handle constraints explicitly. The robust closed-loop stability of the linear uncertain system with input and output constraints is proven under an actuator and sensor faults condition. Finally, satisfactory results of simulation experiments verify the validity of this algorithm.

关键词： RMPC linear matrix inequality H∞ control fault-tolerant control.

Fault reconstruction observer design for continuous-time systems with measurement disturbances via descriptor system approach

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Journal of Systems Engineering and Electronics 2014年第5期25卷 877-885页

作者： Qingxian Jia yingchun zhang Chengliang Li Xueqin Chen Research Center of Satellite Technology Harbin Institute of Technology Aerospace Dongfanghong Development Ltd

This paper addresses a problem of observer-based sensor fault reconstruction for continuous-time systems subject to sensor faults and measurement disturbances via a descriptor system approach. An augmented descriptor plant is first formulated, by assembling measurement disturbances and sensor faults into an auxiliary state vector. Then a novel descriptor state observer for the augmented plant is constructed such that simultaneous reconstruction of original system states, sensor faults and measurement disturbances are obtained readily. Sufficient conditions for the existence of the proposed observer are explicitly provided, and the application scope of the observer is further discussed. In addition, an extension of the proposed linear approach to a class of nonlinear systems with Lipschitz constraints is investigated. Finally, two numerical examples are simulated to illustrate the effectiveness of the proposed fault-reconstructing approaches.

关键词： fault reconstruction descriptor system approach ob- server design measurement disturbance.

GA-BASED PID NEURAL NETWORK CONTROL FOR MAGNETIC BEARING SYSTEMS

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Chinese Journal of Mechanical Engineering 2007年第2期20卷 56-59页

作者： LI Guodong zhang Qingchun LIANG yingchun School of Mechanical and Electrical Engineering Harbin Institute of Technology Harbin 150001 China

In order to overcome the system non-linearity and uncertainty inherent in magnetic bearing systems, a GA（genetic algnrithm）-based PID neural network controller is designed and trained tO emulate the operation of a complete system （magnetic bearing, controller, and power amplifiers）. The feasibility of using a neural network to control nonlinear magnetic bearing systems with unknown dynamics is demonstrated. The key concept of the control scheme is to use GA to evaluate the candidate solutions （chromosomes）, increase the generalization ability of PID neural network and avoid suffering from the local minima problem in network learning due to the use of gradient descent learning method. The simulation results show that the proposed architecture provides well robust performance and better reinforcement learning capability in controlling magnetic bearing systems.

关键词： Magnetic bearing Non-linearity PID neural network Genetic algorithm Local minima Robust performance

Electro-deposition tangsten coating on low activation steel substrates from Na_2WO_4-ZnO-WO_3 melt salt

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Rare Metals 2012年第4期31卷 350-354页

作者： Liu, Yanhong zhang, yingchun Liu, Qizong Ge, Changchun School of Material Science and Engineering University of Science and Technology BeijingBeijing 100083China

Tungsten coating is considered as a promising alternative material for plasma facing materials(PFC) in future fusion *** electro-deposition of tungsten in Na_2WO_4-ZnO-WO_3 melt at 1173 K on low activation steel substrates was studied in this *** and smooth tungsten films were deposited under various pulsed current *** crystal structure and microstructure of tungsten deposits were characterized by XRD,SEM and EDX *** results show that pulsed current density and duty cycle have a significant influence on tungsten nucleation and electro-crystallization *** and smooth tungsten coating with high purity and high adherence is obtained on low active steel substrates as cathodic current density ranges from 35 to 25 mA·cm_(-2).

关键词： tungsten electro-deposition low activation steel pulse current melt

An Improved Heat Transfer Correlation for Supercritical Aviation Kerosene Flowing Upward and Downward in Vertical Tubes

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Journal of Thermal Science 2020年第1期29卷 131-143页

作者： LI Yong CHEN Youqian zhang yingchun SUN Feng XIE Gongnan School of Mechanical Engineering Northwestern Polytechnical UniverisityXi’an710072China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China

Correlations are crucial to the design of cooling channels employed in regenerative cooling systems for *** this paper,correlations for the aviation kerosene flowing upward and downward in vertical tubes are studied and *** existing correlations are assessed against the available experimental *** further improve the prediction accuracy of the heat transfer behaviors of the supercritical aviation kerosene,a new dimensionless parameter(Qi)relevant to the heat flux is proposed and introduced into the construction of a new *** shows that the new correlation is more accurate than existing correlations.

关键词： correlation supercritical n-decane prediction accuracy heat flux vertical tube

Effect of Shape and Placement of Twisted Pin Fins in a Rectangular Channel on Thermo-Hydraulic Performance

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Journal of Thermal Science 2024年第5期33卷 1773-1793页

作者： LI Yong zhang Jin zhang yingchun zhang Jiajie MA Suxia SUNDEN Bengt XIE Gongnan College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Cleaner Intelligent Control on Coal&Electricity Ministry of EducationTaiyuan 030024China Shanxi Provincial Key Laboratory of High Efficiency Heat Storage and Low Carbon Heat Supply Taiyuan 030008China School of Energy and Power Engineering North University of ChinaTaiyuan 030051China Department of Energy Sciences Lund UniversityP.O.Box 118Lund SE 22100Sweden School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal)of twisted pin fins and their arrangements in straight and cross *** ambient air cooling test platform was established to numerically and experimentally investigate the flow and heat transfer characteristics of 360°twisted pin fins at Re=*** findings reveal that straight rows exhibit higher Nu values than cross rows for triangular and rectangular twisted pin fins,and Nu increases with *** contrast,for hexagonal twisted pin fins,only straight rows at Re=19000 exhibit superior overall thermal performance compared to cross ***,the heat transfer performance of the cooling channel with hexagonal twisted fins surpasses both triangular and rectangular configurations,especially at high Reynolds numbers(Re=22800).Although the heat transfer coefficient of the cooling channel with hexagonal twisted fins is significantly enhanced by 132.71%compared to the flat channel,it also exhibits the highest thermal resistance and relative friction among the three types of twisted fins,the maximum of which are 2.14 and ***,the hydrothermal performance factor(HTPF)of the cooling channels with different types of twisted pin fins depends on the Reynolds number and arrangement *** Re=15200,the highest HTPF achieved for the cross-row hexagonal twisted pin fins is 0.99.

关键词： twisted pin fin cross arrangement heat transfer pressure drop HTPF

Preparation of Zr-Cu Coatings on Copper Substrate Using a Molten Salt Method

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Journal of Wuhan University of Technology(Materials Science) 2023年第5期38卷 1155-1160页

作者： LI Yusha zhang yingchun LIU Yanhong LI Guangbin DONG Xiaoxun l.School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China State Power Investment Corporation Science and Technology Research Institute Beijing 100029China

Dense zirconium coatings on copper substrates were obtained in an alumina crucible and a stainless steel crucible from FLiNaK-K_(2)ZrF_(6)molten salt at 1023 *** to the potential difierences between copper and zirconium,zirconium can difiuse into the copper substrate to form zirconium alloys on the surface of copper substrates in the course of *** coating deposited in a stainless steel crucible has a gray *** components of the coating are mainly CuZr2alloy and Cu_(10)Zr_(7)alloy,and,the outermost layer of the coating is a layer of amorphous pure *** coating deposited in an alumina crucible has a silvery white metallic *** components of the coating are mainly Cu-Zr-Al intermetallic compounds,AlCu_(2)Zr,ZrAl,AlCu and ***,two types of zirconium coatings can greatly increase the hardness of the substrate.

关键词： coating Zr-Cu molten salt intermetallic compounds