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Neural integrated control for a free-floating space robot with suddenly changing parameters

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Science china(Information Sciences) 2011年第10期54卷 2091-2099页

作者： ZHANG WenHui 1,2 ,QI NaiMing 2,MA Jing 1,3 & XIAO AYang 2 1 school of Electromechanical Engineering,Xuzhou Normal University,Xuzhou 221116,china 2 school of aerospace,har.in institute of technology,har.in 150001,china 3 Department of Engineering,Northeast Agricultural University,har.in 150001,china 1. school of Electromechanical Engineering Xuzhou Normal University Xuzhou 221116 China2. School of Aerospace Harbin Institute of Technology Harbin 150001 China3. Department of Engineering Northeast Agricultural University Harbin 150001 China

Because the state of a free-floating space robot model is uncertain and sudden changes in the model parameters might undermine the stability of the system,this paper proposes a control strategy based on a variable structure neural integrated *** scheme does not need a precise space robot model,making use of the radial basis function neural network ability approach to learn about an uncertain *** network weights are adjusted online in *** the early period of the control phase and parameter changes,the variable structure controller compensates for the uncertain model which the neural network could not learn *** also creates global asymptotic stability for the whole closed-loop *** results show that the controller can handle bad changeable conditions and has important application value for defense,aerospace and other major security fields.

关键词： neural network variable structure adaptive control global asymptotical stability

Comment on “Recent progress in thermodynamics of radiation——exergy of radiation,effective temperature of photon and entropy constant of photon”

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Science china(Technological Sciences) 2009年第6期52卷 1809-1810页

作者： LIU LinHua school of Energy Science and Engineering,har.in institute of technology,har.in 150001,china school of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 China

Chen et *** the concepts of effective temperature of photon and entropy constant of photon in a recent paper [Chen Z S,Mo S P,Hu *** progress in thermodynamics of radiation―exergy of radiation,effective temperature of photon and entropy constant of *** china Ser E-Tech Sci,2008,51(8):1096―1109] by enduing a single photon with macroscale thermodynamic parameters such as exergy and *** paper argues that applying these concepts and their inferences to macro-scale thermodynamic system will lead to the results which conflict with macroscale thermodynamic *** means that the concepts of effective temperature of photon and entropy constant of photon are not correct.

关键词： thermodynamics of radiation photon entropy exergy

Direct Lyapunov-based control law design for spacecraft attitude maneuvers

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Progress in Natural Science:Materials International 2006年第11期16卷 1188-1192页

作者： HU Likun** and WANG Qingchao (school of Astronautics, har.in institute of technology, har.in 150001, china) [a]school of Astronautics Harbin Institute of Technology Harbin China

A direct Lyapunov-based control law is presented to perform on-orbit stability for spacecraft attitude maneuvers. Spacecraft attitude kinematic equations and dynamic equations are coupled, nonlinear, multi-input multi-output(MIMO), which baffles controller design. Orbit angular rates are taken into account in kinematic equations and influence of gravity gradient moments and disturbance moments on the spacecraft attitude in dynamic equations is considered to approach the practical environment, which enhance the problem complexity to some extent. Based on attitude tracking errors and angular rates, a Lyapunov function is constructed, through which the stabilizing feedback control law is deduced via Lie derivation of the Lyapunov function. The proposed method can deal with the case that the spacecraft is subjected to mass property variations or centroidal inertia matrix variations due to fuel assumption or flexibility, and disturbance moments, which shows the proposed controller is robust for spacecraft attitude maneuvers. The unlimited controller and the limited controller are taken into account respectively in simulations. Simulation results are demonstrated to validate effectiveness and feasibility of the proposed method.

关键词： spacecraft attitude control direct Lyapunov function nonlinear control Lie derivative.

Target selection and transfer trajectories design for exploring asteroid mission

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Science china(Technological Sciences) 2010年第4期53卷 1150-1158页

作者： CUI PingYuan1,QIAO Dong1,CUI HuTao2 & LUAN EnJie3 1 school of aerospace Engineering,Beijing institute of technology,Beijing 100081,china 2 har.in institute of technology,har.in 150001,china 3 National Defense Science and Industry Bureau,Beijing 100048,china 1. school of aerospace Engineering Beijing Institute of Technology Beijing 100081 China2. Harbin Institute of Technology Harbin 150001 China3. National Defense Science and Industry Bureau Beijing 100048 China

Technique of target selection and profiles of transfer trajectory for Chinese asteroid exploring mission are studied systemically.A complete set of approaches to selecting mission targets and designing the transfer trajectory is ***,when selecting a target for mission,some factors regarded as the scientific motivations are ***,when analyzing the accessibility of targets,instead of the classical strategy,the multiple gravity-assist strategy is *** suitable and possible targets,taking into account scientific value and technically feasible,are obtained via selection and *** designing the transfer trajectory for exploring asteroid mission,an approach to selecting gravity-assist celestial body is ***,according to the mission constraints,the trajectory profile with 2-years △V-EGA for exploring asteroid is *** analyzing the trajectory profile,unexpected result that the trajectory would pass by two main-belts asteroids is ***,the original proposal is extended to the multiple flybys *** adds the scientific return for asteroid mission.

关键词： exploring asteroid target selection multiple flybys transfer trajectory

Singular analysis of two-dimensional bifurcation system

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Science china(Technological Sciences) 2010年第3期53卷 608-611页

作者： CHEN YuShu& QIN ZhaoHong school of Astronautics,har.in institute of technology,har.in 150001,china 1. school of Astronautics Harbin Institute of Technology Harbin 150001 China

Bifurcation properties of two-dimensional bifurcation system are studied in this *** unfolding and transition sets of the bifurcation equations are *** whole parametric plane is divided into several different persistent regions according to the type of motion,and the different qualitative bifurcation diagrams in different persistent regions are *** bifurcation properties of the two-dimensional bifurcation system are compared with its reduced one-dimensional *** is found that the system which is reduced to one dimension has lost many bifurcation properties.

关键词： two-dimensional bifurcation system bifurcation singular analysis

Influence of polymer on shrinkage and anti-cracking performance of mortar

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Rare Metals 2007年第S1期26卷 120-123页

作者： LI Jiahe1),OU Jinping2),and WANG Zheng1)1) school of Material Science and Engineering,har.in institute of technology,har.in 150001,china 2) school of Civil Engineering,har.in institute of technology,har.in 150001,china har.in Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China har.in Inst Technol Sch Civil Engn Harbin 150001 Peoples R China

A self-designed restrained ring test was applied to investigate cracking of *** cracking total weigh W and cracking control rate K were applied to evaluate anti-cracking performance of *** the above method,the influence of polymer on the shrinkage and anti-cracking performance was *** microstructures of mortar specimens were investigated by means of *** results indicated that the addition of polymer can efficiently reduce the shrinkage of mortar and improve the anti-cracking performance of mortar.

关键词： mortar shrinkage cracking anti-cracking

Performance of information system implementation based on coupling-cohesion among subunits

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Progress in Natural Science:Materials International 2007年第5期17卷 607-613页

作者： Wang Tienan, Li Yijun and Wang Mingzhu (school of Management, har.in institute of technology, har.in 150001, china) [a]school of Management Harbin Institute of Technology Harbin China

The intermediate information system benefit and the coupling-cohesion of subunits are presented to study the performance of information system implementation. Based on the organizational information processing theory and the organizational behaviour theory, a theoretical model is established from the perspective of coupling-cohesion of subunits. The reliability and validity of the model are checked up with the structural equation models and the data collected with questionnaires. The results of the study give some theoretical and practical guidance.

关键词： information system coupling among subunits cohesion among subunits intermediate benefits.

A proof of the convergence theorem of maximum-entropy clustering algorithm

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Science china(Information Sciences) 2010年第6期53卷 1151-1158页

作者： REN ShiJun & WANG YaDong school of Computers, har.in institute of technology, har.in 150001, china 1. school of Computers Harbin Institute of Technology Harbin 150001 China

In this paper, we point out that the counterexample constructed by Yu et *** incorrect by using scientific computing software *** means that the example cannot negate the convergence theorem of maximum entropy clustering ***, we construct an example to negate Theorem 1 in Yu’s paper, and we propose Proposition 3 to prove that the limit of the iterative sequence is a local minimum of the objective function while v varies and u remains ***, we give a theoretical proof of the convergence theorem of maximum entropy clustering algorithm.

关键词： entropy fixed point clustering algorithm convergence

Relationship between Colored Microstructure under Polarized Light and Shape Recovery Characteristics on the Thermomechanical Cycled CuAlNi Single Crystals

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Journal of Materials Science & technology 2001年第5期17卷 485-489页

作者： Qingfu CHEN, Wei CAi and Liancheng ZHAO school of Materials Science and Engineering, har.in institute of technology, har.in 150001, china har.in Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAlNi single crystals. The two-way shape memory effect in quenched thin bar resulted from the preferential formation/extinction of martensite variant due to the internal quench stress, and the variant was formed at an angle of about 45 deg. with the tension direction ([001] of the βphase). Initial thermomechanical cycling under relatively low stress single variant stress-induced martensite was formed at an angle of 45 deg. with the tension and its morphology was a lath of parallel twins. More than one group of variants were formed after several training cycles and such variants also caused tilting of some thermally formed accommodated martensite. By overheating the trained sample containing stabilized multi-variants of stress-induced martensite, very coarse martensite structure with a strong asymmetry was produced, which caused the reverse two-way shape memory effect.

关键词： Relationship between Colored Microstructure under Polarized Light and Shape Recovery Characteristics on the Thermomechanical Cycled CuAlNi Single Crystals