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Chinese Journal of aeronautics 2010年第1期23卷 68-74页

作者： Liu Jianye,Zhu Yanhua,Lai Jizhou,Yu Yongjun Navigation research center,nanjing university of aeronautics and astronautics,nanjing 210016,China [a] Navigation research center Nanjing University of Aeronautics astronautics Nanjing 210016 China

This article proposes a new inner attitude integration algorithm to improve attitude accuracy of the strapdown inertial attitude and heading reference system （SIAHRS） , which, by means of a Kalman filter, integrates the calculated attitude from the accelerometers in inertial measuring unit （IMU） , called damping attitudes, with those from the conventional IMU. As vehicle＇ s acceleration could produce damping attitude errors, the horizontal outputs from accelerometers are firstly used to judge the vehicle＇ s motion so as to determine whether the damping attitudes could be reasonably applied. This article also analyzes the limitation of this approach. Furthermore, it suggests a residual chi-square test to judge the validity of damping attitude measurement in real time, and accordingly puts forward proper information fusion strategy. Finally,the effectiveness of the proposed algorithm is proved through the experiments on a real system in dynamic and static states.

关键词： navigation strapdown inertial attitude and heading reference system inner attitude integration algorithm internal damping Kalman filter residual chi-square test

research ON NURBS SKINNING SURFACE VIA COMPLEX CURVES

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Chinese Journal of aeronautics 1996年第2期9卷 104-110页

作者： Zhang Lenian Zhou Laisui Zhou Rurong (research center of CAD / CAM Engineering,nanjing university of aeronautics and astronautics, nanjing, China, 210016) Res. center of CAD / CAM Engineering Nanjing Univ. Aero. and Astronaut. Nanjing 210016 China

In order to design the production with complex external shapes, a newmethod is put forward using non-uniform rational B-spline(NURBS)curves to unifythe description of complex curves composed of several segments with different degrees,and then these complex curves are used to construct NURBS skinning surface. Somekinds of skills are used to dispose the knot of NURBS curves and surfaces for practicalproblems. Finally, the method is verified by several complex examples.

关键词： skin (structural member),contours shapes surfaces curves (geometry),elevation

基于小波变换的超声电机启动和关断特性的测试与分析

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数据采集与处理 2004年第4期19卷 376-380页

作者：赵淳生沈寿林南京航空航天大学超声电机研究中心南京210016

叙述了本研究中心研发的超声电机瞬态测试系统及其测试方法。由于噪声的影响 ,启动、关断响应曲线常常不太光滑 ,以往采用平滑技术和数字滤波等处理办法 ,获得启动和关断响应特性精度较差。本文利用小波变换对原始启动、关断响应数据进... 详细信息

叙述了本研究中心研发的超声电机瞬态测试系统及其测试方法。由于噪声的影响 ,启动、关断响应曲线常常不太光滑 ,以往采用平滑技术和数字滤波等处理办法 ,获得启动和关断响应特性精度较差。本文利用小波变换对原始启动、关断响应数据进行分析 ,去除噪声 ,从而较准确地获得了超声电机启动和关断的响应时间。实验结果表明 ,超声电机确实具有毫秒级的响应时间。

关键词：关断特性响应时间小波变换噪声测试系统启动平滑技术超声电机测试方法响应特性

Large-Eddy Simulations of turbulent flows with lattice Boltzmann dynamics and dynamical system sub-grid models

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Science China(Technological Sciences) 2009年第3期52卷 670-679页

作者： GUAN Hui1 & WU ChuiJie2 1 research center for Fluid Dynamics, PLA university of Science and Technology, nanjing 211101, China 2 School of aeronautics and astronautics, Dalian university of Technology, Dalian 116024, China research center for Fluid Dynamics PLA University of Science and Technology Nanjing 211101 China School of aeronautics and astronautics Dalian University of Technology Dalian 116024 China

In this paper, two sub-grid scale (SGS) models are introduced into the Lattice Boltzmann Method (LBM), i.e., the dynamics SGS model and the dynamical system SGS model, and applied to numerically solving three-dimensional high Re turbulent cavity flows. Results are compared with those obtained from the Smagorinsky model and direct numerical simulation for the same cases. It is shown that the method with LBM dynamics SGS model has advantages of fast computation speed, suitable to simulate high Re turbulent flows. In addition, it can capture detailed fine structures of turbulent flow fields. The method with LBM dynamical system SGS model dose not contain any adjustable parameters, and can be used in simulations of various complicated turbulent flows to obtain correct information of sub-grid flow field, such as the backscatter of energy transportation between large and small scales. A new average method of eliminating the inherent unphysical oscillation of LBM is also given in the paper.

关键词： Large-Eddy Simulation Lattice Boltzmann Method dynamics sub-grid scale model dynamical system sub-grid scale model parallel computation

Delayed Hopf bifurcation in time-delayed slow-fast systems

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Science China(Technological Sciences) 2010年第3期53卷 656-663页

作者： ZHENG YuanGuang1 & WANG ZaiHua1,2 1 Institute of Vibration Engineering research,nanjing university of aeronautics and astronautics,nanjing 210016,China 2 Institute of Science,PLA university of Science and Technology,nanjing 211101,China 1. Institute of Vibration Engineering research Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. Institute of Science PLA University of Science and Technology Nanjing 211101 China

This paper presents an investigation on the phenomenon of delayed bifurcation in time-delayed slow-fast differential *** the two delayed's have different *** delayed bifurcation means that the bifurcation does not happen immediately at the bifurcation point as the bifurcation parameter passes through some bifurcation point,but at some other point which is above the bifurcation point by an obvious *** a time-delayed system,the evolution of the system depends not only on the present state but also on past *** this paper,the time-delayed slow-fast system is firstly simplified to a slow-fast system without time delay by means of the center manifold reduction,and then the so-called entry-exit function is defined to characterize the delayed bifurcation on the basis of Neishtadt's *** shows that delayed Hopf bifurcation exists in time-delayed slow-fast systems,and the theoretical prediction on the exit-point is in good agreement with the numerical calculation,as illustrated in the two illustrative examples.

关键词： time delay delayed bifurcation Hopf bifurcation slow-fast systems exit-point entry-exit function

research AND REALIZATION OF MUTUAL TRIMMING OF NURBS

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Chinese Journal of aeronautics 1997年第2期10卷 119-126页

作者： Shen Qingyun Zhou Laishui Zhou Rurong(research center of CAD/CAM Engineering, nanjing university ofaeronautics and astronautics, nanjing, 210016, China) Res. center of CAD/CAM Engineering Nanjing Univ. Aero. and Astronaut. Nanjing 210016 China

Since regular surface is defined by a mapping from 2-D parameter plane to 3-D space, trimming of NURBS surface is equivalent to changing a valid parameter region ofthe surface with the same mapping. In this paper, by presenting a rigid and comprehensi-ble definition of union, difference and intersection of two intersecting loops in the parame-ter region of NURBS surface, and by working out the corresponding algorithm, a rebui1d-ing algorithm of the valid parameter region of NURBS surface is obtained.

关键词： contours surfaces computer aided design parametric surface nonuniform rational B-spline

DYNAMIC RESPONSE OF ROLLER GEAR INDEXING CAM SYSTEM CONSIDERING CLEARANCE AND motor CHARACTERISTIC

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Chinese Journal of Mechanical Engineering 2001年第2期14卷 189-192页

作者： Chang Zongyu Civil Aviation College,nanjing university of aeronautics and astronautics Zhang Ce Yang Yuhu Wang Yuxin Tianjin university 南京航空航天大学国内航空学院江苏南京天津大学天津

The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexibility are developed and *** results show that clearance affects primarily the response on turret,and has little effects on the responses on rotary *** the same time,the velocity fluctuation of motor shaft is not serious for the existence of inertia of reducer,and the high frequency of velocity fluctuation of camshaft is related with the torsion stiffness of shaft and the clearance between pairs.

关键词： Roller gear indexing cam mechanism Clearance motor characteristic Dynamic response

research ON THE 3-AXES ROUGH MILLING OF MULTI-SURFACES

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Chinese Journal of aeronautics 1997年第4期10卷 70-75页

作者： Liu Zhuang, Zhang Deqiang, Zhou Laishui, Zhou Rurong (research center of CAD/CAM Engineering, nanjing university of aeronautics and astronautics, nanjing, 210026, China)

In particular, a fair amount of the machining time may be spent in rough cutting process when a large portion of the raw material has to be removed. Therefore, an algorithm for generating the toolpath for rough cutting is suggested in the paper. The algorithm is based on an extended tracing method for plane/surface intersection is proposed for smooth surface. A 2.5D milling or parallel offset machining is to be used to significantly improve producitvity and lead to lower production costs for the sculptured multi surfaces part rough machining..

关键词： computed aided design computer aided manufacturing numerical control machining rough machining toolpath generation

CONSTRAINTS ON THE CRACK TIP PLASTIC FIELDS UNDER LARGE SCALE YIELD

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Acta Mechanica Solida Sinica 2001年第2期14卷 138-146页

作者： Xu Fei~1 Guo Wanlin~(1,2) (1 State Key Laboratory of Mechanical Structure Strength and Vibration, Xi’an Jiaotong university, Xi’an 710049, China) (2 School of aeronautics and astronautics,nanjing university of aeronautics and astronautics, nanjing 210016, China) State Key Laboratory of Mechanical Structure Strength and Vibration Xl'an Jiaotong University，Xi'an 710049，China State Key Laboratory of Mechanical Structure Strength and Vibration Xl'an Jiaotong University，Xi'an 710049，China School of aeronautics and astronautics Nanfing University of Aeronautics and Astronautics，Nanjing 210016，China

Plane strain elastic-plastic finite element analyses are used tostudy the stress, strain fields around a straight crack in powerhardening plastic material. center crack panel (CCP), single edgecrack panel (SECP) and double edge crack panel (DECP) tensionspecimens are analyzed with various crack lengths. Two localconstraint parameters, i.e. in-plane stress ratio T_x andout-of-plane constraint T_z are an- alyzed, which are defined astangential stress dividing normal (open) stress and out-of-planestress dividing the sum of tangential stress and normal stressrespectively.

关键词： constraint in-plane stress ratio out-of-plane constraint