太阳帆飞行器自适应极点配置控制方法研究

太阳帆航天器对执行机构有着特定的要求,在此基于控制杆和偏置动量反作用飞轮展开研究,就姿态控制系统的物理模型及太阳帆的姿态动力学模型进行分析。并针对此类模型,利用鲁棒极点配置方法设计自适应控制器及太阳帆航天器姿态控制系统,通过数值仿真研究姿态控制中的姿态纠偏。结果表明,采用自适应鲁棒极点配置控制方法的控制系统能够使飞行器能够较快实现大角度的姿态控制要求。     

太阳帆航天器三维动画可视化仿真平台的设计与实现

为了更好地分析和设计太阳帆航天器飞行控制系统,文章开发了太阳帆航天器三维动画可视化仿真平台。文章通过Visual C++6.0编程,MFC开发软件主界面,Creator建立太阳帆模型和飞行环境及利用Vega实现三维可视化显示。通过多通道多视点技术及视点控制技术,实现在不同的通道中分别观察太阳帆的飞行轨迹和姿态变化;通过MATLAB和VC++的交互编程,利用MAT文件仿真数据驱动多个运动体同时运动;利用Vega和Open GL混合编程,增加了飞行轨迹及文字信息显示的功能。本文成功地演示了太阳帆航天器从地球同步轨道转移到火星同步轨道的三维动画可视化仿真,验证了本仿真平台的有效性和先进性。     

基于双框架变速控制力矩陀螺的航天器姿态控制研究

针对航天器的三维姿态控制问题,研究了一种新型的航天器姿态控制执行机构—双框架变速控制力矩陀螺（DGV）,得到基于DGV的精确的航天器姿态动力学方程,分析其力矩放大效应和奇异性。基于Lyapunov稳定性理论设计了航天器姿态跟踪的非线性反馈控制律及基于速度和加速度的操纵律。仿真结果表明,一个DGV即能有效地完成航天器三维的姿态控制。     

可展开伸缩套管式伸展臂结构设计与分析

基于UG软件,对伸缩套管式伸展臂结构的模型进行参数化建模,并采用Adams仿真软件对伸展臂结构的展开方式进行运动学分析。伸缩套管式伸展臂结构采用套筒式结构原理,结构简洁又具有较好的精度和刚性。通过研究与分析表明,该结构具有较大的应用前景,可应用于大型可展开天线、太阳帆、馈源、太空平台等结构的支撑。     

基于粒子群算法的太阳帆同步轨道轨迹优化

本文研究了太阳帆航天器从地球同步轨道到以太阳为中心的火星和金星同步轨道转移的轨迹优化问题。为了获得最小转移时间,给定的任务通常是分析太阳帆方向角连续变化的最小时间最优控制问题。文中采用了分段常值的太阳帆方向角,其目的是为了充分地减少整个任务调整太阳帆方向的复杂性。利用直接离散法将最优控制问题转化为非线性规划的参数优化问题,并基于粒子群算法进行优化参数--太阳帆方向角和轨道转移时间。仿真结果表明,与太阳帆方向角连续变化的相比,所得到的结果更好的满足了轨道终端约束条件,且转移时间仅增加了1%.     

桁架结构遗传算法优化设计与安全性评判综述

本文以桁架结构为研究对象,以结构参数为设计变量,在强度和位移约束条件下,利用有限元软件对模型静力分析,结合MATLAB遗传算法优化工具箱来完成参数化建模的优化设计,最后对桁架结构设计的因素进行安全性评判,得到不同设计的安全系数。这对桁架设计的经济效益和生产安全将有重要意义。     

机抖激光陀螺安装盒优化设计

为获得更轻型有效的机抖激光陀螺安装盒结构,同时保持相对稳定的动力学特性,在现有型号基础上研究了机抖激光陀螺安装盒的优化设计方法.利用ANSYS10.0软件建立了机抖激光陀螺及安装盒的有限元模型,利用Block Lanczos Method进行模态求解,得到结构的各阶谐振频率.以安装盒质量为优化目标,同时以静力学、动力学和其他要求作为约束条件,采用序列二次规划法对机抖激光陀螺安装盒进行了优化设计.通过优化设计,在满足一阶谐振频率不变、二阶以上谐振频率值下降不小于50 Hz的设计要求下,安装盒质量由0.590 kg减小到0.394 kg,减少了33.2%;同时其静强度安全系数由原来的3.73提高到3.96,提高了6.2%.详细地研究了安装盒几何参数(R,L,W,T1,T2)对机抖激光陀螺的影响规律.该优化设计方法提高了机抖激光陀螺安装盒设计的可靠性和效率,对机抖激光陀螺整体优化设计有重要意义.     

小型一体式次镜支架结构优化设计

为了提高结构刚度，利用ANSYS的APDL语言对外径椎95mm的一体式3翼次镜支架进行了参数化建模，以基频为目标函数，对构成支架翼形的梁杆和接杆的截面参数进行了优化。优化结果表明:梁杆与接杆的夹角对基频影响显著，基频最高时梁杆与接杆的连接位置临近于基座，但并不在基座根部。在原结构基础上设计了带6螺旋环绕撑筋的新型次镜支架，撑筋显著提高了整体刚度。优化设计的新型次镜支架质量仅增加14.7g，基频增加33%，横向加速度下次镜安装面变形减小37.5%，可作为适应于力学环境的一种较佳结构。参数优化方法可提高多设计变量条件下的建模、仿真效率和设计水平，优化结果可为质量、体积及遮拦受限的小型一体式次镜支架结构设计提供有力支撑。     

机载SAR天线座结构动力学建模及分析

该文对机载SAR天线座有限元建模及结构动力学特性进行了研究。文中基于结构动力学理论,建立了机载SAR天线座的有限元模型,指出了动力学分析的关键技术,并进行了模态分析和瞬态动力学分析。仿真结果表明:机载SAR天线座的动力学性能满足伺服控制系统带宽和结构强度需求。该文提供的有限元快速建模和分析方法可为机载SAR天线座的轻量化设计提供重要支撑。     

4m SiC主镜硬点定位机构指标性能分析

为了保证4 m SiC主镜的位姿精度和支撑系统的刚度,根据主镜支撑系统的光学指标对六杆硬点定位机构的相关参数指标进行了分析。应用有限元方法并借助于有限元软件,对六杆硬点定位机构进行了优化设计,确定了硬点分布半径、定位夹角、轴向刚度和轴向拉压力极限。分析计算出在主镜背部半径为1 345 mm的圆周上,均匀分布六个硬点机构连接点时,单个硬点轴向刚度达到15 000 N/mm。此时,主镜支撑系统的固有频率大于等于15 Hz,满足设计要求,为后续结构的优化设计提供了依据。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks