不确定环境下多无人机协同搜索算法研究

不确定环境下多无人机协同搜索是多无人机协同控制的一个重要研究内容。多架无人机同时对一个不确定区域进行搜索,目的在于获取搜索区域的信息,降低环境的不确定度,并尽可能发现隐藏在环境中的目标。针对这一问题,提出一种基于协同进化算法的多无人机协同区域搜索算法。首先,建立搜索概率图来描述搜索环境的不确定性,并使用贝叶斯准则更新搜索概率图,然后,使用协同进化算法,在线生成多UAV协同搜索的路径。仿真结果验证了算法的有效性。     

具有时间约束的多无人机协同航迹控制研究

以多架无人机为研究对象,控制多无人机对目标实施协同攻击,并保证多无人机以指定时间到达目标或同时到达目标,最大限度地提高作战效能,是一个极具理论价值和军事应用的问题。确定了多无人机多级分布式协调策略,明确了协同变量与协同函数的概念和相应的数学表达式,以及领机与僚机间的通讯关系,最后利用基于协同变量和协同函数的多级分布式控制策略,有效解决了具有时间约束的多无人机协同航迹控制问题,设计仿真算法,并通过具体的仿真分析,验证了算法的有效性。     

改进粒子群算法的多无人机航迹优化

针对多无人机协同搜索多运动目标航迹优化问题,建立基于搜索概率图的信息环境模型,提出了一种基于人工势场与自适应参数调整粒子群优化的搜索算法(APF-APSO算法),用于不确定环境中的动态目标搜索。利用人工势场中无人机与山体之间、无人机之间的虚拟排斥力进行有效避障,以及无人机与目标之间的虚拟吸引力加快目标搜索;通过非线性的指数函数参数调整法对粒子群参数进行调整,并根据无人机搜索过程中得到的栅格单元信息确定度和目标存在概率对搜索概率图进行实时更新,来引导无人机对目标进行搜索。仿真结果表明,与其他算法相比,所提算法在搜索目标方面具有很大的优势,缩短了路径长度;避免了陷入局部最优解,具有较好的收敛性;能够有效地实现多无人机之间的协同搜索,提高了搜索效率。     

基于匈牙利融合遗传算法的多无人机不平衡目标分配

基于无人机和目标之间的态势,研究不平衡目标任务分配建模和求解问题。首先,分析空战战场下无人机和目标之间的态势,提出一种某时刻的态势评估方法,建立多无人机不平衡目标分配模型;然后,用匈牙利遗传算法的目标分配算法求解该模型;最后,构建仿真算例进行仿真实验。仿真结果验证了所提算法的有效性,同时也表明了匈牙利遗传算法能够提升模型的求解效率。     

基于模糊动态博弈的多无人机空战策略研究

不确定环境下多无人机空战决策问题已成为无人机作战系统的一个重要研究课题。首先通过分析无人机空战态势信息的不确定性, 建立模糊信息下的多无人机动态博弈的作战优势函数; 将动态扩展式博弈转化成静态策略式博弈, 构建基于模糊信息的双方博弈的支付矩阵。将模糊结构元方法和粒子群算法相结合, 给出模糊信息下动态博弈的混合战略的纳什均衡求解方法。最后通过仿真实验验证了该方法的可行性和有效性。     

快速一致性控制算法下的多UAV分布式协同控制

多无人机系统中,系统状态的一致性是实现多无人机分布式协同控制的基础, 一致性控制算法是多无人机系统实现状态一致的有效方法。通信约束条件下, 无人机平台基于局部交互信息, 通过一致性控制算法, 控制系统状态演化一致。为解决改变通信拓扑结构和多跳路由通信的不可操作性问题, 引入状态差值和预测状态,设计新的快速一致性控制算法。给出新算法收敛性和快速性的相关定理,并进行了严格的数学证明, 在分布式协同控制结构下实现多无人机快速任务协同。理论分析和仿真实验验证了算法的可行性和有效性。     

通信约束下的多无人机协同航路规划

针对存在通信约束的多无人机协同航路规划问题,在考虑多无人机同时到达目标点和避免相互碰撞的条件下,使用改进的A*算法规划出多无人机飞行的原始航路;通过不断计算和比较无人机间的距离来限制无人机的飞行,使无人机之间的距离始终保持在允许通信距离范围内;通过减小最大允许通信距离和增大最小安全距离来消除通信时间延迟对协同航路规划的影响,从而建立了存在通信距离限制和通信时间延迟条件下的多无人机协同航路规划算法。仿真结果验证了该算法的有效性。     

多无人机任务集结合作博弈优化自组织协同控制

基于一致性理论的多无人机系统自组织协同作战是未来无人机应对突发任务的重要方式,任务集结是协同作战的首要行动和自组织协同控制的重要内容。为优化集结行动中系统任务状态协调过程能量最优性、协同控制动态响应性和集结行动时效性3个性能指标,采用基于快速一致性控制算法的协同控制结构,在合作博弈框架下给出多无人机系统自组织协同与优化控制问题描述,建立了优化控制输入的Pareto解集,采用Nash讨价还价方法给出基本合作博弈优化一致性控制算法。在基本算法中引入过去状态差值,并以优化目标构建适应度函数,采用遗传算法优化代价函数的加权矩阵,得到改进合作博弈优化一致性控制算法。理论分析和仿真实验验证了方法的可行性和有效性。     

多无人机时序到达协同控制方法

时序到达控制是无人机协同控制方向新近产生的典型问题, 对异构无人机协同执行搜索、跟踪、打击、评估等任务具有重要潜在价值。引入计算几何学中的Laguerre图用于航路规划, 当两个威胁区域不相交时, Laguerre图生成的初始航路必然从它们之间的空隙内穿过。针对时序控制精度不高的问题, 采用周期性的速度修正方法, 有效提高了到达时间精度。仿真结果表明, 所提出的时序到达控制方法能够有效实现多无人机时序到达, 并且具有较高的鲁棒性和控制精度。     

基于改进一致性算法的无人机集群饱和攻击

针对无人机一般难以单独打击空防严密的高价值目标问题,采用低成本无人机集群饱和攻击技术,提出协同控制下的三阶段一致性饱和攻击策略,根据不同阶段的任务特点,设计对应的改进一致性算法,并在满足饱和攻击任务多条件协同的基础上,加入Dubins曲线增加飞行轨迹约束,平滑无人机飞行航迹,缩短航程.此外,在高精度队形保持的任务环境下,设计改进的二阶一致性控制器,确保飞行精度,加快收敛速度.最后,将各阶段改进算法的实际效果与传统算法进行对比,在验证改进算法有效性的同时,检验算法延展性.仿真结果表明,该算法可应用于大规模无人机集群并具有良好的效果,为饱和攻击战略决策部署与战术实现提供了依据和参考.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.