高超声速飞行器超螺旋滑模自适应控制

针对具有强耦合性、严重非线性等特性的高超声速飞行器控制问题,提出了一种改进的自适应二阶滑模控制方法。首先,在高超声速飞行器纵向模型中加入不确定因素,建立了具有参数不确定性、模型不确定性以及干扰的控制模型;其次,在所建立模型的基础上,利用类二次型Lyapunov函数设计了基于super-twisting算法的二阶滑模自适应控制器;最后,仿真结果表明,对具有未知上界不确定性的系统,该方法设计的控制器较普通二阶滑模控制器,有更好的跟踪效果以及鲁棒性。     

BTT导弹自适应反演控制律设计与仿真

针对倾斜转弯(BTT)导弹控制中的多变量强耦合问题,研究了一种适用于BTT导弹的反演算法,以实现自动驾驶仪的自适应解耦控制。根据BTT导弹控制的基本特性,建立导弹的非线性控制模型,并将其转化为适合于反演设计的反馈块模型。在此模型上,基于反演的非线性控制系统综合设计方法,加入自适应神经网络逼近系统中存在的不确定性,利用Lyapunov稳定性定理推导了自适应调节律,设计了导弹控制律。通过仿真验证了该设计方法的有效性和可行性,该控制器能够实现控制解耦目的,且对指令信号跟踪效果良好。     

高超声速无人机的BTT自适应控制器设计及仿真

结合BTT控制与特征建模思想,将黄金分割自适应控制应用于高超声速无人机的横侧向机动控制。对一类高超声速无人机进行了BTT自适应控制器设计和仿真,仿真结果表明,基于特征模型的自适应控制,较好地实现了矢滚角和侧滑角的信号跟踪,验证了该方法的有效性。     

参数不确定高超声速飞行器自适应模糊H_∞控制

针对具有参数不确定性特点的高超声速飞行器输出跟踪问题,提出了一种自适应模糊H∞控制器设计方法。考虑系统存在的参数不确定性,利用自适应模糊系统在线逼近动态逆控制器中的非线性项,同时引入鲁棒补偿项,减轻模糊系统逼近误差和系统外部干扰对控制系统稳定性造成的影响,提高控制器的H∞性能。利用Lyapunov理论对整个系统的稳定性进行证明。对比仿真结果表明该方法能够保证高超声速飞行器具有良好的跟踪性能和很强的鲁棒性。     

临近空间高超声速导弹红外特性研究

研究临近空间高超声速导弹的红外辐射特性,对于反临近空间武器系统侦察监视临近空间目标具有重要意义。通过对临近空间高超声速导弹X-51A试验飞行过程的研究,深入分析了高超声速导弹的红外辐射特征,并建立其红外辐射模型。以导弹蒙皮、发动机及尾喷焰作为高超声速导弹的主要红外辐射源,以X-51A试验飞行器为参考,计算临近空间高超声速导弹在3~5μm和8~14μm波段在不同方向上的红外辐射强度,并针对计算结果进行了分析。     

高超声速飞行器姿态运动协调研究

研究了高超声速飞行器的姿态运动间的强耦合问题并设计了姿态协调控制器,首先基于状态变量间耦合度推导了耦合熵,再基于耦合分析设计了协调因子,其中将状态变量间的耦合熵作为协调因子的参数,然后引入协调因子设计了姿态控制器。仿真结果表明,所设计的协调控制器可有效应对高超声速飞行器姿态运动间的强耦合问题,在保证姿态稳定的前提下,实现了姿态角之间的协调控制。     

基于干扰观测器的导弹自动驾驶仪的反演设计

在分析喷流干扰的基础上,建立了含有干扰放大因子的复合控制的弹体模型.针对导弹气动参数的不确定性及外界干扰对导弹控制性能的影响,利用非线性干扰观测器对干扰的逼近特性,结合反演控制设计了非线性导弹自动驾驶仪,并基于Lyapunov方法,给出了整个系统的稳定性证明.仿真结果表明,设计的控制方案不仅提高了系统响应速度,而且能够保证系统具有良好的鲁棒性.     

面向大跨度机动飞行的高超声速飞行器自抗扰轨迹线性化控制

针对高超声速飞行器大跨度机动飞行所引起的本质非线性及强耦合动力学特性、执行机构输入受限、多源气动参数摄动及外部环境干扰并存情况下的姿态跟踪控制问题,结合模型辅助自抗扰控制技术,构建并阐述了基于轨迹线性化控制框架的集抗饱和与主动干扰补偿于一体的姿态控制体系。首先,面向控制角度,将姿态和角速率子系统描述为带不确定性的严格反馈形式;其次,基于自抗扰控制的设计思路,采用跟踪微分器对姿态标称指令及其微分安排过渡过程,解决单一轨迹线性化控制中的执行机构饱和问题;分别针对姿态与角速率回路构造包含模型信息的扩张状态观测器对总干扰进行观测并补偿,克服大范围不确定性对闭环跟踪性能的影响;基于轨迹线性化控制思想,分别设计前馈跟踪控制律和反馈镇定控制律,实现姿态跟踪误差沿着标称指令镇定。仿真结果表明,该控制方案能够实现给定大幅度制导指令下的高精度抗干扰控制,且对于再入过程中的多源干扰大范围摄动具有较强的适应能力。     

一种自适应双滑模制导律研究

根据导弹-目标追逃问题的相对运动学关系,基于反演思想设计了双滑模变结构导引律,运用自适应方法实现对制导系统参数不确定性和目标机动的估计,该导引律能够保证导弹在击中运动目标的同时满足期望落角;然后运用Lyapunov稳定性理论分析了该制导律进入平衡状态的充分条件.仿真结果表明了该设计方法的有效性.     

高超声速飞行器的轨迹设计与仿真研究

针对高超声速飞行器高速度、高升限、远巡航距离的特点,以高超声速巡航导弹X-43A为研究对象,对其动力学特性进行分析研究,建立飞行轨迹仿真所需要的气动模型、动力模型以及质量模型;并模拟高超声速巡航导弹X-43A试飞试验的飞行轨迹,建立各飞行段弹道仿真模型,构造飞行轨迹并进行仿真验证。仿真结果表明,所得到的轨迹符合高超声速飞行器的实际飞行情况,验证了该轨迹设计方法的可行性和有效性。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.