基于LabWindows/CVI的导弹舵机测控系统设计

舵机是导弹控制系统的重要执行机构,为实现对电动及气动多种型号导弹舵机性能的测试,设计开发了一种基于LabWindows/CVI虚拟仪器的测控系统。介绍了该测控系统硬件组成和软件结构流程,软件设计过程中充分利用多线程、数据库等技术,准确快速完成舵机自动化性能测试。应用结果表明:该舵机测控系统工作稳定,测试精度和自动化程度高,满足舵机试验测试精度和技术指标要求,为舵机的性能研究和维修维护提供了良好的测试环境。     

轮毂电机再生制动LabView测试平台设计

轮毂电机电制动试验是再生制动控制策略研究的前期基础。该研究独立设计了轮毂电机再生制动实验台架,以NI的虚拟仪器系统为平台,基于LabView开发了测控系统软件环境。本文介绍了该试验台的物理组成结构、台架信号采集硬件和测控系统工作原理。试验台可测试轮毂电机的扭矩、转速等信号,可进行电机性能测试及再生制动等实验。通过该试验台的实验测试,进行了空载滑行与电制动实验,实验表明,该台架设计合理,测控系统控制方式可行,可为今后研究再生制动控制策略及电机性能测试提供重要参考依据。     

基于CVI和VC++混合编程的雷达天线测试平台的软件设计

为了提高雷达天线系统外场的测试水平,研制了一种便携式雷达天线系统测试与控制平台;文章介绍了平台的组成结构,并详细地介绍了平台的软件设计;平台的软件设计采用LabWindows/CVI和VC++混合编程的思想,利用LabWindows/CVI开发了上层应用程序, 实现了良好的人机交互界面,采用VC++6.0开发了底层驱动程序,底层驱动程序以动态链接库形式封装,保证了硬件测控的实时性;实际应用表明该软件能满足雷达天线系统测试的需求,并能保证整个测试平台的实时性和可靠性,简化了测试过程。     

基于Simulink和C++混合编程的测试系统建模技术研究

介绍了一种基于Simulink和C++混合编程技术的自动飞行控制系统测试系统建模技术及调试方法;基于Simulink搭建飞行仿真模型,通过RTW自动代码生成工具将各仿真模块分别生成嵌入式代码,并集成应用于C++软件设计环境中;通过对时钟的有效设定,实现了基于Windows系统的实时飞行仿真测试系统的设计,仿真软件的最小运算周期为2 ms;该技术不仅可以满足自动飞行控制系统飞行仿真试验的实时性要求,并且在软件开放性、接口扩展性、板卡驱动的通用性以及软件设计功能多样性等方面占有较大优势;基于这个技术建立而成的仿真测试系统,某型自动飞行控制计算机已经成功的开展了多轮半物理仿真验证试验,并取得了良好的试验效果,从而为产品的试飞定型奠定了坚实的基础。     

基于某模型自由飞试验的测控与信息传输系统设计

针对模型自由飞试验的技术要求,设计了某模型自由飞试验使用的测控与信息传输系统,针对系统设计要点突破了多项关键问题,给出了系统关键点的设计方法和具体实现过程,并结合实例和仿真给出了相应的结果,通过地面试验对整个测控与信息传输系统的性能进行测试,包括地面及机载收发信机的接收灵敏度测试、系统时延测试等,试验结果表明,收发信机接收灵敏度及链路延时等指标都能满足模型自由飞试验的要求;对同类型系统设计有重要参考价值。     

精密离心机测控与加速度计标校自动化系统设计

惯导加速度计在精密离心机上的标校应用试验,涉及精密离心机动态半径和静态半径的精密测量、转速的精确测控以及被校加速度计信号的正确采集与实时传输等操作,需严格控制各类测控仪器的动作时序逻辑实现精密离心机精密测控与加速度计标校应用试验的自动化操作。介绍一种精密离心机测控与加速度计标校应用试验自动化系统设计,硬件上基于LAN总线组网集成精密离心机各类测控仪器,构建分布式测控系统,并应用外部光栅编码器脉冲信号作为触发信号控制测控仪器的硬件时序同步逻辑;软件上应用共享变量技术实现各类测控参数的有序传输,针对动态波形类大数据测试信号的共享变量传输可靠性差问题,提出一种基于文件动态拷贝的网络数据传输方案,设计严格的共享变量传输逻辑机制,实现了各类测控参数正确有序采集与传输。应用试验表明,设计的精密测控与加速度标校应用试验自动化系统满足加速度计在精密离心机上的标校自动化需求,显著提高了加速度计标校应用试验效率。     

基于PID控制的空调器性能测试装置研制

介绍了PID控制技术在空调器性能测试室内温湿度控制中的应用,设计了一个空调器性能测试系统,并基于VB编程技术,在Win2000/WinXP操作系统上,开发了系统数据采集,显示数据处理功能的测控系统。试验证明,该系统稳定、可靠,能满足国家标准的规定。     

基于Labview和Matlab的模糊PID温度控制系统研发

文章以LabVIEW 图形化编程语言、模糊控制工具箱及PID工具包等为开发平台,设计温度测控系统;利用Matlab Simulink 进行仿真实验,并与常规PID的控制效果比较;利用模糊逻辑(fuzzy logic)模块及LabVIEW提供的仿真模块(simulation module)建立系统仿真框图;通过仿真曲线分析模糊PID控制效果及影响因素,动态调整K_p,K_i,K_d的设置,缩短了控制器的设计周期,明显改善系统的稳态性能以及稳态响应,具有较大的工程实用价值。     

基于NIOS II处理器的USB双向数据传输系统

介绍了一种双向数据传输系统设计方案和实现方法,采用USB2.0接口芯片CY7C68013A与FPGA相结合构建硬件系统,FPGA内嵌NIOS II软核处理器负责数据处理;系统通过USB接口向上传输数据到上位机,结合基于VC++开发的数据传输控制软件平台,发送控制命令及数据到硬件系统端,从而实现USB接口的双向数据传输功能;详细描述了系统的硬件电路设计和软件实现过程,实验证明该系统具有高速、便携、通用性强的特点,系统数据最高传输速度达到33 MB/s,且工作稳定可靠。     

基于逻辑门限值的客车ABS硬件在环测试研究

针对ABS控制器开发过程中纯数值仿真过于理想化,实车试验成本高、周期长等缺点,设计并搭建了客车ABS硬件在环仿真测试系统;系统由xPC目标实时仿真环境、气制动系统及整车动力学模型组成;气制动系统按照真实客车制动系统并配合力传感器搭建;整车动力学模型由轮胎模型、七自由度车辆模型、制动器模型等组成,并利用Simulink建模;在ABS控制策略中引入逻辑门限值控制,在客车ABS硬件在环仿真测试系统上测试了客车在高附着系数、低附着系数及对接路面上的制动情况;试验表明:逻辑门限值控制能很好地将车轮滑移率控制在最佳滑移率附近,具有较好的控制精度及鲁棒性。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.     

Fiber Modal Index Measurements Based on Fiber Gratings

A novel method based on fiber gratings for measuring the effective indices of fiber modes is proposed. The effective index difference between the core mode and a cladding mode was obtained by analyzing the interference fringe of a pair of cascaded long-period fiber gratings. In order to extract the core mode index from the measured index difference, an index matching oil immersion method is proposed. By analyzing the interaction between the cladding mode and the oil applied on the cladding surface, the mode order and the effective index of the involved cladding mode might be calculated. Experimental results about the interference fringe shifts induced by the oil index and the oil-applied length are also presented.     

Optical Pulse Compression Schemes That Use Nonlinear Bragg Gratings

Nonlinear optical pulse compression of picosecond pulses typically requires long lengths of optical fiber and multiple components. Periodic structures, such as fiber Bragg gratings, are highly dispersive at wavelengths outside of the photonic bandgap. This implies that such gratings can be used as very short all-fiber compressors. In this paper a number of such compression schemes are reviewed involving uniform and nonuniform fiber Bragg gratings, relying on both soliton and nonsoliton compression principles. Experimental results supporting the corresponding underlying theory are also presented. Finally, an extension of one of the compression schemes is shown, which allows the generation of adjustable high-repetition rate soliton trains.