程控振动疲劳试验系统

航空叶片的疲劳断裂是发动机的常见故障之一,为了研究其失效机理,国内外都采用恒定应力疲劳寿命试验。叶片的疲劳载荷主要以数值分析法来给出,或者按台架试车中实测到的最大振动应力作为载荷,试验做到各组样品均有一定数量的产品发生失效为止,用它来估计产品的各种可靠性特征。传统采用的试验方案是人工操作开环控制激振。      

军用飞机DSI数据采集系统的设计

由于军用飞机航空电子动态仿真与综合(DSI)系统所使用的固定采集周期的数据采集方法限定了采集速度,同时还影响到数据实时采集性能,针对该问题本文提出军用飞机DSI数据采集系统的设计方案.该方案的硬件结构基于MAX1308型AD转换器、DIO-144型采集卡,并设计了接口关系.系统的软件采用事件确认收发应答机制,并能确保在...     

The Lunar Orbiter Attitude Control Simulator

Testing the attitude control system of the LUNAR ORBITER was accommplished in an air-bearing facility specifically designed for that purpose. This facility was designed to minimize external disturbances in the platform by seismic motion of the floor, mass deflection of the platform, turbine torques from the air bearing, and thermal currents in the room. The facility was used for the System Design Verification tests. These tests included limit-cycle operation, maneuver sequences, wide-angle Sun acquisition and the star-acquisition (Canopus) sequence. Maneuver angle resolution was to be at least 0.1°±0.1° with the capability of measuring three-axis maneuvers for angles to 80°. The design philosophy as evolved from the experience obtained on company-funded research activities as well as the constraints and approach are presented. Solutions to the facility problem areas, which were predicted or encountered during testing, are detailed. Test results, verifying the solutions to the problems encountered, are discussed. Typical operating characteristics of the simulator during different phases of the LUNAR ORBITER test program are presented     

固体火箭发动机试验综合软件系统设计

介绍一种固体火箭发动机试验用综合软件系统。该软件系统除具有标定、数据采集、试验数据分析处理功能外,还具有固体火箭发动机性能预估、参数辨识,以及试验数据库管理功能。该系统能自动快捷地分析处理各类试验数据,有效提高了试验效率。      

Minus 35kV Space-Borne Instrument Power Supply

A -35kV power supply has been developed for a plasma experiment on the out-of-ecliptic mission. In addition, an isolation transformer has been developed to provide low voltage power at the -35kV potential. The design features incorporated to produce a spaceflight power supply housed within a 4 × 4 × 2.5 in package are discussed. The supply is powered from an unregulated spacecraft bus and provides a regulated output of -35kV ± 5 percent with less than 0.5 percent ripple over a temperature range -20°C + 60°C. The unit serves as a bias supply with an output current less than 0.5 , ?A. With the supply essentially operating unloaded, 5 percent regulation is achieved by sensing and regulating the first stage of a 12-stage Cockcroft/Walton multiplier. Control of the ac voltage input to the multiplier stack provides the regulation. The isolation transformer utilizes a ferrite u-core with the primary and secondary windings placed on opposite legs for separation. The transformer is encapsulated with the power supply.     

跨音速三维多升力面气动设计

发展了一种跨音速多升力面的气动设计方法和设计程序,它基于已成功应用于亚、跨音速机翼设计和亚音速双翼面设计的"余量修正迭代"概念.当升力面上出现超音速区和激波时自动引用迎风格式对控制方程进行修正.开发了一系列接口程序,包括目标压力设计程序.由此气动设计程羊、TAU程序以及相应的接口程序建立了跨音速多升力面气动反设计软件系统.用两个鸭翼-机翼构型验证了设计方法和设计程序,结果表明在高跨音速下设计迭代有很好的收敛性.     

相位测量轮廓术应用于叶片测量

为解决叶片高精度三维轮廓测量成本高、效率低的问题,搭建了基于相位测量的三维轮廓测量系统.在完成了系统标定后,为了检验系统的测量精度,测量了一个滚珠轴承,测量精度为(0.084±10.01)mm.利用该系统从不同方向对某叶片进行了6次数据采集,采集到的数据通过数据融合得到了整个叶片的三维点云,利用整个叶片三维点云数据得到了叶片的不同截面图,为叶片型面轮廓和几何尺寸的检测提供了依据.相位测量轮廓术用于叶片三维轮廓测量,在保证测量精度的同时大大降低了测量成本,因此将相位测量轮廓术用于叶片三维轮廓测量是非常有意义的.      

Tracking and data acquisition for space exploration

The tracking and data acquisition systems provide the key link between the remote spacecraft and the scientific experimenter on the ground. The operation of the space experiment takes place through the links of command, telemetry and tracking. The evolution from the early very simple spacecraft missions toward more complex and sophisticated missions has been paralleled by a similar evolution in the tracking and data acquisition systems. The early Minitrack interferometer tracking system still carries the major tracking workload for space missions; however greater tracking accuracy requirements for more recent missions, such as the Orbiting Geophysical Observatory and the Apollo mission, have brought about the development of unified tracking and data acquisition systems which utilize hybrid pseudo-random code/sidetone ranging techniques. The data acquisition has evolved from analog telemetry systems to the present day heavy use of PCM digital telemetry. Likewise the command systems have evolved from early simple on/off command systems into PCM digital command data systems. The trend is toward greater real time control of more complex functions on board the spacecraft. Newer spacecraft are incorporating computer-type systems in the spacecraft which require programming and memory load through the ground command link. The most attractive concept for the next generation network for tracking and data acquisition is a network consisting of synchronous-orbit Tracking and Data Relay Satellites for covering launches and low-orbit earth satellites plus a few selected ground stations for supporting spacecraft in high earth orbit and lunar orbit.     

一种高精度数据采集及控制系统设计

数据采集与控制系统是现代检测与控制技术的核心，工业控制领域对数据采集与控制系统的性能要求越来越高。设计了一种可拓展通道数目的高精度数据采集和控制系统，系统采用一主多从的模式，整个控制系统由CAN总线构成通讯网络，中央控制器负责整体调度各节点控制器的工作，节点控制器有3路高精度A／D和6路高精度D／A资源，负责各节点信号采集与控制。     

ATS-6 Radio Beacon Experiment: The First Year

The Radio Beacon Experiment is designed to measure the total electron content and ionospheric content between the satellite and any observer within its field of view. Since Applications Technology Satellite-6 (ATS-6) is visible from about 43 percent of the Earth's surface, an international community of observers have made measurements using it. The radio parameters have to be measured to an accuracy of a few percent, which requires good system calibration and stability. The spaceborne beacon transmits signals on frequencies of 40, 140, and 360 MHz with amplitude modulations of 1 MHz and/or 0.1 MHz for the measurement of modulation phase, Faraday rotation, and amplitude. The overall system objectives and requirements are discussed along with the design of the ATS-6 transmitter and the receiver in Boulder, Colo. The role of the principal investigator in the context of the international program is considered with particular reference to the joint National Oceanic and Atmospheric Administration (NOAA)/Max Planck Institute (MPI) observation program. Monthly median hourly values of total content, plasmaspheric content, and shape factor show distinct diurnal and seasonal variations. A specific event is described to illustrate the use of a spaced receiver network.     

电磁自动平衡式智能测力仪

在表面减阻试验测量中,测力方式有多种多样[1],但是,由于它们测力的基本原理是测量在力作用下使弹性元件产生的位移,这将影响测量摩擦阻力的精度。      

基于单片机的多点温度采集系统设计

随着单片机技术的迅速兴起与蓬勃发展,其稳定、安全、高效、经济等优点十分突出。为了实现多点温度数据的精确采集,采用了一种基于单片机AT89C52为核心的数据采集系统,该系统具有电路简单、功耗低、抗干扰能力强、可靠性高等优点,能够通过DBW热电阻变送器对热电阻随温度的变化而得到的模拟信号进行采集,并通过A/D转换器对模拟信号进行模数转换;同时实现基本的人机对话功能,包括使用按键设定温度报警阀值,通过LED数码直读显示检测点、温度等功能。其温度测量精度可达到1℃。     

基于VXI总线的多通道多采样率数据采集系统实现

介绍一个多通道多采样率的数据采集系统。该系统输入64个模拟量均要转换成数字信号，数据采集卡为基于VXI总线的E1413，多通道之间的变采样率通过特殊的采样列表实现。文中给出了硬件组成、软件设计和测试结果。该系统已用于对飞机燃油试验台的测控。     

计算机辅助切削数据采集与处理系统

 本计算机辅助切削数据采集与处理系统由AA6140普通车床,AppleⅡ微计算机,刀具磨损测量子系统,切削力测量子系统,切削温度测量子系统,车床主轴转速监控子系统以及其它一些传感器、仪表组成。在系统软件的支持下,可同时进行切削力,切削温度和刀具耐用度试验,还可以进行快速刀具耐用度试验。由于实现了计算机化,集成化的数据采集,处理、存贮和输出,试验效率成倍提高。同时由于消除了人为误差因素,试验数据也更为可靠。     

Automatic Target Recognition: Some Considerations

Machine analysis of aerial reconnaissance data is desirable. New acquisition techniques, equipment, and sensors, plus a growing demand for rapidly obtained, accurate information necessitate machine performance of tasks presently accomplished by observers and interpreters. Many of these tasks can be described as pattern recognition or information processing functions. This paper discusses significant problems encountered when attempting to identify objects or regions automatically from aerial photography. Problems include sensor distortions, variations in target environment, and concepts of design and ?teaching? of an actual device. Operational requirements such as processing speed and flexibility restrict the types of solutions available. Approaches to target recognition with relative merits and shortcomings are presented; these include shape correlation, feature extraction, and image quantization. The effect of mission requirements on system parameters is discussed. A bibliography is included.     

18位高精度数据采集系统的设计

以应用实例详细介绍了18位高精度数据采集系统的设计过程,阐述了设计中所遇到的问题和实际的解决方法.该实例采用MCS-51单片机控制一款△-∑型A/D芯片进行数据采集,结构简单、成本低、性能可靠、数据接口方便.实验结果表明,该系统在转换速率为50 Hz时,可获得18位数据精度.     

基于回转体CAD/CAPP结构的图形文件OpenGL处理技术研究

在计算机辅助车削加工自动编程系统中,利用CAD软件系统输入图形,并通过应用程序对其文件格式进行转化,变成CAPP模块所需的基于特征的数据结构。     

AD598的RVDT数据采集系统校准方法研究及分析

RVDT(Rotary Variable Differential Transformer)数据采集系统广泛应用于民用航空领域飞行控制系统功能的研究及测试。RVDT将机械位移信号转换成电信号。数据采集系统接收RVDT输出的差分信号,将信号调理、转化并计算后显示。分析了基于AD598的RVDT数据采集系统的校准方法,并对系统的不确定度来源及分析方法进行了介绍。     

单斜热丝测量叶轮机内三维流动

本文改进了单斜热丝测量三维流动的计算处理方法,其特点是精度高、气流角度测量范围宽。测量中,置斜热丝于三个以上角度位置,借助高速数据采集系统和锁相采样平均技术,进行采样处理,再用本文发展的程序,计算三维速度平均量。用这种方法,成功地测出了轴流压气机转子出口周期性三维流场。对校准风洞流场的测量核实表明,速度测量误差不超过1％,角度测量误差不超过1°。     

一种基于改进太阳子午线拟合方法的仿生偏振光定向系统

为设计一种自主性强、精度高、抗电磁干扰能力强的定向系统,以昆虫获取大气偏振模式的感知机理为基础,设计了一种新型的成像式仿生偏振光定向系统.该系统使用具有微偏振阵列结构的CMOS相机作为主要的偏振信息采集设备,使用DSP/ARM架构的NVIDIA JETSON TX2嵌入式处理器进行信息解算,具有体积小、运算能力强等优点.通过研究大气偏振模式中偏振度和偏振角图像的对称性,针对已有航向角解算方法在太阳子午线提取精度方面的不足,设计了一种对称轴粗提取之后通过连续旋转法精确提取太阳子午线的算法,最终实现定向精度0.3335°,在最小二乘对称轴粗提取法的基础上定向精度提升了19.05％.