遥测中间装置模拟量变换器故障诊断方法CSCD

介绍了遥测中间装置模拟量变换器在调试初期参数输出异常时故障初步分析、工作原理、排除步骤以及常用方法等。将被测对象的电量参数经适当的变换与匹配,使之满足遥测传输设备的要求,起到信号调节和接口作用,它的精确度、可靠性及安全性等指标直接影响系统的总体性能,其工作正常与否,可直接影响测试数据的判别结果。此故障排除方法,可供模拟量变换器单机调试人员、工艺人员参考。     

Robust H∞ controller design for attitude stabilization of flexible spacecraft with input constraints

This paper addresses the attitude stabilization and vibration suppression problem for flexible spacecraft subject to model parameter uncertainty, controller perturbations, external disturbances and input constraints. The attitude model of flexible spacecraft is described and converted into a state space form in terms of passive and active vibration suppression schemes. A novel state feedback controller is proposed based on the exactly available expectation of a new variable, which is introduced to model a randomly occurring controller gain perturbation. Based on Lyapunov stability theory, sufficient conditions for the existence of the nonfragile H_∞ controller considering input constraints are given based on linear matrix inequalities (LMIs) in terms of additive perturbation and multiplicative perturbation. Then, the developed controller subject to required constraints can be obtained, where the nonfragile property is fully considered to improve the tolerance to uncertainties in the controller. Numerical simulations are performed to demonstrate the effectiveness and superiority of the proposed control strategy in attitude stabilization and vibration suppression, where it should be noted that the passive vibration suppression scheme is superior for high natural frequencies while the active vibration suppression scheme is superior for low natural frequencies. Moreover, the low natural frequencies have more influence on the performance of attitude stabilization and vibration suppression.     

Dynamics and operation optimization of partial space elevator with multiple climbers

This work studies the dynamics and optimal stabilization method of a partial space elevator (PSE) system with multiple climbers. All satellites and climbers are assumed as lumped masses that are connected by straight, massless, and inextensible tethers. A general dynamic model is derived for the PSE with multiple climbers. It is found different climber moving patterns of climbers have major influence of dynamic behavior of PSE. Optimal control is used to develop optimal operation modes to suppress the libration of PSE with multiple climbers. Moreover, a new operation mode is proposed to approach the desired mission objectives. It is found that all libration angles can be suppressed to zero by the end of the transfer period if two climbers can be kept at a constant speed. At the same time, the magnitudes of libration angles can be kept bounded by regulating the speed of the middle climber relative to other two climbers.     

基于数值风洞技术的民用飞机系留气动载荷计算研究

基于数值风洞技术,针对在低速风洞进行的民用运输飞机的地面系留载荷风洞试验进行了模拟研究。使用CFD软件建立了风洞试验段和飞机风洞模型的数值模型。根据风洞试验条件设置数值计算条件,计算了侧滑角在0毅~ -180毅范围内的飞机模型气动力。由于数值模型包括了洞壁、地板,计算结果和试验结果吻合良好。结果分析表明:当-120毅臆茁臆-90毅时,前起落架系留装置将承受较大的载荷,该载荷主要源于大偏航角时平尾部件产生的抬头力矩引起的纵向载荷,以及偏航力矩引起的横向载荷;Cl 比Cm 小两个数量级,对系留载荷的影响不占主导地位;将平尾、升降舵或方向舵预偏可降低系留载荷。为民用飞机低速风洞试验数值建模提供了参考。     

座舱排气供某设备通风冷却技术研究

基于某教练机某设备的通风冷却要求,开展利用座舱排气对某设备进行通风冷却的技术研究.通过对该型飞机座舱排气供某设备通风冷却系统的地面模拟试验研究分析,探讨座舱排气冷却电子设备技术在环控系统中的应用问题.     

一种SDH光纤传输系统设备时钟的研究与实现

介绍了一种具有很高频率和相位稳定度的ＳＤＨ设备时钟的构成及设计原理,并给出了有关的测试结果,测试结果表明,该ＳＤＨ设备时钟对时钟基准具有很好的跟踪特性。     

发动机试验台测力机构柔性梁设计研究

柔性梁的刚度性能影响风洞盒式应变天平的精准度,是发动机试验台测力试验数据精确可靠的重要保证,而柔性铰链更是柔性梁设计的关键所在。首先,借助有限元分析方法对四种典型柔性铰链进行计算分析,优选出综合刚性最好的柔性铰链形式;其次,基于选择的柔性铰链形式,研究三个关键结构参数对铰链刚度的影响;最后,设计五种不同厚度的柔性梁进行有限元分析,并加工实物模型进行加载试验验证。结果表明:铰链宽度b=40mm、半径R=5mm、最小厚度t=4mm时双圆弧柔性梁的综合刚度最好,且侧向柔度大,轴向刚度优;有限元计算值和试验值吻合良好,误差小于5%,表明将有限元方法运用于柔性梁的设计优化是可行、可靠的。     

发射率可调型智能热控涂层的发展现状

介绍了用于航天器热防护的电致变色和热致相变2种智能热控涂层的基本原理、制备方法及目前的研究现状，对我国智能热控涂层的发展进行了展望。     

无线电高度表自动测试与诊断系统

论述了一个基于 GPIB总线测试诊断系统 ,它既可对被测对象进行总体性能测试 ,又可对测试对象进行故障定位 ,系统的通用性和自动化程度较高 ,可应用于部队设备的测试、诊断和维修。     

带止裂筋整体翼梁结构的破损安全分析与试验

为了研究带止裂筋整体翼梁结构的裂纹扩展特性,采用ANSYS有限元软件对裂纹尖端应力强度因子进行数值计算,对缩比试验件进行疲劳裂纹扩展试验,当裂纹扩展到止裂筋前时进行剩余强度试验。结果表明:在梁缘条和蒙皮断裂情况下,止裂筋能够降低梁腹板上的应力强度因子幅值,对裂纹扩展起到拟制作用,其能够承担较大的静载荷从而实现破损安全设计,但是用止裂筋阻止疲劳裂纹扩展的效果并不显著;与梁弯曲产生的正应力相比,腹板上的剪应力不足以驱动Ⅱ型裂纹扩展。