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根据某飞机机械检测车试车测试系统检查仪研制任务的需求,分析了航空发动机转速频率信号和振动频率信号,设计了模拟相应频率信号的发生电路,并实际应用于检查仪的研制。 相似文献
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分析了某型飞机飞行自动控制系统(САУ)的信号交联关系,介绍了一种基于虚拟仪器技术的飞行自动控制系统故障检查仪的设计与实现。重点讨论了该检查仪的虚拟仪器配置方案及其软、硬件实现方法。 相似文献
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众所周知,有源雷达系统发射无线电频率能量,并等待回波以跟踪某一目标。与之相反,无源雷达系统则通过其它发射机(通常为无线电或TV信号)不仅采用RF波广播信号,而且还利用来自诸如GPS或敌方雷达的蜂窝式电话、空基系统的发射信号。无源系统要求知晓发射机的位置,并在不被飞行在某一区域内的目标干扰时,还测量整个电磁环境。当某一目标飞行通过时,防空系统可以根据被飞机或巡航导弹反射同来的信号来推断出目标的位置。将从发射机直接传输到雷达的信号与一个由目标反射的信号进行比较,同时测量时间和频率的到达差值。 相似文献
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通过对某引信检查仪的使用情况统计与分析,发现其设计存在问题.据此提出了相应的改进方案,使改进后的检查仪对引信测量合理准确,以确保引信在使用中安全可靠. 相似文献
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航空发动机压气机转子叶片故障多由机械激励和气动激励造成,而高强声波对转子叶片的激振因素不容忽视。通过开展某型涡扇发动机压气机内部噪声测试试验,研究压气机转子叶片振动机理及其与噪声信号的对应关系。阐述了压气机内部旋转不稳定性非定常压力波作用机制,提出了基于刚性壁声波导管技术的导出式噪声测量方法,完成了某型涡扇发动机压气机内部噪声信号测试,对噪声信号进行了频谱分析和声传播特性分析。研究结果表明,某型涡扇发动机压气机内部噪声信号频谱呈现高峰值纯音分量1 402 Hz,并且该纯音分量与转子叶片通过频率呈现特定的频率组合关系。该纯音分量的噪声源在压气机内部沿发动机顺航向方向从后向前传播。利用旋转不稳定性理论,将声源频率在不同坐标系下进行转换,当噪声源周向模态数为13时,该纯音分量可调制出与高压一级转子叶片一阶振动频率相对应的激振频率。 相似文献
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采用非接触式非侵入式的测量方法实现航空发动机叶盘振动测量,对发动机研制、试验、运行安全具有重要意义。提出基于声模态分解的叶盘同步振动辨识方法,在某三级风扇试验器的进气道布置环形声阵列,作为参照并在动叶布置若干应变片,开展升降速试验。分析声压信号的叶片通过频率随转速的变化规律,对动叶一阶通过频率下的声阵列信号进行声模态分解,结合应变片实测的动叶坎贝尔图,建立主导声模态数与叶盘节径数的映射关系。声场和动应力测试结果表明:当主导声模态数与叶盘节径相等时,动叶发生共振现象,此时可有效地对风扇叶盘同步振动进行辨识;动叶与前后叶排静叶都存在转静干涉现象,声压信号呈现为窄带宽频,形成声模态离散,造成动叶表现为多模态振动;声压信号是叶片不同振动模态的气动载荷分布的综合反映,具有好的灵敏性和完备性,可实现航空发动机动叶非接触式非侵入式振动测量。 相似文献
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为了识别某型涡轴发动机喘振时的特征,通过进气畸变方式开展了某型发动机台架试车逼喘试验,利用声压传感器测量采集了轴流压气机和离心压气机两侧的声压信号。对声压信号进行测试环境与背景噪声修正,再采用时频分析方法实现了对由于进气减少引起的压气机叶片失速团特征和低频喘振特征的检测,并采用小波低频重构声压信号方法实现了某型涡轴发动机喘振信号的提取与识别。结果表明:随着进气的增加,轴流压气机和离心压气机转子频率处声压信号幅值会降低,同时会产生失速团,轴流压气机右侧能最先监测到喘振,喘振频率约为60 Hz。 相似文献
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本文论述了直升机关重件在批量生产中,疲劳质量控制所采用的抽检方法以及抽检原则。文中给出的大批量产品的抽样检验判断方法、小批量生产产品的抽样检验判断方法、最佳抽样检验法和改进的最佳抽样检验法均适用于直升机关重件的抽样检验。 相似文献
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On-board/in-flight checkout of future aerospace systems will necessitate a fundamental departure from today's design and checkout activities. The interrelationship of checkout, incorporated into prime vehicular functions, man as a subsystem, and standardization Of hardware/software must be considered as a functional and integral entity if the efforts of today's long-range planning are to become tomorrow's reality. This paper will describe future systems checkout, maintenance and support considerations, and actions and tentative measures necessary for implementation. The realization of the implementation of these concepts into functional elements will depend, accurately and economically, upon the degree of government perceptiveness and the extent of industrial support. 相似文献
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Zaorski R.W. Voss R.A. Nunn E.C. 《IEEE transactions on aerospace and electronic systems》1971,(6):1068-1077
This paper discusses the concept, design, and design verification of the White Sands Range and Range-Rate System. Development of the system has been completed only through the design phase. The system is designed to meet requirements for high-accuracy midcourse tracking under severe target dynamics at the White Sands Missile Range. It is a multistatic Doppler and range tracker which operates at X band and incorporates transmitter, transponder, receiver, and baseline subsystems. The transmitter includes specially designed digital circuitry to synthesize test signals for target simulation during checkout of the system. The transponder signal is processed by a receiver which has been established theoretically to be the optimum realizable processor of continuous tracking data. The receiver incorporates specially designed carrier acquisition circuitry and digital VCO, and directly provides digital Doppler and tone phase data to facilitate real-time processing. The system utilizes data from other tracking systems at the Range for spatial acquisition, for aiding carrier acquisition in the receiver, and for resolving range ambiguities. 相似文献
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描述了TearDrop的原理和危害,提出了针对TearDrop及其变形进行检测和防御的FRD(Fragmentation Recombination Detecting)算法.对FRD算法进行了详尽的描述,并分析了算法的复杂度.最后对算法进行了试验验证,结果表明其对TearDrop及其变形的检测非常有效. 相似文献
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介绍了大型飞机航电系统采用的总线构型,ARINC429总线和AFDX总线的原理、特点和相关技术,并在此基础上提出了相应的实现方案,可作为航电系统及其检测设备的研制参考. 相似文献
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If impending failures in aerospace systems can be predicted deterministically during a test or checkout period, action can be taken to replace or repair the defective parts and a mission failure averted. This has the effect of increasing the mission reliability of the system. There are several methods of predicting specific failures especially adapted to electronic systems, but also applicable to electromechanical and fluid systems and components. These are classified and discussed in detail, with examples. References are cited for additional detail. By way of background, deterministic failure prediction is contrasted with statistical failure prediction. The nature and definition of failure and related concepts are also discussed, together with the physical principles upon which the several failure prediction methods are based. Used selectively and collectively, these failure prediction methods can form an optimal failure prevention strategy for use in a system test or checkout program. 相似文献
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涡扇发动机部件特性的BP网络研究 总被引:2,自引:0,他引:2
在发动机特性计算中,建立了BP神经网络对部件特性数据进行识别学习,实现了特性数据的精确插值和对未知特性数据的推测。通过对网络输出结果的检验与分析,表明该方法精确实用。 相似文献