大量程高精度光纤陀螺的设计与实现

采用增强Sagnac效应的方式提高干涉式光纤陀螺精度时,往往会减小陀螺的量程。从理论角度分析了高精度光纤陀螺实现量程扩展的可能性,完成了相关的算法设计,实现了跨条纹工作的平滑过渡,搭建了实验平台,成功将高精度光纤陀螺的量程从[Ω-π]~[Ω-π]扩展到[Ω-7π]~[Ω7π]。通过对量程扩展前后陀螺标度因数、零偏稳定性等参数的对比,得到了陀螺在量程扩展后不影响其基本参数的结论,进一步验证了高精度光纤陀螺的大量程设计的正确性和可靠性。     

汽车导向系统用光纤陀螺

“汽车导向技术”主要介绍日本住友电工业株式会社用于汽车导向系统的光纤陀螺。“光纤陀螺在汽车中的使用”主要介绍日立电气株式会社用汽车导向系统的光纤陀螺。     

光纤通道标准及其在航空电子中的应用

介绍了光纤通道(FC)的协议结构、拓扑结构、分类服务及标准情况,对其代替MIL-STD-1553总线的可能性进行了分析;阐述并分析了其在航空电子系统中的应用;最后得出结论:我们应瞄准国外先进技术的发展动向,抓住时机,从其基础标准“光纤通道 物理和信号接口”开始,研究并制定适合于我国航空电子系统的光纤通道标准,为新机研制做好技术储备。     

掺铒光纤光源辐照致有源区损耗研究及其抗辐照设计

在辐照环境下,掺铒光纤光源谱宽、平均波长稳定性及功率稳定性与光纤陀螺精度直接相关。为研究高性能、抗辐照掺铒光纤光源,研究了掺铒光纤光源辐射致有源区损耗特性。利用Er³⁺的本征荧光光谱作为光源原始输出光谱,结合“多重光褪色”和“980nm泵浦功率闭环控制技术”,提出了一种高性能、抗辐照掺铒光子晶体光纤光源设计方案。结果表明,在50krad照射剂量下,光源谱宽大于40nm,平均波长稳定性约5.4×10^-7/krad,输出功率衰减小于0.1dB。该宽谱光源在辐射环境下具有良好的综合性能,特别适用于战略级高精度干涉式光纤陀螺。     

光纤陀螺本征频率对准误差引起的零偏漂移抑制方法

在温度环境下,光纤环的伸缩及光折射率的变化等会引起光纤陀螺本征频率发生变化,产生光纤陀螺本征频率与陀螺调制频率对准误差,进而导致探测器信号中的“尖峰脉冲”信号发生变化,使光纤陀螺产生零偏漂移。通过分析光纤陀螺本征频率的变化,提出了一种调制频率自动跟踪本征频率的方法,从而减小了温度条件下光纤陀螺的零偏漂移。试验验证结果表明,采用该方法的光纤陀螺在-40℃～+60℃的温度范围内固定温度点下的零偏极差减小了50%。     

直升机旋翼尾迹研究的进展

 通过对直升机旋翼尾迹分析方法现状的考查,提出相应于“自由尾迹”的“约束尾迹”概念,设想了在约束条件限制下进行尾迹分析的一类新方法——约束尾迹分析法。其基本点在于通过实验分析,建立可靠的尾迹约束条件,既可克服预定尾迹分析的局限性,又可克服自由尾迹分析过于理想化的缺点。其目的是减少计算量,提高计算结果的可靠性。     

黑体式光纤燃气温度测试系统通过鉴定

黑体式光纤燃气温度测试系统通过鉴定由南京航空航天大学完成的“ＨＧＷＣ－１黑体式光纤燃气温度测试系统”，前不久通过了由航空工业总公司组织的技术鉴定。航空发动机高温燃气温度的测量是当前航空发动机测试中迫切需要解决的难题。课题组研制的黑体式光纤燃气温度测试...     

何为“信息高速公路”

何为“信息高速公路”目前，我国正在着手超前研究用于“信息国道”或“信息高速公路”的关键标准化技术研究。何为“信息高速公路”呢？“信息高速公路”是一个以现代化计算机网络通讯技术为基础的、通过光纤传输文字、声音、图像的信息网络。它可融现有计算机联网服务、...     

传输激光能量的光纤滑环结构设计与试验研究

本文设计了一种光纤滑环结构,可实现将激光能量从固定平台传输到旋转平台。该光纤滑环结构可精确控制对接光纤的端面间隙,有效保护传能光纤。实验表明,光纤耦合效率可达90%左右,可满足科研及工业应用需求。     

光子晶体光纤在光纤陀螺中的应用现状及其关键技术

光子晶体光纤技术发展迅速,凭借其自身材料的突出优势已经在干涉式光纤陀螺中得到了应用。从光子晶体光纤的原理出发,阐述了光子晶体光纤的国内外研究现状和应用于光纤陀螺的潜在优势。同时针对两型光子晶体光纤陀螺:干涉式光子晶体光纤陀螺和谐振式光子晶体光纤陀螺,综述了陀螺层级的国内外研究现状及目前面临的主要技术问题,最后提出了光子晶体光纤陀螺后续发展需要攻克的技术瓶颈。     

Modeling novel methodologies for unmanned aerial systems–Applications to the UAS-S4 Ehecatl and the UAS-S45 Bálaam

The rising demand for Unmanned Aerial Systems(UASs) to perform tasks in hostile environments has emphasized the need for their simulation models for the preliminary evaluations of their missions. The efficiency of the UAS model is directly related to its capacity to estimate its flight dynamics with minimum computational resources. The literature describes several techniques to estimate accurate aircraft flight dynamics. Most of them are based on system identification. This paper presents an alternative methodology to obtain complete model of the S4 and S45 unmanned aerial systems. The UAS-S4 and the UAS-S45 models were divided into four sub-models, each corresponding to a specific discipline: aerodynamics, propulsion, mass and inertia, and actuator. The‘‘aerodynamic" sub-model was built using the Fderivatives in-house code, which is an improvement of the classical DATCOM procedure. The ‘‘propulsion" sub-model was obtained by coupling a two-stroke engine model based on the ideal Otto cycle and a Blade Element Theory(BET) analysis of the propeller. The ‘‘mass and the inertia" sub-model was designed utilizing the Raymer and DATCOM methodologies. A sub-model of an actuator using servomotor characteristics was employed to complete the model. The total model was then checked by validation of each submodel with numerical and experimental data. The results indicate that the obtained model was accurate and could be used to design a flight simulator.     

Effects of surface topography and specimen thickness on high-speed raindrop impact damage of CFRP laminates

Raindrop impact erosion has been observed since early days of aviation, and can be catastrophic for exposed materials during supersonic flight. A single impact waterjet apparatus is established for mimicking drop impacts at the velocities between 350 m/s and 620 m/s. Carbon Fiber Reinforced Polymer(CFRP) laminates with three different surface morphologies and specimen thicknesses are tested here. A central region with no visible damage has been noticed, surrounded by a “failure ring” with common...     

解构二元对立 建构社会乌托邦

库切的代表作《耻》是一部寓意丰富，思想深刻的小说。文章将从解构主义文学理论来颠覆传统的二元对立关系即黑人与白人，男人与女人，人类与动物，粉碎西方文明中的白人中心主义，男人中心主义和人类中心主义，揭示库切对人类生存状态的忧虑、人道主义的关怀和创建乌托邦的理想。     

Aeroelastic prediction and analysis for a transonic fan rotor with the “hot” blade shape

This paper focuses on aeroelastic prediction and analysis for a transonic fan rotor with only its “hot” (running) blade shape available, which is often the case in practical engineering such as in the design stage. Based on an in-house and well-validated CFD solver and a hybrid structural finite element modeling/modal approach, three main aspects are considered with special emphasis on dealing with the “hot” blade shape. First, static aeroelastic analysis is presented for shape transformation between “cold” (manufacturing) and “hot” blades, and influence of the dynamic variation of “hot” shape on evaluated aerodynamic performance is investigated. Second, implementation of the energy method for flutter prediction is given and both a regularly used fixed “hot” shape and a variable “hot” shape are considered. Through comparison, influence of the dynamic variation of “hot” shape on evaluated aeroelastic stability is also investigated. Third, another common way to predict flutter, time-domain method, is used for the same concerned case, from which the predicted flutter characteristics are compared with those from the energy method. A well-publicized axial-flow transonic fan rotor, Rotor 67, is selected as a typical example, and the corresponding numerical results and discussions are presented in detail.     

Study on Friction Torque Loading with an Electro-hydraulic Load Simulator

This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of “torque-zero velocity” switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a “torque-zero velocity” switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a “torque-zero velocity” switching controller and, correspondingly, provides a “dual-threshold judgment” algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.     

下游畸变对压气机性能影响的预测

高技术航空发动机因结构紧凑、气动耦合密切而面临着下游畸变问题,影响压气机的性能,因而有必要研究下游畸变对压气机特性和喘振裕度的影响。本文提供了一种预测轴流压气机出口流场畸变对其特性和喘振裕度影响的方法,并具体分析了下游周向总压畸变对某单级轴流压气机特性和喘振裕度的影响。      

一种用于机动目标跟踪的新自适应卡尔曼滤波算法

在“当前”模型的概念下,从工程实现的背景出发,提出了一种用于机动目标跟踪的新自适应卡尔曼滤波算法。基本思想是通过对加速度项引入加权因子来进一步突出“当前”信息的作用,为“当前”模型提供更加准确的“当前”信息。蒙特卡罗模拟结果表明,算法不仅克服了“当前”模型自适应卡尔曼滤波算法的缺陷,而且使跟踪性能得到进一步的提高。     

数据库的工程界面

 系统地论述了数据库的工程界面、数据库管理系统、程序设计语言三者之间的层次关系。以ＳＴＥＰ标准的ＳＤＡＩ（ＳｔａｎｄａｒｄＤａｔａＡｃｃｅｓｓｌｎｔｅｒｆａｅｅ）作为数据库工程界面的具体例子,详细地论述了它向ＯＤＢＭＳ及ＲＤＢＭＳ的映射。对于向ＲＤＢＭＳ的映射,提出了“知子女联系”向“知子女联系”的映射策略,为简化映射算法、提高系统效率提供了一种选择。     

Effect of gap and overlap on mode Ⅱ interlaminar fracture toughness of automated fiber placement prepreg laminates

Automated Fiber Placement(AFP) technology facilitates the manufacturing process of composite structures with complex geometry owing to its high efficiency and accuracy.However,the unavoidable imperfections induced by the automated layup method bring challenges to the stability of the final mechanical properties of composites.The influence of AFP-induced gaps and overlaps on the mode Ⅱ interlaminar fracture process of oven-cured laminates is experimentally investigated and explicitly revealed.End...     

涡轮后机匣的结构动力学精确建模

构建精度高、规模适中的部件动力学模型,是航空发动机在研制初期实现从结构部件到整机的动力学特性准确分析的有效途径。为构建满足工程需求的部件结构动力学模型,依据某装配组合式涡轮后机匣的结构特点,提出了其各构件的“超模型”建模及装配组合形式的连接件分类建模的方法,实现装配组合式涡轮后机匣的整体“超模型”建模。同时,进一步介绍了各构件的“超模型”建模步骤、基于有限元单元网格尺寸变化的收敛准则,建立了自由度490万的后机匣构件“超模型”,“超模型”构件的频差精度可达1%以内;利用薄层建模法模拟多螺栓连接结构、采用接触对模拟支板搭接处的接触连接。装配组合后的涡轮后机匣“超模型”通过动力学分析,结果表明后机匣前8阶为整体振动模态。整体“超模型”的建立,可以代替研制样机提供虚拟试验数据,实现简化模型的修正和确认,为研制初期的结构动力学特性精确分析提供技术支撑。可推广应用到发动机其他部件及整机的精确建模中。