飞机大部件对接测量方案的研究与应用

自从飞机开展数字化设计后,大大提高了飞机装配精度和质量,同时对装配过程的测量也提出了新的要求,因此,只有通过高效的测量手段和方案才能满足飞机装配精度。以大型灭火/水上救援水陆两栖飞机——AG600的三大部件对接为研究对象,基于测量体系的建立和激光跟踪仪测量转站技术,研究飞机大部件调姿的测量技术。该飞机大部件调姿的测量是利用激光跟踪仪对部件上的多个基准点进行测量,通过柔性装配工装实现飞机的姿态调整,进而达到飞机安装要求的测量调姿过程,对于传统测量方法,采用激光跟踪仪进行转站测量的方法,不失为最简单有效的大飞机部件对接测量方法。     

激光跟踪仪在飞机雷达天线面板安装精度测量中的应用

简述了激光跟踪仪的基本组成及测量原理,结合总装生产特点,介绍了利用激光跟踪仪测量飞机雷达天线面板底座的基本方法,并对测量误差进行了精度分析     

飞机大部件装配外形数字化组合测量方法

飞机装配部件外形尺寸大、曲面形状复杂,型面测量数据量大。现有的单一测量设备测量精度和效率之间的矛盾突出。为此,构建包含激光跟踪仪、关节臂测量仪和摄影测量的数字化组合测量系统。基于坐标变换将多测量站点的测量信息统一到全局坐标系下,通过测量数据模型与理论模型对比,获得部件外形测量结果,在保证测量精度的条件下,提高型面测量效率。以飞机内襟翼上翼面装配过程外形精度保证为例,验证了所提方法的正确性。     

拉削工艺用于飞机总装精加工

拉削工艺在机械制造业中被广泛地用于零件的内孔精加工,但是很少用干机械装配(包括飞机装配)的最后精加工。我厂为了提高飞机总装的结合工作效率和精加工质量,采用了拉削工艺。首先在部件装配中进行偿试,进而用于飞机总装大部件结合交点孔的精加工。这项工艺改革的成功,取得了显著的技术经济效果。飞机部件交点孔的精加工,有两种类型:一种是飞机的几何参数,靠部件处于水平测量的状态下,在精加工台中用铰孔来保证;另一种是飞机的几何参数靠总装时全机处于水平测量的状态下,采用手工铰孔的办法来保证。我     

基于激光跟踪仪、iGPS的飞机水平测量技术研究

针对传统飞机水平测量方法的不足,提出一种基于激光跟踪仪、iGPS数字化测量系统联合应用的水平测量新方法。介绍激光跟踪仪、iGPS两种测量系统的组成及工作原理。制定了包括iGPS测量场布局、iGPS系统标定、激光跟踪仪布站、统一坐标系、激光跟踪仪转站及水平测量点测量等环节的飞机水平测量方案。应用表明,该方案测量精度高、劳动强度低,完全满足新一代飞机的装配需求。     

飞机装配大尺寸多系统测量场构建及应用

针对飞机装配对大尺寸、高精度、兼容性强、扩展性好、快速组网的测量技术需求,开展面向飞机装配的大尺寸多系统测量基准场构建技术研究,提出基准点优化设计原则,采用基于激光跟踪仪的多站位冗余测量长度约束算法,构建兼容飞机装配现场设备的三维精密测量基准场,并通过试验对比验证了测量基准场的标定精度.最后通过典型应用案例阐述了在飞机...     

飞机总装数字化脉动生产线技术

飞机总装生产线作为新型生产组织模式,对提高飞机装配效率和质量,满足飞机批量生产要求具有重要作用.在分析总结国内外典型飞机总装生产线及其应用情况的基础上,对飞机数字化总装脉动生产线涉及的大部件数字化对接技术、数字化检测技术、精准移动技术、集成装配平台技术、物料精益配送技术等关键技术进行了探讨,为构建适合我国飞机总装配的脉动生产线提供思路.     

机身部件柔性装配数字化测量技术应用

随着航空制造技术的不断发展,我国现代飞机的装配工艺正由传统的模线模板、刚性工装等模拟量传递协调的方法向柔性装配的数字量传递的方法转变.数字化、自动化和信息化已经成为飞机装配的主流趋势.在"十一五"期间,各大主机厂、航空院校和研究所充分发挥产学研模式的优势,对数字化柔性装配技术进行了深入研究和应用,在飞机壁板类组件级柔性装配和大部件对接柔性装配方面取得了部分成果,有了比较成熟的应用,基于激光跟踪仪的数字化测量技术已经普遍应用于各主机厂[1-3].     

飞机数字化装配系统中工艺球头入位测量方法研究

为提高飞机数字化装配系统中机身部件工艺球头入位的准确性,提出了基于激光跟踪仪测量的工艺球头入位方法,并设计了绝对和相对测量法,确定采用相对测量法完成球头入位测量,建立了相对测量法的计算模型,最后设计一套工艺球头入位测量流程。     

机身部件数字化柔性装配技术

飞机机身部件装配是根据尺寸协调原则,将框、桁梁、壁板、隔板及各类角片按结构设计进行组合、连接的过程.其装配过程主要包括骨架装配、部件总装、外形检查等.机身部件装配精度直接影响后续大部件对接的装配质量,是保证飞机产品装配精度的重要环节.     

基于飞机油箱模型形状特征油量测量切片步长选择方法研究

 在分析飞机数字式油量测量过程中目前广泛使用的切片法油量测量原理的基础上,针对现有的定步长切片法无法得到准确、可靠的燃油质量特性数据库的缺陷,结合对飞机油箱模型形状特征的分析,提出了基于飞机油箱模型形状特征的油量测量切片步长选择方法。此方法包括切片步长整体和局部选择两个过程,整体选择以实现相邻两切片平面所夹油箱模型体积近似相等为目的来确定切片步长,以体现油箱模型截面整体变化规律;局部选择以设计切片平面与截面突变平面重合或尽可能接近的方式,突出油箱截面的局部变化特征。实验结果表明：该切片步长选择方法较定步长方法能够建立更为合理、可靠的燃油质量特性数据库,从而提高了油量测量精度。     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation.      

二维翼段颤振的μ控制

 采用超声电机作为作动器来实现含控制面的翼段颤振鲁棒抑制。针对作者设计的二维翼段颤振主动抑制系统，通过理论与实验相结合的方法，建立了考虑沉浮方向阻尼和作动器模型参数不确定性的控制系统模型，设计了μ控制器，并对控制器做了降阶处理。数值仿真和风洞试验表明，μ控制器可有效地抑制颤振的发生，将颤振临界速度提高23.4%。相对于H_∞控制器，μ控制器的控制效果和鲁棒性更好。     

Abnormal Shape Mould Winding

为解决网格化芯模的缠绕问题,本文提出了复合材料面片缠绕机理;接着详细分析了面片缠绕过程中的芯模凹曲面上纤维滑线和架空现象,应用微分几何曲面理论和空间几何理论,提出判据及其解决方案;最后,针对飞机发动机进气道的缠绕成型,编制缠绕控制程序并进行相应的实验,验证了面片缠绕方法的可行性。     

基于H∞性能指标的质量矩拦截弹鲁棒控制

 以所建立的质量矩拦截弹数学模型为基础，利用微分几何的反馈线性化理论，得到一个解耦线性系统，考虑到拦截弹的鲁棒性要求和3个滑块的协调控制问题，提出采用双回路的设计方法，内回路采用线性二次调节器（LQR），外回路采用考虑混合灵敏度问题的H_∞控制设计。仿真结果证明了该方法动态性能满足设计要求，同时对系统参数的不确定性具有较强的鲁棒性。     

航天器返回地球的气动特性综述

航天器返回地球的飞行过程中,气动特性是实现将宇宙飞行速度减到落地前速度、保证再入飞行得到有效控制以及再入防热安全可靠的关键因素。针对简单旋成体气动外形、半弹道式再入控制、烧蚀防热类返回航天器,综述了返回地球过程中变化的空气流域特性、航天器周围的气体绕流环境、空气与航天器作用产生的动力学与热效应等。系统地给出了该类航天器的再入气动特性参数与飞行性能的共性规律,包括:气动阻力与再入减速、气动升力与再入轨迹控制、配平攻角与飞行稳定性、气动加热与防热,以及再入过程中不同气动特性航天器、气象条件变化等对再入飞行性能的影响规律。为航天器开展返回飞行过程的跨流域气动性能工程研制提供设计参考。     

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.     

Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters

The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃).     

Preparation of Highly Dispersed Antimony-doped Tin Oxide Nano-powder via Ion-exchange Hydrolysis of SnCl4 and SbCl3 and Azeotropic Drying

Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.