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1.
日本的数据中继试验卫星系统(DRTSS)   总被引:1,自引:0,他引:1  
日本国家航天开发局(NASDA)已经在1995年使用工程试验卫星(ETS)-VI进行了轨道间通信的基础实验,在ETS-VI实验的基础上,于1997年发射通信与广播工程试验卫星(COMTES)。继ETS-VI和COMETS之后,NASDA计划用两颗数据中继试验卫星(DRTS)进行高速率数传网络操作实验。DRTS预计于2000年前后由H-Ⅱ火箭发动射升空,本次实验的目的是为地球观测国际空间站等日本航天  相似文献   

2.
本文介绍了基于ORACLE关系数据库的叉车机械零件图纸管理系统MDMS(MachineDrawingManagementSystem)该系统是一个集图纸的图形管理和图号(文本数据)管理为一体的图文数据库系统,该系统建立了与AUTOCAD连接的接口,实现了在ORACLE环境下显示AUTOCAD图形的功能。  相似文献   

3.
CUTTINGTEMPERATUREOFCBNTOOLSWHENMACHININGSTEELOFMEDIUMHARDNESSChenWuyi1(陈五一),DavidK.Aspinwal2,HanShuwen3(韩书文)1BeijingUniversi...  相似文献   

4.
SMALLTARGETTRACKINGTECHNIQUEWITHDATAFUSIONOFDISTRIBUTEDSENSORNETCHENGHongwei(程洪玮),ZHOUYiyu(周一宇),SUNZhongkang(孙仲康)(Faculty406,...  相似文献   

5.
NUMERICALSTUDYOFTOPOLOGICALSTRUCTUREOF3DTRANSONICVISCOUSFLOWFIELD(TVFF)INSIDETURBINECASCADEGuoYanhu,ShenMengyu,WangBaoguo(De...  相似文献   

6.
多通道动态测试分析系统   总被引:1,自引:1,他引:0  
张令弥  张春宁 《航空学报》1994,15(6):767-768
多通道动态测试分析系统张令弥,张春宁(南京航空航天大学振动所,南京,210016)DEVELOPMENTANDAPPLICATIONSOFMULTI-CHANNELDYNAMICTEST&ANALYSISSYSTEM(DTAS)ZhangLingmi...  相似文献   

7.
诊断专家系统基于故障树的知识获取   总被引:1,自引:0,他引:1  
近年来,诊断专家系统(FDES)得到了广泛的应用和发展,而知识获取被公认为是建造FDES的一个瓶颈问题。本文提出了一种简捷、通用的知识获取方法:利用系统故障树(FT)进行知识获取。该法在给故障树增加诊断信息的基础上,通过求解故障树的割集自动生成FDES的知识库。  相似文献   

8.
ANALYSISOFSHEARSTRESSDISTRIBUTIONINHONEYCOMBAIRCRAFTWINGSTRUCTURESUBJECTEDTO(S.T.)TORQUEKhalidM.Tahir,ZhangXing(DepartmentofF...  相似文献   

9.
RESEARCHONKINEMATICDEXTERITYOFREDUNDANTMANIPULATORSCHENWeihai(陈伟海),ZHANGQixian(张启先),YANGZongxu(杨宗煦),LIJian(李健)(InstituteofRob...  相似文献   

10.
ANALYSISOFLOCATIONACCURACYFORANEMITTERUSINGSATELLITE┐MOUNTEDINTERFEROMETERZhouYiyu(周一宇),GuoZhigang(郭志刚)(NationalUniversityofD...  相似文献   

11.
ν-gap度量及其在飞行控制律评估中的应用   总被引:1,自引:0,他引:1  
刘林  纪多红  唐强 《航空学报》2007,28(4):930-934
 传统控制律评估方法主要用于单输入单输出(SISO)系统,且对模型参数摄动考虑不够全面,针对这些不足,研究了ν-gap度量方法。在介绍系统广义稳定裕度相关概念的基础上,给出了ν-gap度量的定义、特点和性质以及近似摄动模型的计算,提出ν-gap度量评估控制律的步骤。实例结果表明,该方法不仅克服了上述传统评估方法的缺陷,而且还有根据所求的各摄动影响情况忽略影响小的元素,以减少计算量及可以找到最坏情况下的参数摄动组合等优点。  相似文献   

12.
A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertain-ties are presented to demonstrate the capacity and reliability of this method.  相似文献   

13.
杨朋涛  牛量  蒋军昌 《航空学报》2008,29(3):657-663
 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。  相似文献   

14.
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.   相似文献   

15.
二维翼段颤振的μ控制   总被引:1,自引:0,他引:1  
 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。  相似文献   

16.
航空发动机管路测量数据分割方法   总被引:2,自引:0,他引:2  
 为了提高航空发动机管路测量数据的反求建模效率,提出了一种区域增长分割算法。该方法主要是利用管路表面在曲面索引系数映射、主曲率映射、高斯映射上的特性,并基于均值漂移算法和遗传算法提出了区域分割算法中种子区域的选择策略。然后利用区域增长分割方法实现了对管路测量数据的分割。经过仿真和实测数据验证,所提管路分割算法具有较好的分割质量和效率。  相似文献   

17.
Abnormal Shape Mould Winding   总被引:1,自引:0,他引:1  
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。  相似文献   

18.
This work was dedicated to performing surface oxidation and coating treatments on carbon fibers (CF) and investigating the changes of fiber surface properties after these treatments, including surface composition, relative volume of functional groups, and sur- face topography with X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) technology. The results show that, after oxidation treatments, interfacial properties between CF and non-polar polyarylacetylene (PAA) resin are remarkably modified by removing weak surface layers and increasing fiber surface roughness. Coating treatment by high char phenolic resin solution after oxida- tion makes interface of CF/PAA composites to be upgraded and the interfacial properties further bettered.  相似文献   

19.
本文利用有限元法对冷心放肩微量提拉法(SAPMAC)生长大尺寸蓝宝石单晶过程中的热应力进行了模拟计算,应用临界缺陷理论解释了裂纹的萌生与扩展机理。研究表明,晶体内的热应力主要与晶体生长速率,环境温度和结晶取向有关;较大热应力多出现在结晶界面,放肩、收尾以及直径急剧变化等位置;最大热应力总是出现在籽晶与新生晶体的界面附近。裂纹将在临界缺陷位置产生,并在应力作用下沿a或m面扩展。计算结果与实验结果基本吻合,通过晶体生长系统和生长工艺的改进,对晶体的开裂问题得到了有效的抑制。  相似文献   

20.
To solve the topology optimization of complicated multi-objective continuous/discrete design variables in aircmit structure design, a Parallel Pareto Genetic Algorithm (PPGA) is presented based on grid platform in this paper. In the algorithm, the commercial finite element analysis (FEA) software is integrated as the calculating tool for analyzing the objective functions and the filter of Pareto solution set based on weight information is introduced to deal with the relationships among all objectives. Grid technology is utilized in PPGA to realize the distributed computations and the user interface is developed to realize the job submission and job management locally/remotely. Taking the aero-elastic tailoring of a composite wing for optimization as an example, a set of Pareto solutions are obtained for the decision-maker. The numerical results show that the aileron reversal problem can be solved by adding the limited skin weight in this system. The algorithm can be used to solve complicated topology optimization for composite structures in engineering and the computation efficiency can be improved greatly by using the grid platform that aggregates numerous idle resources.  相似文献   

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