Cardinality compensation method based on information-weighted consensus filter using data clustering for multi-target tracking

In this paper, a cardinality compensation method based on Information-weighted Consensus Filter(ICF) using data clustering is proposed in order to accurately estimate the cardinality of the Cardinalized Probability Hypothesis Density(CPHD) filter. Although the joint propagation of the intensity and the cardinality distribution in the CPHD filter process allows for more reliable estimation of the cardinality(target number) than the PHD filter, tracking loss may occur when noise and clutter are high in the measurements in a practical situation. For that reason, the cardinality compensation process is included in the CPHD filter, which is based on information fusion step using estimated cardinality obtained from the CPHD filter and measured cardinality obtained through data clustering. Here, the ICF is used for information fusion. To verify the performance of the proposed method, simulations were carried out and it was confirmed that the tracking performance of the multi-target was improved because the cardinality was estimated more accurately as compared to the existing techniques.     

齿轮传动对转桨扇发动机总体性能建模

为了开展齿轮传动对转桨扇发动机总体性能计算,在双轴涡桨发动机性能模型基础上完善了减速器与对转桨扇性能计算模型,通过构建求解方程组完成了齿轮传动桨扇发动机总体性能建模。计算表明,本模型设计点性能计算结果与公开文献计算结果误差不高于0.1%。本模型可在控制规律设计中选择桨距角为被控参数,且桨距角的调节对对应桨性能及转速影响最大;选定燃气发生器某一参数作为被控参数,再从前后桨桨距角、转速及自由涡轮转速中选取两个被控参数,组合形成的10种三变量组合控制规律均能在本模型中完成计算。结果表明,本模型可支持开展桨扇发动机控制规律设计与性能计算,具有良好的适用性与收敛性。     

焊接接头典型缺陷的数字X射线尺寸测量技术

为了准确测量焊接接头典型缺陷的尺寸,提出了一种基于半波高法(HWH)的焊接接头缺陷数字射线尺寸测量技术。首先,分析了数字射线检测系统的调制传递函数(MTF),确定了检测系统的空间分辨率。其次,对焊接接头的典型缺陷进行模拟,通过半波高法测量其尺寸。结果表明:依据瑞利判据,运用双丝像质计测定该检测系统的空间分辨率为4.5 Lp/mm;运用该方法测量焊接接头缺陷尺寸,与实际尺寸基本相符,误差小于6.3%,该方法避免了人为因素的影响,精度可满足日常产品的检测需求。     

超声电喷推进微细驻波形成及影响因素分析

对超声电喷推进微细驻波进行了研究,试验观测了微细驻波形成形态,并在不同频率下对比分析了微细驻波波长的理论值和试验值;同时分析了不同推进剂条件下,振动频率对微细驻波波长和形成驻波所需振幅的影响规律。结果表明：不同频率下,形成微细驻波波长的理论值和试验值具有较好的一致性;微细驻波的波长和振幅随着振动频率的增大而减小,同时推进剂的粘度越大,形成微细驻波所需的振幅也越大。     

微型镓场发射电推力器的推力和比冲测量

电推进技术的发展推动了微推力测量技术和比冲测量技术的研究进程。为了评估已研制出的微型镓场发射电推力器的性能,进行了推力和比冲测量。研制了一种用于场发射电推力器的微推力测量平台;进行了LabVIEW开发;对测量平台进行了标定与分析,并通过试验比较了推力实测值与理论值,实测值范围为3~28μN。另外,利用飞行时间法,测得推力器在不同发射电流下的比冲数据,比冲范围为5917~8875s。     

分离模块航天器研究综述

对分离模块航天器产生的背景及概念进行了阐述和分析,介绍了包括F6系统、天基群组系统、SkyLAN（空间局域网）等在内的几种主要分离模块航天器系统,并在此基础上归纳总结出了分离模块航天器在同轨多模块系统设计、功能系统设计、信息交互技术、队形保持重组及功能适变技术、无线信息传输技术、分布式天线技术等方面的技术特点及难点,最后讨论了分离模块航天器进一步的研究方向和发展前景。     

Generation of Accelerated Stability Experiment Profile of Inertial Platform Based on Finite Element

The residual stress generated in the manufacturing process of inertial platform causes the drift of inertial platform parameters in long-term storage condition.However,the existing temperature cycling experiment could not meet the increased repeatability technical requirements of inertial platform parameters.In order to solve this problem,in this paper,firstly the Unigraphics(UG) software and the interface compatibility of ANSYS software are used to establish the inertial platform finite element model.Secondly,the residual stress is loaded into finite element model by ANSYS function editor in the form of surface loads to analyze the efficiency.And then,the generation based on ANSYS simulation inertial platform to accelerate the stability of experiment profile is achieved by the application of the analysis method of orthogonal experimental design and ANSYS thermal-structural coupling.The optimum accelerated stability experiment profile is determined finally,which realizes the rapid,effective release of inertial platform residual stress.The research methodology and conclusion of this paper have great theoretical and practical significance to the production technology of inertial platform.     

气壁镀镍和冷却剂入口对再生冷却的影响

考虑冷却剂入口模型及气壁镀镍,对液体火箭发动机推力室再生冷却通道和冷却剂进行三维流动与传热耦合计算.采用经验公式计算燃气侧对流及辐射换热,冷却剂为甲烷,考虑其物性随温度和压力的变化.所得结果表明:冷却剂入口二次流及突扩流场的叠加,使局部压力损失变大,影响进口下游较大区域流动传热状况;气壁镀镍能提高气壁的耐高温性,降低气壁锆铜的温度.      

叶顶吹气对低速轴流压气机间隙流动 影响的数值研究

为了评价叶片顶部吹气对间隙流动的影响,采用NUMECA软件对带有叶顶吹气的叶栅流场进行了计算,并将其与不带吹气的基准叶栅流场结果进行了对比、分析.结果表明:叶顶吹气的位置和角度都对间隙流动有着较大影响.按周向和径向方向吹气时对泄漏流量密度的分布有一定的影响,但对稳定工况范围的影响不大;按一定的轴向方向吹出时可抑制间隙引起的流动分离,进而增大压气机的失速裕度.      

仪表级SiC/Al复合材料的应用研究与实践

针对下一代惯性仪表结构材料在应用中存在问题的现状,开展仪表级复合材料的应用研究,攻克了复合材料稳定化组分设计,高致密、大尺寸复合材料制备技术,尺寸稳定化评价技术和仪表级复合材料稳定化工艺四项关键技术,实现了仪表级SiCP/Al在惯性仪表结构件上的成功应用,分析了该材料应用于惯性仪表可能带来的效果,并指出了制约仪表级SiCP/Al在惯性仪表零部件上应用的问题。