基于声波传播时间估计的气流速度测量方法

 为实现对亚声速和超声速气流速度的统一测量,提出了一种基于声传感器的新型测量方法。首先,根据声波在亚声速和超声速气流中的传播特性,利用特定的测量装置建立了声波传播时间与气流速度之间的数学模型,从而将气流速度的测量问题转化为声波传播时间的测量问题。然后,在此基础上,利用计时法和最大似然估计(MLE)方法来估计声波传播时间;其中,计时法在实时性上优势明显,而MLE方法则在可靠性上优于前者。最后,分别从阵元位置扰动性、计时误差和克拉美-罗界(CRB)3个方面对所提算法的性能进行了分析与仿真验证。结果表明,该算法能够实现对亚声速和超声速气流速度的精确测量。     

Identification and standardization of maneuvers based upon operational flight data

To find a way of loads analysis from operational flight data for advanced aircraft,maneuver identification and standardization jobs are conducted in this paper. For thousands of sorties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneuvers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recognition theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as averaging and smoothing, the idealization standard time history of each maneuver type is established.Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program(IATP).     

Intelligent modeling and identification of aircraft nonlinear flight

In this paper, a new approach has been proposed to identify and model the dynamics of a highly maneuverable fighter aircraft through artificial neural networks（ANNs）. In general, aircraft flight dynamics is considered as a nonlinear and coupled system whose modeling through ANNs, unlike classical approaches, does not require any aerodynamic or propulsion information and a few flight test data seem sufficient. In this study, for identification and modeling of the aircraft dynamics, two known structures of internal and external recurrent neural networks（RNNs） and a proposed structure called hybrid combined recurrent neural network have been used and compared.In order to improve the training process, an appropriate evolutionary method has been applied to simultaneously train and optimize the parameters of ANNs. In this research, it has been shown that six ANNs each with three inputs and one output, trained by flight test data, can model the dynamic behavior of the highly maneuverable aircraft with acceptable accuracy and without any priori knowledge about the system.     

基于灰色关联聚类的空中交通复杂度评估方法

为了准确评价空中交通态势的复杂程度,进行有效的空中交通管理,提出了一种空中交通复杂度评估方法。在已有的理论研究成果及实际运行经验的基础上,归纳了定义明确、可定量分析的基础空中交通指标集,使用灰色关联聚类方法对指标集进行聚类分析,利用信息熵理论对聚类指标求解权重,加权求和获得空中交通复杂度。方法弥补了目前使用单一维度指标描述空中交通运行态势的弊端,能更好地体现空中交通复杂度。     

飞机故障排除专家辅助系统的设计与开发

简要介绍了飞机故障排除的专家辅助系统设计与开发,该系统以飞机专家在维护飞机过程中所积累的经验知识为例,结合故障隔离手册的内容,通过建立数据库的形式,依据人工智能的理论,使其具有查询功能,自动优选排故方法以及对故障内容的添加、修改、删除功能。     

一种基于潜在语义索引的谱聚类方法研究

传统的文本聚类算法存在文本向量维度过高,算法易陷入局部最优问题。针对上述问题,提出了一种适用于文本的基于潜在语义索引的谱聚类方法,该方法应用了潜在语义索引和谱聚类方法的优点。不仅分析了词与词之间的语义关系,而且适用于任意形状分布的样拳数据聚类。针对航空安全报告的聚类实验表明,该方法取得了较好的聚类效果。     

利用飞参数据实现飞机机体结构寿命的动态监控

首先,通过对某型直升机重心法向过载飞参数据的研究得到直升机在实际飞行中的重心过载谱;然后,发展了一种基于飞参数据的名义应力法并对某机群中的每架直升机进行了相对疲劳损伤的计算,计算结果比较符合实际情况;最后,对由相对损伤计算得到的寿命进行了可靠性分析,分析表明机体结构的寿命管理是个动态的过程,利用飞参数据实现从定时维修到...     

一种固体发动机光线投射体绘制加速方法

固体发动机ICT断层图像构成的体数据场规模大、空体素比例小,现有的光线投射加速方法效果不明显,并且在其三维可视化故障诊断中,不是体数据场中的所有信息都对内部故障检测有意义,三维重建出所有体数据大大增加了计算量.为此,提出一种在同体发动机体数据分割基础上的光线投射加速方法.该方法利用分割结果,建立分割信息体数据场,结合现...     

一种不完备粗糙集的航电设备故障诊断方法

针对已获得的航电装备测试数据中存径不完备数据的问题,在分析不完备决策表和差别矩阵属性约简的基础上,给出了一种在航电装备故障诊断中基于不完备数据获取最优诊断规则的模型,并在某型超短波抗干扰机载通信电台中应用验证,结果表明其有效性,从而为提高部队航空装备的可靠性和维修性提供了一条途径。     

CAN总线在航空领域应用的探讨

本文从Controller Area Network(CAN)总线的特点出发,通过将CAN总线与机载领域应用最成熟的1553B总线进行对比,分析了在航空领域,尤其是在航空机电系统中,局部采用CAN总线的可行性.然后从可靠性和实时性两个方面指出了CAN总线需要在机载适应性上进行的改进.最后结合国外已经发布的CANaero...