状态X~2检验法在联邦滤波器中的应用

针对联邦滤波器的特殊性,基于残差故障统计检验原理,详细研究了状态检验法应用时存在的几个问题。由于信息分配,造成子滤波器局部估计次优,从而基于残差的故障统计检验方法不能够直接使用;针对这一问题,修正了残差方差阵的计算方法,并提出一种次优自适应补偿方法,能够有效改善局部估计次优性对故障检测灵敏度的影响。最后的仿真结果表明了研究的有效性和可行性。     

发动机隔热缸套热强度有限元分析

针对低散热发动机存在的热负荷状况,分析了非稳态导热有限元计算的特点:运用经验公式求出了发动机燃烧室部件燃气侧的传热边界条件;运用有限元法对隔热部件进行了热强度分析。计算结果表明:热负荷和热应力增大是造成隔热件可靠性降低的主要因素之一。     

Verification and validation of detonation modeling

The mathematical model used to describe the detonation multi-physics phenomenon is usually given by highly coupled nonlinear partial differential equations. Numerical simulation and the computer aided engineering (CAE) technique has become the third pillar of detonation research, along with theory and experiment, due to the detonation phenomenon is difficult to explain by the theoretical analysis, and the cost required to accredit the reliability of detonation products is very high, even some physical experiments of detonation are impossible. The numerical simulation technique can solve these complex problems in the real situation repeatedly and reduce the design cost and time stunningly. But the reliability of numerical simulation software and the serviceability of the computational result seriously hinders the extension, application and the self-restoration of the simulation software, restricts its independently innovational ability. This article deals with the physical modeling, numerical simulation, and software development of detonation in a unified way. Verification and validation and uncertainty quantification (V&V&UQ) is an important approach in ensuring the credibility of the modeling and simulation of detonation. V&V of detonation is based on our independently developed detonation multi-physics software-LAD2D. We propose the verification method based on mathematical theory and program function as well as availability of its program execution. Validation is executed by comparing with the experiment data. At last, we propose the future prospect of numerical simulation software and the CAE technique, and we also pay attention to the research direction of V&V&UQ.     

考虑落角约束与驾驶仪特性的自适应RBF空间末制导律

为使大口径舰炮制导炮弹在打击近岸机动目标的末制导段满足落角约束,现考虑自动驾驶仪动态特性,基于自适应RBF逼近网络与动态面滑模提出一种空间末制导律。构建空间弹目相对运动模型,通过带改进微分跟踪器的扩张状态观测器估计目标加速度。为零化视线角跟踪误差与视线角速率,采用自适应指数趋近律设计非奇异终端滑模动态面,并运用自适应RBF逼近网络削弱控制指令抖振。通过Lyapunov第二法证明了全系统中视线角跟踪误差与视线角速率均最终一致有界。仿真实验表明：该末制导律使制导炮弹在空间中打击具有不同机动形式的近岸目标时,均具备良好的末制导性能。     

基于多指标相似性的T/R组件剩余寿命融合预测方法

为实现对T/R组件剩余寿命的准确预测,及时掌握装备当前健康状态和提高装备维修保障水平,分析T/R组件的故障特点,筛选出反映T/R组件状态退化过程的状态监测指标,通过计算每个指标对应的剩余寿命信息和权重,得到T/R组件的剩余寿命预测结果。通过算例分析与比较,验证了预测方法的实用性与有效性。研究结果可为电子装备剩余寿命预测提供理论指导,对合理计划维修资源和提高装备战斗力具有重要意义。     

非合作目标视觉/惯导相对导航及敏感器自标定方法

利用视觉/惯导对空间非合作目标进行相对导航时,两敏感器的外参数对导航精度有较大影响。考虑到敏感器间的外参数标定复杂且耗时,提出一种利用视觉/惯导在估计相对状态过程中对其外参数进行标定的方法。该方法将视觉/惯导的外参数作为状态变量,与相对轨道运动学方程、相对姿态方程及惯导模型共同组成系统状态方程。利用该状态方程和单目视觉的观测量设计扩展卡尔曼滤波器对相对位姿、惯导偏差及视觉/惯导外参数进行估计,并通过数学仿真对该方法的有效性进行验证。仿真结果表明,该方法能够在视觉/惯导初始外参有偏差的情况下,有效估计相对位姿及惯导漂移,并对视觉/惯导外参数进行标定。     

加权模糊C均值聚类算法实现BDS三频组合观测值优选

在对BDS三频载波相位组合观测值进行误差分析的基础上,确定了优选载波相位线性组合系数的筛选标准。针对传统聚类算法在高维多频混合数据集分类中存在的不足,采用一种基于加权的模糊C均值聚类算法,通过对同一维度在不同簇上赋予不同的权重值,对传统遍历搜索法所获得的部分BDS三频载波相位组合观测值进行了优化分类选取,有效解决了传统全球导航卫星系统载波相位观测值选取方法效率低的问题,同时为多系统多频数据组合观测值系数的优化选取提供了一种新的思路。对分类结果进行分析,确定了各类组合观测量的适用范围,并结合实测数据,利用无几何层叠模糊度解算方法对优选组合进行了整周模糊度的解算,结果验证了该方法的可行性。     

Approximations for heavily loaded G/GI/n + GI queues

Motivated by applications to service systems, we develop simple engineering approximation formulas for the steady‐state performance of heavily loaded G/GI/n+GI multiserver queues, which can have non‐Poisson and nonrenewal arrivals and non‐exponential service‐time and patience‐time distributions. The formulas are based on recently established Gaussian many‐server heavy‐traffic limits in the efficiency‐driven (ED) regime, where the traffic intensity is fixed at ρ > 1, but the approximations also apply to systems in the quality‐and‐ED regime, where ρ > 1 but ρ is close to 1. Good performance across a wide range of parameters is obtained by making heuristic refinements, the main one being truncation of the queue length and waiting time approximations to nonnegative values. Simulation experiments show that the proposed approximations are effective for large‐scale queuing systems for a significant range of the traffic intensity ρ and the abandonment rate θ, roughly for ρ > 1.02 and θ > 2.0. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 187–217, 2016     

基于参数辨识的电动舵机系统健康仿真和评估

针对目前电动舵机系统故障诊断方法不能有效预测缓变故障,提出基于舵机系统模型的状态变量检测法对飞行器常用的执行机构电动舵机系统进行健康分析与仿真评估。分析电动舵机系统子系统电机本体、控制器、传动机构的常见故障,对其中反映系统性能的关键参数进行数学建模;通过对系统注入不同的健康参数得到相关故障状态下的状态变量特征,进而作为定位故障源的知识库,引入健康因子评估故障参数的变化趋势;仿真算例选择电机本体的主要物理参数电机绕组阻值和反映永磁体性能的电机力矩常数作为健康因子,通过定位知识库建立的健康因子评估算法验证了方法的可行性。     

基于状态约减的信息攻防图生成算法

针对攻防图构建中存在的状态爆炸问题,提出一种基于状态约减的攻防图生成算法。该算法在分析攻击者和目标网络特点的基础上,对独立状态节点的权限进行对比;其在保留最高权限节点的前提下,实现对低权限节点的约减,并去除冗余攻击路径。仿真实验表明算法具有计算复杂度低、能有效降低状态爆炸以及控制攻防图规模等优点。