考虑多性能参数的引信弹簧可靠性评估

弹簧作为引信中常用的储能源,是影响引信可靠性的重要零件,而引信失效会形成重大安全隐患。为了准确预估某引信弹簧贮存期间的可靠度变化,提出了一种基于修正Arrhenius模型的多元正态可靠性评估方法。以应力损失率和永久变形率作为性能参数,设计了恒定应力加速退化试验,获取弹簧在120℃、130℃、150℃和160℃下的退化数据,并采用Anderson-Darling统计量验证退化量的最优分布为正态分布。根据修正的Arrhenius方程,得到弹簧在贮存温度下的退化轨迹曲线。基于多元正态分布建立弹簧贮存可靠度模型,分析弹簧贮存期间的可靠度变化特点。通过与其他可靠度模型对比,该模型预估结果更准确,可为引信的视情维修提供依据。     

Many‐server loss models with non‐poisson time‐varying arrivals

This article proposes an approximation for the blocking probability in a many‐server loss model with a non‐Poisson time‐varying arrival process and flexible staffing (number of servers) and shows that it can be used to set staffing levels to stabilize the time‐varying blocking probability at a target level. Because the blocking probabilities necessarily change dramatically after each staffing change, we randomize the time of each staffing change about the planned time. We apply simulation to show that (i) the blocking probabilities cannot be stabilized without some form of randomization, (ii) the new staffing algorithm with randomiation can stabilize blocking probabilities at target levels and (iii) the required staffing can be quite different when the Poisson assumption is dropped. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 177–202, 2017     

基于倾斜开关曲线的小推力器姿态控制方法分析与准极限环控制方法

研究了利用小推力器进行航天器姿态控制问题。从理论上推导了在给定姿态控制精度、小推力器参数以及倾斜开关曲线参数的前提下,能够形成理想极限环控制效果的充分必要条件。对相关文献中倾斜开关曲线设计方法不能形成理想极限环的情况进行了理论分析,提出了一种新的基于倾斜开关曲线的准极限环控制方法,并推导了其控制精度。研究对于航天器应用小推力器实现高精度姿态控制具有较大的工程应用价值。     

用于纯方位目标跟踪的修正极坐标自适应卡尔曼滤波算法

针对纯方位被动目标跟踪中,直角坐标系下的扩展卡尔曼滤波器容易发散而导致滤波精度很差的问题,提出了一种修正极坐标系下的自适应卡尔曼滤波算法,对虚拟系统噪声进行估计,动态补偿模型线性化误差,对其滤波理论及算法进行了研究和仿真。仿真结果表明,该算法提高了滤波的稳定性、快速性和精确性,优于一般的扩展卡尔曼滤波算法。     

基于Theta-D次优控制器设计的相对姿轨耦合控制

针对在轨服务航天器的快速机动和姿轨协同控制的特点,研究了基于姿轨耦合一体化模型的最优控制方法。建立了包括转动和平动的六自由度相对运动耦合非线性模型,连续偏心推力矢量既可以提供位置控制力,也可以输出姿态控制转矩。利用动态模型线性化方法和θ-D构造性优化算法给出相对运动姿轨耦合最优控制问题的数值解法,同时控制服务航天器相对位置和相对姿态,使其直线逼近一个失效慢旋目标。仿真结果证明,由于在动态优化问题中采用了构造性求解,所提方法在保证相对运动稳定和动态性能的前提下计算量小,对未来应用具有一定现实意义。     

基于MVEKF的单站无源定位跟踪方法研究

单站无源定位是电子战中的一项重要技术。采用基于到达方向(DOA)和到达时间差(TOA)测量信息,可以实现固定观测站对运动辐射源的无源定位和跟踪。讨论了扩展卡尔曼滤波(EKF)及其改进形式修正协方差的扩展卡尔曼滤波(MVEKF)2种算法的原理,指出了应用场合和适用条件,并运用EKF和MVEKF对无源定位进行滤波估计。通过仿真,说明了2种算法的有效性,并验证了MVEKF对定位性能的改善。     

一阶交流电路暂态分析

以RC串联电路为例,介绍一阶线性电路交流暂态过程的基本分析方法.通过三种不同方法的比较,归纳出对于不同电路应当采取不同处理办法.     

基于非均匀线阵和修正MUSIC算法的DOA估计

研究了基于非均匀线阵的DOA估计问题。提出了利用修正MUSIC算法进行DOA估计,并设计了对称布阵方式。仿真结果表明在对称布阵非均匀线阵中使用修正MUSIC算法,空间谱分辨率高、栅瓣小,且分辨率要高于均匀线阵。本算法获得了较高的空间谱分辨率,提高了DOA估计性能。     

Establishment,simulation and verification of firepower safety control model

On a narrow warship platform, the coordinated use of shipborne weapon systems may cause firepower conflicts, which seriously endangers the ship safety. Meanwhile, with directed-energy weapons mounted on ships, firepower conflicts between weapons become a “high probability event”. Aiming at the problem of firepower safety control, based on the research about the collision probability model of air crafts and space targets and according to the cone of fire model of conventional weapons and directed-energy weapons, this paper solved the firepower conflict probabilities between conventional weapons as well as between conventional weapons and directed-energy weapons respectively using the methods of probability theory, and established the firepower safety control model. Then the calculation of firepower conflict probability was carried out using the dimensionality reduction method based on the equivalent conversion of polar coordinates and the power series method based on Laplace transform. The simulation results revealed that the proposed model and calculation methods are effective and reliable, which can provide theoretical basis and technical support for resolution of firepower conflicts between weapons.     

含软判决引导的修正恒模盲均衡算法

在CMA算法基础上,提出了一种混合的修正恒模盲均衡算法MCMA SDD。新算法对CMA算法进行修正,同时引入软判决思想。理论分析和计算机模拟表明,该算法克服了CMA收敛速度慢、稳态误差大的缺点,同时可以纠正相位偏转。与CMA SDD算法相比,具有更快的收敛速度和更低的稳态均方误差。