任意二维目标散射的复射线分析

复射线分析是处理高频电磁散射的一种有效方法，本文以分段直线及圆弧来模拟任意二维散射体，给出了散射场的复射线表达式，作为应用举例，计算了涂层二维角反射器的雷达散射截面，计算结果与实验结果吻合良好。     

薄壁高硬度精密齿形的加工工艺

某发动机节流阀齿条的结构特点是薄壁、高硬度、高精密.本文通过合理的工艺安排,对齿形加工选用特殊的加工工艺和为了保证精度设计了一套工装,加工出了满足设计图纸要求的薄壁精密齿条,并为以后加工此类零件积累了经验.     

纤维缠绕固体火箭发动机壳体大变形有限元分析与仿真软件介绍

将全拉格朗日（Ｔ．Ｌ）法用于轴对称大变形问题，并对纤维缠绕固体火箭发动机壳体进行有限元分析，在此基础上完成了纤维缠绕复合材料壳体大变形有限元分析软件的编制，对壳体的缠绕情况，有限元网格划分、应力、应变、位移等的有限元计算进行一体化仿真。     

SIMULATION OF BLEED AIR BEHAVIOR DURING AIRCRAFT IN FLIGHT BASED ON FLOWMASTER

Bleed air system is one of the most important components of air management system(AMS).It acts as transfer pipes responsible for air supply at high temperature and pressure.The thermal and flow performance of the bleed air system is a key issue for the design of AMS since the characteristics of air source have a great influence on the anti-ice system,the environmental control system and other downstream system in need of high temperature pressurized air.Based on the one-dimensional lumped parameter technology,a computer analysis model of bleed air system is developed in order to analyze the thermal and flow behaviors of the nodal points in the pipeline network.The simulation are performed with a given flight assignment using the analysis model,and the results verify that the system meets the design requirements.     

基于落点预测的高旋火箭弹弹道修正算法

高旋火箭弹的修正控制是基于等效力实现的二维弹道修正控制，由于弹体存在陀螺进动和马格努斯效应，在控制力作用下产生的附加攻角引起的升力与控制力的矢量合为等效力，其大小与方向在控制过程中不断变化，不能简单根据偏差量（修正量）的比例关系来确定控制力的方向。基于此，分析了控制力与等效力的关系，提出了一种基于弹道落点预测的控制算法。首先利用弹道落点预测模型实时预测落点与目标的偏差量，然后利用小扰动法构造偏差量对控制量的敏感系数矩阵，通过偏差量与敏感系数矩阵解算出纵、横两个方向的需用控制量。采用修正前后速度矢量的位置关系得到控制量的合矢量及其方位角，并利用控制量的合矢量与等效力计算出控制周期，在控制周期内按照等效力方位角调整控制力的方向实现对高旋火箭弹的精确控制，解决了非线性耦合问题。仿真结果表明该算法具有较高的控制精度，为工程应用提供理论依据。     

A novel signal processing approach for LEO space debris based on a fence-type space surveillance radar system

The increase in space debris can seriously threaten regular activities in the Low Earth Orbit (LEO) environment. Therefore, it is necessary to develop robust, efficient and reliable techniques to understand the potential motions of the LEO debris. In this paper, we propose a novel signal processing approach to detect and estimate the motions of LEO space debris that is based on a fence-type space surveillance radar system. Because of the sparse distribution of the orbiting debris through the fence in our observations, we formulate the signal detection and the motion parameter estimation as a sparse signal reconstruction problem with respect to an over-complete dictionary. Moreover, we propose a new scheme to reduce the size of the original over-complete dictionary without the loss of the important information. This new scheme is based on a careful analysis of the relations between the acceleration and the directions of arrival for the corresponding LEO space debris. Our simulation results show that the proposed approach can achieve extremely good performance in terms of the accuracy for detection and estimation. Furthermore, our simulation results demonstrate the robustness of the approach in scenarios with a low Signal-to-Noise Ratio (SNR) and the super-resolution properties. We hope our signal processing approach can stimulate further work on monitoring LEO space debris.     

基于ANCF的松弛绳索动力学建模与仿真

传统绝对节点坐标方法(ANCF)绳索模型是基于梁单元建立的,其不能反映纤维绳索的不可抗压和松弛特性。考虑纤维绳索初始松弛余量,给出了绳索非线性轴向应力-应变关系。绳索在松弛状态下轴向力接近于零,在张紧状态下表现出线弹性特性。在此基础上,采用绝对节点坐标方法推导了松弛绳索动力学模型。通过静力学和动力学仿真,将传统绳索模型和松弛绳索模型进行对比,结果表明:在重力及不同集中载荷作用下,松弛绳索相比于传统绳索都具有更大的变形;分析移除集中载荷后绳索的动力学响应可知,传统绳索在振动过程中始终处于张紧状态,且绳索上各点振动同步,而松弛绳索会在张紧和松弛状态之间不断转换,绳索上各点的振动存在相位差,能够更好地反映绳索在松弛状态下的动力学特性。     

Period selection for integrated controller tasks in cyber-physical systems

Performance optimization of cyber-physical systems(CPS)calls for co-design strategies that handle the issues in both computing domain and physical domain.Periods of controller tasks integrated into a uniprocessor system are related to both control performance and real-time schedulability analysis simultaneously.System performance improvement can be achieved by optimizing the periods of controller tasks.This paper extends an existing model to select task periods in real-time for CPS with fixed priority controller tasks scheduled by rate-monotonic algorithm.When all the tasks can be integrated,the analytic solution of the problem is derived by using the method of Lagrange multipliers and gradient descent method is evaluated to be suitable online.To further deal with the condition that the system is overloaded,an integrated method is proposed to select periods of tasks online by selecting a subset of tasks first and then optimizing the periods for them.Experimental results demonstrate that our method yields near-optimal result with a short running time.     

国内常用分散式数据采集器的性能介绍

介绍了三种数据采集器，并对其性能进行比较。     

计及复合材料受剪板后屈曲的薄壁结构分析

 本文提出了一种具有后屈曲复合材料受剪板的薄壁结构分析方法。假定后屈曲受剪板处于半张力场应力状态。以等效受剪板代替上述的后屈曲板,则可利用常规有限元法进行该结构分析。等效受剪板的刚度等于后屈曲复合材料受剪板的增量刚度,而后者系由余虚功原理与最小余能原理决定的。利用常规有限元法确定增量位侈,然后再根据余虚功原理求得后屈曲复合材料受剪板的应力增量和应变增量。