叶轮盖板侧的流动对离心泵泄漏量的影响

利用动量矩定理,建立了叶轮盖板中流体旋转角速度的一阶微分方程,得到了计算离心泵泄漏量的方法.为了获得泄漏量,需要进行迭代求解.从该微分方程出发,可得到容积效率、轴向力等参数.试验研究表明,用此公式计算的理论泄漏量和试验值之间的相对误差在7%～10%以内,验证了该方法的合理性和正确性.     

组合式航天器概念及构型变换最优脉冲控制

为应对多种多样的不确定性对传统航天器的挑战,提出了一种更具灵活性、可靠性的组合式航天器概念。从模块化设计、标准化接口、运行模式、空间任务构型方面对此航天器概念进行描述。它在可维护性、规模可缩放性、可重构性等性能显著增强,特别是具有根据空间任务的不同而进行构型变换的能力。并从相对运动动力学方程出发,本文针对组合式航天器空间任务构型变换,设计了给定机动时间的、以燃料消耗最少为目标的最优脉冲控制方法,生成最优脉冲序列。仿真结果表明,最优脉冲控制方法是实现组合式航天器构型变换的一种有效途径。     

陀螺随机游走对导弹自瞄准精度的影响

介绍了激光陀螺随机游走误差的基本概念和误差模型,通过理论分析、计算机仿真以及试验研究了激光陀螺随机游走误差对导弹自瞄准精度的影响,研究结果具有一定的工程应用价值.     

基于改进层次分析法对航天发射安全风险的评估

针对航天发射安全风险评估涉及因素较多和等级划分的模糊性,提出了航天发射安全风险递阶层次的评估指标体系,并利用正态分布密度函数对层次分析法确定的权重指标进行修正,使风险评估结果更加科学合理。可以为航天发射确定安全风险管控重点、优化防控措施提供重要技术支撑。     

面向可信的航空嵌入式软件开发方法框架

针对航空综合化软件的可信内涵,即可靠性、安全性和实时性,开展了开发方法的研究,提出了针对性的可信内涵模型和相应的开发过程模型,并设计了基于模型的需求分析、组件化设计以及系统配置综合的开发方法框架.在开发方法框架研究过程中,重点分析了航空综合化软件平台的特征,即因为物理资源的限制,软件任务之间存在复杂的交互、资源竞争和共享关系,并分析了这些特征对其可靠性、安全性和实时性的影响.     

Attitude stability criteria of axisymmetric solar sail

Passive attitude stability criteria of a solar sail whose membrane surface is axisymmetric are studied in this paper under a general SRP model. This paper proves that arbitrary attitude equilibrium position can be designed through adjusting the deviation between the pressure center and the mass center of the sail. The linearized method is applied to inspect analytically the stability of the equilibrium point from two different points of views. The results show that the attitude stability depends on the membrane surface shape and area. The results of simulation with full dynamic equations confirm that the two stability criteria are effective in judging the attitude stability for axisymmetric solar sail. Several possible applications of the study are also mentioned.     

The dynamical environments analysis of surface particles for different shaped asteroids

Asteroids are coming to be a popular topic in the areas of astrophysical studies and deep space exploration recently. However, surface dynamics of asteroids is still a difficult problem. This paper aims at the motion analysis of surface particles for different asteroids. The dynamical analysis method of particles’ movement is given for three parts: global motion trend, local motion trend and static analysis. A dimensionless parameter ζ is defined to distinguish the predominant term to determine the distribution of effective potential. Three kinds of common asteroids: spheroidal asteroid, spindle-shaped asteroid and dumbbell-shaped asteroid are all discussed for those three parts with different parameter ζ. The motion trend of particles on the surface of each kind of asteroid is given. The static analysis of surface particles for different asteroids is also illustrated. Based on them, some common rules for different shaped asteroids are revealed. This paper could not only provide a reference for asteroid exploration missions but also be meaningful for the research of morphologic evolution of asteroids.     

满足一等量块检定要求的接触式激光量块干涉仪

最新研制的接触式激光量块干涉仪主要用于测量一、二等量块的中心长度，其长度测量不确定度达到（0.02 0.2L)μm。文中介绍了其工作原理、测量不确定度分析，给出了量块测量的验证数据。     

Tracking considerations in selection of radar waveform for rangeand range-rate measurements

The conventional approach for tracking system design is to treat the detection and tracking subsystems as completely independent units. However, the two subsystems can be designed jointly to improve system (tracking) performance. It is known that different radar signal waveforms result in very different resolution cell shapes (for example, a rectangle versus an eccentric parallelogram) in the range/range-rate space, and that there are corresponding differences in overall tracking performance. We develop a framework for the analysis of this performance. An imperfect detection process, false alarms, target dynamics, and the matched filter sampling grid are all accounted for, using the Markov chain approach of Li and Bar-Shalom. The role of the grid is stressed, and it is seen that the measurement-extraction process from contiguous radar "hits" is very important. A number of conclusions are given, perhaps the most interesting of which is the corroboration in the new measurement space of Fitzgerald's result for delay-only (i.e., range) measurements, that a linear FM upsweep offers very good tracking performance     

大型空间环模设备总控系统工作站间的互连

本文给出了大型空间环模设备总控系统工作站间实现互连的原理和具体的实现步骤以及在实现的过程中各个部分的具体组成和实际物理含义及注意事项,并在具体实践中圆满地实现了各个工作站间的互连。