基于动态数据建模的机载火控系统精度测定

现代时间序列分析方法是解决最优滤波问题的不同于Wiener滤波和Kalman滤波的方法,其基本分析方法是ARMA新息模型。而构造ARMA新息模型可归结为求MA参数。介绍了基于动态数据建模确定观测信(?)模型参数的方法,并利用某型机载火控雷达的实测数据进行系统精度测定,结果显示出快速收敛性。     

刚架结构的优化设计方法

 本文利用优化准则法解刚架结构优化设计问题,可以处理工程上常用的宽缘工字梁型剖面结构在应力、位移、板局部稳定性和几何约束条件下的最小重量设计。为保证迭代过程的收敛性质和解的可行性,建立了一种新的射线步。算例结果表明本方法是相当有效的。     

飞机飞行操纵优化研究

从战术飞行管理系统角度出发,在RJ—Ⅱ工程飞行模拟器的基础上,通过在模拟器座舱内安装的最优控制仪表及与其匹配的优化轨迹生成应用软件的设计,对飞机飞行的操纵优化进行了重点的探讨。     

国产民用运输类飞机障碍物限重计算模型优化研究

航空公司使用多年的某国产民用飞机性能软件,在障碍物限重计算准确性方面虽能获得较满意的结果,但计算时间较长。分析该软件所用计算模型计算效率较低的原因,通过对比采用最小改平高和采用最大改平高两种模型的计算结果和计算效率,建立优化模型,计算不同障碍物、不同风速条件下,优化模型与原模型的障碍物限重、改平高度和计算时间,并进行比较分析。结果表明：两种模型的障碍物限重和改平高度计算结果基本相同;无障碍物时,不论有风无风,采用最小改平高的优化模型相对采用最大改平高的原模型均可减少计算时间25%;有障碍物时,无风情况下,采用最小改平高的优化模型可减少计算时间78% 以上,有风时,则可减少计算时间75% 以上。采用最小改平高的模型可以兼顾准确性和高效性。     

Optimal predictive sliding-mode guidance law for intercepting near-space hypersonic maneuvering target

The design of optimal guidance law for intercepting a near-space hypersonic maneuvering target with bounded inputs is considered. Firstly, a maneuvering model for near-space hypersonic aircraft is given. Then, the aircraft acceleration prediction can be obtained using this model with two neural networks. By using the target acceleration prediction, which is taken into account when calculating the Zero Effort Miss(ZEM), an optimal sliding-mode guidance law is proposed to fulfill the guidance task...     

A unified formulation of optimal guidance-to-collision law for accelerating and decelerating targets

This paper provides a unified formulation of optimal guidance-to-collision law for a target with an arbitrary acceleration or deceleration. The collision course for general target acceleration or deceleration is first determined from the engagement geometry in conjunction with the nonlinear engagement kinematics in the proposed approach. The heading error defined in the collision course is then adopted as a variable to be nullified for accomplishing the intercept condition.The proposed guidance ...     

Optimal control in the east/west station-keeping manoeuvres for geostationary satellites

This paper addresses the optimal computation in terms of fuel consumption of the sequentially required tangential correction manoeuvres to control geostationary satellites within the longitude band. In fact, by using optimal control techniques, the Sun pointing perigee strategy (which only determines the best time of the day for the tangential manoeuvres) is formulated as a nonlinear programming problem with inequality constraints so that the proposed approach provides an optimal way to determine the remaining parameters for the station keeping, i.e., the time interval between successive corrections and the value for the eccentricity control to totally optimize the computation. Furthermore, by minimizing a cost function derived for the total manoeuvres sizes required in a year, a numerical simulation is performed to illustrate this approach. The computation shows how geostationary mission lifetimes may be extended up to half a year or more.

Resumen

En este papel se trata el cálculo óptimo en términos de consumo de fuel de las maniobras tangenciales periódicas necesarias para controlar satélites geoestacionarios dentro de la banda en longitud. En concreto, utilizando técnicas de control optimal, la estrategia perigeo hacia el Sol (que solo determina la mejor hora del día para las maniobras tangenciales) se formula como un problema de programación no lineal con constreñimientos, de tal forma que el tratamiento propuesto proporciona una forma óptima de determinar los parámetros restantes para el mantenimiento en estación, esto es, el intervalo de tiempo entre dos correciones sucesivas y el valor para el control de excentricidad para optimizar totalmente el cálculo. Además, mediante la minimización de una función de coste obtenida para todas las maniobras necesarias en un año, se realiza una simulación numérica para ilustrar esta metodología. Los cálculos muestran cómo se puede extender el tiempo de vida de una misión geostacionaria hasta medio año o más.     

布雷顿和卡诺热机循环性能比较(Ⅰ)定常态流恒温热源循环

研究定常态恒温热源热机循环性能，导出内可逆卡诺热机和布雷顿热机的最佳功率、效率关系和最大功率及相应的效率界限，并对这两种热机循环的最优性能进行了比较。理论分析表明，只有当工质的热容率趋于无穷大时，布雷顿循环才能达到卡诺循环的性能。数值计算显示，当布雷顿循环的工质热容率为高、低温侧换热器的热导率总量的1．5倍时，布雷顿循环的功率已为卡诺循环功率的99％以上。     

Optimal terminal guidance for exoatmospheric interception

In this study, two optimal terminal guidance (OTG) laws, one of which takes into account the final velocity vector constraint, are developed for exoatmospheric interception using optimal control theory. In exoatmospheric interception, because the proposed guidance laws give full consideration to the effect of gravity, they consume much less fuel than the traditional guidance laws while requiring a light computational load. In the development of the guidance laws, a unified optimal guidance problem is put forward, where the final velocity vector constraint can be consid-ered or neglected by properly adjusting a parameter in the cost function. To make this problem ana-lytically solvable, a linear model is used to approximate the gravity difference, the difference of the gravitational accelerations of the target and interceptor. Additionally, an example is provided to show that some achievements of this study can be used to significantly improve the fuel efficiency of the pulsed guidance employed by the interceptor whose divert thrust level is fixed.     

基于可拓学的武器装备体系效能评估

文章以武器装备体系(Weapon System-of-Systems,WSoS)发展论证需求为牵引,结合现代战争复杂电磁环境下武器装备体系特点,综合考虑武器装备体系效能评估方法,采用我国原创的可拓学理论,从定性与定量两个角度对武器装备体系效能进行评估,结合层次分析法、Delphi法,建立武器装备体系效能评估模型,利用Matlab进行实例仿真实验,表明该方法能够根据隶属等级对武器装备体系效能进行评估,并可分析得出二级指标的弱项,对各指标的优化具有指导作用。