基于刚体转动四元数模型的航天器再定向方案

介绍了一种新的刚体转动的四元数模型。这些模型可以提高再定向控制的对边界条件的适应能力，在此基础上还介绍了这些模型的一些实际应用。     

Determination of parameters of attitude motion of a small communication satellite using the data of measurements of current of solar panels

A communication satellite (small spacecraft) injected into a geosynchronous orbit is considered. Flywheel engines are used to control the rotational spacecraft motion. The spacecraft after the emergency situation has passed into a state of uncontrolled rotation. In this case, no direct telemetric information about parameters of its rotational motion was accessible. As a result, the problem arose to determine the rotational satellite motion according to the available indirect information: current taken from the solar panels. Telemetric measurements of solar panel current obtained on the time interval of a few hours were simultaneously processed by the least squares method integrating the equations of rotational satellite motion. We present the results of processing 10 intervals of the measurement data allowing one to determine the real rotational spacecraft motion and to estimate the total angular momentum of flywheel engines.     

攻角变化对超音速进气道再起动特性的影响

以二维非定常可压缩流的N-S方程为控制方程,采用SST k-ω湍流模型对攻角变化引起的超音速进气道再起动过程进行了数值模拟,研究了攻角变化对超音速进气道再起动特性的影响.结果表明,当超音速进气道不起动时,可通过合理改变攻角实现进气道的再起动工作;超音速进气道的再起动攻角随攻角变化速率的增大近似呈线性增加;攻角变化速率较...     

多自由度微振动环境时域波形复现的数值仿真

为满足航天器微振动环境模拟的需要,开展了多自由度微振动时域波形复现控制方法研究。首先,介绍了基于时域波形复现的多自由度微振动环境模拟控制理论方法。其次,针对六自由度微振动激励系统,应用MATLAB软件建立了基于实测传递函数矩阵的多输入多输出微振动激励仿真系统,针对微振动时域波形复现闭环控制过程进行了算法编程,并给出了仿真的闭环控制流程图。最后,通过算例对多自由度微振动时域波形复现进行了数值仿真,以给定的白噪声为输入,模拟对实际存在的系统非线性、测量误差等影响因素的控制效果。仿真结果验证了多自由度微振动时域波形复现控制方法的可行性及有效性,所得结论可以为研究多自由度微振动时域波形复现控制系统提供参考。     

多通道功率放大器中幅度和相位一致性影响分析

文章利用传输矩阵方法,建立了MPA分析模型,并通过引入幅度和相位随机性,结合各路放大器幅度和相位组合概率,对通道隔离度的影响进行了计算和分析。     

Determination of an Estimation of Parameters of Motion of a Spacecraft on the Stage of Its Descent on the Basis of Integration of Inertial and Optoelectronic Navigation Systems

The problem of determining an estimation of current spacecraft motion parameters on the stage of its descent is solved on the basis of readings of an optoelectronic navigation system and additional information from the self-contained inertial navigation system at the most general assumptions on the nature of motion of the object and the statistical properties of the noise of the measuring devices.     

国际空间大学董事会主席访问航天科技集团公司

10月14日,国际空间大学董事会主席拉姆·哈迪姆访问中国航天科技集团公司,就集团公司承办国际空间大学2007年暑期进修项目的筹备情况与集团公司人力资源部部长陈学钏、副部长白燕强交换了意见。陈学钏部长向哈迪姆通报了集团公司筹备这次活动的工作进展情况。据陈部长介绍,中国     

On solving the problems of optimization of trajectories of many-revolution orbit transfers of spacecraft

The problem of optimal control over many-revolution spacecraft orbit transfers between circular coplanar orbits of satellites is considered. The spacecraft flight is controlled by a thrust vector of a jet engine with restricted thrust (JERT). The mass expenditure is minimized at a limited time of flight. The optimal control problem is solved based on the maximum principle. The boundary value problem of the maximum principle is solved numerically using the shooting method. A modified computation scheme of the shooting method is suggested (multi-point shooting), as well as a method (correlated with the scheme) of choosing the initial approximation with the use of a solution to the optimization problem in the impulse formulation. The scheme and method allow one to construct many-revolution spacecraft orbit transfers.     

热变形对一种天线指向机构指向精度的影响分析

热变形对天线指向机构的指向精度具有重要影响,但利用传统的设计方法很难实现对指向精度的准确计算,尤其是热变形对指向精度影响的研究工作更是少见。为此建立了机构的三维实体热-结构耦合有限元分析模型,根据有限元分析结果并结合机构的运动链关系,构建了各关键运动副运动误差的计算方法;在此基础上实现了机构指向误差的计算,研究了运动副名义、最大以及最小配合间隙条件下,温度载荷对各关键运动副运动误差和指向精度的影响。研究结果表明,温度载荷对关键运动副的运动误差以及机构的指向精度具有重要影响,随着温度载荷偏离常温数值的增加,指向误差不断增大,名义配合间隙条件下的指向误差最大。     

MBD技术在航天器研制中的应用探讨

概述了基于模型的定义(Model-based Definition,MBD)技术的研究和发展,分析了以MBD为载体的特征演化过程,作为航天器设计-制造一体化协同实现的基础。从MBD在航天器研制中的应用需求出发,构建了MBD协同平台框架,探讨了MBD模型成熟度管理的协同设计方法,提出了应用MBD研制模式所面临的技术、管理等问题,并给出了相应的建议。     

降落伞特性对伞舱系统运动稳定性的影响

建立了伞舱系统刚性连接和弹性连接时的数学模型,针对联盟号飞船回收系统进行了动力学仿真。分析了降落伞侧向力系数、吊带长度、降落伞和载荷质量比以及吊带性质对伞舱系统运动稳定性的影响,其结论可为伞舱回收系统的设计提供参考。     

电缆屏蔽金属网屏蔽效能的工程计算

金属网由于柔韧性好、使用方便等优势而在电缆屏蔽工程上得到广泛应用。本文对电缆用的金属网屏蔽效能进行工程计算,通过计算,对金属网不同材料、不同规格、单层与双层屏蔽及有缝隙情况下的屏蔽效能进行比较与分析,对工程应用有一定的指导意义。     

目标光学伪装效果评价方法分析

对现有伪装效果评价方法进行了简要分析,旨在形成更加科学合理的伪装效果评价方法。认为伪装效果主要表现在两个方面,一是目标本身暴露特征的降低或消除;二是目标与背景的融合程度。因此伪装效果评价也应从这两个方面进行分析。另外目标是否被发现,除了目标特征与背景特征是否一致等客观因素,还与观察判别人员的知识、经验以及分析判别能力等主观因素有关。     

塑封微电路老炼研究综述

文章介绍了塑封微电路在高可靠性领域的应用,塑封微电路可靠性研究的现状,以及塑封微电路老炼研究在塑封微电路可靠性研究中的地位。具体分析了商用塑封器件老炼当前所面临的主要问题,其中重点介绍了随着器件集成度和工艺水平的提高,元器件漏电流的增加和元器件参数差异增大是老炼研究中不可忽略的因素。针对上述问题,指出了塑封微电路老炼过程热稳定研究的迫切性,尤其对我国高可靠应用领域,并介绍了国内外相关研究现状和我国在这一领域的差距。     

Analysis of evolution of multi-orbit perturbed trajectories of a spacecraft in a central field of attraction

Properties of differential equations of multi-orbit trajectory motion of a spacecraft are investigated analytically. The spacecraft moves under the action of small perturbations (in particular, low thrust) in the plane of a central Newtonian field of attraction. The conditions are specified for existence of a partial singular aperiodic solution, in the neighborhood of which the behavior of osculating elements changes sharply. In this case, phase variables (the angular position of the pericenter and the true anomaly) are found to undergo the sharpest changes. The exact superposition of solutions is suggested for the equations of motion transformed to the form of a quasi-linear, weakly non-stationary system: a partial singular aperiodic solution and fast solutions oscillating around it. Asymptotic representations are obtained for both components of the superposition. They are fairly exact in the region of smallness of perturbing terms at a long variation of the argument.     

Results of Measurements of Accelerations of Technological Devices onboard the FotonSpacecraft

This paper generalizes the results of measuring the residual accelerations arising when investigations in space materials science are carried out onboard the unmanned Fotonspacecraft. The levels of vibroaccelerations are analyzed in the frequency band of 1–500 Hz for the technological devices UZ01, UZ04, and POLIZON, developed by the Federal Unitary State Enterprise Barmin Design Bureau of General Machine Building (V.P. Barmin KBOM). The levels of accelerations are estimated in the frequency band of 0–1 Hz in the zone of technological operations of these facilities. The basic sources of vibroaccelerations acting upon the frames of devices are determined in the capsule zone, where technological processes of producing new materials take place. In the frequency band of 1–500 Hz the vibroaccelerations are shown to be generated by the operation of Fotonspacecraft units and a drive of capsule translation during the technological process. On the capsule frame they reach the values of (1–3) × 10^–3 g. The level of linear accelerations in the infralow-frequency band is determined by rotational motions of the Fotonspacecraft. It depends on the device location with respect to the spacecraft center of mass and does not exceed (1–7) × 10^–6 gin the steady-state regime in the zone of technological activity.     

导弹折叠翼展开机构运动功能可靠性分析

通过建立等效动力模型得出导弹弹翼展开机构的运动规律，进而对弹翼展开机构进行动态静力分析。针对某型飞航导弹的折叠弹翼展开过程，对机构运动功能可靠性进行了较为全面的探讨和研究。该方法可用于 飞行器分离机构，展开机构和折叠机构等的可靠性分析。     

Application of the method of potentials in problems of fracture mechanics

The theory of generalized elastic potentials is used for solving the problem of a space with cracks of arbitrary shape. Two solutions are proposed. In the first case, the solution is represented by a double-layer potential and a functional equation for determination of the unknown density is constructed in which difficulties stipulated by high polarity of the integrand may be eliminated. The other method consists of an analysis of a space with a thin smooth cavity and the solution of corresponding singular integral equations.Methods to improve the convergence of successive approximations used in solution of the equations are described and some particular cases of three-dimensional solids are considered. A special function is introduced on the external surface of the solid, which allows consideration of a whole space with cracks having fictitious stresses on their edges; this solution has some bearing on the main problem and also provides an integral equation for the auxiliary function. Another approach consists of the elimination of cracks by introduction of corresponding potentials and solution of the auxiliary problem for a continuous solid with special boundary conditions.     

Stability of dynamic algorithms of determination of quasi-stationary satellite orbits

A method of estimating the stability of the problem of orbit determination under disturbances caused by finite accuracy of calculation and geographical siting of observation stations is proposed.