参数不确定空间机械臂系统的自适应鲁棒性联合控制

本文讨论载体位置与姿态均不受控制的自由浮动空间机械臂系统的控制问题，基于增广变量法，提出当机械臂与载荷参数不确定时自由浮动空间机械臂追踪惯性空间期望轨迹的自适应棒性联合控制方法。通过仿真运算，证实了方法的有效性。     

International involvement in the US space station programme

This article considers the issues surrounding the nature and extent of involvement in the US space station initiative. The motives and objectives of US cooperation with its allies are analysed from the perspective of both the USA and its potential partners. Guidelines for the forthcoming negotiations between these parties are elaborated through a review of past experience in international space cooperation. Developing a framework for collaboration will require significant trade-offs and will have to accommodate a number of not always consistent interests.     

月球探测中通信跟踪(C&T)技术遇到的新问题

以技术成熟的GEO以下近地轨道的C&T技术为参照点,提出月球探测遇到的新问题———长时间、远距离地月转移轨道测量、环月轨道段测量和月面登陆段测量中的新问题,给出解决这些问题的合理方法。     

Future spacelift projection

In 1996 the NASA Advisory Council asked for a comprehensive look at future launch projections out to the year 2030 and beyond. In response to this request NASA sponsored a study at The Aerospace Corporation to develop long-range space transportation models for future commercial and government applications, and to analyze the design considerations and desired characteristics for future space transportation systems. Follow-ons to present space missions as well as a wide array of potential new space applications are considered in the study. This paper summarizes the space transportation system characteristics required to enable various classes of future missions. High reliability and the ability to achieve high flight rates per vehicle are shown to be key attributes for achieving more economical launch systems. Technical, economic and policy implications are also discussed.     

Some Technical Issues of an Optically Focused Small Space Debris Tracking and Cataloging System

Congressional language in the 1998 US Senate Armed Services Committee authorization bill directed ... the Secretary of the (United States) Air Force to undertake a design study of a system that could catalog and track debris down to one centimeter in size out to 1000kilometer in altitude. The US Air Force Research Laboratory, in conjunction with other US National Laboratories and the National Aeronautics and Space Administration (NASA) conducted a study that examined what technical systems and operations would be required to perform such a mission. This paper outlines the study process, details the findings, draws conclusions, and makes recommendations as to what would be needed to develop an optically based system capable of cataloging and tracking small debris in low Earth orbit.     

大型柔性空间结构的极点配置变结构主动控制

本文针对大型柔性空间结构(LFSS)的主动控制问题,提出耦合主动控制的方法。该方法不要求对象模型解耦,而以结构动力学变量作为系统状态,通过敏感器和执行机构的协调配置,对各动力学变量进行直接测量和控制。基于该方法,本文设计了LFSS的多变量极点配置变结构主动控制系统,并针对对称型两板空间站进行了仿真,取得了满意的结果。     

European spaceflight at the crossroads

Plans for Europe's future participation in space development are still under active discussion. This article offers a contribution to the debate, considering how Europe can best fulfil its own objectives. Choice of launch vehicle and its payload, as well as of other tools such as space station, re-entry vehicle, and launch site equipment are analysed. The article also discusses the purposes of space research for Europe, and the costs of a useful programme. A far-reaching European space programme still needs to be drawn up if Europe is not to lose out.     

有外力作用的多臂自由飞行空间机器人协调操作动力学特性

利用牛顿-欧拉方法分析了有外力作用时多臂自由飞行空间机器人协调操作的动力学特性。首先推导出多臂自由飞行空间机器人协调操作的机械臂关节驱动力矩和关节角速度及角加速度间的关系，其次建立了多臂自由飞行空间机器人系统的动力学方程和动力学计算模型，经仿真分析得到了在不同外力作用下多臂自由飞行空间机器人的本体的位置干扰规律，验证了有外力作用下的多臂自由飞行空间机器人的动力学特性。     

基于窄相关技术的GPS接收机多径误差分析

GPS接收机的误差受多种因素影响,多径干扰便是其中一项。特别在差分GPS地面站接收机中,更有必要研究多径误差对测量的影响。减少多径干扰的办法有两大类:一类是采用特殊天线;另一类是在接收机中采取一定的措施。文中针对第二种方法中的利用窄相关技术的GPS接收机展开分析。分析影响接收机多径误差的因素及利用窄相关技术的接收机对多径误差消除的效果,并给出仿真及分析结果。