A multi-stage regulation strategy of space manipulators with a free-swinging joint failure

To ensure tasks can be completed after a free-swinging joint failure occurs, a multi-stage regulation strategy of space manipulators is proposed. Considering all terms of the dynamics equation, an evaluation model of the regulation ability (EMRA) of active joints over the fault joint is established based on the fuzzy entropy. And then a multi-stage regulation strategy based on the EMRA is designed to regulate the fault joint. The strategy divides the regulation process into several stages, and select a certain active joint to regulative the fault joint in every stage. With this multi-stage regulation strategy, the fault joint can be regulated to the desired angle without huge torque on regulative joints. The simulation is carried out with a 7-DOF space manipulator, verifying the correctness and effectiveness of the multi-stage regulation strategy. The strategy has three advantages: Coriolis and centrifugal terms are both considered for the first time in selecting the regulative joint, making the selection result more in line with the actual regulation process; The influence of the model uncertainty is eliminated in establishing the EMRA, making the evaluation of regulative ability more precise; The fault joint is successfully regulated to the desired angle without huge torque on regulative joints.     

一种卫星间跟瞄方向的控制策略与实现

进行自由空间的光通信或空间对抗，需要在卫星间实现精确的跟踪与瞄准。因为地面测控站的设置非常有限，指令与数据注入的范围受到很多限制，所以要求这种跟瞄在很多时候是无主控制状态下完成的。提出了一种利用在地面测控站的范围内向星上数管中心注入目标卫星、本体卫星的轨道参数，其它时间依靠自主导航飞行和GPS修正的方法，结合本体星的姿态测量、振动测量实现卫星瞄准指向的方位角与俯仰角的精确控制的方法，提高了在地面站无法注入指令与数据时卫星的捕获概率。通过仿真，将计算结果与卫星仿真工具软件STK的数据进行比较，结果一致。最后在嵌入式DSP平台上实现了这一策略。     

求解含多个右端向量非对称线性方程组的自适应块拟最小残量IOM(q)算法

许多实际应用问题需要求解含多个右端向量的大型非对称线性方程组 ,通常是把原来方程组分成单独几个含一个右端向量的方程组 ,再用某种迭代法分别单个求解 ,而更加经济有效的方法是应用能同时产生几个迭代向量的块迭代法来直接求解。本文在 IOM(q)算法的基础上 ,提出一种求解此类方程组的块拟最小残量 IOM(q)算法 ,讨论了如何收缩掉已收敛的部分方程组以及如何从产生的块 Krylov序列中删除线性相关或几乎线性相关向量的自适应技术。数值试验表明 ,此新的自适应块算法比块 GMRES算法及其他相关算法具有更好的收敛行为、更少的计算量和 CPU计算时间 ,是求解此类方程组的一种更加经济有效的算法。     

错位与缺失

性权利是人类自然权利和社会权利的集合体,大学生拥有性权利是无可辩驳的事实。分析部分大学生漠视性隐私权、性教育权,只关注性自由权、性快乐权和自主选择权的原因,会发现其性价值观的错位和义务观的缺失是主要根源,加之媒体的不当报道也起到了推波助澜的作用。这样的现实要求我们必须加强大学生性权利的伦理教育以及性权利与性义务的对等教育。     

Digital Aircraft Sheet Metal Part Manufacturing System and Its Key Technology

The architecture of digital sheet metal manufacturing system is proposed based on the classification of sheet metal manufacturing information.The essence of digital manufacturing is the definition,management and transfer of information,and the key technologies are brought forward and described.It is pointed out that knowledge-based manufacturing elements design is necessary to make digital technology efficient.The management of all kinds of sheet metal manufacturing element information is to build single source of manufacturing data.Multi-state model-based digital transfer and coordination method is designed to provide a foundation for digital manufacturing of aircraft sheet metal part.The application of digital sheet metal manufacturing is exemplified with an aircraft sheet metal part.The application result is compared to that of the traditional analog transfer technology.It is shown that the developed technology can improve part quality,shorten manufacturing time and lower manufacturing cost.     

培育企业核心竞争能力途径探讨

以互联网为基础的信息时代改变了传统的竞争模式。本文提出以学习型组织的建立、品牌创造、专有核心技术的掌握等方式整合企业资源，是企业培育核心竞争能力的有效途径，指出中国企业在加入WTO临近之时要重新审视自己，培育自己的核心竞争能力，创造持续的竞争优势。     

区域开发战略目标定量研究--兼论区域开发战略目标矛盾的协调

文章在回顾我国区域开发战略的基础上,结合我国区域经济发展现状,利用层次分析法建立了区域开发战略模型.通过定量研究,得出了我国区域经济发展必须以社会公平为主目标,同时兼顾效率和可持续发展目标.     

滑阀稳态液动力的计算和分析

以液氧/煤油补燃循环火箭发动机中流量调节器中滑阀为例,介绍了滑阀稳态液动力的一种计算方法,分析了不同结构参数下稳态液动力的变化规律,得出了滑阀的稳态液动力与滑阀位移、液流出口处的流道形状以及刃边厚度关系的一些初步结论。     

水洞动态测力和流动显示一体化实验技术

研制能够用于低速水流中的三分量内式测力天平,结合氢气泡(或染色液)方法,在水洞(槽)中实现测力和流动显示实验同步进行的动态实验系统,克服了通常测力和流动显示分别在风洞和水洞中进行,实验条件不同给结果分析带来的困难。天平采用高精度位移传感器,避开传统的应变片技术应用于水中所遇到的技术困难。简易飞行器模型的静态和等速俯仰实验结果表明了测量系统的可靠性。