基于碰撞检测的自适应阻抗控制机械臂系统(英文)

针对柔性关节机械臂,本文阐述了机械臂能够像人手一样安全操作的方法。3种方法相结合,以便机械臂能够柔顺的接触操作对象并控制接触力在预设定范围内。首先,提出采用虚拟分解法的笛卡尔阻抗控制用来实现机械臂在笛卡尔空间的柔顺控制。其次,引入自适应关节动态补偿器使得机械臂能够实施更为精确的控制。最后,设计了基于笛卡尔力反馈的实时路径规划,从而使机械臂能够检测碰撞并控制接触力。基于碰撞检测的自适应阻抗控制器能够简化其在机械臂上的实施,保持机械臂对环境的友好操作,并且严格满足系统的全局稳定性。实验在4自由度的卫星在轨自维护机械臂平台得以验证。碰撞检测实验和轨迹跟踪实验结果证明了所提出方法的有效性和可行性。     

基于案例推理的机场应急预案管理

为提高机场应急处置能力,提出一种新的基于案例推理方法的机场应急救援模型。利用XML技术来表示案例和构造预案库,给出机场应急预案库的分类方法,构建预案特征属性的层次结构。采用两两比较打分法确定航空器紧急事件预案特征属性的权重．运用最邻近算法对已有救援案例进行检索与匹配。实例证明该方法能有效提高机场应急救援效率,检索结果客观合理。     

交变电场清除介电颗粒的作用

电帘除尘被认为是最有可能在深空探测中应用的除尘方法之一. 利用电动力学基本理论分析了平行电极清除颗粒的条件, 引入克服范德瓦尔斯力对颗粒运动影响的临界悬浮电压判据, 并获得了该除尘临界电压与交流电频率之间的关系. 理论计算和实验结果表明, 在频率较低和较高的情况下, 临界电压取决于不同的物理机制.      

Dynamic and figure parameters of Venus and Mars

Parameters of the best-fitting tri-axial ellipsoids representing external equipotential surfaces of Venus and Mars have been determined from satellite data. The dynamic consequence of the equatorial flattening of Venus has been discussed from the point of view of the s.c. synodic resonance rotation. The major gravitational anomalies of Venus have been interpreted, space locations and magnitudes of anomalous masses determined and their contribution to the second zonal Stokes' constant in the gravitational potential computed. The conclusions were done: The figure of the aphroditoid is strange even if there is a relatively small polar flattening; an equatorial “disc” of Venus is enormous. Recent space data do not support hypothesis that the Earth controls the spin of Venus.     

Global Muon Detector Network Used for Space Weather Applications

In this work, we summarize the development and current status of the Global Muon Detector Network (GMDN). The GMDN started in 1992 with only two muon detectors. It has consisted of four detectors since the Kuwait-city muon hodoscope detector was installed in March 2006. The present network has a total of 60 directional channels with an improved coverage of the sunward Interplanetary Magnetic Field (IMF) orientation, making it possible to continuously monitor cosmic ray precursors of geomagnetic storms. The data analysis methods developed also permit precise calculation of the three dimensional cosmic ray anisotropy on an hourly basis free from the atmospheric temperature effect and analysis of the cosmic ray precursors free from the diurnal anisotropy of the cosmic ray intensity.