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浏览/检索结果: 共2条，第1-2条 帮助 限定条件 专题：长春光学精密机械与物理研究所    第一署名单位    第一作者单位    通讯作者单位     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 Analysis of inertia dyadic uncertainty for small agile satellite with control moment gyros (EI CONFERENCE) 会议论文 2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010, August 4, 2010 - August 7, 2010, Xi'an, China Sun Z.; Zhang L.; Jin G.; Yang X. 收藏  |  浏览/下载：12/0  |  提交时间：2013/03/25 With the increasing demands for the agility of the next earth imaging satellite  control moment gyro (CMG) is considered to be the most suitable actuator because of its torque amplification capability. However  a CMG system may introduce uncertainty of inertia dyadic to a satellite's attitude control system. The uncertainty is negligible for large space vehicles  but it has not been tested whether it can be ignored for small agile satellites. How to model the CMG system inertia dyadic varying with gimbal angles  and what influence it will put on the performance of attitude control system haven't been test accurately as well. All of them are dealt with mathematically and accurately in this paper. This paper firstly gives mathematic descriptions of the inertia dyadic of the 4-CMG pyramid configuration system  varying with gimbal angles  and then designs a variable structure control law for small agile satellite using CMGs. Finally  numerical simulation suggests that the inertia dyadic variation of a 4-CMG pyramid configuration system is approximately centesimal of the total inertia dyadic of the satellite  and that the designed variable structure control law is of good robust performance for an example of large-angle attitude maneuver  despite of the variation of the inertia dyadic. 2010 IEEE.   Design of optical elements for imaging the earth's plasmasphere (EI CONFERENCE) 会议论文 International Symposium on Photoelectronic Detection and Imaging, ISPDI 2007: Optoelectronic System Design, Manufacturing, and Testings, September 9, 2007 - September 12, 2007, Beijing, China Wang L.-H.; Wang X.-K.; Chen B. 收藏  |  浏览/下载：22/0  |  提交时间：2013/03/25 Studying the distribution of He+ in Earth's plasmasphere by detecting its resonantly-scattered emission at 304A will record the structure and dynamics of the cold plasma in Earth's plasmasphere on a global scale. EUV imaging systems usually utilizes near normal incidence optics including multilayer mirror and filter. In this paper  the space condition of the Earth's plasmasphere to confirm the expected performance of mirror and filter for this task were analyzed and some guidelines for the design of the optical elements were introduced. In order to achieve higher response at 304A and reduce 584A radiation for the optical system  a new multilayer coating of Mo/Si with UOx (x=2-3) was developed  and it is indicated that promising filter material is Al/C with a nickel mesh. In addition  we compute the reflectance of multilayer mirror based on optical constants and the transmission of the filter based on atomic scattering factor. The results show the multilayer mirror has high reflectance of 26.27% at 304 Aand low reflectance of 0.60% at 584A. Finally  the conversion efficiency of mirror coupled with filter is 6.88% at 304A and 0.01% at 584 A.