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柔性卫星角加速度轨迹规划与振动抑制方法 被引量:4
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作者 耿云海 侯志立 黄思萌 《宇航学报》 EI CAS CSCD 北大核心 2016年第12期1449-1456,共8页
针对柔性卫星在快速机动过程中会激发柔性附件振动的问题,提出一种通过设计角加速度轨迹来抑制振动的方法。在存在振动频率不确定性的情况下,所规划的角加速度轨迹能够将残余振动幅值抑制在指定的范围内。类比不同幂次余弦函数激发的残... 针对柔性卫星在快速机动过程中会激发柔性附件振动的问题,提出一种通过设计角加速度轨迹来抑制振动的方法。在存在振动频率不确定性的情况下,所规划的角加速度轨迹能够将残余振动幅值抑制在指定的范围内。类比不同幂次余弦函数激发的残余振动表达式,设计一种含有多个待定系数的角加速度曲线,并根据残余振动幅值对待定系数进行约束,从而求解出所有的待定系数。这种设计方法改进了余弦函数抑制低频振动需要增加较大机动时间的问题。相比输入成型方法,所规划的轨迹光滑,增加的机动时间较短,对高频振动有着更好的抑制效果。 展开更多
关键词 柔性卫星 振动抑制 轨迹规划 频率不确定性 姿态机动
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Hierarchical Cognition Cycle for Cognitive Radio Networks
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作者 WANG Jinlong FENG Shuo +2 位作者 WU Qihui ZHENG Xueqiang XU Yuhua 《China Communications》 SCIE CSCD 2015年第1期108-121,共14页
Cognitive radio(CR) can bring about remarkable improvement in spectrum utilization.Different cognition cycles have been proposed in recent years.However,most of the existing works only emphasize functional or operatio... Cognitive radio(CR) can bring about remarkable improvement in spectrum utilization.Different cognition cycles have been proposed in recent years.However,most of the existing works only emphasize functional or operational aspects of cognition cycle,regardless of other indispensable aspects and the connection between them.To deal with the emerging situation of "data rich,information vague,knowledge poor" in cognitive radio networks(CRNs),we propose the hierarchical cognition cycle(HCC) as a new transdisciplinary research field in this paper.HCC investigates a fundamental problem,which is how to manage available resources in the complex environment to meet various demands in CRN.A comprehensive theoretical framework of HCC is established in terms of the core,the essence loop,the function loop,the operation loop,and the external loop of HCC.The reduction of uncertainty in CRN is studied and several new metrics in HCC are defined.Furthermore,a few research challenges ahead are presented as well. 展开更多
关键词 cognitive radio network hierarchical cognition cycle theoretical framework UNCERTAINTY research challenge
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