卫星姿轨控制对大型柔性索网天线在轨指向影响分析
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摘要
文章针对星载天线大尺寸、大柔性,引起卫星姿轨控时卫星本体姿态运动与柔性天线自身弹性变形相互耦合,进而导致天线指向精度下降的问题,提出了一种计算卫星姿轨控制引起的大型柔性天线在轨波束指向偏差的计算方法。首先,结合有限元法和混合坐标法,通过理论推导,建立了卫星与大型柔性索网天线刚柔耦合动力学模型;然后,以某在轨成像卫星东西位保为例,通过有限元法对该柔性索网天线进行模态分析,得到描述天线弹性振动的模态矩阵与质量矩阵,结合天线的模态矩阵、质量矩阵及天线与卫星本体的坐标转换关系,得到天线振动相对于星本体坐标系的平动耦合系数与转动耦合系数,再与星本体的刚体运动参数组合起来,求解卫星天线刚柔耦合动力学模型,即可得到天线实际振动位移。最后,根据天线实际振动位移进行天线型面拟合,并选取其最差型面进行了天线电波束指向仿真。仿真结果表明,天线方位向的波束指向偏差最大为0.0576°,可为天线在轨指向设计提供依据。该算法同样适用于卫星其他姿轨控制工况。
A method is proposed to calculate the antenna beam pointing error induced by the coupling of satellite rigid motion and antenna flexible vibration,which is caused by the big size and large flexibility of antenna. Firstly,a general rigidflexible coupling dynamic model for satellite with large flexible antenna is derived by hybrid coordinate and finite element method. Secondly,taking the east-west station-keeping control of an optical imaging satellite as an example,modal analysis of flexible antenna is done first by the finite element method,to calculate the modal matrix and mass matrix of antenna.Based on the two matrices and coordinate transformation relation between the antenna and satellite,the translational coupling coefficient and rotational coupling coefficient are obtained. Coupling coefficient,combined with satellite rigid motion parameters,the vibration displacement of antenna is calculated by solving the rigid-flexible coupling dynamic model. Finally,based on the vibration displacement of antenna,the electric beam pointing error is simulated. It can be observed that the beam pointing error in azimuth is 0. 0576°.,which may offer reference for design. The method is applicable to other control operations of satellite.
A method is proposed to calculate the antenna beam pointing error induced by the coupling of satellite rigid motion and antenna flexible vibration,which is caused by the big size and large flexibility of antenna. Firstly,a general rigidflexible coupling dynamic model for satellite with large flexible antenna is derived by hybrid coordinate and finite element method. Secondly,taking the east-west station-keeping control of an optical imaging satellite as an example,modal analysis of flexible antenna is done first by the finite element method,to calculate the modal matrix and mass matrix of antenna.Based on the two matrices and coordinate transformation relation between the antenna and satellite,the translational coupling coefficient and rotational coupling coefficient are obtained. Coupling coefficient,combined with satellite rigid motion parameters,the vibration displacement of antenna is calculated by solving the rigid-flexible coupling dynamic model. Finally,based on the vibration displacement of antenna,the electric beam pointing error is simulated. It can be observed that the beam pointing error in azimuth is 0. 0576°.,which may offer reference for design. The method is applicable to other control operations of satellite.
引文
[1]冯涛,冀有志,肖勇,等.星载环形天线结构及其应用综述[J].空间电子技术,2015,12(2):22-28.
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[6]史纪鑫,曲广吉.跟踪与数据中继卫星柔性动力学建模[J].航天控制,2007,25(1),31-35
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[8]陆毓颖,刘铸永,洪嘉振.挠性航天器系统动力学耦合特性研究[J].空间科学学报,2012,32(4):550-554.
[9]王从思,段宝岩,仇原鹰.基于最小二乘法的天线变形反射面的拟合[J].现代雷达,2004,26(10):52-55.
[2]Craig R,Bampton M C.Coupling of Substructures for Dynamic Analysis[J].AIAA,1968,6(7):1313-1319.
[3]Likins P W.Large-deformation Modal Coordinates for Non-rigid Vehicle Dynamics[D].Jet Propulsion Laboratory,TR32-1565,1972.
[4]曲广吉.航天器动力学工程[M].北京:中国科学技术出版社,2000.
[5]缪炳琪,曲广吉,夏遂勤.柔性航天器模态综合-混合坐标动力学建模[J].浙江工业大学学报,2002,30(2):139-152.
[6]史纪鑫,曲广吉.跟踪与数据中继卫星柔性动力学建模[J].航天控制,2007,25(1),31-35
[7]徐小胜,曲广吉.柔性航天器动力学模型降阶的方法和策略研究[C].中国宇航学会飞行器总体委员会2004年学术研讨会.北京,2004.
[8]陆毓颖,刘铸永,洪嘉振.挠性航天器系统动力学耦合特性研究[J].空间科学学报,2012,32(4):550-554.
[9]王从思,段宝岩,仇原鹰.基于最小二乘法的天线变形反射面的拟合[J].现代雷达,2004,26(10):52-55.