卫星刚性载荷体在轨对称摆扫特性分析
Analysis of symmetric sweep motion characteristic of satellite rigid loads
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摘要: 为实现卫星摆扫成像,降低载荷体摆动过程中对卫星姿态的影响,提出两个相同载荷体对称摆动的方案,并规划给定角度范围内的摆动规律,使载荷体在滚动轴和俯仰轴分别具有0.6()/s、6 ()/s的角速度,通过对两载荷体摆动特性及动力学、运动学特性的分析,提出以反作用飞轮对卫星偏航轴剩余力矩进行补偿控制的方法。以某卫星示例进行仿真分析,结果表明:两载荷体对称摆动过程中滚动轴和俯仰轴的合成力矩和角动量对卫星姿态无影响,而偏航轴存在周期性变化的力矩,采用0.2 Nm的飞轮进行动量补偿后得到卫星姿态指向精度和姿态稳定度可以控制在0.032、0.006()/s以内,能够实现较高精度的对地面区域摆扫成像。说明以两载荷体对称摆动的方案实现卫星摆扫成像并满足成像需求,在设计理念上是可行的。Abstract: In order to realize satellite sweep imaging and reduce the influence on satellite attitude during the process of load swing, a method of two same loads swing symmetrically was put forward. And the swing principle with angle in the given range was planned. Each load had angular velocities of 0.6()/s, 6()/s in roll and pitch axis. Through the dynamics and kinematics analysis of two loads swing motion, the proposal of satellite yaw axis extra moment compensated by reaction flywheel was raised. Then some satellite was used as an example to carry out simulation and analysis, the results showed that the mixed moment and angular momentum in roll and pitch axis had no impact on satellite attitude in the process of two loads swing symmetrically, respectively, an extra periodic moment existed in the yaw axis. 0.2 Nm reaction flywheel was used to compensate momentum, and the satellite attitude pointing accuracy and attitude stability achieved were within 0.032and 0.006()/s, which could guarantee higher accuracy on the surface area of sweep imaging. It was concluded that two symmetrical load body schemes could satisfy the demand of satellite sweep imaging and the design concept was feasible.