采用单个连续小推力推力器以及反作用飞轮作为执行机构的编队卫星相对轨道与姿态耦合控制问题。采用单个连续小推力推力器时,相对轨道控制推力作用时间较长,同时在任意时刻或一段时间内推力矢量不能指向空间任意方向,且其依赖于卫星当前姿态和姿态机动能力;一些编队任务对姿态确定精度有较高要求,为了能够提供较高的姿态测量精度,星敏感器应避免对准太阳,因此姿态动力学的非凸性和非线性使得编队耦合控制问题进一步复杂化。考虑以上约束,采用高斯伪谱法把连续控制问题直接转换成离散形式非线性规划问题。最后以双星编队队形初始化最优控制为例进行数学仿真,结果表明了该方法的有效性和实用性。
The problem of the relative orbit and the attitude coupled control of the formation satellite is studied by using single body fixed low-level continuous thruster and reaction wheels. Actually, the action time of the thruster is much longer for the relative orbit control by a low-level thruster, andthe thrust vector cannot point out in any direction at a certain time or during a period of the time interval, thus, the thrust vector depends on the current attitude and its maneuverability of the satellite. In particular, the star camera cannot point out in the sun during formation maneuvering due to the high attitude determination requirement of some formation mission. The formation coupled control is a difficult prob- lem with nonlinear and non-convex attitude dynamics. Then, it is transferred as a nonlinear optimal control problem via direct transcription using the Gauss pseudo-spectral method. Examples demonstrate that the proposed method is effective for the simulated trajectory optimization of a dual-satellite formation initialization.