中文摘要：

考虑带可控机械臂绳系卫星的面内运动，研究其释放阶段的子星位置和姿态控制问题．系绳释放时，通过调整机械臂转角实现子星姿态的无动量轮控制．控制律设计分为两步：首先，基于非线性最优控制理论，研究在状态和控制约束下的子星位置及其姿态控制，通过二阶Legendre伪谱法求解开环最优控制律；其次，以开环解为参考，基于轨迹跟踪思想设计反馈控制器，其中反馈控制增益由开环最优控制算法及数值插值确定．最后通过算例研究验证了该方法的有效性．

英文摘要：

The paper presents an investigation on the position and attitude control problem concerning the in- plane motions of a tethered sub-satellite, the attitude of which is controlled by using a controllable arm instead of momentum-wheel actuation in the phase of tether deployment. There are two main steps in the design of the controller. Firstly, a study accounting for the state-control constraints is presented on the nonlinear optimM control problems of the position and attitude of the sub-satellite, the open-loop solution of which is determined by using the Legendre pseudo-spectrM algorithm in the second-order form. Secondly, a feedback control law is derived to track the reference trajectory prescribed by the open-loop control law, and the gains of online feedback control are determined by interpolating a open-loop optimal control. The case studies in the strategy sequence of gain data pre-computed via the Mgorithm of paper well demonstrate the performance of the proposed