一种基于几何分析的单轴指向磁控算法

A Geometry Approach to Single Axis Pointing Control Using Only Electromagnetic Actuation

为满足微小卫星安全模式与其它特定工作模式下的单轴指向需求,提出一种单轴指向磁控方法。该方法包含以下步骤:首先采用空间几何分析方法将指向控制转轴的选择范围扩展到一个平面内,进而在卫星角速度较小的情况下通过惯量阵仿射坐标变换获取当前磁场下可控的角加速度平面,然后在该角加速度平面内以及该平面与转轴平面交线上进行速率阻尼与转向控制,从而实现单轴精准指向。相较于传统方法,本方法的优势包括:无额外的干扰磁场力矩产生,几乎不受轨道形状制约,不要求惯量积为零。在仿真中成功实现卫星单轴对地或对日,进一步校验了该方法的正确性。

A control strategy for single axis pointing of micro-satellites is proposed which uses only magnetictorquers. This method is useful in satellites＇ safe modes and other specific situations. It contains the following steps： firstly, a geometry algorithm is utilized to extend the collection of the rotation axis to a plane, along which the current and target directions can coincide; secondly, an angle acceleration plane is found by affine transaction from the perpendicular plane of the local geomagnetic field with the satellite＇s inertial matrix; thirdly, a controller that works along the intersecting line of the rotation axis plane and the angle acceleration plane is constructed to control both the rotating direction and the speed. Compared with the existing methods, this new method has advantages such as no additional disturbance from magnetic torque, less limitation from orbit shape as well as inertia products need not to be zero. The performance of the controller is validated in simulation, in which the Sun pointing and the Earth pointing with single axis are realized.