采用平行构型变速控制力矩陀螺群的航天器姿态控制

Spacecraft attitude control using parallel-gimbaled variable speed control moment gyros group

研究了平行构型变速控制力矩陀螺群的控制律及其在航天器姿态控制中的应用。首先建立了以变速控制力矩陀螺为执行机构的航天器姿态动力学模型,并给出了全局渐近稳定的姿态反馈控制律。将每一对框架平行的陀螺作为独立的单元控制,引入了与控制力矩陀螺的框架运动相关的动坐标系,在此基础上给出了控制力矩陀螺的一种控制律。此控制律使陀螺群在奇异状态下仍具有可控性,并且力矩误差在动坐标系的某一方向始终为零,从而利用共轴的构型特点和陀螺转子的可变速性补偿控制力矩陀螺的力矩误差,使变速控制力矩陀螺群的输出力矩与期望的力矩相等。最后以双平行构型为例,对航天器的姿态稳定控制进行了数值仿真,并给出了一种控制力矩的分配方案。仿真结果证明了控制律算法的有效性。

This paper studies the control law for parallelgimbaled variable speed control moment gyros(VSCMG) and it's application in attitude control of a spacecraft.The attitude dynamics equation of a spacecraft with VSCMG and a globally asymptotical stable attitude feedback control law is firstly presented.A pair of parallelgimbaled VSCMG is controlled as one separate unit and a rotational coordinate is introduced.Furthermore,a control law for CMGs is presented,it makes the CMGs controllable in singularity configuration,and the torque error keeps zero in one axis of the rotational coordinate.The parallelgimbaled configuration and the variable speed of rotors are used to compensate for the torque error of the CMGs to make the torque produced by VSCMG equivalent to the required torque.Finally,the numerical simulation of the attitude control of a spacecraft is implemented on the sample of a double parallelgimbaled VSCMG.A control torque distribution scheme is presented in the simulation,and the simulation results demonstrate the proposed control law to be valid.