关键词: 过驱动卫星, 姿态控制, 反作用飞轮, 动态控制分配, 修正伪逆法

Abstract: The reaction wheels play an important role in shaping satellite attitude command. To ensure the reliability of satellite in orbit, the reaction wheels are often overactuated with more than three reaction wheels. Therefore, dynamic control allocation method based on pseudo-inverse method distributing the desired control command among the reaction wheels is proposed. But for controls constrained to operational limits, the pseudo-inverse approach yields admissible control deflections for only a small portion of the set of attainable moments. So a null-space method is used to modify the results. Under the assumption that the attitude changes smoothly when satellite is stabilized, the minimum-torque dynamic control allocation can remove the unexpected signals and reduce noise effect in attitude control by limiting the differences between current value and one-step previous value. In this way, the precision of attitude control system is improved. Finally, the proposed dynamic control allocation method is tested in removing undesired signals and reducing noise effects. The method is proved to be feasible and effective after simulation.

Key words: overactuated satellite, attitude control, reaction wheels, dynamic control allocation, modified pseudo-inverse