带有两个飞轮的欠驱动航天器姿态稳定控制研究

Attitude Stabilization of an Underactuated Spacecraft with Two Reaction Wheels

在系统总角动量不为零的前提下,仅带两个飞轮的航天器无法实现本体系相对于惯性系三轴姿态角为零的稳定控制,而已实现的角速度稳定控制和自旋稳定控制也无法满足姿态控制任务的多样化需求。于是在系统总角动量不为零时,首次提出存在最大程度姿态稳定形式为航天器本体三轴角速度稳定,同时固连于航天器的某一特定视线轴指向任意给定惯性方向。利用一种新的姿态描述形式推导出了角速度为零时航天器的目标姿态,然后基于线性化后的系统设计了线性二次型最优控制器。数值仿真表明利用此控制器能实现所提出的姿态稳定形式,这对于无须实现本体系相对惯性系三轴姿态角为零,而只需对固连于本体的天线或相机进行惯性空间定向控制的航天器将完全满足其姿态控制要求,同时也能提高欠驱动航天器的可靠性。

Under the assumption that the total angular momentum of the system is not zero, Euler angles of the spacecraft at rest with respect to the inertial frame can not be controlled to zero when there are only two flywheels output torque. Furthermore, the angular rate stabilization and spin-axis stabilization achieved based on the assumption can not satisfy various demands of attitude control. A kind of attitude stabilization scheme to the most extent was firstly proposed, which was the spacecraft angular velocity stabilization as well as the spacecraft line-of-sight aiming at an arbitrarily given inertial direction. Then, the expected orientation of spacecraft with zero angular velocity was derived with a new attitude parameterization and LQR controller was designed based on the linearized system. The simulation results demonstrate that the LQR controller can achieve the expected attitude stabilization scheme, Which not only satisfies the attitude control demand of the spacecraft with antennae or camera, but also enhances the reliability of the underaetuated spacecraft.