利用变速控制力矩陀螺的航天器集成能量与姿态控制

Integrated Power and Attitude Control of Spacecraft using Variable Speed Control Moment Gyros

利用变速控制力矩陀螺(VSCMG)的航天器姿态与能量一体化控制问题。针对以VSCMG为姿态控制执行机构的刚体航天器设计了全局渐近稳定的姿态跟踪控制律。将VSCMG的框架角速度和转子角加速度作为控制输入向量设计操纵律。利用加权的最小范数解得到VSCMG的姿态控制输入向量,并用与之正交的控制输入向量来以给定的功率存储/释放能量。提出了同时表征力矩陀螺模式构型奇异和转子轮速平衡的混合指标函数。对控制自由度有冗余的系统,在混合指标函数的基础上利用梯度法构建了VSCMG的空转运动,以回避力矩陀螺模式的构型奇异,并同时减小转子转速差过大引起的转速饱和以及VSCMG零奇异的可能性。利用反馈转子动能的方法规划日照期间的储能功率,以维持系统长时间工作的能量平衡。基于某太阳同步轨道卫星的数值仿真结果验证了系统的有效性。

This paper studies the integrated power and attitude control of a spacecraft using variable speed control moment gyros （VSCMG）. A globally asymptotically stable control law for attitude tracking is designed for a rigid body spacecraft with VSCMG as attitude control actuator. The angular velocities of gimbals and the angular accelerations of rotors are treated as a control input vector in the steering law design. A weighting minimum norm solution is applied to determine the attitude control vector of the VSCMG, while an input vector which is orthogonal to the attitude control vector is used to store/release energy based on given power. A hybrid cost function symbolizing both CMG singularity and wheel speed equalization is constructed. For a redun dant system, the null motion of the VSCMG is designed using the gradient method based on the hybrid cost function. The null motion is employed to avoid the singularity in CMG mode, as well as to reduce the possibility of rotor speed saturation and VSCMG zero singularity due to large differences among the rotor spin rates. The energy storage power during sunlight is programmed using kinetic energy feedback to keep long-term ener gy balance. Numerical simulation results based on a sun synchronous satellite demonstrate the validity of the system.