逼近无控旋转目标航天器的混合势函数安全制导

研究了追踪航天器逼近无控旋转目标航天器的安全制导问题，逼近过程中，追踪航天器需要躲避空间中的障碍物，同时需要避免与目标航天器的太阳能电池帆板和天线等附件发生碰撞。建立了视线坐标系下的两航天器间的相对运动方程，采用四元数描述目标航天器的姿态运动。将参考位置设为引力源，设计了吸引势函数。针对安全逼近问题，建立了球面安全区和锥面安全走廊，设计了安全势函数。将障碍物假设为具有一定半径的球体，设计了障碍物势函数。吸引势函数、安全势函数和障碍物势函数一起组成了混合势函数。为了解决整个势场中除参考位置外还可能存在其他局部极小点问题，对混合势函数进行了修正，保证参考位置位于混合势函数的最低点。利用Lyapunov稳定性理论对混合势函数进行了稳定性分析，推得符合要求的控制加速度，使追踪航天器沿着混合势函数的负梯度方向逼近无控旋转目标航天器。最后通过数值仿真验证了该方法的有效性。

Hybrid potential function safety guidance for approaching uncontrolled rotating target spacecraft

The safety guidance of the chaser spacecraft approaching the uncontrolled rotating target spacecraft is studied in this paper. During the approach, the chaser spacecraft needs to avoid obstacles in the space and avoid collisions with accessories such as the solar panels and antennas of the target spacecraft. The relative motion equation between two spacecraft under the line of the sight coordinate system is established. The quaternion is used to describe the attitude motion of the target spacecraft. The attraction potential function is designed by setting the reference position as the gravitational source. To ensure safe approaching, the spherical safety zone and the cone safety corridor are designed, and the safety potential function is designed. The obstacle is assumed to be a sphere with a certain radius, and the obstacle potential function is designed. The attraction potential function, the safety potential function, and the obstacle potential function constitute a hybrid potential function. In order to solve the problem that there may be other local minima in the whole potential field besides the reference position, the hybrid potential function is modified to ensure that the reference position is at the lowest point of the hybrid potential function. The stability of the hybrid potential function is analyzed by Lyapunov stability theory, and the required control acceleration is derived, which makes the chaser approaches the uncontrolled rotation target spacecraft along the negative gradient of the hybrid potential function. Finally, the effectiveness of this method is verified by numerical simulation.