基于Frenet和改进人工势场的在轨规避路径自主规划

在轨道间机动的航天器规避空间目标，需兼顾沿转移轨道飞行的绝对运动和规避空间目标的相对运动，路径自主规划难度较大且目前国内外公开研究成果较少。针对上述问题，提出了一种将Frenet坐标系与改进人工势场相结合的在轨规避路径自主规划方法。首先，构建Frenet坐标系表述空间规避运动，解决了路径规划中航天器与既定转移轨道相对位置不易表述的难题，实现了空间规避运动的简便表示；其次，改进人工势场函数、调整势场作用区域，避免了传统人工势场法存在过早轨迹偏离以及局部震荡现象，实现了对空间目标的自主规避；最后，考虑规避安全、轨道保持、制动时效以及燃料消耗因素构建全局优化函数，能够满足不同任务的需求与偏好，实现了沿转移轨道飞行的最小偏移与快速恢复。算法比对与算例求解表明:所提方法应用优势明显，路径平滑、偏移量小，满足航天器规避空间目标的路径规划需求。 

Autonomous planning of on-orbit evasion path based on Frenet and improved artificial potential field

In the process of evading the space target, the spacecraft should take into account the absolute motion of flight along the transfer orbit and the relative motion of evading the space target. The corresponding path automatic planning is difficult, and there are few public research results at home and abroad. In view of the above problems, a method of autonomous planning of on-orbit evasion path combining Frenet coordinate system and improved artificial potential field is proposed. Firstly, this method constructs Frenet coordinate system to express spacial evasive motion, solves the problem that the relative position of spacecraft and the given transfer orbit is not easy to express in path planning, and achieves a simple representation of spatial evasive motion. Secondly, this method improves the artificial potential field function, adjusts the area of action of the potential field, and avoids the phenomena of premature trajectory deviation and local oscillation in the traditional artificial potential field method, so as to achieve the autonomous evasion of the space target. Finally, the global optimization function is constructed by taking into account the factors of evasion safety, orbit holding, braking time and fuel consumption, which can meet the requirements and preferences of different tasks, so as to realize the minimum deviation and fast recovery of the flight along the transfer orbit. The results of algorithm comparison and numerical examples show that this method has obvious advantages in application, with smooth path and small offset, and can meet the requirements of path planning for spacecraft to evade space targets.