复杂环境下翼伞系统的组合式航迹规划

传统翼伞系统的航迹规划主要考虑落点精度及逆风着陆等指标，而当空投区域环境较为复杂，在翼伞系统归航路径上存在障碍时，如何规避这些障碍也成为翼伞系统航迹规划所必须要考虑的因素。针对翼伞空投过程有可能遇到高山或者高大建筑物阻碍的问题，提出了一种复杂环境下翼伞系统的组合式航迹规划策略。该方法将翼伞空投的区域分为障碍区和着陆区，在障碍区中采用快速搜索随机树（RRT）算法进行可行路径搜索，考虑到RRT算法生成的轨迹包含棱角，导致路径不够平滑的问题，结合翼伞系统质点模型的运动特性，对其进行了适用性改进，以使规划的航迹满足实际翼伞空投需求。为了解决RRT算法搜索方向随机，难以满足逆风着陆的问题，当翼伞系统进入着陆区后采用分段归航的方式设计航迹，并借助遗传算法（GA）求解目标参数，实现翼伞系统能量控制及逆风着陆。提出的复杂环境下翼伞系统的组合式航迹规划策略求解速度较快，能够同时满足翼伞系统避障、能量控制及逆风着陆要求，得到的参考航迹较为平滑。

Combined trajectory planning of parafoil systems in complex environments

Traditional trajectory planning of parafoil systems mainly considers indicators such as landing accuracy and headwind landing. When the environment of the airdrop area is complicated with obstacles in the homing path of the parafoil system, obstacle avoidance has to be considered. Aiming at the problem that the parafoil airdrop process may encounter obstacles of mountains or tall buildings, this paper proposes a combined trajectory planning strategy for parafoil systems in complex environments. This method divides the parafoil airdrop area into an obstacle area and a landing area. In the obstacle area, the Rapid exploration Random Tree (RRT) algorithm is adopted to search for a feasible path. Since the RRT algorithm may cause edges and corners in the trajectory planning, it has been improved to meet the actual requirements of the parafoil airdrop by combining the characteristics of the parafoil model. The random search direction of the RRT algorithm makes it difficult to meet the requirements of headwind landing and the energy control of a parafoil system. Therefore, the multiphase homing is employed to design the trajectory in the landing area. The parafoil system energy control and headwind landing are realized by the Genetic Algorithm (GA) to solve the target parameters. The combined trajectory planning strategy for parafoil systems proposed in this paper can be solved quickly, and can simultaneously meet the requirements of parafoil system obstacle avoidance, energy control and headwind landing, obtaining a relatively smooth reference trajectory.