摘要：

在限定场景内, 无人转运车辆在路径规划过程中不能与周围障碍物保持安全距离, 导致发生车辆与障碍物发生剐蹭的问题, 提出基于混合A^*算法和修正RS曲线融合的路径规划。首先, 将提出的基于KD-Tree算法的距离代价函数加入到混合A^*算法的代价函数中。其次, 改变混合A^*算法的扩展策略, 根据车辆周围环境动态改变节点扩展距离, 实现节点的动态扩展, 提高算法的节点搜索效率。最后, 改进混合A^*算法的RS曲线生成机制, 使生成的RS曲线直线部分与周围障碍物边界保持平行, 从而符合厂区内道路行驶要求, 通过对局部路径进行平滑处理, 在保证路径符合车辆运动学约束的条件下满足路径曲率变化的连续性, 从而提高生成路径的质量。实验结果表明, 与传统算法相比, 提出算法的搜索时间缩短了38.06%, 最大曲率减少了25.2%, 路径到障碍物的最近距离增加了51.3%, 有效提高了混合A^*算法生成路径的质量, 并能较好地在限定场景中运行。

关键词: 限定场景, 路径规划, KD-Tree算法, 混合A^*算法, RS曲线

Abstract:

This paper proposes a path-planning method based on hybrid A^* and modified RS curve fusion to address the issue of unmanned transfer vehicles in limited scenarios being unable to maintain a safe distance from surrounding obstacles during path planning, resulting in collisions between vehicles and obstacles. First, a distance cost function based on the KD Tree algorithm is proposed and added to the cost function of the hybrid A^* algorithm. Second, the expansion strategy of the hybrid A^* algorithm is changed by dynamically changing the node expansion distance based on the surrounding environment of the vehicle, achieving dynamic node expansion and improving the algorithm's node search efficiency. Finally, the RS curve generation mechanism of the hybrid A^* algorithm is improved to make the straight part of the generated RS curve parallel to the boundary of the surrounding obstacles to meet the requirements of road driving in the plant area. Subsequently, the local path is smoothed to ensure that it meets the continuity of path curvature changes under the conditions of vehicle kinematics constraints to improve the quality of the generated path. The experimental results show that, compared with traditional algorithms, the proposed algorithm reduces the search time by 38.06%, reduces the maximum curvature by 25.2%, and increases the closest distance from the path to the obstacle by 51.3%. Thus, the proposed method effectively improves the quality of path generation of the hybrid A^* algorithm and can operate well in limited scenarios.

Key words: limited scenarios, path planning, KD-Tree algorithm, hybrid A^* algorithm, RS curve