基于路段时间窗考虑备选路径的AGV路径规划

针对自动化集装箱码头基于卸箱任务的自动导引车（automated guided vehicle，AGV）路径规划问题，结合最优路径数学模型、路径搜索方法和时间窗，提出了一种基于路段时间窗的AGV路径规划方法。首先，在给AGV下派任务的基础上，用最优路径数学模型为AGV规划出最短路径；其次，用路径搜索方法搜索AGV的备选路径，在路径长度相同的情况下，按照路径中转折次数确定备选路径优先级，转折次数少的备选路径优先级高；最后，在各AGV最短路径下，设置各个路段的时间窗，时间窗无重叠则表明AGV无冲突，对于时间窗重叠的路段，采用在原路径上插入时间窗或者在备选路径上插入时间窗的方法，再进行时间窗重叠测试，若还存在重叠的，则继续调整至最终实现多AGV的无冲突路径规划。为了验证方法的有效性，以8台AGV分区同时工作为例，用实例证明所提出的路径规划方法的避碰效果。结果显示该方法能为多台同时工作的AGV规划出一条无冲突优化路径，并且用时较短；在试验中发现选择在备选路径上插入时间窗的方法效果更好。研究表明所提方法能有效实现AGV的避碰，提高AGV利用率和自动化集装箱码头的运作效率。

AGV path planning considering alternative paths based on time window of road section

To solve the problem of the automated guided vehicle (AGV) path planning based on the unloader task of automated container terminal, an AGV path planning method based on time window of road section was proposed through combining the optimal path mathematical model, path searching method and time window. First of all, the AGV with dispatched task was planned the shortest path by the optimal path mathematical model. Secondly, AGV alternative paths were selected through path searching method. When the path length was the same, the selection priority was determined by the number of turning times in the path, and the alternative path with fewer turning times had higher priority. Finally, time windows of road section were set up under AGV shortest path. If the time windows on the same road section were not overlapped, then the AGV was collision free on the path. As for the overlapped time window of road section, the time window would be inserted into the original path or the alternative path. Then time window's overlap test and adjustment continued if there still existed overlaps until the multiple AGV paths planning without time window overlap. In order to verify the validity of the method, a case of eight AGVs working simultaneously was experimented to prove that the proposed path planning method had good free-collision effect on AGVs. The results showed that this method could be used to plan a non-conflict optimization path for AGVs working simultaneously and to get the shorter time path availably. It was found that the method of insert time window on the alternative path was better. The reasearch shows that the proposed method has good free-collision effect on AGVs. Besides, it can effectively improve the efficiency of AGV utilization and automatic container terminal operation.