Abstract: Multi-load Automated Guided Vehicle (AGV) has high vehicular transportation capacity and dispatching operation flexibility,but its changing length brings about great difficulty to traffic control.To deliver various materials to different workstations of a production line in time,traffic control of a multi-load AGV system was addressed.Two motion conflicts that were different from a unit-load AGV system were analyzed.A path-space conflict avoidance method was designed for a variable-length multi-load AGV.Moreover,the influence of its changing length to the deadlock of a blocked path-loop was investigated.An intersection-access sequence optimization approach with deadlock prevention was proposed.A synthetic bid-price model was formulated in terms of AGV urgency degree and traffic load balance.A multi-load AGV deadlock prediction and prevention technique was developed for the blocked loop related to a target path that the bid winner AGV would enter.The results of simulation test showed that the priority to access an intersection was allocated to AGV with a high task urgency degree by means of the proposed approach,which could mitigate the traffic congestion on paths related to the intersection,and prevent loop deadlocks for a high-density AGV system.Consequently,task punctuality was improved significantly for material delivery in a production line.

Key words: automated guided vehicle, traffic control, access control, deadlock prevention, collision avoidance

摘要： 多载量自动导引车(AGV)具有更高的单车运输能力和更强的配送作业柔性,然而其长度不断变化的特点也加大了交通管控的难度。为保证生产线多种物料准时配送,研究了多载量AGV系统的交通管控问题。首先分析了与单载量AGV差异较大的两种运动冲突：针对多载量AGV变长特性,设计了一种变长度AGV路径空间冲突避免方法;针对交叉路口冲突,考虑到多载量AGV变长特性对阻塞环路死锁的影响,提出一种带防死锁策略的交叉路口通行顺序优化方法。根据AGV紧迫度和交通负荷均衡度构建了综合竞标价模型,并对获标AGV即将进入的目标路径段的阻塞环路进行死锁预测与避免。仿真实验结果表明,所提方法可保证任务紧迫度高的AGV优先通过,降低路口相关路径段的交通拥堵,并避免高密度AGV系统的环路死锁,从而提高生产线物料配送的任务准时率。

关键词: 自动导引车, 交通管控, 通行控制, 防死锁, 避碰