Integrated Research Of Storage Location Assignment And Task Scheduling In Automated Storage And Retrieval System

Automated warehouse plays an important role in the whole logistics process. It is mainly used in the distribution and manufacturing sectors, in order to accelerate the speed of completing tasks, to ensure supply of materials on time. It has major implications for just-in-time delivery and production.Firstly, this paper discussed the classification of the automated warehouse: traditional single-fork and multi-fork automated warehouse. During the introduction of the traditional single-fork automated warehouse, the method of calculating the time between different positions and the stacker’s ability to work was explained. And during the introduction of the traditional multi-fork automated warehouse, we described its operating methods and show the advantage of multi-fork stacker. In this paper, we combined the method of location assignment and task scheduling to improve the operating efficiency of the warehouse.Secondly, for single-fork automated warehouse, a single operating cycle contains only one pair of tasks and its operating method is simple. In this paper, we mainly introduced the methods of Nearest-Neighbor and Shortest Travel-Time for the location assignment of single-fork automated warehouse. But pure location assignment could only play a certain role in optimization, the change of task order could also minimize the operating time. So we designed four methods of combing the location assignment and task scheduling, including the global search algorithm based on NN and STT strategy and the multiple population GA based on NN and STT strategy, to solve the problem.And finally, for multi-fork automated warehouse, a single operating cycle contains several pairs of tasks. In every cycle, we not only need to do location assignment but also arrange the order of tasks, so its operating method is complex. In this paper, we designed an improved operating principle based on shelf partition mode, and then proved that it is efficient. In the end, we designed the multiple population GA based on the improved operating principle to do the integrated study of location assignment and task scheduling for the multi-fork automated warehouse.