Research on Scheduling Optimization of Multi-layer Four-way Shuttle System Based on Composite Tasks

Automated Storage and Retrieval Systems (AS/RS) play a key role in many applications, which include flexible manufacturing systems and dense storage. Reasonable and efficient equipment scheduling and vehicle path planning are two important aspects of AS/RS design. The type of AS/RS discussed in this article belongs to the four-way shuttle system. This paper takes the combined equipment of four-way shuttle and elevator of AS/RS as the research object. Considering the complex and diverse types of tasks in the actual working conditions, an optimal scheduling mathematical model for multi-type task operation and route planning problems of four-way shuttle system is established based on minimizing the total task completion time. An improved genetic algorithm is used to solve the problem to find an appropriate combination of four-way shuttle and elevator equipment to perform the task, so as to improve the system operation ability and reduce the invalid wait time. At the same time, a dynamic scheduling strategy is proposed, which constrains and optimizes the tier-changing phenomenon in the multi-tier four-way shuttle system to reduce the energy consumption and time consumption caused by unnecessary tier-changing. This article also proposes a collision free path planning strategy suitable for multi depth storage scenarios to improve the system's efficiency and avoid collisions. Through simulation example analysis and practical engineering project applications, the strategy proposed in this article has been verified to have significant optimization effects on the model.