Optimizing parcel sorting process of vertical sorting system in e-commerce warehouse

Abstract The vertical sorting system is an emerging system in warehouse section. It achieves higher level of automated sorting by applying conveyor sorter and AGVs. This paper investigates the optimization problem of parcel sorting in an e-commerce warehouse where parcels are waiting to be sorted and delivered. The assignment among the parcels, picking stations and AGVs are determined together with the objective of minimizing the finishing time of processing the last parcel, so that a detailed operational plan for warehouse sorting can be worked out. A mixed-integer linear programming model is developed based on the problem, and particle swarm optimization (PSO) algorithm is employed for problem solving. Numerical experiment shows that the proposed PSO algorithm can solve the model with high efficiency, and sensitivity analysis give suggestion about the arrangement of trailers’ location.