The Pod Assignment Model and Algorithm in Robotic Mobile Fulfillment Systems

Abstract

This paper studies the pod assignment in the Robotic Mobile Fulfillment Systems which is a parts-to-picker storage system where robots carry movable shelves, called pods, to stationary pickers. On the basis of deciding which product to put in which pod depending on the product correlation, we establish a mathematical model with the objective of minimizing the total picking distance to decide which pod to put in which position. A two-stage hybrid algorithm is proposed to solve the model. In the first stage a Greedy Algorithm is designed to generate initial solution which consider the pod correlation. In the second stage, a simulated annealing algorithm is used to optimize the initial solution and get the final pod layout results. The experimental results show that the pod assignment model and algorithm optimization scheme proposed in this paper can improve the order picking efficiency.