Storage Location Assignment and Task Scheduling Optimization in Warehouse Management

Abstract

Storage location assignment is of great significance in warehouse management. According to the characteristics of task scheduling, time-based multi-objective models for storage allocation and scheduling optimization are proposed in this paper. Then, a genetic algorithm is used to solve the multi-objective optimization problem for storage location assignment and scheduling, and it adopts matrix codes and crossover operation of different objectives. Finally, simulation experiments show the effectiveness of the proposed model and algorithm. With the intensification of market competition, manufacturing companies have to reduce costs continually in order to improve adaptability and competiveness. In distribution center, order picking time accounts for more than 40% of total operation time while picking cost accounts for at least 65% of total operating cost. Consequently, a reasonably well-optimized order picking operation will dramatically improve operating efficiency. Storage includes all activities involving in holding products at a point for temporary custody and subsequent distribution. Storage assignment and scheduling problem has been widely studied by a lot of scholars in recent years (Goetehslekx and Asheri, 2012). Yang, Li and Zhong (2005) considered it as a TSP problem and studied the optimal path in AS/RS order picking operation with Genetic Algorithm. Marcele and Cristiano (2014) adopted a class formation and allocation model and a preference ranking organization method for enrichment evaluations. Ene and Ozturk (2012) used stochastic evolutionary optimization approach to establish a integer programming model, which is developed to form optimal routes and quickly response to picking orders. Simulation experiments of the studies verify the operating models are feasible and efficient. The criteria that should be considered in determining the location in a storage facility for each product are often conflicting (Zhao, Wu, and Li, 2004). In order to solve this problem, a multi-objective model of designing optimized storage assignment and order picking system is conducted in this paper using a developed mathematical model. A genetic algorithm is also proposed to solve the model.