Order Picking Problem in a Warehouse Hospital Pharmacy

Abstract

Abstract This paper presents an optimization method for simultaneously routing improvement and items location as part of order picking operation in a warehouse of a hospital pharmacy. In this precise context, the classical order forms are replaced by medical services endowment lists which are not modified over time (or not significantly). This particularity allows new considerations and modifications of the order picking optimization methods. This study focuses on the items location determination in the warehouse and the pickers rooting in a picker-to-part low level policy context. In order to solve the considered problem, the paper details an exact mathematical solving method through a mix integer programing model which can easily be extended to a linear version. For real case, this class of model may need prohibitive computation times to be solved. Consequently, a genetic algorithm and a dedicated heuristic are presented in order to implement a hybrid genetic algorithm which is the combination of both methods. Results are provided to highlight the contribution of the hybrid method compared to the others in terms of computation times and solutions quality.