Jochen Rethmann, Hochschule Niederrhein, FB Elektrotechnik und Informatik, Reinarzstraße 49, 47805 Krefeld


An Experimental Study of Algorithms for Controlling Palletizers
OR 2015 (Springer Verlag, pp. 27-34)

F. Gurski
J. Rethmann
E. Wanke

Abstract

We consider multi-line palletizing systems which are used by delivery industry and warehouses, where bins have to be stacked-up from conveyor belts onto pallets. Given are k sequences of labeled bins and a positive integer p. The goal of the FIFO Stack-Up problem is to stack-up the bins by iteratively removing the first bin of one of the k sequences and put it onto a pallet located at one of p stack-up places. Each of these pallets has to contain bins of only one label, bins of different labels have to be placed on different pallets. After all bins of one label have been removed from the given sequences, the corresponding stack-up place becomes available for a pallet of bins of another label. The FIFO Stack-Up problem is computational intractable (Gurski, Rethmann, Wanke, CoRR 2013).
We consider two linear programming models for the problem and compare the running time of our models using GLPK and CPLEX solvers. For lack of benchmark data sets we use randomly generated sequences. We also draw comparisons with a breadth first search solution for the problem (Gurski, Rethmann, Wanke, MCO 2015). Further we discuss the influence of different parameters on the running time needed to solve the problem.