Optimization of Production Planning

Abstract

The challenge proposed by PRIMAVERA BSS software company was to find an effective scheduling algorithm that can add new features to their production planning software, with a good performance (being able to run in less than 10 minutes), and that can be su�ciently generic and adaptable to be used by different industries (metal, furniture, wood, textile, and food industry). The requirements configured a NP-hard problem known in the literature as the Flexible Job Shop Scheduling Problem (FJSSP), for which sophisticated mathematical models and heuristic methods are widely available. The wherein proposed approaches consider sequence dependent setup times and different priorities for the operations. Two approaches are considered in the present report. First, two mathematical models were created to address this problem and give insight to the structure of the problem and its constraints. A second approach proposed the use of heuristics. A constructive heuristic used to find initial solutions is followed by the use of an improvement heuristic, which allows to obtain better solutions at reasonable computational costs. The solutions obtained by the heuristics can be used to warm start the optimal solving procedure using mathematical models with commercial solvers.