A new mathematical model for integrated production planning and scheduling problem in capacitated exible ow shop with sequence-dependent setups

Abstract

The main contribution and novelty of this paper is proposing a more efficient mathematical model for integrated lot-sizing and scheduling in a multi-product multiperiod capacitated exible ow shop with sequence-dependent setups. A new approach for modeling the problem has been proposed and its complexity has been compared with former models. In comparison to the former models, fewer continuous and binary variables and constraints of the proposed model make it easy to solve. Comparison between the new model and the former models proves the superiority of the proposed model. Due to complexity of the problem, three mixed-integer programming based heuristics, all based on iterative resolutions of reduced-size MIPs and rolling horizon, have been implemented to solve the model. To evaluate the performance of the proposed model and solution method, problems of different scales have been studied. The used algorithms search the solution space for both lot-sizing and scheduling and find a combination of production planning and scheduling that is feasible and close to optimum. Computational results show that HA2 is superior for this problem and can find good quality solution to it in a reasonable computational time. Also, sensitivity analysis is used to clarify the problem and ensure suitability of the proposed model.