Robust Permutation Flow Shop Scheduling Model Based On Min-max Regret Criterion

Under this condition,as one of the important parts of production system.Production scheduling system on the one hand,it should continue to play the role in term of reducing production costs,shortening production makespan,improving production efficiency,and optimizing resource allocation.On the other hand,the flexibility and stability of the production system should be taken into account in the scheduling model to improve the stability of the production system and the ability to withstand risks.Stable and timely delivery under uncertain conditions,strengthen satisfaction of downstream customers,enhance the competitiveness of enterprises and seek strategic cooperation opportunities with enterprises in the supply chain.To overcome the deficiency of traditional flowshop scheduling model with deterministic production environment and single optimization objective,this paper considers a permutation flowshop scheduling problem with uncertain processing time and also construct a multi-objective robust scheduling model to minimize the tardiness and total completion time under min-max regret criterion.Directed graph is used to analyze the scenario of the maximum regret value scenario(i.e.the worst-case scenario),and genetic algorithm is applied to solve this scheduling model.Through the experimental simulation results,it can be found that the proposed model is effective.Moreover,it could cover the shortage that the classical scheduling model only consider the robustness of total completion time.The following work are finished in this paper:1)The processing time of the workpiece on the equipment is represented by the interval.The representation method of such uncertain factors is simpler and has higher accuracy than the random or fuzzy variable representation method.At the same time,combined with the directed graph tool to reduce an unlimited number of processing time scenarios to a limited number of computable processing time scenarios.And based on the minimum and maximum regret value criterion,a robust scheduling model with the maximum completion time regret value as the objective function is constructed.2)Considering production delays into the scheduling model and improving the ability of the dispatch system to deliver on time.In this paper,by introducing the method of adjusting parameters and combining the genetic algorithm,the scheduling scheme of the scheduling scheme in which the production delay exceeds the maximum delay tolerance upper limit is eliminated,so as to ensure the robustness and punctuality of the scheduling scheme solved by the scheduling model.2)The proposed model had been verified by the simulation on the historical data of company L.