Research On MRO Task Scheduling Optimization Based On Distributed Service Resources

Promoting the transfer of China’s equipment manufacturing industry to the middle and high-end links of the global value chain is the core of realizing the transformation from China’s speed to China’s quality.In the entire life cycle of high-end equipment,after-sale services occupy a high-profit segment of the manufacturing value chain,and its profit share far exceeds that of complete machine manufacturing.Especially,MRO services are an important part of it.The scale of China’s MRO business is expanding rapidly,and how to reasonably allocate maintenance resources to achieve the optimization goal of "reducing costs and increasing efficiency" is an urgent problem for enterprises to solve.This paper studies the MRO task scheduling optimization problem under the distributed resource environment,analyzes the task scheduling optimization process considering on two type of MRO services,namely depot repair and on-site maintenance,and proposes MRO task scheduling model based on distributed factory and MRO task scheduling model oriented to field maintenance respectively.The modeling process and solving algorithm of the two models are introduced in detail.The main work is as follows:(1)Based on the distributed factory environment,this paper studies the MRO task scheduling optimization problem considering the dual resource constraints of machines and workers,and establishes a dual-objective optimization model to minimize the makespan and total costs.The model takes into account both the heterogeneity of maintenance processes and the distributed characteristics of maintenance workshops.In order to solve this model,this paper proposes a novel encoding and decoding method for double-digit operation sequence,and proposes an improved algorithm NSGA-LS based on the well-designed local search operator.Finally,the simulation comprising15 benchmarks is carried out and the results show the performance of NSGA-LS is significantly better than the classic NSGA-II algorithm.(2)From the coordination of multi-site,multi-task,and multi-resource demand,this paper studies the MRO task scheduling optimization problem regarding to field maintenance,and establishes the multi-objective optimization model to minimize the maximum completion time,minimize the redundancy of skills and maximize the cost performance index of material resources.This model considers elements such as heterogeneous maintenance service processes,multi-skilled service teams and multiple material resources comprehensively.The MRO service process is decomposed into multiple subtasks with dependent or independent relationships.During the service period,the multi-skilled workers in the team are concentrated together,and the maintenance materials are provided by the supplier.(3)The MRO task scheduling model of field maintenance is simulated.In this paper,a three-layer coding and decoding method comprising OS,TS and MS is proposed,and six MOEAs including NSGA-II,MOEA/D-DU and IBEA are introduced to solve the problem,then the optimal combination of key parameters of the six algorithms is determined based on the design of experiment method.Finally,20 benchmark instances of multiple MRO tasks are tested.Experiment results show that MOEA/D-DU algorithm could obtain higher quality scheduling solutions with relatively low computational costs.