Research On Flexible Job-shop Scheduling Problem Considering The Faults Influence

With the continuous development and progress of a new generation of intelligent manufacturing,the flexible production mode of multi-variety and small-batch has become an important means for the upgrading and transformation of the manufacturing industry.Compared with traditional manufacturing,the flexible production mode can allocate processing equipment,materials and organize production management more efficiently.Job shop scheduling is the key link for the efficient operation of flexible manufacturing system,however,the actual workshop scheduling environment is generally variable and complex,among which random fault disturbance is the most prominent and has the greatest impact.Therefore,it is necessary to study about formulating a reasonable scheduling optimization scheme to deal with the impact of random disturbances in the scheduling process of flexible work workshop,in order to ensure the stable operation of the production system,improve the flexibility of the system to respond quickly in the face of disturbance events,and help manufacturers gain a competitive advantage.This paper studies the characteristics of flexible job-shop scheduling and the influence of random fault disturbance.The main contents of this paper are as follows:Firstly,take the flexible job-shop scheduling problem as the subject,in-depth analysis and summary of the influence of fault factors for the standard processing time and scheduling scheme of equipment,and explored the calculation model of equipment standard processing time,based on the reliability theory,probability theory,optimization theory and other related basic theories.Then,combined with the characteristics of flexible process sequence and flexible equipment selection,taken the maximum completion time and the deviation of completion time before and after scheduling as optimization goals of the scheduling,to build a model of flexible job-shop scheduling considering the impact of machine breakdown.Secondly,to explore the optimization method for solving the flexible job-shop scheduling problem considering the influence of machine breakdown.It includes two aspects: scheduling optimization strategy and optimization algorithm.On one hand,a scheduling optimization strategy based on equipment failure time is designed,and then the scheduling strategy evaluation index is proposed.On the other hand,analyzed and summarized the advantages and disadvantages of genetic algorithm and greedy algorithm in solving the NP-hard problems,and proposed a hybrid optimization algorithm with both global search ability and local search ability.The algorithm is based on a genetic algorithm,by embedding the greedy algorithm to improve the basic feasible solution which experienced genetic and introducing the destruction-reconstruction rule to expand the search neighborhood of the algorithm and accelerate the convergence of the algorithm,to improve the solving ability and efficiency of the overall algorithm under the premise of maintaining the diversity of the population.Finally,used the standard examples of FJSP to compare the operation results and performance of the genetic greed algorithm and other optimization algorithms,tested the effectiveness and superiority of the proposed hybrid algorithm.Solving the actual production cases of typical flexible manufacturing enterprises,it is shown that the designed scheduling optimization strategy and hybrid optimization algorithm can deal with the impact of random breakdown on FJSP,and perform better than other methods.