| With the promotion of personalized production and dynamic changes of market demand,multi-variety,small and medium-sized order(Make-to-order manufacturing,MTO)production methods have increasingly become the mainstream development trend of manufacturing enterprises.Virtual Cellular Manufacturing System(VCMS)as a new development of traditional cellular manufacturing system in practical application,is an advanced production organization method.Since the current market demand has the characteristics of short order delivery time and high dynamic complexity,the application of the virtual celluar production organization method will help to improve the production flexibility of the enterprise and achieve rapid response to disturbances.After the summary and analysis of existing researches,it is found that the existing researches on problems of virtual celluar reconfiguration and rescheduling generally deconstructs dynamic problems into multi-stage static problems through phase division to achieve simplification of the problem.The influence of dynamic disturbance factors on the production system at the workshop level and the executive level is insufficiently considered,which is obviously inconsistent with the actual production situation.Therefore,this thesis studies the problems of virtual celluar reconfiguration and rescheduling according to the random disturbances of machine failure.In view of the impact of fault disturbance on the production system at the workshop level,this thesis makes the virtual celluar reconfiguration decision based on the matching degree between the processing capacity of the remaining machines in the current celluar and the actual demand of the order.Constructe a non-linear integer programming model that considers production cost indicators including machine usage costs,logistics transportation costs in inter and intra celluars and tardiness penalty costs,as well as workload balance indicators based on machine utilization.The discrete particle swarm algorithm based on adaptive inertia weights(DPSO-AIW)is designed to solve the model.Based on above mentioned,the feasibility and effectiveness of the virtual celluar reconfiguration method are verified in combination with a calculation example.Based on the completion of the virtual celluar reconfiguration,this thesis proposes a virtual celluar rescheduling method considering the combination of multiple strategies and machine failures to deal with the impact of failure disturbances on the production system at the execution level.This method constructs a virtual celluar rescheduling model with the goal of minimum makespan and deviations caused by machine adjustment due to disturbances,and the model is solved by the non-dominated sorting genetic algorithm with elite strategy(NSGA-Ⅱ).In order to improve the applicability of the rescheduling scheme,this thesis adopts the maintenance strategy,the transfer rescheduling strategy and the complete rescheduling strategy to adjust the pre-made production scheme and generate the corresponding rescheduling schemes.This thesis constructs a rescheduling cost evaluation function based on the system analysis of the rescheduling cost and realizes the joint consideration of the rescheduling driven decision-making and strategy selection,which not only improve the rationality of the rescheduling scheme formulation process,but also has a good reference value in practical applications.On the basis of above researches,this thesis takes curved surface segmentation production process of hull-machine processing workshop in ZJ Shipbuilding(Group)Co.Ltd.as the research background,and applies the proposed methods to the actual enterprise.In the case of random disturbances of the failure,the scheme proposed in this thesis is compared with the scheme actually adopted by the enterprise.The results show that the scheme proposed in this thesis has good performance in terms of completion time,production cost and machine utilization,so that the proposed method is feasible and effectiveness have been verified. |
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