Virtual Cellular Reconfiguration And Rescheduling Under Random Arrival Of New Orders

With the dynamic variety of market demand,the mainstream of manufacturing presents the feature of small batch,species diversity and making-to-order manufacturing(MTO).Virtual cellular nanufacturing System(VCMS)is an advanced mode of production developed from group technology and traditional cellar manufacturing.The current market demand is characterized by dynamic characteristics.The adoption of virtual cell can improve manufacturing flexibility and agility effectively.The study of dynamic reconfiguration for virtual cell and rescheduling are simplified as a static reconfiguration and rescheduling,which ignored the existence of random dynamic disturbance factors and do not suitable for the actual production significantly from the point of the present study.Therefore,this paper studied the problem of virtual cellular reconfiguration and rescheduling under random arrival of new orders.In the process of virtual cell production,with random arrival of new orders,the original structure of virtual cellular may not adapt to the later processing requirements,so that leads to reconfigurate the virtual cellular frequently.This paper reconfigurates the virtual cell in a hybrid driven approach combining the new orders with the time window in response to this disturbance.If the workshop of surplus equipment processing capacity can't meet the demand of the production of new order,that the time window will be frozen,the new orders will be added to virtual cellular to product in the next cycle.The reconfiguration of virtual cellular is different from general modes of virtual cell dynamic reconfiguration,enterprises need to implement on the basis of the existing virtual cellular plan for rapid reconfiguration of virtual cellular.The reconfiguration solution not only implements the efficient operation of the subsequent virtual cellular production,but also inherits the structure of the original virtual cellular with the maximum extent.Based on the existing research,this paper puts forward the way of inheritance virtual cellular reconfiguration to avoid the negative effect of the reconfiguration.This inheritance virtual cellular reconfiguration method takes the high efficiency and stability characteristics of virtual cellular into accountl.The high efficiency includes the similarity of production process,the number of multi-cells,equipment utilization and logistics cost;Stability contains the number of machine change in the virtual cellular.In order to solve the model effectively,a multi-objective genetic optimization algorithm based on dynamic level analysis was designed in this paper.This algorithm is optimized by random search of Preto optimization solutions.If the rest of the workshopprocess capability can meet the production demands of the new orders,we will reconfigurate the new virtual cellular by use of surplus equipment in the current.In this way not only ensures that response to the event disturbance on time but maintains the stability and continuity of the production system.The problem of virtual cellular rescheduling which cased by the random arrival of new orders,this paper puts forward a new way of rescheduling judgment which based on time completion trigger and machine idle trigger,simulated the arrival time the new orders,with rolling window technology,according to hybrid driven.At the same time,the dynamic rolling window size is determined according to the average load of the machine,and the dynamic random scheduling period is divided into a continuous static dispatching interval.A nonlinear multi-objective 0-1 integer programming rescheduling model which considers makespan,weighted with target of minimizing the total tardiness,initial scheduling deviation,is given.And to solve the model,this paper designed a discrete particle swarm optimization(pso)algorithm.In order to verify the validity of the inheritance reconfiguration of virtual cellular and the rescheduling method based on the rolling window technique under random arrival of new orders.Applied the solutions to the machining workshop of HDZH shipbuilding which proposed in this paper,under study of workshop production status and existing problems.In the dynamic production environment under random arrival of the new orders,through compared the present mode of production with the production mode of the virtual cellular,the results show that the proposed method is feasible and effective.