Research On Modeling The Inventory System Of Logistics Center Based On Petri Nets

The Inventory System of Logistics Center often has a complex network structure, supply and demand relations, varieties of mass inventory and a large number of uncertain factors, how to quickly and efficiently build a large-scale complex model of inventory system, and carry on the simulation analysis, is an important topic in recent years.On the basis of the introduction of inventory system, its operating processes and the basic theory of Petri net, a study on the application of Petri nets was introduced to the logistics center inventory system modeling. Storage subsystem, circulation processing subsystem and output subsystem in inventory system were established by Stochastic Petri net analysis methods based on the in-depth analysis of inventory operating procedures.A part-to-whole research method was adopted. Firstly, equivalent simplification rules of Stochastic Petri nets were applied to storage subsystem, circulation processing subsystem and output subsystem, the time performance of each system was obtained. In addition, a method based on the analysis of stochastic Petri nets with fuzzy parameters was proposed, and this method was applied to the circulation processing system. The study of circulation processing system was conducted from two aspects of qualitative and quantitative research. Among them, qualitative research was done according to the characteristic that continuous-time stochastic Petri nets is isomorphic to continuous-time Markov chain, and then analyzed the activity, accessibility, and boundedness, etc of the model. Quantitative analysis was to use the stochastic Petri nets with fuzzy parameter to solve the busy probability of each place, the utilization rate of each system transition, the average delay time of the system, as well as the mark flow rate flowing into the system, the data showed that the processing link should be further improved. The feasibility of this method was verified, and the same method is also used in the inventory system and dispatch system. Finally the whole inventory system has been carried on the simulation analysis, the activity, reachability and boundedness of the system were analyzed, and several key inventories were monitored, the utilizations of each personnel and each equipment were calculated.In this thesis, the research method on inventory system which is based on the Stochastic Petri nets modeling and CPN Tools simulation, can also be applied to the research of other systems with stochastic dynamic characteristics in the field of logistics, therefore this thesis can provide reference to the design and evaluation of the logistics system.