Extended Logical Petri Nets And Its Application In Fault Diagnosis And Maintenance

With the development of industrial informatization,Petri nets are widely used in fault diagnosis and maintenance process modeling.Petri net can intuitively and dynamically describe the fault diagnosis and maintenance process,and analyze the fault diagnosis and maintenance process,so as to improve the efficiency of fault detection.However,in the actual fault diagnosis process,Petri net lacks dynamic and visual behavior analysis on the uncertainty information and fuzzy information in the fault diagnosis process.Therefore,to solve the above problems,we first proposed the fuzzy logical Petri net.For the propagation of fault,we put forward the algorithm of accessibility analysis and the algorithm of fairness analysis,and simulate the propagation path of fault information.Then,in order to improve the time efficiency of fault diagnosis and maintenance,Petri net of transition time assignment logical is proposed to analyze the timeliness of fault maintenance system.Finally,the effectiveness and feasibility of this method are verified by modeling and analyzing the fault diagnosis and maintenance process of centrifugal compressor,which improves the accuracy and efficiency of the fault diagnosis and maintenance process.The main research contents of this paper are as follows:(1)Fault propagation and fault analysis for complex systems of fuzziness and uncertainty,in Petri net and fuzzy logical based on Petri net theory,according to the logical of Petri net value uncertainty and fuzzy Petri nets to the characteristics of the fuzzy information representation and reasoning ability,put forward the concept of fuzzy logical Petri net and inference rules,considering the influence of different fault source of the fault degree,introducing information probability fuzzy logical Petri nets,the source of trouble give confidence,make more accord with the actual fault diagnosis process.(2)The fault diagnosis system to make use of fuzzy logical Petri net modeling,at the same time,fuzzy logical Petri nets to describe the logical relationship between the system fault state,and gives the corresponding model simplified rules,simplified the system model of the form of expression,has a good encapsulation,reconstruction and maintainability,to a certain extent,ease the combination of state space explosion problem.Aiming at the propagation of fault,the reachability analysis algorithm and fairness analysis algorithm are proposed to simulate and demonstrate the propagation path of fault information,which further improves the fault diagnosis efficiency.(3)In the actual process of fault maintenance,the start and end time of a fault maintenance in the system,as well as the duration of the fault maintenance,will have a certain impact on the fault maintenance.In order to improve the efficiency of fault maintenance,Petri nets and their initiation rules are proposed in this paper.Petri nets of transition time assignment logical add time factor to transition,establish fault maintenance model and analyze the timeliness of fault maintenance process,and verify the timeliness of fault maintenance process through simulation tools.