Research On Testing Maintenance Control Model Based On Petri Net

Maintenance testing is an important part of virtual maintenance training,and it is very important to accurately simulate the maintenance testing process for training fault isolation ability of aircraft crews.Now most of the testing maintenance training is carried out on the aircraft simulator,so that aircraft crews can be systematically trained and training efficiency is improved.Aiming at the problem that the A320 aircraft maintenance training simulation device which is developed by laboratory doesn't model for the testing maintenance process resulting in poor sharing and scalability,so a testing maintenance control model based on Petri net is proposed.Specific work is as follows:Firstly,the line maintenance testing process is taken as the research object and testing maintenance process is classified through analysing various types of aircraft manuals.The system testing process is analyzed by using A320 centralized fault display system(CFDS),and a structured model which consists of the Built-In Test Equipment(BITE),the Centralized Fault Display Interface Unit(CFDIU),and the Multifunction Control Display Unit(MCDU)is presented.Secondly,taking an example of A320 aircraft maintenance training simulation device independent which is researched by the laboratory,the simulation of testing maintenance process are analyzed in detail.The trainer simulates the system structure and function of the real CFDS system mainly through the establishment of fault setting module and cockpit module;the MCDU testing process and its realization simulated is summarized,the shortcomings of low efficiency and poor scalability which are caused by no universal model is summed up in the repair process.Thirdly,according to the requirement of testing maintenance process,the modeling methods of testing maintenance process are compared,the Petri net is selected to model the testing maintenance process.First of all,the MCDU page is divided into jump page and test result page,and the model is processed separately;Second,the MCDU test process is corresponded to the basic elements of Petri nets,the MCDU test process model is set up;Third,the display logic is expressed by using the production rules,the precondition and theconclusion of the page shows' production rules are translated into place,triggering rules are translated into transition,page shows production rules Petri net is created.At last,the Petri net of the MCDU test process is merged with the page display production rule Petri net,and the maintenance control model based on Petri net is established.Finally,the Petri net model is applied to the A320 aircraft maintenance training simulation device in the laboratory,and the testing process of VHF system is taken as an example to verify the model of testing maintenance process.The rationality and validity of the model is verified.