The Safety Research Of Flight Control Based On CPN

It is very important for application of system security analysis to improve aircraft safety and solve the security problems of airworthiness certification. The system security analysis runs through the whole airworthiness compliance verification process. At conceptual design and preliminary design stage, the security analysis is used to determine the event which causes the fault condition in FHA, and allocate safety requirements. At detailed design stage,according to the reliability data of the various components, the security analysis is used to calculate the occurrence of fault conditions to determine whether they meet the requirements of the maximum allowable probability.In this article, the concept of system safety assessment is explained, and system safety assessment process is researched. Then the characters and the relations of every step of assessment process(Functional Hazard Assessment, Preliminary System Safety Assessment and System Safety Assessment) are summarized. Confronting the improvement of the complexity of system, the limitation of traditional safety modeling methods was analyzed. In this case, the description and analysis idea based on classical Petri Nets and its extension for safety systems were studied, and the way to model systems using Colored Petri Nets(CPN)was present. The dynamic safety analysis method based on colored Petri net(CPN) for complex system was proposed.The paper uses Pitch channels of aircraft flight control system as an example, selects a failure state of grade ?, applies colored Petri net method for modeling, and uses CPN Tool as the simulation platform to simulate, analyses the model and gens the numerical results.Compared with traditional methods, the paper overcomes the characteristics of the shortcomings of static analysis, and simulation results show the applicability of the colored Petri net model in the system safety analysis of the aircraft.