基于GSPN的飞机前轮转弯系统安全性评估

为解决在缺乏统计数据时无法对系统安全性进行评估的问题,提出将系统广义随机Petri网(GSPN,Generalized Stochastic Petri Nets)与经典评估相结合的方法.以某型尚处于设计阶段的飞机前轮转弯系统为研究对象,通过分析该系统结构功能图,建立出系统故障类型和影响分析(FMEA,Failure Modes and Effects Analysis)表;依照经典公式,求出系统各单元及其故障类型的故障率、维修度、平均无故障时间和平均维修时间等数据;将求得的数据与前轮转弯系统的GSPN模型相结合,利用TimeNET软件求得系统各故障类型的稳态失效概率;联立经验公式及危险度矩阵图对系统的安全性进行评估.经测评,该型飞机前轮转弯系统安全性符合设计要求. 

Security evaluation of nose wheel steering systems based on GSPN methods

To solve the problem of how to evaluate the safety of a system without relative statistical data, the generalized stochastic petri nets(GSPN) and classical evaluating method were hung together. Taking a certain type of airplane's nose wheel steering system, which was still at the stage of design, as an example, the failure modes and effects analysis (FMEA) list was set up by analyzing system's function structure figure. The failure rate, maintenance rate, the mean time between failure and the mean time of the maintenance were calculated by the experiential formula. According to these parameters and the nose wheel steering system's GSPN model, the steady failure probabilities were calculated by the TimeNET software package. The safety of the nose wheel steering system was evaluated with the experiential formula and the risk matrix. After the evaluation, this nose wheel steering system conforms to the design demands.