基于随机Petri网的机载系统动态可靠性建模

Dynamic Reliability Model for Airborne Systems Based on Stochastic Petri Net

机载系统的可靠性对飞机的安全性有重大影响,现代飞机的机载系统自动化与集成化程度高,导致其失效特性具有显著的动态性,即系统失效不仅取决于单元失效的组合方式,还与单元失效顺序相关。提出了一种基于随机Petri网的机载系统的动态可靠性建模方法,针对温储备、冷储备、载荷共担等典型动态结构,构建了随机Petri网模型以表征其动态(时序)失效行为。在所构建的随机Petri网模型的基础上,提出了基于蒙特卡罗仿真的可靠性分析方法,以用于生成系统寿命样本、进行可靠性参数的计算。最后,以某飞机交流电源系统为例给出了应用实例,结果表明:所提方法与传统解析法的误差在2×10^-7以内,能够满足工程应用的需要。

The reliability of the airborne systems have a significant influence on the safety of aircraft.The modern airborne systems have a high degree of automation and integration,which lead to obvious dynamic failure characteristics.Namely,system failure is not only dependent on the combination of units’failures but also related to their sequence.A dynamic reliability method for modeling airborne systems is proposed based on the stochastic Petri nets.Stochastic Petri nets are applied in reliability modeling for typical dynamic structures including warm standby,cold standby and load sharing,which are widely used in airborne systems.In this way,the dynamic(time-dependent)failure behaviors of the airborne system can be represented.In terms of the stochastic Petri net based reliability model,a reliability analysis method based on Monte Carlo simulation is proposed by generating system life samples for system reliability parameter calculation.Finally,an electrical power system is used as a case to illustrate the application and effectiveness of the present approaches.The results show that the difference by using the present method and the analytical method is below 2×10^-7,which can be neglected in practice.