基于BDD的多阶段任务系统可靠性

Reliability based on BDD for phased mission systems

针对多阶任务系统中考虑共因失效后,系统的阶段依赖性和共因失效而增加了系统可靠性分析的复杂度,采用分析显式和隐式方法存在不足的问题,提出了一种基于二元决策图考虑共因失效的故障树可靠性分析方法.该方法首先忽略共因失效情况下的故障树并将其转化为多阶段任务系绕的二元决策图(PMS-BDD),求出系统的不可靠度表达式;然后,通过隐式方法将该表达式转化成包含共因失效信息的不可靠度或可靠度表达式,并依据求得的表达式进行相应的可靠性分析.研究结果表明:该算法与显示式算法的结果相同.该研究结论为多阶任务系统可靠性分析提供一种更加简便方法.

In order to solve the Phased Mission System with Common Cause Failures, the dependencies across phases and common causes of system make the reliability analysis more complex. Through analysis of both inadequacies of the explicit and implicit methods, binary decision diagram-based reliability analysis method for CCF-included failure trees was proposed. The failure tree was converted into a PMS-BDD without common cause events and the reliability analysis was carried out by the implicit methods to transform the diagram into a new unreliability or reliability expression with CCF. The results show that the result is same between this algorithm and explicit methods. This study provided a more convenient way of reliability analysis for Phased Mission System.