由于空间索杆铰接式展臂伸机构复杂,部分失效过程出现动态特性,如冗余备份以及功能相关性等,故采用基于离散时间贝叶斯网络的动态故障树分析方法对伸展臂系统进行可靠性评估.首先分析逻辑门向离散时间贝叶斯网络的转化方法,建立逻辑门的贝叶斯网络模型以及相关事件的条件概率分布.根据上述转换原理,将空间索杆铰接式伸辰臂的动态故障树转化为对应的离散时间贝叶斯网络模型,最后利用贝叶斯网络推理计算伸展臂系统的失效概率以及各失效模式的后验概率,实现对其可靠性的评估.
Duc to the complexity in the space deployable articulated mast, there exists dynamic characteristics within part of the system failure process, such as the spares and functional dependency. Thus, a dynamic fault tree analysis based on discrete-time Bayesian networks is adopted to evaluate the reliability of the space mast. Firstly, the approach of converting logic gates into Bayesian networks is explored. Then the corresponding Bayesian networks models and conditional probability distribution of related events are conducted. In accordance with the conversion principle above, the dynamic fault tree of the space mast is transferred into discrete -time Bayesian networks. Eventually, by utilizing the established Bayesian networks, the failure probability of the space mast system is calculated, and so is the posterior probability of each failure mode. Consequently, the reliability assessment of the space mast system is accomplished.