考虑阶段备份的多态多阶段任务系统可靠性建模方法

Reliability Modeling of Aerospace Multistate Phased Mission Systems with Phase Backups

近些年来,由于在航空航天、分布式计算以及核电系统等系统中广泛的应用,多阶段任务系统(phased mission system, PMS)可靠性理论与方法得到了广泛的关注与研究。在现代航天系统,尤其是载人航天系统,为了使整个系统的任务可靠性更高,经常会采用任务备份的方法来提高系统的任务可靠性。针对该类型的问题,提出一种基于多态多值决策图(multistate multi-valued decision diagram, MMDD)的方法。首先,将阶段故障树模型转化为阶段模型,其次,根据阶段代数方法将阶段模型融合为系统模型。在阶段模型融合过程中,通过增加随机变量的方法对单元经历的阶段进行统计,从而实现降低所建立的系统模型大小,提高建模效率,并以某型航天器推进子系统为例对建模方法进行说明。

In recent years,the reliability of phased mission systems(PMSs)has attracted much attention,due to their wide application in the aerospace industry,distributed computing and nuclear power systems.For many PMSs,especially in the aerospace industry,the backup phases are commonly designed for higher mission reliability.To deal with this problem,a multistate multi-valued decision diagram-based method was proposed.Firstly,the multistate multi-valued decision diagram(MMDD)models for phases were constructed,converting from fault tree model.Then,the system MMDD model was established by integrating phase MMDD models through phase dependency operation.And during the integration,an extra variable was added to measure the phases that each component passes by.By this method,the system model scale and the model efficiency could be improved.At last,the proposed modeling method was shown by a thrust subsystem in a spacecraft.