针对以往试验中出现多种模式的结构失效现象，在对新型舵机系统进行可靠性预计时，有必要在传统电子学预计基础上，加入多失效模式下结构可靠性预计。首先，采用专家评分分配法将系统可靠性指标分配到相应模块与组件，然后由元器件计数法、均值一次二阶矩法分别得到电子学部分与各失效模式下结构部分的可靠性指标，进而得到系统的可靠性指标。从预计结果看出，设计方案达到总体分配到舵机系统的可靠性指标要求，在考虑滚珠丝杆机构多失效模式下的可靠度要低于其他电子学部分，与以往试验中结构失效多于电子学部分的现象较为吻合。

In view of the multiple structure failure modes appeared previously in experiments,we added a structure reliability prediction under multi-failure mode based on the traditional electronics prediction when implementing system reliability prediction to a new type actuator system.Firstly,the Expert Grading Allocation Method was used to allocate system reliability index to the corresponding modules and components.Then,the reliability index of electronic components was obtained by Component Counting Method,and the structure reliability index under each failure mode was obtained by FOSM method.Thus the system reliability index was obtained.The prediction results show that:1) The reliability indexes of design scheme achieve the requirement of reliability index allocated for the missile;and 2) The reliability index of ball bearing screw under multi-failure mode is lower than that of the other electronics modules,which is consistent with the previous failure phenomenon in experiments.