空间可重复锁紧装置可靠性评估

为了对空间可重复锁紧装置在轨执行多次锁紧分离动作的任务可靠性进行评估，针对装置在轨受到航天器交会对接冲击和空间环境下性能退化综合作用的特点，建立了考虑冲击与退化相依竞争失效的可靠性评估模型。首先，以空间可重复锁紧装置的功能、结构及工作原理为出发点，结合在轨主要故障模式确定可靠性特征量。其次，同时考虑在轨承受极端冲击和累积冲击两种情况，构建冲击作用下的性能退化模型，并针对装置小子样、高可靠、长寿命特点，采用加速退化试验和贝叶斯方法进行模型参数估计。然后，基于冲击与退化过程的相依竞争失效理论，建立装置可靠性评估模型。最后，以某型号空间可重复锁紧装置为例，开展装置在轨冲击承载模拟试验及加速性能退化试验，同时融合相似产品历史试验数据，采用贝叶斯公式进行模型参数估计，得到装置可靠度函数曲线。研究结果表明，装置在轨运行25 a后仍能以0.973的高可靠度运行，评估结果符合工程实际；运用所提出的方法及模型，能够紧扣装置在轨任务工况，结合试验和研制数据综合进行可靠性评估，为在轨任务可靠性分析提供了有效的技术途径，为设计改进和使用策略制定提供了理论依据。

Reliability evaluation of space reusable locking device

To evaluate the reliability of space reusable locking device performing locking separation actions on orbit, aiming at the combined effect of spacecraft rendezvous and docking shock and performance degradation in the space environment, a reliability evaluation model considering interdependent competitive failure was established. Firstly, based on the function, structure and working principle of the device, the reliability characteristics were determined by the main fault modes on orbit. Secondly, considering both extreme and cumulative shock, a performance degradation model under shock was constructed. In view of the characteristics of small sample, high reliability and long life, accelerated degradation test and Bayesian method were implemented to estimate model parameters. Then, a reliability evaluation model was attempted based on the interdependent competitive failure theory of shock and degradation processes. Finally, taking a space reusable locking device as an example, the on-orbit shock simulation test and acceleration performance degradation test of the device were carried out. The model parameters were estimated by integrating the historical test data of similar products according to Bayesian formula, and the reliability function curve of the device was obtained. The result shows that in line with engineering practice, the device can still operate with a high reliability of 0.973 after 25 years on orbit. The proposed method and model proves to be capable of following closely the working conditions, and conducting a comprehensive reliability evaluation on the basis of the test and data available, providing an effective technical approach for mission reliability analysis and a theoretical basis for the design improvement and formulation of use strategy.