时间限制性派遣中短时派遣时长的优化方法研究

航空发动机全权限电子控制系统(FADEC)的时间限制性派遣(TLD)分析是飞机系统安全性分析的重要内容之一。针对目前TLD分析中都假定短时故障派遣时长(ST)为固定值(125h或250h)的问题,开展了短时派遣时长的优化方法研究。采用故障树和马尔科夫方法,以推力控制丧失率(R)要求为约束,分析和建立了ST和长时故障派遣时长(LT)的函数关系;在此基础上,构建了以短(长)时故障派遣时长为变量,系统平均维修时长和带故障运行时长期望值为目标的多目标优化模型,使TLD分析中故障派遣时长的选取更灵活、更合理。通过实例表明:与ST取固定值250h相比,优化后ST取25h时,带故障运行时长期望增大4.2%,系统平均维修时长增大8.6%,验证了方法的有效性。

Study on Optimization Method of Short-Term Dispatch Time in Time-Limited Dispatch

Time-limited dispatch (TLD) analysis of full authority digital engine control (FADEC) is one of the important contents of aircraft system safety analysis. Aiming at the problem that the short-term fault dispatch time is assumed to be a fixed value (125h or 250h) in TLD analysis, the optimization method of short-term fault dispatch time is studied. Firstly, by using fault tree and Markov method, and taking the loss of thrust control rate (R) requirement as constraint, the functional relationship between short-term fault dispatch time and long-term fault dispatch time is analyzed and established. On this basis, a multi-objective optimization model with short (long) fault dispatch time as variable, average maintenance time of the system and long-term expectation of running with fault as objective is constructed, which makes the selection of fault dispatch time in TLD analysis more flexible and reasonable. Finally, an example shows that compared with the fixed value ofST for 250h, the long-term expectation increases by 4.2% and the average maintenance time of the system increases by 8.6% whenST is optimized for 25h, which verifies the effectiveness of the method.