飞行控制系统中最优事前更换策略的研究

为了最大限度地有效地利用现有资源,并尽可能地提高余度飞行控制系统的可靠性,对单点故障单元在发生故障前的某一时刻t₀,采取事前更换或预防性维修,这是一个十分值得研究的问题。 本文对单点故障单元无故障工作时间分布服从K（≥2）阶爱尔朗分布的情况进行了研究（爱尔朗分布在很多实际问题中具有广泛的适应性）,并求出了使连续折扣总期望费用、长期每单位时间平均期望费用达最小的最优事前更换时间t₀^*所满足的方程。这比一般情形的结果简单,易于作数值计算。若利用爱尔朗分布表与指数函数表,用本文的结果作近似数值计算,手算也是可行的。在文章末尾,对K=2的情形,通过一个实例进行了数值计算。

A STUDY ON TACTICS OF OPTIMUM ADVANCED CHANGE FOR FLIGHT CONTROL SYSTEM

In order to utilize the resources available at present with maximum efficiency and enhance the reliability of a redundant flight control system to the utmost extent,it is of great value to study the change or the maintenance of a single stoppage unit in advance of a stoppage for a definite time t0 This paper investigates how the distribution of stoppageless work time of a single stoppage unit follows K（K=2）order Erlang distribution（in many practical problems Erlang distribution is of extensive adaptability）and then proposed an equation for the optimum advanced change time t0*,which minimizes both the continuous expection cost and the average expec-tion cost per unit time in a long period.This equation is simpler than the available ones and easy to make numerical calculation.By the aid of Erlang distribution table and exponential function table it is possible to make an approximate numerical calculation even by hand on the basis of the results in this paper.Finally,a numerical example is given for K=2.