Operation optimization model for warm standby system based on nonperiodic and imperfect multiple active switching policy

Abstract

Traditional standby system models predominantly assume that a standby unit is activated only after an active unit fails. However, a periodic active switching policy is adopted for some critical subsystems of on-orbit satellites. For this problem, an operation optimization model for warm standby systems under multiple active switching is studied. First, the multiple active switching processes of the warm standby system are described, and virtual age theory is introduced to analyse the lifetime distributions of the unit in different states. Next, since switching does not always occur perfectly, analytical expressions of the system reliability and mean time-to-failure (MTTF) are derived for the warm standby system under nonperiodic, imperfect multiple active switching, which can be applied to units or systems with arbitrary time-to-failure distributions. Furthermore, by maximizing the MTTF of the warm standby system, the corresponding nonperiodic or periodic switching intervals can be determined by the genetic algorithm (GA). Finally, a numerical example of a gyroscope warm standby system following the Weibull distribution is provided to verify the model applicability, and sensitivity analyses of related parameters are performed to identify useful conclusions.