Optimal Joint Inspection and Mission Abort Policies for Degenerative Systems

Abstract

This article investigates the optimal joint inspection and mission abort policies for deteriorating systems which execute a mission continuously. The system degradation is modelled by gamma process and the information on the system state can only be obtained via inspections. To enhance the system survivability, the mission can be aborted and the rescue procedure will be initiated immediately. Different from previous research, the decision to abort or to continue the mission depends on the predictive reliability other than the fixed degradation level, which is proved to be more effective in cost saving. The inspection period and the mission abort threshold jointly form a two-dimensional policy. Under this policy, the explicit expressions for mission success probability and system survivability are derived analytically. The optimal joint policy is investigated to balance the tradeoff between mission success probability and system survivability. It aims to determine the inspection period and the reliability threshold simultaneously such that the expected total cost including mission failure cost, system loss cost and inspection cost is minimized. Some structural properties of the optimal policy are obtained theoretically. Finally, numerical examples are provided to demonstrate the model.