On Fault Diagnosis and Inspection Policy for Deteriorating System

The fault diagnosis and inspection policy were discussed for a system which has two operating states (normal, abnormal) and a failure state. The system is inspected periodically. The purpose of inspection is to identify the state of system and adopt appropriate repair strategy by measuring the value of diagnosis parameter. Because the system is deteriorated gradually and a replacement is expensive, several imperfect repairs are allowed until a replacement is needed. The objective of this paper is to determine the optimal critical value of diagnosis parameter and the optimal inspection cycle such that the expected profit per unit in steady states is maximized. Reliability indexes of the system are also derived. Probability analysis and vector Markov process are used in this paper. Researches on the numerical example show the feasibility of the policy.