Continuous time predictive maintenance scheduling for a deteriorating system

A predictive maintenance structure for a gradually deteriorating system (continuous time/continuous state) is proposed in this paper. Two maintenance decision variables are considered: the preventive replacement threshold and the inspection schedule based on the system state. In order to assess the performance of the proposed maintenance structure, a mathematical model for the maintained system cost is developed using renewal processes theory. Numerical experiments show that the maintenance cost rate on an infinite horizon can be minimized by a joint optimization of the replacement threshold and the aperiodic inspection times and that the proposed maintenance structure performs better than classical preventive maintenance policies which can be treated as particular cases.