Abstract: To investigate the optimal policy of complex system with economical dependence, a kind of condition-based maintenance model is presented based on opportunistic policy. The maintenance mode and corresponding control threshold are determined by the analysis of failure rules of system units. Then the opportunistic maintenance threshold is proposed to unify two kinds of control parameters-time and state-on the system level, which are laid on the different measurement spaces. Therefore the optimization problem of system is solved through combining the corrective maintenance and on-condition maintenance. According to the theory of renewal process and Markov decision process, the value iteration algorithm is given to determine the optimal inspection interval and the opportunistic threshold of system, which achieve the minimization of long-run average cost rate of the whole system. Finally, a kind of mechanical equipment is presented as an example to illustrate the implementation and effectiveness of the model and iteration algorithm. Simultaneously, the applicable area of this model is qualified by comparing the trend curve of system average cost rate as the value of parameters change. The results show that the stronger economic dependence is, the more effective in reduction of system maintenance cost the decision model is, if proportion of units’ failure rate is in proper range.

Key words: Condition-based maintenance, Deteriorating system, Markov decision process, Opportunistic policy