Joint optimization of condition-based maintenance and component reallocation for phased-mission balanced systems with flexible structure considering imperfect substitution

In many practical situations, many balanced systems need to operate in multiple phases. Such systems usually have a different system structure for each phase. The system is balanced when the maximum state difference between all working components is less than a predetermined value. Component degradation is described by a Markov process and the state can be checked periodically. We propose a joint policy of condition-based component reallocation and maintenance for this balanced system. Non-working components can be used to replace working components for operation. Components can be repaired to an arbitrarily better state. The operation process of the balanced system is described as a Markov decision process and the optimal joint policy is obtained by a finite stage backward recursive iterative algorithm. In addition, two contrasting policies are proposed to compare with the proposed policy. Based on flexible manufacturing systems, a numerical study shows that the proposed joint policy is significantly better than the other two policies.