Optimal Availability of Maintainable Systems

Operating a system for optimum availability is a key aspect in many a complex system. Failure of the system can have serious consequences both in monetary terms as well as in loss of production or disruption of service. Optimal control theory provides a convenient tool to obtain the optimal maintenance policies of maintainable systems. These optimal policies are obtained by applying the generalized maximum principle of Gamkrelidze. The prescribed objective function is represented in terms of the cost of repair as well as the downtime cost. The models considered are Markov in that their present state provides sufficient information about the system. Constant as well as time-varying optimal maintenance policies during the planning or operating period can be considered by the proposed method. The optimal maintenance policy very much depends on the failure rates of the individual system components.