| Abstract: |
Condition- based maintenance (CBM) is a moderm approach to measure the condition of a machine while it is inoperation and carry out maintenance action only when the measurements indicate it necessary. When a fault has been detected and the cause diagnosed, trend analysis can be used to predict the proper time-to- maintenance. This allows maintenance to be scheduled. Thereforg, criteria of maintenance scheduling are :- 1- Identification of the items to be maintained.2- Identification of the proper time of each.Sometimes, scheduling is purely allocation, in these cases mathimatical models can be employed to determine theoptimal decisions [34]. Therefore, the connection between the scheduling problem and the optimization problem is found.The up to date trends in r~search works and their recommendations show that, the optimum scheduling concentrates on time-based maintenance (TBM) , so, manystudies shoulld be worked out to solve the problem of optimization in CBM scheduling, and to make a connectionbetween TBM and CBM to gain advantages and experiences of TBM scheduling and advantages of CBM program. To achieve this objective, an integrated system for maintenance and servicing is designed.MDTCAL is an intended system to verify the above objective, MDTCAL expression is an abbriviation of Measure,Diagnose, Tighten, Clean Adjust and Lubricate. When MDTCAL is applied, the optimum scheduling is made as follows;1- Servicing actions is based on the fixed time. So, the preceding experience ,in TBM scheduling can be used.2- Maintenance actions (MD term) is based on the machine condition using modern techniques for scheduling is based on the optimization criterion.Criterion of the optimization problem in maintenance scheduling is minimizing the total, expected cost of maintenance per unit operating time. To verify this objective in CBM scheduing, mathematical models are designed. Thesemodels consist of two types; general model and special model; according to the machine independence. The general model of the optimum scheduling of CBM activities in MDTCAL system
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