A KNOWLEDGE-BASED SIMULATION ARCHITECTURE TO ANALYZE INTERRUPTIONS IN A FLEXIBLE MANUFACTURING SYSTEM

One of the major issues in controlling a flexible manufacturing system (FMS) is the handling of interruptions due to machine breakdowns and rush orders. These interruptions may or may not require revisions in the manufacturing plan. By minimizing the effects of interruptions, supervisors can achieve more effective control and increase the utilization of an FMS. However, the control problem in an FMS is inherently complex and difficult to solve. Furthermore, the total time spent in analyzing interruptions, evaluating several alternative control policies, and choosing the best decision becomes critical. This issue is even more critical if on-line control is of interest. This paper describes a new integrated system that has been designed, implemented, and tested for analyzing and handling interruptions in an FMS. The design utilizes knowledge-based on-line simulation concepts. The implementation is restricted to two types of interruptions-machine breakdowns and rush orders. The recommended control decisions affect the original loading and scheduling of parts and machines in the FMS. Several experiments have been conducted to evaluate the performance of the implemented system. A case example is presented to illustrate the applicability and validity of the new system.