Progress Control Support System for Batch Processes

Abstract

In a batch process, the processing time changes according to various unforeseen factors. The delay of pre-assigned schedule lowers productivity and acts as a trigger for operational faults. Thus, the delay should be recovered within a reasonable time period. In the proposed system, several delay recovery strategies are defined in advance, and for each strategy the maximum reduction time and its cost are assigned to each processing stage. Then, the problem of finding the revised schedule is formulated as the problem of optimizing the recovery cost under the constraint of the number of batches within which the schedule should be recovered. A progress control support system using the proposed optimization method has been developed. When the delay of the operation occurs, the proposed system graphically indicates the operations where the processing times should be shortened. The effectiveness of the developed system was evaluated by applying the system to several test problems.