Optimum schedule control of conveyer line

In the automobile industry today, various options are allowed on a single type of vehicle to meet the variety of customer tastes, and vehicles of different work specifications are carried along the same conveyer line accordingly. Since different semifinished articles on the conveyer require different work times in work zones, the work load in each work zone varies largely with the conveyer-in sequence. If the conveyer-in sequence is not proper, there is an increased risk of conveyer shutdown or an unnecessary reduction of conveyer speed and production. In this paper, the work condition of a conveyer line having N work zones is mathematically expressed, and the optimization of the conveyer-in sequence is shown as maximizing the minimum work allowance for all work zones and all semifinished articles. The problem is complicated, however, because the work allowance at the point of time when a semifinished article is worked on is a function of the work time and work sequence of semifinished articles in the previous work zones. Moreover, the real work is liable to be disturbed unexpectedly and requires the work schedule to be done dynamically and updated constantly so as to reflect current circumstances. A conveyer-in sequence control system which is optimum in this sense is presented together with its proofs.