Scalable Control System for Dense Transfer Vehicles in Flexible Manufacturing

Abstract

We propose a method for scalable transfer control of dense transfer vehicles with dynamic platooning to improve the end-to-end throughput of an entire factory in a flexible manu-facturing system. Since transfer tasks are created based on un-predictably fluctuating stock levels in the flexible manufactur-ing system, the transfer vehicles have unpredictable arrival time at intersections. Thus it is difficult to optimize schedules to pre-vent congestion of transfer vehicles at intersections. In addition, transfer routes may have multiple intersections within a short distance where influence from congestion at neighboring inter-sections is not ignorable for platooning. To solve these issues, the proposed method synthesizes transfer tasks to suppress overconcentration of the transfer vehicles in a particular area so that the transfer vehicles can form platoons to pass through without stopping at all the intersections on the transfer routes. Through numerical experiment, we find that the throughput for the proposed method is significantly larger than that for the industry standard best practice and the proposed method is more scalable in the number of transfer vehicles and more tol-erant of large input loads.