A New Digital Twins Technique for Minimizing Setup Times in Reconfigurable Stations of a Mixed Model Flow Lines

The integration of reconfigurable manufacturing systems (RMS) with digital twin (DT) technology presents both opportunities and complexities. Since many reconfigurations in mix-model flow lines are related to product variety, and thus product arrival from upstream station contains the information for most of the reconfiguration requirements, we propose a novel scheme for the use of workstation DTs to best handle the frequent reconfigurations. We present the concept of two alternating DT replicas for reconfigurable stations. One of these DTs (referred to as the current twin) is focused on processing the current product, while the second twin (the incoming twin) is focused on the incoming product and its process requirements. This mechanism allows the incoming twin to prepare for changes and start the reconfiguration as early as possible. Some reconfigurations may be done before the workpiece arrival, and a plan for minimizing the reconfigurations time would be ready for the switching moment between incoming and outgoing products. The hand-off process of the workpiece, as it switches stations, is reflected by real-time digital hand-off process at the station where the incoming twin and current twin interchange roles. This is a key to the improved efficiency of the process which is also the paper's major contribution to enhancing the flexibility and responsiveness of mixed model flow lines. The paper concludes with a discussion of future research directions, including the integration of artificial intelligence for predictive reconfiguration and the extension of the digital twin concept to entire production networks.