Digital twin-based methodology for schedule execution in hot strip rolling

Hot strip rolling (HSR) is a critical process in the iron and steel industry, significantly impacting manufacturing efficiency. While schedule optimisation for HSR has received considerable attention in industry and academia, there is a lack of research focusing on schedule execution, which directly affects the makespan, despite its significance. During schedule execution, various factors such as uncertain events, information asymmetry and abnormal disturbances can lead to deviations from the planned schedule, impacting both productivity and stability. However, traditional methods are inadequate in effectively addressing these challenges. To tackle this issue, the concept of a digital twin (DT) is introduced to facilitate the integration of the physical and information spaces, leading to a novel method for HSR schedule execution. This paper presents the development of a mathematical model for HSR schedule execution. Subsequently, a focused five-dimensional DT model is established, emphasising the key influencing factors of the model. Moreover, this research explores DT-based methods for start time prediction, deviation detection and rescheduling, resulting in the development of a comprehensive methodology for HSR schedule execution. Finally, the proposed approach is validated by implementing the DT system in a HSR production line at a company.