Precise looper simulation for hot strip mills using an auto-tuning approach

A looper is an uplifted device, which is always installed between adjacent stands in a hot strip finishing mill. A virtual looper system incorporating powerful computation capability of digital computers becomes an efficient and cost-effective tool for controller design and system analysis of this complicated and gigantic system. Accurate simulation of the looper system can not only restore the actual looper’s dynamic behavior, but can also analyze the factors that affect the looper response and provide useful information for further improvement of the control system. In this paper, a looper simulation system based on a conventional hot strip mill is established. Sensitivity analysis indicates that the reduction ratio is the most important parameter for the looper dynamics. Therefore, an auto-tuning technique for a variable reduction ratio is developed. Simulation results, compared with actual loopers behavior, demonstrate significant improvement in terms of accuracy.