Looper and tension control in hot rolling mills: A survey

Looper and tension control is important in hot strip mills because they affect the strip quality as well as strip threading. Moreover, the most difficult challenge in controller design and control performance arises from the interaction between looper angle and strip tension. Disturbances from several sources cause a deterioration in control performance, and thus a major role of the control algorithm is effective disturbance rejection. Many authors have proposed and applied a variety of control schemes to this control problem, but nevertheless, the increasingly strict market demand for strip quality requires further improvements in this control area. Hence, this paper critically surveys the strengths and weaknesses of several existing academic and industrial approaches and explores the potential for development in this area.