“…Conventionally, in steady-state high-speed rolling, the tandem cold mill is controlled using an approximate linear model of rolling. 1,2) However, when the rolling speed changes rapidly, such as during periods of acceleration and deceleration, the effect of nonlinear dynamics, which has an undesirable influence on thickness and tension control, is not negligible, and the linearized model is often inaccurate, resulting in variations in quality. Although a method of determining gains based on a transfer function model depending on the rolling speed has been proposed, 3) the transfer function used was essentially a linear model under the assumption of a constant rolling speed, and a rapid change in the rolling speed inevitably deteriorated the control performance.…”