Strip gage and tension control at cold tandem mill based on ILQ design theory

An automatic gage control (AGC) system is important for the cold tandem mill rolling of steel. A new gage and tension control system based on inverse linear quadratic (ILQ) design theory which is superior to the conventional cross control law in preventing undesirable strip vibration, is studied. First, the ILQ controller for the first stand of the cold tandem mill is designed. Next, the ILQ control law is analyzed, and the original controller is modified. Finally, we confirm that the modified ILQ controller is able to improve the strip gage accuracy through simulation and experimental test. The focus of the study is the analysis of the function of the control loops, using parametric representation of the control law.