The control of a high-speed steel-rolling mill is a challenging problem. The goal is to keep the strip thickness accurate and readily adjustable. The model of the control system is shown in Figure DP9.8. Design a control system by selecting K so that the step response of the system is as fast as possible with an overshoot less than 0.5% and a settling time (with a 2% criterion) less than 4 seconds. Use the root locus to select K, and calculate the roots for the selected K. Describe the dominant root(s) of the system.
