Robust Repetitive Control of Roll Eccentricity for Cold Mill

A robust repetitive controller for roll eccentricity compensation of cold mill is designed.First,a cut-off fre-quency for the low-pass filter is selected based on the closed-loop expected characteristics and disturbance signal frequency.Next,the state feedback is introduced to robustly stabilize the closed-loop system and treat the controller design problem as an H_∞ state feedback controller design problem,and an algorithm for the controller parameters tuning is given.Finally,a forward gain is introduced into the control system to improve dynamic performance and static control accuracy,and the tuning method for forward gain is given.Simulation results show that even though there is perturbation in the parameters of the system objects,the controller can also achieve high-precision compensation for the roll eccentricity.