APPLICATION OF REPETITIVE CONTROL TO ECCENTRICITY COMPENSATION IN ROLLING

Repetitive control is applied here to compensate for roll eccentricity disturbances in thickness control of the cold rolling process. A uniq ue aspect of the process is that the eccentricity disturbance may be f rom multiple rolls and hence may be composed of multiple periodic comp onents whose periods may not be commensurate, namely, divisible by a c ommon factor an integral number of times. The paper presents a multipl e-period repetitive controller structure that can compensate for such a disturbance. The structure proposed is also applicable to other trac king and regulation applications involving multiple periodic signals. Procedures to analyze and design control systems with such a structure , to ensure stability and performance, are presented.