A new control scheme for hydraulic rolling mill

Aiming at the typical electro-hydraulic position servo system of hydraulic screw down of rolling mill, the merits and demerits of both PID control and repetitive control for the AGC compensation and roll eccentricity compensation are analyzed, then a novel multiple control scheme is presented, based on the PID control with inserted repetitive control. The structure of the new system and the method of important parameters tuning are described. The results show, that the structure of the proposed control scheme is simple; new control scheme can be easily designed and realized; dynamic and steady characteristics of the system are quite good; the novel system can realize the efficient and highly accurate compensation of AGC and roll eccentricity.