Decoupling Strategy and Dynamic Decoupling Model of Flatness Control in Cold Rolling Strip

• Published in: ISIJ International Vol. 60; no. 2; pp. 286 - 296
• Main Authors: Song, Ming-ming, Liu, Hong-min, Wang, Dong-cheng, Xu, Yang-huan
• Format: Journal Article
• Language: English
• Published: The Iron and Steel Institute of Japan 15.02.2020
• Subjects: dynamic decoupling matrix; flatness control; influence matrix; process decoupling; relative gain array; static decoupling matrix
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2019-328

Taking a 1420 mm UCM six-high cold rolling mill as the research object, by calculating and analyzing the relative gain array of flatness adjustments, the flatness control strategy of independent control primary flatness, decoupling control quadratic and quartic flatness is proposed, which simplifies the complex three-loop decoupling to the two-loop decoupling, and facilitates the design of flatness control system. In order to overcome the shortcomings of the long response time and the process fluctuation of the static matrix decoupling control, based on the multi-input and multi-output decoupling control theory, a method and model for the whole process decoupling of quadratic and quartic flatness control loops is proposed by introducing dynamic decoupling matrix instead of static decoupling matrix. The simulation results show that the dynamic matrix decoupling control method can make the system adjust quickly and smoothly, and by controlling the primary, quadratic and quartic flatness, the cubic flatness can also be controlled effectively. This paper opens up a new way and method for developing a simple, practical and high performance flatness control system.