Robust decoupling mixed sensitivity controller design of looper control system for hot strip mill process

Yufeng Gao,Xu Yang,Yuri Aw Shardt

doi:10.1177/1687814018810282

Abstract

This article considers a robust decoupling controller design for a multivariate control system with parameter uncertainties for the hot rolling mill process. The left and right coprime factorization theory is used to properly select the free and weighting matrices. The necessary and sufficient conditions for robust decoupling controller are also proposed. Then, by analyzing the changes in the dynamic response resulting from perturbations in the tension and angle system parameters in the hot strip rolling process, a modified multivariate model is developed. Furthermore, the selection method for a practical weighting function is studied, so that the robust and decoupling performance can be simultaneously realized for the controller implementation. Finally, the effectiveness of the proposed control approach is demonstrated using a case study from an industrial hot rolling mill.

Highlights

The hot strip mill process (HSMP) is a high-speed, transient metal machining molding process.[1,2,3] In the steelmaking process, stable product quality and safe, reliable operation of a hot strip rolling mill are the main control objectives
Compared to the two references which primarily focused on the theoretical part, Jing et al.[15] proposed a feed-forward decoupling–based robust control method to guarantee the decoupling performance under parameter uncertainties and verified its effectiveness on the gauge-shape control system benchmark in the strip rolling process
If we focus more on the robustness performance, the weighting functions W2(s) and W3(s) are the design targets, which make the system output signal remain stable against uncertain parameter perturbation

Summary

Introduction

The hot strip mill process (HSMP) is a high-speed, transient metal machining molding process.[1,2,3] In the steelmaking process, stable product quality and safe, reliable operation of a hot strip rolling mill are the main control objectives. Compared to the two references which primarily focused on the theoretical part, Jing et al.[15] proposed a feed-forward decoupling–based robust control method to guarantee the decoupling performance under parameter uncertainties and verified its effectiveness on the gauge-shape control system benchmark in the strip rolling process. This result is a good initial application of robust controller in industrial fields. The performance and effectiveness are demonstrated through an experimental case study from the last rolling stand of a 1580-mm hot rolling mill

Background

Conclusion