Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지

H$_{\infty}$ Control System for Tandem Cold Mills with Roll Eccentricity

  • Kim, Seung-Soo (Research Center for Machine Part and Materials Processing, University) ;
  • Kim, Jong-Shik (School of Intelligent and Mechanical Engineering, Pusan National University) ;
  • Yang, Soon-Yong (School of Mechanical-Automotive Engineering, University) ;
  • Lee, Byung-Ryong (School of Mechanical-Automotive Engineering, University) ;
  • Ahn, Kyung-Kwan (School of Mechanical-Automotive Engineering, University)
  • Published : 2004.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

In order to meet the requirement for higher thickness accuracy in cold rolling processes, it is strongly desired to have high performance in control units. To meet this requirement, we have considered an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation as well as roll eccentricity as the major disturbances, a synthesis of multivariable control systems is presented based on H$\sub$$\infty$/ control theory, which can reflect the knowledge of input direction and spectrum of disturbance signals on the design. Then, to reject roll eccentricity effectively, a weight function having some poles on the imaginary axis is introduced. This leads to a non-standard H_ control problem, and the design procedures for solving this problem are analytically presented. The effectiveness of the proposed control method is evaluated through computer simulations and compared to that of the conventional LQ control and feedforward control methods for roll eccentricity.

Keywords

References

  1. Bland, D. R. and Ford, H., 1948, 'The Calculation of Roll Force and Torque in Cold Strip Rolling with Tensions,' Proc. of Institute of Mech. Eng., Vol. 159, pp. 144-153 https://doi.org/10.1243/PIME_PROC_1948_159_015_02
  2. Doyle, J. C., Glover, K., Khargoneker, P. P. and Francis, B. A., 1989, 'State-space Solutions to Standard $H_{\infty}$ and $H_2$ Control Problem,' IEEE Trans. on Automatic Control, Vol. 34, pp. 831-847 https://doi.org/10.1109/9.29425
  3. Edwards, J., Thomas, P. and Goodwin, G. C., 1987, 'Roll Eccentricity Control for Strip Rolling Mill,' Special Case Study Paper, 10th IFAC World Congress, Munich, Vol. 2, pp. 200-211
  4. Francis, B. A. and Wonham, W. M., 1975, 'The Internal Model Principal for Linear Multivariable Regulators,' Applied Mathematics & Optimization, Vol. 2, No. 2, pp. 170-194 https://doi.org/10.1007/BF01447855
  5. Goodwin, G. C., Evans, R. J., Leal, R. L. and Feik, R. A., 1986, 'Sinusoidal Disturbance Rejection with Application to Helicopter Flight Data Estimation,' IEEE ASSP, Vol. 34, pp. 479-485 https://doi.org/10.1109/TASSP.1986.1164834
  6. Hattori, S. and Katayama, Y., 1987, 'Development of Blocked Non-interacting Optimal Control System for Rolling Mill Control,' 30th Automatic Control Federation, A Lecture, pp. 3059-3060
  7. Hill, R., 1950, 'Relation Between Roll Force, Torque and the Applied Tensions in Strip Rolling,' Proc. of Institution of Mech. Eng., Vol. 163, pp. 135-140 https://doi.org/10.1243/PIME_PROC_1950_163_017_02
  8. Lisini, G. G., Toni, P. and Valigi, M. C., 2000, '$H_{\infty}∞$ Control System for a Four-high Stand Rolling Mill,' Proc. of Institute of Mech. Eng., Vol. 214, Part I, pp. 79-86
  9. Mita, T., 1994, $H_{\infty}$ Control (in Japanese), Shokodo, Tokyo, Japan
  10. Teoh, E. K., Goodwin, G. C., Edwards, W. J. and Davies, R. G., 1984, 'An Improved Thickness Controller for a Rolling Mill,' Proc. 9th IFAC Congress, Budapest, pp. 1741-1746