Tandem Cold Metal Rolling Mill Control

The tandem rolling of cold metal strip is a large, highly complex nonlinear multivariable process the control of which poses a significant engineering challenge. Existing controllers have proven to be susceptible to disturbances and uncertainties in process variables and attempts to increase robustness to these phenomena have had their own drawbacks so a new approach is needed. Tandem Cold Metal Rolling Mill Control deals primarily with a novel and practical advanced method for control of the tandem cold metal rolling processes based on the state-dependent Riccati equation technique which is recently emerging as a useful method for control of complex nonlinear systems. Background material is presented to assist the reader with a general control background to appreciate the significance and practical advantages of the new advanced control scheme over conventional and more recently proposed advanced techniques. A short history of tandem cold rolling is followed by descriptions of various types of cold rolling processes and a basic mathematical model of the process. The diverse conventional and advanced control methods and their advantages and disadvantages are compared, and a detailed treatment of the theoretical and practical aspects of the state-dependent algebraic Riccati equation technique given. The specific details of the new procedure are described in a manner not requiring detailed expertise in the control of tandem cold rolling. The results of simulations performed to verify the control model and overall system performance with the new controller coupled to the process model are included. Simulation results and data derived from actual operating mills are compared so as to make concrete the improvements in performance using the new method. Additionally, material is included which shows the new technique to be capable of extension to the control of a broad range of large-scale complex nonlinear processes. Engineers working with control systems in the metal processing industries will find that the advanced control ideas promulgated here will be of considerable benefit in increasing the robustness of their systems and, therefore, the quality of their products. Tandem Cold Metal Rolling Mill Control also will be useful to academics and graduate students interested in advanced automatic control and its practical application and in the uses of the state-dependent Riccati equation in particular.

Auteur

The authors of the book together have a combined experience of over 30 years in the control of metal processing areas, including tandem rolling applications. Dr. Pittner has over 20 years experience in the development, design, and commissioning of the control of these processes in both a national and international context. In addition he has presented many related papers on the theoretical and practical aspects of the control of tandem cold metal rolling at various technical conferences and has contributed papers which are published in several archival journals. Professor Simaan likewise has a wide background in the control of both steel and aluminum processes and is recognized internationally for his superior expertise in optimal control. He has published extensively on the control of various areas of metal processing which include tandem hot and cold rolling applications. With these backgrounds the authors are highly qualified and appreciative of what issues are encountered in the various facets of control development, design and commissioning and how the proposed material can significantly improve the performance of the tandem cold rolling process, as well as being an aid to the associated personnel in both a theoretical and practical sense. Moreover, they recognize not only the importance of the new technique for control of tandem cold rolling, but also the significance of its broader impacts which include the potential for improvement in the control of other large-scale nonlinear processes.

Résumé

This book deals with a novel and practical advanced method for control of tandem cold metal rolling processes based on the emerging state-dependent Riccati equation technique. After a short history of tandem cold rolling, various types of cold rolling processes are described. A basic mathematical model of the process is discussed, and the diverse conventional control methods are compared. A detailed treatment of the theoretical and practical aspects of the state-dependent algebraic Riccati equation technique is given, with specific details of the new procedure described and results of simulations performed to verify the control model and overall system performance with the new controller coupled to the process model included. These results and data derived from actual operating mills are compared showing the improvements in performance using the new method. Material is included which shows how the new technique can be extended to the control of a broad range of large-scale complex nonlinear processes.

Contenu

Introduction.- Cold Mill Types.- Mathematical Modeling.- Control Techniques.- Simulations.- Broader Impacts Beyond Tandem Cold Rolling.- Comments and Conclusion.