DocumentCode :
1662510
Title :
An Optimal Control Method for Improvement in Tandem Cold Metal Rolling
Author :
Pittner, John ; Simaan, Marwan A.
Author_Institution :
Univ. of Pittsburgh, Pittsburgh
fYear :
2007
Firstpage :
382
Lastpage :
389
Abstract :
Controlling the tandem cold rolling of metal strip is a significant engineering challenge mostly because of the complexity of the interactions between the process variables, the nonlinearities which change with the operating conditions, and the long time delays which change significantly with the mill speed. The present technology is based on methods that divide the control problem into several independent control sub-problems, which results in a limited capability for improvement in performance. This paper describes a new control strategy wherein the control of the mill is treated as a single interconnected problem that is addressed by solving a state-dependent algebraic Riccati equation pointwise to establish a control law for a multi-input-multi-output (MIMO) controller which is enhanced by appropriate trimming functions. Simulation testing of the new controller coupled to a nonlinear model of the process showed that the tolerance in mill exit thickness could be held to about .2% for typical rolling operations, which compares favorably to the tolerances of .5% to .8% using existing techniques. In addition to this improvement in performance, the simplicity of the new control method also offers the potential to reduce the efforts required for design, commissioning, and maintenance.
Keywords :
Riccati equations; cold rolling; interconnected systems; nonlinear control systems; optimal control; rolling mills; MIMO controller; interconnected problem; multi input multi output controller; nonlinear model; optimal control; rolling mill control; state-dependent algebraic Riccati equation; tandem cold metal strip rolling; trimming functions; Control nonlinearities; Delay effects; MIMO; Milling machines; Nonlinear equations; Optimal control; Riccati equations; Strips; Testing; Thickness control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Industry Applications Conference, 2007. 42nd IAS Annual Meeting. Conference Record of the 2007 IEEE
Conference_Location :
New Orleans, LA
ISSN :
0197-2618
Print_ISBN :
978-1-4244-1259-4
Electronic_ISBN :
0197-2618
Type :
conf
DOI :
10.1109/07IAS.2007.20
Filename :
4347813
Link To Document :
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