The Integrated Robust Control of Interstand Strip Tension for Tandem Cold Rolling Mill

Abstract

We describe an integrated tension controller design for a tandem cold rolling mill in steel plants. To achieve stable rolling and ensure strip quality, it is very important to control the tension of the cold rolling mill. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. To solve the problem, this paper proposes an integrated control strategy for tension control of tandem cold mill, the full stand model for the tension system of a tandem cold mill is built, and the interaction of all the stands is analyzed. Then applying the method of μ-synthesis design a integrated robust tension controller. Simulation with the practical data proves the integrated robust tension controller can achieve more robust performance than that of typical industrial approach.

Vertical Vibration Control of Cold Rolling Mill’s Rolls Based on Time-delay Feedback Control Method

“…In order to restrain vertical vibration of rolls and improve stability of rolling process, the active control theory and technology has been used and to control the vertical vibration phenomenon. Zhang adopted the robust theory to control the strip tension of cold rolling mill and then inhibited the occurrence of vertical vibration [1]. Fuzzy neural network is used in hydraulic AGC system and the accuracy of strip is improved [2].…”

“…1 and m 2 are defined as the equivalent mass of top work roll and top back-up roll, respectively. k 1 is defined as equivalent stiffness between the top work roll and top back-up roll.…”

Lyapunov Based Reference Model of Tension Control in a Continuous Strip Processing Line with Multi-Motor Drive

“…To control the tension in the Central Section Continuous Line (CSCL), robust control structures providing stability and invariance against the disturbances have been proposed, but the robustness is often ensured only within a narrow range of changes of parameters [18][19][20][21][22][23], while using relatively complex correction couplings [24,25]. Advanced control methods, such as feedback control using observers [26][27][28], time-optimal control [29], and H-infinity control [30,31] are methods that achieve relatively good control performance but they are too complex in terms of structure and design of parameters of the controllers and this presents their main disadvantage in their wider implementation in industrial practice.…”

Robust Tension Control of Strip for 5-Stand Tandem Cold Mills

“…Among the previous investigations, some notes focus on tension control problem in cold rolling mills [12,13]. There are numerous uncertainties and disturbances in the model of tandem cold rolling process [14].…”