Use of fault-tolerant techniques with virtual rolling to improve the robustness to measurement faults in the control for tandem hot metal strip rolling.

In the control of the tandem rolling of hot metal strip a degree of robustness to faults in measurements is important to avoid degradation of the availability of this process. Typical of these faults are those in the tension or roll force measurements which would preclude a valid measurement of these variables. Such faults could degrade the process availability and seriously reduce the quality of the output, which could result in a major loss of production and possible equipment damage. We investigate in this paper a method of control for this process that permits continuity of operation during possible faults in the tension or roll force measurements, and without major disruptions in process operation or significant reduction in the quality of the output. The effectiveness of this method is shown by simulations.