Within the framework of the simulation study the new concepts for active compensation of thickness disturbances due to backup roll eccentricities (Rec) and harmonic hardness variations (Hdc) were to be tested and optimized.
For this purpose the two-stand mill, see Fig. 1, including decoiler, coiler and all relevant control loops was modelled and simulated.
The simulation platform in Matlab/Simulink® as used and developed by ABB enables a scalable, modular and dynamic simulation of single and multi-stand rolling mills for the development and analysis of new control concepts.
After the successful simulation study, the control concepts were implemented on the two-stand cold rolling mill.
In observation mode the functions for eccentricity and hardness compensation could be monitored and preoptimized in parallel to normal operation with no effect on the current operation of the mill.
Additional monitoring functions were provided to safeguard against signal errors, e.g. to switch to a backup mode or deactivate the compensation should important signals fail or the evaluation or suppression of harmonic disturbances give implausible results.
If normal operation is detected again, the compensation loops are automatically and bumplessly reactivated.