Slab curvature compensation in a hot rolling mill by means of fuzzy control
In the flat products steel industry, the hot rolling mill transforms the incoming slabs in a thin coil which then can be processed to obtain the final products. Thickness is reduced by pulling the plate between two parallel rolls while moving the upper work roll. The effect of uneven thickness at both sides can produce deviations in the longitudinal direction of the slab, which have to be manually compensated for an human operator. In this paper a multivariable control system and a fuzzy control system are described and compared. Results are illustrated with real data from ACERALIA STEEL CORPORATION.
Способ согласования нагрузок электроприводов горизонтальных валков клети толстолистового прокатного стана
This paper overviews recent advancements in research into the emergence of frontal upward bends; it also covers papers on the distribution of load between the electric drives of upper and lower rolls in horizontal platemill stands. The bulk of research lacks appropriate emphasis on the alignment of these systems. The paper dwells structuring a speed regulator for Mill 5000, which is a platemill; the regulator runs load distribution and frontal upward bending algorithms. The paper substantiates the need to research their parameters for the purpose of better alignment. It presents oscillographs of upper- and lower-roll torques that prove the load is non-uniform in any roughing pass. The paper also analyzes the oscillographs of speeds and torques in a single pass. The existing speed configuration is shown to cause the lower-roll torque to reach its limits, whereas the upper-roll drive switches to the generator mode. The authors propose and validate a set of solutions to address these challenges. They herein present a load regulation method based on forced alignment of upper- and lower-roll drive speeds by disabling the integral part of the load distribution controller. An algorithm based on this method has been implemented in the APCS of Mill 5000; the resultant oscillographs prove better accuracy and shorter time to align the torques. It is herein recommended to apply the research results in the real-world setting.
The Effectiveness of Two Approaches to the Teaching of High School American History
The purpose of this study was to test the effectiveness of studies in depth utilizing selected materials which had been developed for teaching high school American history.