Papers by Keyword: Actuator Efficiency

Abstract: In order to improve the flatness of cold rolled strips, the accurate knowledge of actuator performance in flatness control is required. As the basis of flatness control, efficiencies of flatness actuators provide a quantitative description to the law of flatness control. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of individual actuators analyzed for better flatness control. For the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical rolling processes. The actuator efficiency factors can be determined and improved continuously by the self-learning model with correlative measurement flatness data input. With this study, performance of actuators in flatness control of UCM cold rolling mill has been obtained, which provides a theoretical basis for better flatness control.

Abstract: When there appeared catastrophic asymmetrical flatness defects in rolling processes, especially when the incoming strip is with a wedge shape, the tilting roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting roll will lead to strip break. In order to improve the ability of cold rolling mill for asymmetrical flatness defects control, performance of the work roll asymmetrical bending as well as the intermediate roll asymmetrical bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical roll bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical roll bending is significant for asymmetrical flatness control.

Abstract: The work roll bending is one of the most effective flatness actuators in flatness control of cold rolled strips, as a result of its characteristics such as high speed response, powerful effects on the elimination of flatness defects such as edge-waves, central waves and so on. The existing research on flatness control mainly focuses on the calculation of optimal adjustment of individual flatness actuator. However, the final output of a flatness actuator is required to be limited firstly for some special cases. If the incoming strip is coming with big symmetrical flatness defects, it happens that the position limit of work roll bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. In order to avoid this situation, substitution control by intermediate roll bending in case of work roll bending control over-limitation have been developed, which is based on actuator efficiencies and in accordance with the practical conditions. Applications show that the substitution control of intermediate roll bending for work roll bending over-limitation can play an important role in the residually symmetrical flatness control.