Multivariable control of wire rod rolling and precision rolling and precision rolling system

摘要

This paper deals with the multivariable control and precision rolling system for the No-Twist rod finishing block mill. The roll gaps of 1st and last stands (control inputs) greatly influence the exit height and width of the last stand (controlled variables) due to a common drive. First, we derive a linear state-space model which is applicable to the discrete-time optimal regulator theory, by adding a feedforward control. The control law is implemented by the state vector feedback and the disturbance vector feedforward. In order to evaluate the control performance, responses to entry diameter and entry temperature changes are computed and measured on a model mill and computed on production mills. On the basis of the computed and experimental results, the validity of the present control system is confirmed. With the multivariable control system, the precision rolling of a wire rod with a nominal diameter tolerance of to ±1 mm has been put into practical operation.