Design and Simulation of an Entry Edge Guide Control System for Tandem Cold Mills

Abstract

A new entry edge guide control system for cold mills was designed using a dual-mode control system. One control loop regulated the cylinder pressure to prevent machine damage due to pressure surge while the other loop provided edge guide position control. The target control level was ±1.59 mm accuracy for a maximum operating strip speed of 530 mpm with coil sidewall location variations of ±12.5 mm/sec. A mathematical model was developed to simulate the dynamic behavior of the control system using the state space design method. The control system features two PID controllers, two hydraulic proportional valves, and a digital edge sensor. The PID tuning constants and the hydraulic proportional valves were specified by simulation results considering system response and signal noise. Data from 35 coils was used to investigate control performance. The results show that the average standard error is entirely acceptable. The majority of the coils are expected to have tracking errors less than the required accuracy.