Method for controlling fine rolling thickness of hot continuous rolling

Abstract

The invention provides a method for controlling fine rolling thickness of hot continuous rolling. The method comprises the steps of acquiring rolling machine parameters and steel strip specification parameters; performing unit step response test for the tail rack rolling machine; determining the unit step response cycle which is the time parameter of hydraulic cylinder transmission function; monitoring the control cycle of an AGC (Automatic Gain Control) system and the quantity of sampling dispersing points after unit step response lag; controlling the tail track rolling machine through the Smith pre-estimation control strategy of a proportional plus integral controller with an inertial element; monitoring an AGC system control model by fine rolling of the hot continuous rolling; controlling the thickness of the next cycle by adjusting a hydraulic system. According to the method, the AGC monitoring control process is treated as a control object with pure lag; the Smith pre-estimation compensation is introduced into the monitoring of the AGC control system; the GM method is carried out to directly perform soft measurement for roller gaps of the rolling machine; therefore, the possible calculation error caused by inaccurate HGC (hydraulic gap control) transmission function can be avoided; the response speed, stability and control precision of the control system can be obviously improved.

Description

technical field [0001] The invention belongs to the technical field of rolling process automatic control, and in particular relates to a thickness control method of hot continuous rolling and finishing rolling. Background technique [0002] In the strip rolling process, one of the most commonly used thickness control methods is to measure the actual thickness of the strip through the rack outlet thickness gauge, and then adjust the hydraulic roll gap of the rolling mill to perform feedback control on the thickness. Due to the limitation of the rolling mill structure, the maintenance of the thickness gauge, and in order to prevent the damage of the thickness gauge due to the broken strip, the thickness gauge is generally installed far away from the roll gap that directly produces the thickness change, for example, the exit gauge of the hot continuous rolling mill The thickness gauge is installed at a distance of about 2000-4000mm from the center line of the work roll, such as...

AI Technical Summary

Problems solved by technology

It reduces the stability of the control system, especially the characteristic parameters that measure the influence of pure lag on the system object (here T is the time constant of the object), it is difficult to obtain good control quality by using conventional PID control

[0009] In the prior art, regarding the large lag control system, although a lot of research work has been done in China, the actual control effect in the strip rolling is not ideal

There are many control strategies for MN-AGC. However, these existing control strategies are difficult to balance the rapidity of dynamic adjustment of the system and the high precision of static state, and the improper selection of regulator parameters will cause the system to easily oscillate.

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