Network feedforward control method of cold rolling mill thickness control system

Abstract

The invention provides a network feed-forward control method for thickness control system of a cold rolling mill, which is characterized in that: a thickness control equipment comprises an entrance thickness gauge, Ethernet, a controller and a hydraulic pressing device; wherein, the entrance thickness gauge measures the entrance thickness of strip to the cold rolling mill, and the thickness value is then transmitted to the Ethernet network by using a communication interface of the Ethernet; the controller receives the thickness value by using an Ethernet communicating interface from the Ethernet, after calculation of control algorithm, the controlled variable is then sent to a servo valve to drive the hydraulic pressing cylinder, and a calculation of the controller is finished; the thickness gauge sends entrance thickness values of the strip in sequence, meanwhile the controller receives the thickness data successively for calculation, and the thickness feed-forward control of the cold rolling mill is finished. The invention has the advantages that: as the invention changes the transmission method of a thickness feed-forward channel to digital transmission from analog transmission by utilizing the Ethernet, thus the control precision and anti-interference capability are greatly improved; the connecting cables are reduced; the connecting distance is lengthened, and the trouble diagnosis and restoration capability are obviously strengthened.

Description

technical field [0001] The invention relates to a network feed-forward control method for a thickness control system of a cold rolling mill, belonging to the technical field of cold rolling mill control. Background technique [0002] In the metallurgical industry, the cold rolling mill production line of metal pressure processing equipment is very complex, and the computer control level is relatively high, and the automatic control system plays an important role in it. The automation control system of cold rolling mill can be divided into basic automation system and process automation system. For the basic automation system, the thickness control system is a key component and a key means to ensure the thickness accuracy of the rolled strip outlet. When the thickness control system of the cold rolling mill uses the feedback control method, the thickness is measured from the exit of the strip, which inevitably produces a lag in the transition process, which limits the improve...

AI Technical Summary

Problems solved by technology

[0003] ①The control accuracy is low. In the analog signal measurement method of the thickness gauge, multiple A / D (analog / digital) and D / A (digital / analog) conversions are required, and each conversion will increase the conversion error , which reduces the control precision;

[0004] ② There are many connecting cables, and each analog feedforward connection requires at least two wires. When there are multiple analog feedforwards, the connecting cables are multiplied, which increases the production cost;

[0005] ③The connection distance is short. When using analog feedforward connection, the connection distance is generally short due to the resistance of the transmission cable, which causes energy loss and voltage drop;

[0006] ④ The anti-interference ability is weak. When using analog feed-forward connection, the analog voltage or current is greatly affected by the surrounding environment. The change of the electromagnetic field in the surrounding environment may easily cause the analog voltage or current to change, reducing the accuracy of the measurement data;

[0007] ⑤ Fault diagnosis and recovery are difficult. In the analog feedforward connection, due to the increase of cables and contact points, the number of possible faults also increases, making fault diagnosis more difficult and recovery more troublesome

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