A real-time optimization control method and system for air knife pressure in galvanizing process

Abstract

The invention relates to an air knife pressure real-time optimization control method in the galvanizing process. On the basis of a plating thickness neural network prediction model, the corresponding error correction based on variable lag time and the real-time optimization technology based on an increment PID algorithm are adopted, and a good anti-interference and follow-up control effect is adopted. When the plating thickness deviates from a set value because of the outside interference, the air knife pressure is optimized in real time based on the difference between a plating thickness predicted value after being subjected to the error correction, and the set value, and the plating thickness is made to be kept nearby the set value; and during product switching, iterative optimization is performed on the air knife pressure based on a plating thickness predicted value not subjected to the error correction, and the plating thickness is made to fast complete the switching process closely along with a changing curve of the set value. According to the pressure real-time optimization control method in the galvanizing process, bad influences caused to the plating thickness by the outside interference are effectively overcome due to the above technology, fast switching between products in different plating thicknesses is achieved, the plating quality fluctuation can be obviously reduced, the excessive zinc consumption is reduced, and the percent of pass of galvanized products is increased.

Description

technical field [0001] The invention relates to the technical field of galvanizing technology and the technical field of real-time optimization control of industrial process, in particular to a method and system for real-time optimization control of air knife pressure in the galvanizing process. Background technique [0002] Entering the 21st century, our country is moving from a big steel country to a strong steel country. Adjusting industrial structure, developing deep processing and high value-added products, and improving product competitiveness are the development directions of my country's iron and steel industry. [0003] However, according to statistics, metal products discarded due to corrosion in my country account for one-third of the world's total annual metal output, which shows that solving the corrosion problem of steel has very important economic significance for our country. The galvanizing process can effectively prevent steel corrosion and prolong the ser...

AI Technical Summary

Problems solved by technology

[0006] (1) The on-line measurement of the coating thickness requires a thickness gauge, and due to the limitation of the measurement process principle, the accurate measurement value of the coating thickness can only be obtained after the coating zinc solution is cooled. In order to wait for the coating zinc solution to cool, the thickness of the thickness gauge The installation location is often far away from the air knife, so it takes a long time to detect the influence of the control action of the air knife on the coating thickness, that is, the system has a large measurement lag

[0007] (2) The galvanizing process is affected by multiple complex physical factors such as aerodynamic force, boundary flow layer, and heat transfer. The final thickness of the zinc layer and the uniformity before and after the coating are mainly affected by three factors: the distance of the air knife, the air pressure of the air knife, and the speed of the strip. The influence of variables, and the influence of these variables on the thickness of the coating and the lateral uniformity of the coating is relatively complex and has a strong nonlinearity. It is difficult to establish an accurate system model using traditional mechanism modeling methods;

[0012] 2) Follow-up issues

[0016] To sum up, in the existing coating thickness control system, when dealing with external strong interference (speed up and down) or switching of coating thickness, the air knife pressure adaptive adjustment calculation or feedforward control is used to overcome the zinc layer thickness fluctuation caused by external disturbance, The control quality of this type of method is limited by the accuracy of the model, and it cannot guarantee that the control effect in the entire range of operating conditions meets the product quality requirements; at the same time, when the system is in a steady state, traditional feedback closed-loop control or general model-free adaptive control is used. The device, the correction speed of coating thickness deviation is slow, it is easy to cause overshoot of the control amount, causing the coating thickness to fluctuate around the control target value

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