Research on high-precision temperature controller for annealing furnace

1, Overview:
Annealing is a process in the production of cold-rolled products in steel enterprises, and the annealing furnace is a key equipment of the continuous annealing unit. The efficiency of furnace temperature control directly affects the quality of cold-rolled products and is one of the key skills in continuous annealing control.
Due to the high inertia and large lag of the furnace itself, it is difficult to adjust its temperature. Currently, the dominant position in furnace temperature control is still the traditional simple PID temperature controller. However, traditional PID control skills have inherent defects in dealing with nonlinear, large lag, and difficult to establish accurate mathematical models of control objects such as furnaces, which can easily cause oscillation and other phenomena. In conventional furnace control, automatic control is generally used, which not only shortens the production cycle but also reduces pollution, making a contribution to the construction of sustainable technology.
2, Temperature controller structure:
The temperature controller mainly consists of the following parts: a fuzzy control type PID controller, a strip steel parameter corrector based on a data table, and an accelerating heating and cooling regulator, a gas pressure corrector, etc.
3, Specific operation of temperature controller:
1. Fuzzy control type PID controller:
PID control is one of the traditional industrial control methods, with the advantages of simple structure and low cost. However, this conventional controller is suitable for stable adjustment processes with small delays, but for controlled processes with oscillations such as annealing furnace temperature control, the control efficiency is poor. Therefore, a combination of PID control and fuzzy control can be used to achieve automatic control, which can not only solve the above problems, but also adjust in a shorter time than conventional control methods, with good stability and small errors, Achieve good control efficiency.
(1) PID controller:
The principle of the entire PID controller is composed of proportional, differential, and integral links. After passing through three links, an output is given to the controlled object. Then, the entire controller compares the output result with the set value. If there is any deviation, it will be fed back to the proportional, integral, and differential links for further adjustment, forming a closed-loop loop.
(2) The advantages of fuzzy control:
Fuzzy control is an automatic control in industrial control nowadays, and annealing furnaces have a wide range of applications, not only in industrial control, but also in household appliances. As a familiar operator, it is not necessary to know whether the controlled object is an accurate digital model, and one needs to have very familiar operating experience to complete this complex control process, If these familiar practical experiences can be summarized and described in language, a fuzzy control library suitable for the controlled object can be developed.