Design And Research Of Control System For Continuous Annealing Furnace

The continue annealing furnace is a very important equipment for heating treatment of the strip. The stabilization of the furnace temperature directly influences the quality of the products. In the temperature control system of the continue annealing furnace, characteristics of the controlled subject are big inertia, lagging, non-linear. When we use the classic optimized control method, it's difficult to get ideal result. So in order to improve the self-adaptation and anti-jamming of the system, the only thing that we can do is adjusting set points of the control system by OP. But when the conditions are changing, there is always big difference between the real values and target values, so normally the quality goes down, and the cost goes up. being aimed at this kind of situation, this thesis studies the temperature control problems of continue annealing furnaces, according to the continue annealing furnace of SHOUGANG cold rolling company.Until now, in many furnaces, the temperature is controlled by manual or PID, so controlling procession is low, and result is not so ideal. In recent years, the whole world do a lot of deeper and wider research about temperature control units, and with the development of computer technology, the research of temperature control units is well developed, then a series of control units are produced, such as intelligent PID, fuzzy controller, self-adaptation controller, nerve net controller, etc, these controllers are stable, and efficient, and now are widely used.So for the continue annealing furnace the deviation of temperature is too big, and adjusting time is too long, in order to find one solution for these problems, basis on the analysis of process and requirements of the continue annealing furnace, I find one solution for the temperature control base on fuzzy PID, and with this method the precision is well improved. Integrating fuzzy controller into classic PID controller, using fuzzy control theory to set the coefficients of ratio, integration, differentiation, building the table for parameters of fuzzy controller, with the fuzzy inference I get the decision table for the fuzzy controller, at the same time I simulate the temperature curve of the furnace, then the results show that the parameter table is reasonable, and considering of the response speed, stationarity precision, it is better than classic PID. For the fuzzy PID controller, the requirements of system model are not very critical. Even with some disturbing signal or system model changing, the controller always satisfies the process demand of the furnace, also it can increase the precision of temperature controlling, improve the quality of annealing strip, and suits for all kinds of temperature control system for continue annealing furnaces whose systems are non-linear, lagging and with serious random disturbing.