A Novel Decoupling Control Research Of Gas Heating Furnace Temperature System

Gas heating furnace is an important equipment for the billet heat treatment in metallurgical industry.In order to ensure the heating quality and mechanical hardness of cold-roll billet,a very narrow range of heating temperature error is required.How to guarantee the temperature of gas heating furnace at each temperature zone control system that has the characteristics of high precision and high uniformity.It has been the focus of research in this field.Gas heating furnace is too bulky,and the method of gas heating furnace is heating in different temperature zones.However,it has many drawbacks,such as more random interferences of each temperature zone in the combustion process,nonlinear,large delay,large inertia,strong coupling and so on.It is worth noting that these characteristics can directly affect the accuracy and uniformity of temperature control.The idea of adjoint matrix decoupling is proposed to design the decoupler by analyzing the shortcomings of traditional and existing decoupling methods in this paper.Amplitude frequency characteristics and phase frequency characteristics of the decoupled high-order model is utilized,and the model is reduced to the first order inertial pluses time delay form.In order to verify the feasibility of the proposed decoupling method.Firstly,the coupling model of gas heating furnace temperature system should be established to implement the decoupling strategy.In this paper,the furnace body structure and production process are analyzed in detail,and we find that it is difficult to establish a precise model for the temperature characteristics of gas heating furnace in long flow productive process.However,the optimization of control objective and the implementation of advanced control schemes usually depend on the mathematical model of the object.In order to resolve these problems,the weighted least squares recursive identification method is applied to the modeling experiment of gas heating furnace,and the actual running data was used to establish an accurate transfer function matrix control model of three input and three output coupling system.Lastly,The controller of gas heating furnace temperature control system is designed by using the principle of internal model control with time delay process for each control channel after decoupling,afterwards the decoupling control algorithm of gas heating furnace three temperature zones system is realized.In addition,the pontryagin double curvature method is adopted to the robust stability analysis of the controlled object system with the first order inertia pluses time delay,then the stability margin of delay time parameters ? of the three control channels can be obtained under the condition of satisfying stability margin.The simulation models of the system have heen established by using the MATLAB simulation software in SIMULINK for the simulation study.Obtatining the dynamic and steady-state performance parameters of decoupling,robustness and anti-interference of decoupling control scheme that mentioned in the paper.Compared with the more influential solution of the normalized decoupling,it is superior that the performance index of the decoupling control system designed based on the adjoint matrix decoupling control method in this paper.In theory,the effectiveness of the proposed scheme is proved.