| Due to the low level of automation in heat treatment in China at present,and the competition of iron and steel enterprises is very fierce,so to ensure the economic and stable operation of heat treatment furnace is an important basis to improve the benefits of enterprises.With the continuous improvement of the rolling level,the requirements for the precision of billet temperature control are getting higher and higher,so in order to improve the robustness of the combustion system control of the heat treatment furnace,it is necessary to adopt advanced intelligent control.Regenerative trolley heat treatment furnace as the main heat treatment equipment is widely used in the machinery manufacturing and machining industry.The task of its control is to realize the precise control of furnace temperature,and then improve the strength,hardness,wear resistance and toughness of the heated billet,and finally meet the requirements of rolling process.The regenerative trolley heat treatment furnace is a typical complex control system in industrial process,because of its characteristics such as non-linearity,time-varying,large inertia and pure hysteresis in the process of operation,combined with some external interference factors.In this thesis,the 2# regenerative trolley heat treatment furnace in the heat treatment workshop of a steel plant is taken as the research object,aiming at the existing problems such as the uneven furnace temperature control,the difficulty in controlling the air-fuel ratio and the complex characteristics of the heat treatment furnace are studied in detail.The research contents and innovations are as follows:(1)Through the comparison and analysis of the relationship among the heat loss,thermal efficiency and excess air coefficient of the heat treatment furnace,and the analysis and study of the conventional control loop of the heat treatment furnace,a control scheme of the combustion system based on double cross limiting cascade loop control is finally determined.(2)By analyzing the control demand and influence factors of the heat treatment furnace,it is pointed out that the traditional PID control adopted at present is difficult to achieve the desired effect.Therefore,this thesis combines the traditional PID control with the intelligent fuzzy control,and designs the main controller in the cascade loop,and finally determines the control scheme of the main controller is using fuzzy PID control.Then using MATLAB to build a simulation test model of the control system,the PID algorithm and fuzzy PID algorithm are applied to the main controller for simulation,through the analysis of their simulation results,the superiority of fuzzy PID algorithm in the control of the heat treatment furnace is obtained.(3)The control system of the heat treatment furnace adopts the control scheme of distributed control system(DCS),through centralized management and decentralized control to complete the collection and monitoring of information.Siemens SIMATIC S7-1500 series PLC is used as the control layer,Win CC configuration software is used as the monitoring layer,and modular programming is used to achieve fuzzy PID algorithm.Then according to the site process requirements to complete the selection of hardware configuration,detection components and actuator,and draw the electrical schematic diagram of the heat treatment furnace.In conclusion,this control method and simulation modeling analysis could improve the control quality of heat treatment furnace,and also provide valuable experience and reference value for future research on combustion system control strategy of the heat treatment furnace. |
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