The Research Of Fuzzy Control In Lead And Zinc Melting Control System

Lead and zinc are widely used in electrical,mechanical,military,metallurgy,chemical and pharmaceutical area and so on.There is a large quantity of lead-zinc ore in our country. Because of the low level of smelting automaticity,the metal returns-ratio is very low. Although a lot of large scale enterprises adapt DCS,for the lack of optimal control supporting, the equipment only replaces the original typeⅢinstruments,far from playing the role of its control.Therefore enhancement of lead and zinc smelting automatic level becomes one of urgently needed research topics.This thesis is set in the engineering of melting technical upgrade in Baiyin third smelting factory.Combined with melt process and control requirements,this paper puts forward and designs the overall program of the control system.Programming software Step7 is adopted. The complex automated duty was decomposed into the independent function blocks.When executed by the main loop module these blocks,to make the control easier.With Wince V6.0 for development software,monitor and control menu are designed,and corresponding monitor program is worked out,which makes the system process obtain such functions as dynamic monitor,archiving history data,singularity alarm and so on.Making full use of fully integrated automation idea,top-down implementation of the smelting workplace vertically integrated and PN-IO equipment hanging on PROFINET bus horizontally integrated are realized in this system.In view of the characteristics of temperature's dynamic change in combustion process and difficulty in realizing real-time control,the thesis studies the system's control method with emphasis.Based on analyzing the general theory of fuzzy control method,the design of fuzzy controller about the best ratio of air to fuel ambiguous is completed by the serial process of constructing the fuzzy rule,watch and anti-faintnesses etc.The practice shows that the algorithm has the characteristic of smaller overshoot,better stability and faster response rate.The system is now operated in the third smelting factory of Baiyin.The real-time monitor and control are realized successfully,and system operates stably.It has the value of practical production and application and achieved good economic benefit.