Research Of Compound Intelligent Control Of PH Value For System In Soft Water Treatment

sHaving studied the historical backgrounds as well as the current situation of intelligent control, it can be concluded that the research has been oriented towards resolving nonlinearity and uncertainty problems which are in trouble with traditional control theory and methods.Although a single intelligent control alone can partially resolve some problems, it can not be fit into the complex process which is characteristic of nonlinearity and time-variability. What's more ,the adaptability is always rather limited and the scope allowed for regulation is not wide enough .Therefore ,in order to place complex production process under better control ,it is necessary to develop continuously the theory and application of intelligent control ,to find out new ways to control ,to turn intelligent control of system into reality .As a result ,the research and application gave birth to a brand-new type of intelligent control -compound intelligent control ,which aims to combine every aspect of intelligent control organically ,so as to make full use of the advantages while get rid of the disadvantages .This is not only a new fashion of intelligent control with a bright future but also one of the highlights recently .The object of this paper is a process of PH of control system in middle tank in soft water treatment in XuChang tobacco factory. In the process of designing for the system, we discuss the intelligent control of objects of process of PH. A few practical problems have been found. To solve these problems, and want to develop some new conclusions in practice and theory.The highlight of this paper is research of control methods for process of PH in middle tank. Process of PH is of large lag, nonlinear and time-varying. It is hard to establish a precise mathematical model for a PH process. On the basis of a detail introduction for the intelligent control and fuzzy control, neural network control, expert system. Thought of features of PH process in middle tank in system of soft water treatment, this paper designed a kind of neural fuzzy controller combined feed-forward and feedback based on control strategy simulating human intelligence. The most important feature of the controller is that it imitates the control ideas of human beings who have been manipulating an object with large lag. It mainly emphasized on the problem of large lag, but could be adapted to nonlinear and time-vary of PH process through a neural fuzzy controller with ability to self-studying and self-adapt. It adopteda BP neural network with a lag factor to identify the counter static model of process and decided parameters of feed-forward control through a model image so this can have better ability of robust feature, adopted a control strategy simulating human intelligence-expert system to harmony works of system by switching among each control combination, adopted a feedback controller that can adjust fuzzy logic according to the changes of object's parameters to improve dynamic control effect.After adjustment and operation, it can be seen that the PH value control system of soft water treatment is stable and reliable and the algorithm of controller can meet all the requirements of control.