Applications Of Expert-Fuzzy Control In Pulping And Papermaking Wastewater Treatment

Pulping and papermaking wastewater treatment is an important processing section of papermaking enterprise.It is related with the survival,development and interests of papermaking enterprise.In addition,the quality of wastewater treatment is related with the human living environment,health and other issues.Therefore,the research of intelligent control algorithm in the process of pulping and papermaking wastewater treatment has the profound significance.Most of the controlled objects in the process of wastewater treatment have the characteristics of interference,nonlinear,time-varying,large time delay,inaccurate mathematical model,and the conventional PID control can't satisfy the control precision of the control system.They are widely used intelligent control methods.The biggest advantage of them is not dependent on the accurate mathematical model of the controlled object.Expert control and fuzzy control depend on the control rules which are from the experience of experts or long-term attendants.Expert control has the characteristics of quick response,short setting time,small overshoot;fuzzy control has the characteristics of high control precision,strong anti-interference ability.To some extent,the expert control and fuzzy control in different control mode can improve the response speed of the control system,control accuracy and stability at the same time.The paper selected three controlled objects in the control process of wastewater treatment,which are causticizing temperature in alkali recovery stages,pH in the anaerobic process,and dissolved oxygen concentration in the aerobic treatment process.The paper put forward different expert fuzzy control schemes,which are dual-model improved Smith predictor based on expert and fuzzy PID controller of causticizing temperature,feed-forward fuzzy-PID based on expert supervisory of pH,dissolved oxygen concentration control system based on expert feed-forward and fuzzy PID feed-back control.The paper introduced the structure of all kinds of control scheme system,the design of the controller,and the determination of control rules in detail.And the simulation model of the proposed control schemes is established for simulation in the Simulink of MATLAB.The simulation results show that the control effect of the control scheme is good,with small overshoot and short adjustment time,strong anti-jamming capability.Finally,the expert-fuzzy control algorithm is applied in THJSK-1 experimental platform,which realize the control algorithm on the industrial PC by the MCGS configuration software.Finally the experimental results show that the control result of the expert fuzzy control algorithm is better than conventional PID control,which is with less overshoot,short transition time and small steady state error.The simulation results and experimental results show that the expert-fuzzy control algorithm has certain feasibility.