The Development Of Control System For Paper-drying Based On PLC And Fuzzy-tuning Parameter

The paper making process is a complicated process.Its control parameters are easy to change, and are very unsteady. In allusion to this characteristic of paper making process, designers have adopted many intelligent control methods,such as nerve cell network control,expert control, learning control and so on.This paper has discussed the aspects about characteristics of paper making, control strategy common used in paper making, technical flow of paper making, PLC technology,the makeup of PLC control system, the selection and connection of system' s hardware, the PID control arithmetic, fuzzy self-tuning technology and so on. This paper has also brought forward the solutions to the problems which are met in practical project application and has got some achievements comparing to other methods.In the synchronous control system, the paper has the problem of weak tension, and it can break easily.This problem can be solved by the way of PID operation by fuzzy self-tuning the proportion coefficient. The speed of dring-vat can be adjusted by the operation result. By controlling with the PLC and transducer, this system has been praised well in the continuing yield in the factory.Oven temperature control is a big pure lag system. We have adopted the PID cascade control to solve this problem. The inner loop controls the pression variable and the outer loop controls the temperature variable. When debugging this system, we analyse the effection factors, such as electric machine' s rotation speed, oven' s temperature, tension roller' s location and paper' s characteristic,the control system has completely achieved the technical request.