The Fuzzy Parameter Self-tuning Pid Temperature Control System Design And Research

At present, in all of the control methods in industrial control field, the PID method still accounts for over 90 percent. It has the advantage of simple structure and is easy to adjust parameters. Its efficiency depends on its parameters. In terms of those control objects whose precise models are established difficultly, the PID method has very great limitation. Moreover, because of the contradiction between quickness and the small overshoot, PID control cannot meet control demand. Fuzzy control has the advantage of quickness, it has a strong robustness. There is no need to know the object's mathematical model. But it can cause easily steady-state error because it is restricted by limited grades of the fuzzy rules. This paper analyses the advantages and disadvantages of the PID control and fuzzy control and comes to the method of combining them together. This method can make use of the advantages of them and avoid the disadvantages of them. This paper present a first-order time delay model for the annealing furnance temperature control system,and idetifies the parameters of it.Baseed on the transfer function of the model ,a simulation research is carried on .Foil annealing furnace has the disadvantages of the slowly heating rate and big overshoot. Against these disadvantages,a temperature control system based on PID parameter-adaptive fuzzy control is designed.The temperature control system can make the furnace obtain the uinformly distributed temperature in uprising and stable stage and hign efficiency and low consumption. In the light of the long distance between control room and foil annealing furnace,the paper designed a fieldbus system of PROFIBUS-DP. Via fieldbus, DP master, DP slave, TP, transducer and the intelligent devices can communicate with each other directly to make the control system easy to supervise concentratively and handle distributed.A PID parameter-adaptive fuzzy control arithmetic is put forward based on s7-300PLC. The paper realize the function of inquire online by the method of using the cursor to address the form in STEP7. That makes control arithmetic brief. The foil annealing furnace has been in good operation for half a year in Huaxi Aluminum Co., Ltd.The result showed that the foil annealing furnace has good perfermance,small overshoot, quick heating rate, quality of control ,good uniformity and high thermal efficiency.