Research On Electrical Furnace Temperature Control System Based On Fuzzy Smith Intelligent Control

The time delay is widely existed in modern industrial process. It has negative effects on the control performance of the system, especially when delay time is large. When this happens, the common PID control method does not work very well, It will cause the stability of the system worse. Therefore, how to improve the control quality of the system with delay time has been studied by many schools and experts.The web-strip heating furnace is commonly used in industrial process. It is a typical large time-delay system, has large time-delay, time-varying parameters and various disturbance. The performance of temperature control system affects directly the product quality and production cost, so it has widespread actual use value to improve the control performance.The paper analyses particularly the Smith Predict Control, Fuzzy-Control and the Inter Model Control. The Smith Predict Control solves the time-delay in theory, but it is sensitive to the error between a model and practical object, lack of robustness, and it is hard to be varied used in industry. Fuzzy-Control does not need the exact model of the object and has good approximation capacity and robustness, but it cannot solve time-delay in essence. The Inter Model Control has lots of merits such as simple design, good regulation capacity, high robustness and elimination of the unknown disturbance etc. Aimed the large time-delay, this thesis puts forward the fuzzy smith intelligent control method, improves the common Smith Prediction Control as the Inter Model Control method, joins a feedback filter, and adjusts the parameter of the filter on-line.On the foundation of the Smith predictor with a one-order inertia tache, the paper does lots of simulation when the object parameters is changed and get some regulation rules about the parameter of inertia. A fuzzy controller is designed and realized based on these rules. Simulation results shows that the fuzzy Smith intelligent control method can improve the control performance and enhance the robustness and stability of the temperature control system.At last completes the electrical furnace temperature control system as a industrial computer and configuration software. Practical application shows that the system works well and has good control performance.