A Research On The Fuzzy Self-tuning PID Parameters Controller Used In The Mould Level Control System

The control system of mould level is crucial to improve the slab quality in the continuous casting process, PID controller is used in the traditional mould level control, and it has some defaults, such as: at the start-up or finishing period of casting or during the changeover of tundish, PID control has a bad effect, its overshoot is large and its transient time is long; the erosion of the tundish stopper and the submersed nozzles lead to the accuracy of control become bad; the abrupt falloff of block in the submersed nozzles makes the level acutely fluctuate, and PID control can not overcome the disturbances resulted from the change of casting speed.Based on the careful analysis on the difficulties, which the mould level control system encounters, and scrupulous research on many controllers which applied to the mould level control system, a fuzzy self-tuning PID parameters controller is adopted in this paper, which aimed at taking place the old PID controller for which bad control effect. Although the fuzzy self-tuning PID parameters controller has been applied in many control fields, it not be reported that the fuzzy self-tuning PID parameters controller be applied to the mould level control system, according to the present information.The fuzzy self-tuning PID parameters controller consists of self-tuning parameters PID and fuzzy controller. Based on the normal PID controller, in this controller the fuzzy controller be applied to adjust the PID parameters: kp, ki,, kd on line. Generally, twoinputs and three outputs fuzzy controller is applied to fuzzy self-tuning PID parameters controller. In order to avoid intricacy fuzzy rule and complex calculation, fuzzy self-tuning PID parameters controller in this paper only tune kp, the fuzzy rule is an intelligence function.After researched fuzzy self-tuning PID parameters controller, a simulation experiment is shown in this paper, which demonstrated this controller is feasible. At last, a practical experiment is made with the EFPT process-control equipment, the result of the experiment manifests: fuzzy self-tuning PID parameters controller integrate theadvantage of PID controller and the fuzzy controller, it has the following character: small overshoot; short transient time; excellent control accuracy and no stabilizing error.