Research And Implementation Of Parameter Self-modify Fuzzy-pid Control Algorithm Based On Prediction Model

Due to the time-delay and nonlinear of the object, and its dynamics indeterminacy and indeterminacy caused by external condition disturb in industry process control, the controller's parameters is difficult to determine, which makes control quality bad and process control complicated. In order to get satisfying control effect, Parameter self-modify PID control or Smith discreet controller is adopt usually, and have been used in industry. However, as accurate mathematic model is always required, and the request that system needs in different condition to parameter self-modify can not be satisfied when model changes, the control effect is bad. The research of intelligent control theory has gone deeply, and the appearance of field bus didn't only change the structure of traditional control system, but also makes the application possible in industry. Thereby, traditional control method and fuzzy prediction control algorithm are researched in this paper, and the method how to apply advance control policy to practical system is put forword, which offers useful experience to the application of intelligent control in industry.On the basic of the research of fuzzy control and prediction control, a kind of Fuzzy-PID controller based on prediction model is put forword, which combines fuzzy-PID parameter self-modify control and prediction control. It utilizes the merit of fuzzy control that can settle uncertain mathmatic model, the self-study function, and adapts to uncertainty system to realize best parameters combined PID control. Moreover, it uses prediction model to estimate process future deviant in order to determine current best input policy by roll. So, the disadvantage that the control effect needs long time to system output caused by time-delay can be prevented and realize time-delay control.the realization process in S7-300 PLC is given.Due to the method of Fuzzy-PID controller based on prediction model, the realization process in S7-300 PLC is designed and a series of experiences are made in process control experience set. The SIMATIC NET and soft and hardware of SIMENS are used as flat in this experience. The program of parameter self-modify Fuzzy-PID control algorithm and prediction control algorithm are designed by compiling STL and downloading them to PLC, and the application of intelligent control method in practice is realized. PID control experience and prediction fuzzy PID parameters experience are carried out in FCS setting, and ideal effect is got. The experiment results and application in industry approve the effectivity of this method.,by which the delay and uncertainty of object is settled and realize PID parameters self-regulating. The response speed is faster, traceability is stronger,regulate time is shorter obviously, and control precision is increased.