Research On A Class Of Delay Process Control

For a long time, how to control the dead-time process has been a hotspot anddifficulty in the research of control theory. Classical control algorithm ofdead-time process is Smith predictive control, IMC (Internal model control),Predictive control, and so on. This paper focuses on the Smith prediction control.Smith predictive control algorithm is simple, the system structure is clear: it canget good control effect if the model accurately. However, to get a precisemathematical model is nearly impossible, this makes the application of Smithpredictive control hampered. For a class of time-delay process can be runrepeatedly, this paper proposed a Smith predictive control algorithm with adaptivemodel. The main works of this paper are about four aspects:(1) Deformed the structure of traditional Smith predictive control. Predictorinto a closed-loop transfer function, simply use the system input and outputinstead of the closed-loop transfer function can be used as predictor. As long as thepredictor model convergence can overcome the time delay effect on systemperformance. In order to realize the algorithm, proposed "iterative model" Smithpredictive control method, it only needs to know the system output can beobtained adaptive prediction model, and identify system dead-time；(2) Proposed fuzzy phase trajectory model Smith predictive control. In-depthstudy of the Iterative model Smith predictive control, proposed Smith predictivecontrol based on fuzzy phase trajectory model. Using fuzzy method to obtain thephase trajectory of the system output, and use it to replace the "iterative model".The fuzzy method has its own characteristics, makes the system learn less,improve the learning efficiency；(3) Analysis of stability and convergence of the algorithm. In order to makethe algorithm is based on theory, the algorithm is described in mathematicallanguage. Closed-loop transfer function is written as iterative formula and get a differential equation. Get general solution of the closed-loop transfer function, andthen gives the model convergence condition and the stability criterion of thesystem;(4) Numerical simulation of algorithm. In order to verify the algorithm, aseries of numerical simulation was done. The simulation shows that Iterativemodel Smith predictive control and fuzzy phase trajectory model Smith predictivecontrol algorithm is effective.