The Simulation Research Of Roller Gauge Control System

The research of the thesis is based on the AGC system used in the No.1and No.4frames of the cold rollers and part of frames of the hot rollers in Benxi Iron and Steel Plant, which employees the Smith predictor control strategy.The thesis introduces AGC system’s basic work principle and control theory. Against degraded product as the system aging or the delay time changed, the thesis carries on the simulation search to the control strategy. Through the result, we obtain the conclusions:under the accurate model circumstance, the control strategy has the good product quality and with the inaccurate model, the product quality becomes bad. So draws the conclusion that the AGC system based on Smith predictor strategy has degraded product quality with changed model parameter because of the Smith predictor controller requiring the accurate model.The thesis applies the fuzzy PI controller to the AGC system. Designing the fuzzy PI controller is the main idea. The controller adjusts the parameters in real time by the fuzzy control strategy according to the input error and its changing rate. The simulation result indicates that the controller can greatly reduces the depending to the accurate degree of the model and the overshoot comparing to the Smith control strategy and has lower overshoot by contrasting to the traditional digital PI controller. So the fuzzy PI controller has more fitness.With the simulation result, we also know the fuzzy PI controller has poor dynamic character disadvantage contrast to lots of advantage. Considering this, the thesis puts forward to a kind of improved fuzzy PI controller. By the simulation, the improved controller not only shows the good points of the fuzzy PI controller. but also indicates the better dynamic character than traditional digital PI. The improved controller has almost the same dynamic character of the Smith prediction controller based on the accurate model, but the former has weaker require to the model than the latter. So the improved controller can replace the present Smith predictor strategy according to the simulation result and may be applied to AGC system.