The Research And Design Of Agitator Control System Based On PROFINET

As an important part of modern industrial production,mixing process is widely used in production industries such as chemical industry,pharmaceutical industry,dairy industry,etc.At present,industrial agitator control systems mainly work in the network environment.In order to improve the quality of mixing,the agitator system needs to work according to the set parameters as much as possible.In order to achieve mass production,it usually requires multi-mixing systems to operate coordinately.However,the existence of uncertainties such as time delay in network is against to the control effect of a single mixing system and the coordinate control of multi-mixing systems.And it will affect the mixing quality of product.Therefore,it is necessary to deal with the time delay of the agitator control system in network environment.This thesis simulates the actual mixing process in industrial production under laboratory condition,and it builds an experimental platform for agitator control system in PROFINET network environment.Based on the analysis and research of time delay existing in PROFINET network platform,it achieves both the fast and stable control of the speed and the coordinate control of speed in multi-mixing systems.When analyzing the time delay of the system,this thesis first designs an improved Smith predictor,which is based on fuzzy control and Smith predictor because of the uncertainty of the time delay in the mixing system and the inaccuracy of the controlled object model.By adjusting the open-loop coefficient of Smith predictor online,the dependency on the accuracy of model prediction of traditional Smith predictor is reduced.In order to reduce the systematic influence because of fixing the random delay of the predictor,this thesis combines the improved Smith predictor with the fuzzy PI controller,and designs an improved fuzzy Smith controller to make up the random delay of the system.In the simulation,the comparison of the control effects among different controllers shows that the improved fuzzy controller can minimize the adverse effect caused by the time delay when controlling the single system.The multi-system simulation result shows that the fuzzy smith controller can help to achieve the coordinate control of systems.In the end of this thesis,it compiles and runs the relevant control program on the built system platform.The results of system operation show that the stirring speed of the single mixing system can be quickly followed.The multi-mixing systems can quickly achieve the following control of speed.The simulation results and actual system operation results verify the feasibility and effectiveness of the controller designed in this paper.