Research And Application Of System Identification And Internal Model Control Method Based On LabVIEW

The continuous development of modern society has promoted the improvement of industrial technology,and intelligent control has been applied to various industrial fields involved in human life.These industrial process objects have the characteristics of large lag,multivariate,strong coupling,and uncertainty.The effective control of this system is the key to whether the production efficiency can be improved,so as to achieve the purpose of saving resources and saving industrial costs.Based on this background,this subject studied the application of the internal model control method.This method is based on the object model,so the method of low-order model identification was studied,and the software system for model identification and internal model control was developed.This paper studies the problem of model identification for low-order time-delay systems.According to different input signals,there are traditional non-parametric identification methods such as two-point method and tangent method for system identification methods based on step response and parameter identification methods are based on integration method for identifying first-order lag systems,second-order systems based on least squares and arbitrary order systems;in addition,recursive least squares is used for the identification of discrete models based on input signals that are pseudo-random sequences;And for the above methods simulation and analysis were carried out;in addition,an identification system was developed based on Lab VIEW software,and programs for filtering,identification and model evaluation were independently written,packaged into a dynamic link library and further developed on this platform,and a manual operation interface was designed to make this identification method has practical engineering utility.The principle and basic structure of the internal model controller are introduced.The internal model controller for continuous and discrete control objects are designed respectively,and the formula derivation of the continuous transfer function is converted into a discrete transfer function.For the first-order and second-order systems,specific control algorithm implementations are given.The influence of the main parameters of the internal model control on the system performance is analyzed,and a simulation analysis is made.Finally,the internal model control software based on the Lab VIEW platform is designed and written independently.The control program is packaged and developed again on this platform.The control operation interface is designed to make the control more convenient and simple.What’s more,a simulation system is developed to verify the effect of the control algorithm in real time.Taking the main steam circuit of the boiler combustion system and the temperature control system of the 3D printer as the object,the system was modeled,and the identification results were more accurately fitted to the real sample output data,and the internal model control was applied to the system to compare the control effect with traditional compared with PID control,the results show that the internal model control has a fast response speed,which is convenient for program implementation,and there is only one adjustable parameter,which is easy to adjust,can solve the problem of model mismatch,and the internal model control is more robust and has better stability.