Model Parameter Identification And Algorithm Research Of Liquid Level Control System

Liquid level is a common control object in industrial control process.Many industrial control processes can be abstracted into liquid level control system models.The liquid level control system can measure and control the parameters such as liquid level,flow and pressure,and can simulate the industrial production process well.In order to improve the ability of the liquid level control system to process the experimental data and strengthen the combination of the control system and advanced control algorithm,this subject relies on the tank liquid level experiment device independently developed by the laboratory to study the visual monitoring of the liquid level control system,the level control algorithm and the parameter identification of the level control system model.The main work and research results are as follows:(1)According to the actual demand,combined with the GUIDE toolbox of the universal simulation software MATLAB,a set of visual operation platform matched with the liquid level control experimental device is designed.The software platform can monitor and control the controlled object in real time,obtain the performance parameters of the controlled object dynamically.Process the original experimental data according to different index requirements with the help of the powerful data calculation and image processing ability of MATLAB,display the real-time data in the form of curve at last,and simulate the liquid level change of the water tank dynamically.Through the joint use of MATLAB and Access database,the storage and management of experimental data is realized.(2)Step response method and least square method are used to identify the gain coefficient K,delay coefficient ? and time response coefficient T in the liquid level control system model,and the obtained identification model is compared according to the model evaluation index.The results show that the model structure identified by the least square method fits the measured data well,which provides a more accurate mathematical model for the performance analysis of liquid level control objects and facilitates the research and analysis of the application effect of the liquid level control algorithm.(3)In order to improve the control quality of the fuzzy PID controller in the liquid level control system,the influence of the original PID control parameters on the control effect of the fuzzy PID controller is analyzed and studied,and the original PID control parameters are optimized by using the global optimization ability of the genetic algorithm,and the design of the genetic fuzzy PID controller is completed.In order to solve the "premature" problem of general genetic algorithm,an improved strategy for genetic operators is proposed,and the control effect of fuzzy PID controller optimized by the genetic algorithm before and after the improvement is verified by simulation experiment.The experimental results show that the improved genetic algorithm has faster convergence speed than the general genetic algorithm,and the original PID control parameters effectively improve the dynamic performance of the controlled object.In this subject,the software interface of liquid level control system developed by MATLAB GUIDE toolbox is used to realize the combination of general simulation platform and special control system;the model parameters of the second-order liquid level control system are identified to provide a mathematical model for the simulation of liquid level control algorithm.