Application Of Model-Free Adaptive Control In Water Level-Temperature Regulation System

With the continuous improvement of the degree of industrialization,the control accuracy requirements for a series of indicators of the controlled plant become higher and higher,whereas the mathematical models of corresponding controlled plants become more and more complex,which makes the traditional model-based control methods have been unable to meet the modern control requirements.At the same time,with the development of sensor technology,massive data can be obtained during the industrial processes,so the data-driven control theories based on the input and output data of process system have gradually become the mainstream of current automatic control researches.In the actual process industry,the liquid level and the temperature are two representative system state variables,such that the good or bad of the quality of these two objects are often has a significant impact on industrial production.Moreover,the liquid level and temperature control system in practice due to their own complex characteristics,making it difficult to establish the mathematical model accurately.Therefore,controlling these indicators in a data-driven manner is a very significant topic of automation research.Meanwhile,a good experimental platform for the implementation of advanced control theory and verification is particularly important.Thus,the development,construction and reconstruction for this kind of platform are also the research focus in engineering field.Therefore,this thesis has completed a lot of researches for the problem of data-driven control of liquid level and temperature in process control and platform construction in process industry,which can be described as follows.(1)A series of control schemes have been proposed which can be applied to the level control system,temperature control system as well as the temperature-level coupling control system based on the model-free adaptive control.In this way,the problem of large time-delay,uncertain models and difficulty in modeling the process of liquid level and temperature control could be perfectly solved.(2)The hardware and software platforms of the regulation system based on the THJ-2 process control experimental apparatus are built.Specifically,the schematic and PCB diagram is designed via Altium Designer software,athnd then develop the software platform is developed by Microsoft Visual Studio2010.This platform can be the realization of the control algorithm,DA/AD conversion,and serial communication,etc.(3)A series of liquid level control experiments and temperature control experiments have been done on the well-builded platform of the regulation system,which can simulate the complicated situations in the industrial production.The results showed that the proposed model-free adaptive control schemes have good control precision,stability and robustness for nonlinear systems with large time-delays and time-varying system structures,which mean the applicability of the proposed schemes are verified.(4)The controller parameters of the proposed control schemes are analyzed in detail,and some experiments have been carried out to compare with the existing control scheme simulations on the simulation platform.Meanwhile,the effectiveness of the proposed model-free adaptive control scheme is further verified for a series of numerical simulations for the proposed controller parameters.