Design And Realization Of Remote Fractional PID Controller For Liquid Level Control System

Fractional-order PID control is an extension of fractional calculus and PID control theory.In recent years,with the development of computer technology and fractional calculus theory,the research of fractional PID control and corresponding remote control is attracting more and more attention.Fractional-order differential equations can well describe the mathematical model of fractional-order control system,and by using PI~?D~?controller for remote control,can make the system has better control effect and delay performance.In this paper,taking the system of THJDS-1A double-tank as the research object,introduces the theoretical foundation of fractional-order calculus,time-varying fractional-order calculus theory,the network time delay,fuzzy control,etc.Based on the discussion,an adjustable-order fractional PID controller is designed,and simulation verify its reliability and good delay performance,and it is shown that fractional PID can be applied in the network control system.The specific work is as follows:(1)According to the double-tank system experiment and working principle,the approximate integer-order mathematical model of double-tank is obtained by combining the analytical method and the experimental method.(2)Based on variable-order derivatives,by using fuzzy control theory and fractional-order operator approximation,an adjustable-order fractional PID controller is designed,and through the parameters setting method to determine the coefficient of its each link,and compared with conventional PID controller verified its feasibility and reliability.(3)The influence of time delay on the control system is analyzed,and a method of fractional PID controller parameter setting for second-order delay model is studied;Taking the typical second-order time-delay model as the object,the influence of the time delay coefficient is discussed.The experimental results show that the controller has better time delay and robustness.(4)Developed the upper computer software with adjustable fractional PID control algorithm under the C#programming environment,and combined the technology of OPC and Kingview to remote control of water level,and analyzes the time delay problem of the remote control.The results show that the simulation results are in good agreement with the experimental results,and the controller can be effectively applied in the remote control system.