Valve Positioning Control Parameter Tuning And Algorithm Research

The control valve is applied in many fields of industrial control and is an indispensable terminal regulating component in the automation industry.As a core accessory,the intelligent valve positioner can effectively improve the dynamic and static performance of the valve,improve the accuracy of the control,and the response speed.At the same time,the diversity of control is enhanced.As the core technology of the intelligent positioning of the valve positioner,the control parameter setting and algorithm structure research of the positioner are the key to the development of the positioner product.However,the stability of the control algorithm of the domestic locator compared with the foreign advanced locator is not high,and there is much room for improvement and improvement in dynamic and static performance.Therefore,it is necessary to study the parameter tuning and control algorithms of the positioner positioning control system.This paper belongs to the application type research.For the torque motor-nozzle baffle type intelligent electric valve positioner,the model parameters of the control valve positioning control system were first identified by using the MATLAB system identification toolbox.Secondly,the control was obtained by IMC internal mode method.The control parameters of the device,and finally the intelligent positioner based on the segmentation PID control algorithm based on PID-PD-half dead zone control realizes the precise control of the valve position of the regulating valve.Firstly,in-depth analysis of the working characteristics of the regulating valve positioning control system and the results of the system input and output data,the first-order inertia plus pure hysteresis model was proposed to represent the regulating valve positioning control system.The offline system identification theory such as least squares method,feature area method and two-point identification method were introduced.Finally,the MATLAB system identification toolbox was used to realize the online identification of the system model and model parameters.A large number of simulation and experimental data of CVM simulation model and laboratory control valve positioning control experimental platform show that the method can quickly and accurately identify the model and parameters of the system.Secondly,the Z-N empirical formula setting method,Z-N critical proportional setting method,Cohen-Coon setting method and internal model method are used to adjust the parameters of the PID control algorithm for the control valve CVM model and the solid valve.Comparing the closed-loop step response curves corresponding to each method,the parameter tuning based on the internal model method is the best in the dynamic and static performance of the step response.Therefore,the internal parameters method(IMC)is used to set the PID parameters.Finally,the segmentation control strategy of PID-PD is proposed based on the rapidity and accuracy of the closed-loop positioning control of the regulating valve.At the same time,in order to meet the stability requirements of the control valve position,the effect of conventional dead zone control was tried.However,due to its unsatisfactory control of valve position fluctuation and frequent oscillation,the algorithm of half dead band control was finally implemented.The control valve provides excellent control of stability at steady state.The multiple simulations of the control valve simulation model and the large number of experiments on the laboratory physical valve show that the MATLAB system identification toolbox and the IMC control-based parameter tuning method and the segmentation control algorithm based on PID-PD-half-edge dead zone control can be used in this paper.Effectively improve the accuracy of the control valve positioning control,and enhance the anti-interference ability under steady state.