Research On Flow Control Of Perfusion Machine Based On Fuzzy PID

The perfusion machine flow control system has the characteristics of hysteresis,time-varying,and strong coupling,etc.It is difficult to achieve satisfactory control results with conventional flow control methods.In addition,the performance of the perfusion equipment also severely restricts the progress and quality of the project.This has become an important issue that restricts the in-depth promotion of perfusion technology,and most of the current market is a single-liquid perfusion machine.Therefore,the development of a high-precision control system with two liquids has not only important practical significance,but also has great market value.In this paper,the perfusion machine control technology is studied and the control algorithm is optimized according to the specific project of the domestic perfusion manufacturer.The characteristics of the control system of the perfusion machine,the flow control and the characteristics of the flow control valve and the DC motor speed-flow rate are studied in detail.Based on the engineering practice and its technical requirements,a predictive fuzzy PID control perfusion machine flow ratio control system was designed for low pressure conditions,and a perfusion machine flow ratio control system with fuzzy PID control was designed for high pressure conditions.Both control systems have good control accuracy and high degree of automation.Among them,the main controller is Mitsubishi FX3 U type PLC,based on the MCGS touch screen,real-time monitoring,alarm,data analysis and statistics of the flow control process.This article mainly completed the following aspects of the work:1.Conduct a corresponding study on the control method for the flow rate of the dual-liquid perfusion machine,and give the overall design of the control scheme and controller for the low-pressure and high-pressure perfusion systems.2.Using predictive control,fuzzy control and PID control theory and technology,a fuzzy PID controller for predicting low-pressure perfusion machines and a fuzzy PID controller for high-pressure perfusion machines are designed.3.the control system design: hardware,mainly for the perfusion machine flow control system of various types of module selection and overall design,the Mitsubishi FX3 U PLC and geared motor,stepper motor combined;software,mainly based on PLC The fuzzy PID control algorithm as well as the program design of the predictive fuzzy PID control algorithm and the design of the touch screen program.Through the compound control of PID control,predictive control and fuzzy control,the control of the perfusion machine flow ratio and holding pressure is realized.The effects of the two pressure filling machine control systems were verified through experiments,and the flow difference between low pressure(2MPa)and high pressure(4MPa)perfusion machines was obtained under the ratio of 1:1,2:1,and 3:1 for three flow ratios.Values are within the error allowed by the project.