Research And Design Of Micro-metering Pump Control System Based On Fuzzy Control

As the precision metering equipment to deliver material, micro-metering pump hasbeen widely developed in many fields, such as industrial production and scientificexploration, etc.. With the continuous development and enhancement of information andauto-control technology, it’s more and more increasingly demanding to get high meteringaccuracy and control requirements on the micro-metering pump. The domestic research onpump has a late start, and sometimes its structure and control have difficulties in adaptingto processing requirements on the modern large-scale production. So micro-meteringpump should not only improve the structure, but also perfect the control mode, in order toensure the measurement accuracy, so that the pump could get a higher adaptation.The topic mainly aims to improve the control mode for micro-metering pump anddoes a more deep study of the flow control algorithm and hardware and software systemsof the controller. Below are the main contents of study:Firstly, Proper Math. Model for the control system is established and fuzzy PIDcontrol algorithm is designed for analyzing the control system. Through simulationexperiment, it’s proved that this algorithm has a high stability and accuracy on twodifferent drive modes: Single phase excitation and two-phase excitation.And then, at the base of the master chip—AT89S52, a set of hardware circuit isdevised, which can receive detection signal from the cam of sensor through the externalterminal, speed up in the liquid filling stage in order to reduce the pulsation of the flow.The power circuits and the control circuits are separated from each other, so that the wholesystem could keep reliable. The composition of controller software is the main program,system self-test module, keypad / display module, pulse frequency module of the steppermotor, detection module on cam, the timer interrupt service module, etc.. The mainfunction to accomplish the system is keypad / display, speed regulation to stepper motor,alarms, data storage, and the communication between upper and lower computer.At last, the micro-metering pump would be connected and get communication withthe upper computer through standard serial port communication function. And a human machine interface is designed by using the VB6.0. The Optical encoder would detectcamshaft speed signal, send it to the upper computer, change into the actual flow, anddisplayed in the window of the measured values. The Optical encoder measure the speedof the camshaft and be compared with the setting speed. By the use of Fuzzy PID controlalgorithm, the speed of the stepper motor can be controlled and the error of the flow canbe reduced, in order to achieve accurate flow measurement of the metering pump.