Design Of Automatic Control System Of Tea Kneading Machine Based On PLC

Twisting is a key process in the processing of tea primary tea processing,to make fresh tea leaves into sticks,broken tea and leaf tissue cells breakage,etc.However,the twisting time,pressure and rotating speed of the twisting barrel are the main fator of affecting the rate of tea leaves,the rate of broken tea and the leaf tissue.In this paper,PLC automatic control technology is used to develop an automatic control system for the tea kneading machine,which can realize the continuous pressure and real-time display of pressure,and the automatic opening and closing of the kneading cover and the discharge cover.Through fuzzy PID control,the tea kneading machine can be used in the kneading barrel.The rotating speed of kneading drum of tea rolling machine is stable when rolling tea leaves.And Through Smith-fuzzy PID control,the pressure of twisting barrel cover is stable when rolling tea leaves,and automatic operation of rolling process is achieved.The project research can solve the problems of automatic continuous pressure and real-time display of rolling pressure in the tea machine industry,and reduce the labor intensity of workers,and improve the stability of tea quality is stable when kneading tea leaves;through Smith-fuzzy PID control,the pressure of the.The main research contents of this paper are as follows:(1)The key parameters in the tea kneading process were analyzed,and the requirements for the automatic control system of the tea kneading machine were put forward.The quality of tea leaves after rolling includes the rate of tea leaves,the rate of broken tea,and the degree of damage to leaf tissue cells,etc.In the rolling process,the main factor affecting the rate of tea leaves,the rate of broken tea and the degree of breakage of leaf tissue cells are kneading speed,pressure and time.According to these parameters and combined with the development status of the rolling machine,the demand for the automatic control system of the tea rolling machine was proposed.(2)The fuzzy PID control method of the rotating speed of the kneading barrel of the kneading machine was studied.According to the speed analysis of the tea rolling machine,the speed of the rolling barrel is constant and adjustable during the rolling process.So the fuzzy PID algorithm was used to control the speed of the rolling barrel.Through the kneading experiment of the kneading machine,the curve during the speed control of the kneading barrel was obtained,and the mathematical model of the kneading speed control system was determined.Use MATLAB was used to simulate and analyze the model without correction,PID and fuzzy PID.It was concluded that fuzzy PID was reduced by 33% and22.5% compared with uncorrected and PID control overshoot,and the adjustment time was reduced by 13 s and 12 s respectively.Thus the feasibility of PID control on the speed of the kneading barrel.(3)The Smith-fuzzy PID control method of rolling pressure was studied.According to the analysis of the rolling pressure of the tea rolling machine,the rolling pressure is constant and adjustable during the rolling and pressing stage.In order to achieve this rolling pressure demand,Smith-fuzzy PID control technology was introduced in the speed control of the rolling barrel.Through the rolling experiment of the rolling machine,the curve of the rolling pressure control process is obtained,the mathematical model of the rolling pressure control system was determined,and PID,fuzzy PID and Smith-fuzzy PID simulation and analysis wree carried out on the model,and the Smith-fuzzy PID comparison was obtained.The overshoot of PID and Smith-PID control was reduced by 19% and 8%,respectively,and the adjustment time was reduced by 930 s and 390 s,respectively.Thus the feasibility of Smith-fuzzy PID control on the rolling pressure was also verified.(4)The automatic control system for tea kneading machine was designed and realized.Based on the design requirements of the kneading machine,the design requirements of the control software were clarified,and the control system software of the tea kneading machine based on the FX3 U series PLC was designed to realize the functions of automatic switch of rolling drum cover and discharge cap,automatic return to the origin of rolling drum,adjustable constant rotating speed of rolling drum and adjustable constant rotating speed of rolling pressure.The touch screen software was designed with Easy Builder Pro software to monitor the rolling state of the tea rolling machine and modify the rolling pressure,time and rotating speed of the rolling barrel in the rolling process.