Design And Study Of Electric Fertilizer Discharge And Monitoring System For Stratified Fertilizer Applicator

Fertilization is an important part of crop growth.At present,there are problems such as large amount of fertilizer application and low fertilizer utilization rate,and timely and appropriate fertilization plays an important role in the growth of cotton.In view of the low fertilizer utilization rate of the existing layered fertilizer applicator,the fertilization depth does not meet the agronomic requirements and the lack of control system of the existing layered fertilizer applicator,this thesis formulates the precise fertilization scheme based on the layered fertilizer applicator,and takes the intelligent control of the layered fertilizer applicator as the research goal.Through the operation mechanism of the key components of the layered fertilizer applicator and the actual operation needs,the intelligent control system of the layered fertilizer applicator is built.The main research contents and conclusions are as follows:(1)Overall scheme design.The key components of the layered fertilizer applicator were designed.Through the analysis of the filling and discharging process of the groove wheel,the parameters affecting the working performance of the fertilizer discharging box were determined,including arc center distance,groove wheel radius,groove number and operating speed.With arc center distance,groove wheel radius and groove number as the test factors,and fertilizer discharge as the test index,the arc center distance,groove wheel radius and groove number were determined to be 22-30 mm,25-35 mm and 5-7 respectively by single factor test.Through the orthogonal experiment of three factors and three levels,the results show that the radius of the groove wheel has the most significant effect on the amount of fertilizer.The optimal combination of groove wheel parameters is 6 groove number,27 mm groove wheel radius and 25 mm arc center distance.(2)Design of electric fertilizer control system.The mathematical model of the control system of the layered fertilizer applicator is established between the parameters of the speed of the machine,the speed of the fertilizer axis and the amount of fertilizer.Through the simulation test of the fuzzy PID algorithm optimized by PID,fuzzy PID and genetic algorithm,the optimal control algorithm is determined to ensure the stable fertilization and uniform fertilization in the operation process of the layered fertilizer applicator,and realize the intelligent control of the layered fertilizer applicator.The STM32 microcontroller is used to measure the moving speed and the rotational speed of the fertilizer discharge shaft in real time,and the calculation processing and error correction are carried out.(3)Monitoring system design.The ultrasonic sensor,optical fiber sensor,Hall encoder and encoder are used to obtain the height information of the machine,fertilizer flow,ground wheel speed and fertilizer discharge shaft speed respectively,and the relevant information is transmitted to the controller to realize the communication with the touch screen.(4)Human-computer interaction interface design.Mainly for the display of relevant working parameters,machine fertilizer information input and working fault alarm.In this thesis,the touch screen of Taojingchi HMI is selected.The touch screen transmits the relevant information to the main control system through the serial communication protocol.The display of relevant working parameters and the alarm of operation faults are also conducted to facilitate the driver to observe the fertilization status in real time.(5)Test and result analysis.The electric fertilizer discharge test of layered fertilizer applicator was carried out in the scientific research base of Xinjiang Academy of Agricultural Reclamation by using Leivo 1204 tractor.The test shows that the uniformity coefficient of fertilizer discharge is 93.02%,which meets the actual fertilization requirements.The coefficient of variation of electric fertilizer discharge during operation,monitoring system failure alarm accuracy≥85%,ultrasonic sensor performance test shows that the maximum error of ultrasonic sensor measurement is 2.97%.The field test results show that the fertilizer applicator works well,the actual fertilizer discharge is close to the target fertilizer rate,and the electric fertilizer discharge and monitoring system works well.The electric fertilizer discharge and key parameters monitoring of the layered fertilizer applicator are realized.