| The strip compound planting mode of soybean and maize is one of the important methods to effectively solve the problem of maize and soybean land competition.Spraying chemical herbicide is one of the important links in the production of this mode.At present,the chemical herbicide,spraying amount and spraying range of soybean and maize are not the same.The traditional spray rod sprayer can only spray one pesticide,so it cannot solve the problem of plant protection faced by soybean and maize strip composite planting mode.Based on the above problems,an online mixing system of spray rod sprayer for soybean-maize strip compound planting was designed to meet the plant protection requirements of soybean-maize strip compound planting.In this study,a set of on-line mixing system of spray rod sprayer for soybean and maize strip composite planting was designed by studying the function relationship between mixing ratio and conductivity value,system structure and mathematical model,control algorithm,hardware design and selection,and software design.The system prepared glyphosate solution and fomesafen solution suitable for maize and soybean by adjusting the mixing ratio of glyphosate solution and fomesafen solution.The main work completed in this paper is as follows.(1)The on-line detection law of pesticide mixture ratio based on the principle of electrical conductivity measurement was studied.Through the calibration test,the variation relationship between the ratio of glyphosate mixture,the ratio of fomesafen mixture and the electrical conductivity was found.The calibration work is completed,and the real-time detection function of the mixture ratio of the two drugs is realized.(2)The mathematical models of glyphosate control system and fomesafen control system were studied.The mathematical model of the peristaltic pump was established by analyzing the working principle of the peristaltic pump,the working principle of the electrical conductivity transmitter and the functional relationship between the ratio of glyphosate to fomesafen and the electrical conductivity value.Combined with the functional relationship between the ratio of two herbicides and the electrical conductivity value,the mathematical models of the controlled system of the ratio of glyphosate to fomesafen and the controlled system of the ratio of fomesafen to fomesafen were established.(3)The simulation model of on-line mixing system of spray rod sprayer for soybean-corn belt compound planting was studied.According to the mathematical model of glyphosate mixing ratio control system and the mathematical model of fluorosulphonamide ether mixing ratio control system,the fuzzy PID controller of the on-line mixing system of the spray rod sprayer for soybean and maize belt compound planting was designed,and the simulation co MParison analysis was carried out with the traditional PID controller.The simulation results show that the comprehensive performance of the fuzzy PID controller is better than that of the traditional PID controller,with the set mixing ratio of glyphosate 1.5:100 and the set mixing ratio of fomesafen0.18:100 as examples.(4)The development of on-line mixing system of spray rod sprayer for soybean and maize strip compound planting was carried out.According to the control idea of ’ hardware in the loop ’,the controller of on-line mixing system of spray rod sprayer for soybean and maize strip compound planting was designed.The key components such as peristaltic pump and jet were selected and designed.The control system mainly includes: a laptop as the upper computer of the control processing center(including Simulink model),a PLC as the lower computer of the control processing center,power module,transmitter module,actuator and human-computer interaction interface.The power module provides power for the whole control system.The transmitter module collects the parameters of glyphosate and fomesafen solution.The upper and lower computer processes the data and controls the actuator.Human-computer interaction interface for real-time display and control.The on-line mixing system of spray rod sprayer for soybean and maize belt compound planting realized the accurate preparation of glyphosate mixing ratio and fomesafen mixing ratio.(5)The stability test of online mixing system,the accuracy test of mixing ratio of online mixing system,the uniformity test of mixing ratio of online mixing system and the stability test of mixing ratio of online mixing system were carried out.The system stability test shows that the online mixing system can work stably when the pipeline pressure is between 0-0.45 MPa.In the system accuracy test,glyphosate solutions with the mixing ratios of 1.5:100 and 1.8:100 were prepared,and the mixing ratios of 0.18:100 and 0.15:100 were prepared.Their response curves were obtained respectively.The rise time of their response curves is less than 90 s,the stability time is less than 110 s,the overshoot is less than 7%,and the absolute value of the maximum relative error is less than 5%.Therefore,it can be obtained that the online mixing system can meet the plant protection requirements of soybean-maize strip composite planting in terms of response time and accuracy.By co MParing the simulation response curve of the on-line mixing system of the spray rod sprayer for soybean and maize strip compound planting with the actual response curve of the on-line mixing system of the spray rod sprayer for soybean and maize strip compound planting,it is found that the simulation response curve is basically consistent with the actual response curve,so the simulation model of the on-line mixing system is correct.Through on-line mixing system mixing uniformity test and on-line mixing system mixing stability test can be obtained,when the setting pressure is 0.3MPa,mixing uniformity,stability and nozzle atomization effect can be guaranteed. |
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