Design And Experiment For Self-adaptive Optimization Control System During Electrostatic Sprayer Work Process

China is not only a country with a large population,but also a large agricultural country.However,in the prevention and control process,the effective utilization rate of pesticides is less than 30%,which leads to serious environmental pollution and waste of resources.Electrostatic spray technology is a new type of pesticide application technology recognized internationally that can increase the efficiency of pesticide application.However,the operating parameters of the electrostatic spray applicator are fixed during the application process.When the ambient wind speed changes,the operating parameters cannot be adjusted which is not conducive to maintain the best deposition effect.Therefore,in this study,an adaptive optimization control system for the electrostatic spray applicator working process was developed.Based on the exploration of the interactive effects of wind speed,spray pressure and electrostatic voltage on the deposition rate of droplets,a mathematical model for the deposition rate of droplets was established to design.In order to achieve the purpose of improving droplet deposition efficiency,an adaptive optimization control system was applied to the electrostatic spray applicator.The main research and conclusions are as follows:(1)Online Adjustable High Voltage Electrostatic Generator was designed and tested.The generator includes an input power supply,an adjustable voltage regulator module,a PWM wave generation module,a high-frequency inverter module,and a voltage doubler rectifier module.The output characteristics and load characteristics of the online adjustable high-voltage electrostatic generator was adjusted.Tests show that the online adjustable high voltage electrostatic generator has a good output,and the load has almost no effect on the output.(2)The influence of wind speed,spray pressure and electrostatic voltage on the deposition of droplets during spraying was experimentally studied.The experimental results showed that the deposition rate of droplets increases first and then decreases slowly with the increase of voltage.When the electrostatic voltage is 8kV,the deposition rate reaches a maximum of 43.31%.The deposition rate of dropletsincreases first and then decreases slowly with the increase of pressure,reaching a maximum of 46.21% at 0.35 MPa and the deposition rate decreased with increasing wind speed.The response surface method was used to process the electrostatic spray deposition test data.The results showed that the influence of the three parameters on the deposition rate of the charged droplets was the secondary term of the electrostatic voltage,the secondary term of the spray pressure,the wind speed,and the electrostatic voltage.The influence of spray pressure and electrostatic voltage factor on the deposition rate is mainly quadratic.The influence of wind speed on the deposition rate of droplets is mainly linear.A mathematical model for the deposition rate of droplets was established.The combination of the highest deposition rate of droplets and the optimal combination of electrostatic voltage and spray pressure at different wind speeds was obtained.(3)According to the mathematical model of electrostatic spray deposition rate,Kalman filter and PI adjustment technology are adopted to design a control system for on-line adjustment of spray pressure.The real-time voltage regulation system is integrated in the adaptive optimization control system of the electrostatic spray applicator working with the STM32 microcontroller as the main control element,and its control effect was tested.The experiment shows that the deposition rate can provide up to 17.3%,and the prediction value of the mathematical model does not exceed 5% after the adaptive optimization control system is opened.The coefficient of variation of deposition at different wind speed is reduced relative to that when it is not open.