Research On Variable Spraying Pesticide Control System Based On The Prescription Map

Our country has been a large agricultural country since ancient times,with a wide variety of crops,and the planting area of many crops is among the top in the world,but it lags behind many developed agricultural countries in terms of production and quality of agricultural products,mainly because of the problems in the control of crop diseases,pests and weeds on the application of pesticides,the use of a large amount of pesticides,and the utilization rate is low.With the research of precision agriculture has become a hot spot in recent years,experts have proposed variable application techniques to solve these problems.In this paper,by studying the current status of research on precision spraying technology at home and abroad,comparing and analyzing various different variable application methods,a variable application control system is designed,which is based on prescription map data information and uses a solenoid valve pulse width modulated variable application method,and conducts field tests and performs system performance tests.The main studies are as follows:(1)The overall scheme design of the variable application control system was carried out,and the effects of real-time flow,pipeline pressure and operating speed on the system were studied.By comparing the advantages and disadvantages of five variable application methods and their specific requirements,the solenoid valve PWM(Pulse width modulation)type variable application control method was determined,and the overall scheme design and control scheme design of the system were briefly described.(2)The hardware scheme of the variable application control system is designed.The hardware part includes the control part with the core processor as the core,three kinds of application parameters sensors and acquisition module,variable actuator with solenoid valve as the main component and battery power supply.The core processor is STC8A4K32S2A12 MCU(Micro Control Unit)of STC8 series;the sensor and acquisition module include turbine electromagnetic flowmeter,diffusion silicon pressure transmitter,BD-8953 DN receiver;the solenoid valve adopts direct-acting solenoid valve;the power supply adopts 5V and 10 V dual power supply.(3)The software scheme design of variable application control system is carried out,including two parts: upper computer and lower computer.The upper computer software is mainly used for the user’s personal computer,including data receiving,display,storage and processing module;the lower computer software is mainly used for the MCU,which can be divided into six modules according to its functions: LCD display module,keyboard processing module,data acquisition module(flow rate,speed,pressure),SD card storage module,serial communication module and PWM module.(4)Variable application control system performance tests and field trials were conducted.Including system commissioning and verification,system flow rate,pressure,speed,application volume control accuracy test.The results are as follows:the average values of absolute relative errors of flow rate,pressure and speed are2.07%,1.99% and 1.82% respectively,which are all within the controllable range and meet the design requirements.The average value of the absolute value of the relative error of the application amount is 2.04%,which is within the controllable range and indicates that the control effect is good.