Design Of Precision Spraying Machine Control System In The Orchard

Variable pesticide application is an important measure to ensure the spray volume of perunit area，increase the pesticide utilization and reduce the pollution. In the orchard sprayingarea, some spraying machines and technologies are very backward, and the controlperformance is very poor, the control system can’t monitor the spraying parameter online.Base on such situations, a variable application monitoring and control system used in theorchard was designed by the embedded and automatic control technology. The main contentand conclusions of the paper are as follows.(1) The whole system requirements was based on the technology needs, include thevariable application based on the changed speed, the parameters monitored online and thenozzles controlled independently. Through the analysis and coMParison to the every scheme,the whole scheme of the system was determined. The system’s scheme, which used theEmbedded Linux Operating System and the ARM chip, to control the volume based on thespeed of the tractor, to monitor the spraying parameter and the working model, and to controlthe nozzles independently by the switches.(2) The testing components, executive components and the other equipment were choseaccording to the system design and functional requirements. Mircro2440development boardwas adopted as the controller core of the system. The power circuit was designed based onLM2576and GS3663.74HC08was used to design the signal collection circuit and solenoidvalve controlling circuit. The electric ball valves circuit was designed based on non-standardsolid-state relay. PCB board was made by the integrated circuit of each module selection. Thespeed simulated system was designed by the brushless DC motor and motor controller.(3) The device driver programs and the low computer software were designed by the Clanguage. The device program includes buttons driver program, the speed collection driverprogram, the flow collection driver program and the ball valve driver program. The lowcomputer software includes sensor signals collecting program, volume controlling programand nozzle workstation display program. The upper computer GUI software was developed bythe QT Creator and written in C++, which including the main GUI, the parameter setting GUIand the numerical keyboard GUI.(4) The Embedded Linux Operating System was installed, and the cross compilingenvironment was established according to system development requirements. The Linux kernel was compiled, configured and transplanted and the QT environment was configuredand transplanted.(5) The spraying performance simulation test bench was built and the system control boxand cable connector were designed. The test of hardware and software joint debugging andthe application experiment of the whole system were made. The results showed that thesystem can collected and displayed the spraying parameters, the nozzles station and workmodels. The measuring accuracy of speed, pressure and flow value were97.8%、98.0%、98.3%. The opening and closing of each nozzle could be controlled by the independent switch.The amount of pesticide was monitored and controlled by hysteresis control algorithm. Thecontrol precision of the amount of pesticide could meet with the requirements of agriculturalproduction.