| Effective prevention and control of pests and diseases is an important basis for achieving high yield and stable production of agriculture to ensure sustainable development of agriculture.At present,the main way to control pests and diseases is chemical treatment,but in the process of prevention and control,most of the pesticides sprayed are lost and wasted on the field and the environment.With the large-scale use of pesticides,the ecological environment has been seriously damaged.Today,the primary means of solving the above problems is variable spray technology.In this thesis,aiming at variable spray technology,a spray controller is designed and developed to improve the utilization rate of pesticides.In this thesis,the research status of large-scale plant protection machinery is studied at home and abroad,and a spray system of a plant protection machinery and its structure and working progress are analyzed.Then the proportional valve used in the spray system is analyzed and modeled.An overall design of the plant protection machinery spray control system is completed,additionally,a design and development of the plant protection machinery spray controller based on the embedded system is carried out.In the design process,the hardware circuit design of the controller is firstly carried out.The STM32F103RBT6 chip is selected as the main control unit of the controller,and the peripheral circuit design of the main control unit is completed.At the same time,the circuit schematics of the input circuit,serial communication circuit,rectifier circuit,LCD display circuit,output circuit and download circuit of the controller are also designed and developed on PCB.In order to ensure the control effect of the spray controller and its applicability in engineering,a fuzzy PID controller is designed and the effect of the controller is verified on Simulink.Then the software design of the drive controller and the overall software design of the controller are carried out.Moreover,the software design including LCD display,initialization of various parts,serial communication and A/D and D/A conversion,and fuzzy PID controller are all completed.An experimental verification is carried out to test the control effect of the controller.The ACCT-I control experiment box is used as the experimental platform on which the second-order system model of the proportional valve is built.By contacting the ACCT-I and the PCB the experimental system is built to test the control effect of the controller.The experimental results show that the controller can quickly make the voltage value of the proportional valve reach to the designated value,and the control performance is reliable and stable.At the same time,the LCD of the controller can correctly display the working process of the controller. |
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