Control System Design Of Orchard Target Spraying Machine Based On PLC

Large scale orchard planting has much developed in recent years in China,while the method of pesticide spray for fruit trees lags relatively behind.The traditional ways of applying pesticides cause the waste of solution and serious environmental pollution,bringing great losses to people.So it is urgent to develop a spraying machine control system suitable for the current large-scale orchard to improve the utilization rate of the solution to protect the environment.Aiming to improve the accuracy of spray and reduce the waste of solution,this article has designed a PLC-based control system for orchard target spraying machine according to actual needs,which takes sprayers’ structure,hardware design,software design and algorithm selection into consideration.Specifically,the hardware part is based on Mitsubishi FX2NPLC,which completes signal acquisition and system control.The software part includes modbus communication programs,manual/automatic control programs and target spraying programs,etc.The algorithm part selects the self-tuning fuzzy PID control method to control the spray volume.The article introduces the realization of the system functions and analyses the results of the system operation test.The content of the article is as follows:(1)The lower computer uses PLC as its control core.The controller analyses the tree target information obtained by infrared sensors and ultrasonic sensors,and then controls the electromagnetic valve to achieve precise spraying.The controller analyses the travel speed information of the sprayer and controls the opening degree of the electric valve to achieve variable spraying.The system monitors the working parameters of the sprayer according to the data information of the flow sensor and pressure sensor,thus achieving automatic control.(2)The host computer uses HC-Suk9102 as the man-machine interface.Users can not only easily input spray parameters for automatic control,but also manually control through the man-machine interface.Moreover,users can monitor the working status of the sprayer and control the opening and closing of a single nozzle on the man-machine interface.(3)The self-tuning fuzzy PID control algorithm is used to adjust the spray volume,and the three algorithms of PID control,fuzzy PID control and self-tuning fuzzy PID control are simulated.By comparison,the self-tuning fuzzy PID is selected as the control algorithm of spraying volume,which improves the control accuracy of the system.The control system of the orchard targeted spraying machine is stable and practical.It can meet the user’s requirements for orchard spraying,and has broad application prospects.