| At present,the control of pest and insect disaster is mainly based on spraying chemical agents.However,our application technology is relatively backward,and the conventional large dose application is easy to cause low utilization rate of pesticides,serious environmental pollution and drug harm to crops.In view of the above problems and combined with the agronomic requirements of plant protection application in Heilongjiang region,this paper designed a variable spray system with flow regulation.The spray amount of the system can change the flow of the loop system with the change of the unit’s traveling speed,so as to meet the operational requirements of variable spraying.In this paper,the mathematical model of electronically controlled proportional valve is established,the control system model is constructed,the simulation analysis is carried out,and the laboratory test and field test are carried out.The main research contents of this paper are as follows:According to the review of the research status of variable spray control system at home and abroad,combined with the work characteristics of flow regulating variable spray system,the design purpose and research content of the system were determined,and the technical route was finally determined.Set up the hardware system platform of flow-regulating variable spray control,designed the electronic control system,selected the relevant electrical components,developed the PLC control program,planned the PLC external circuit,and determined the control scheme.According to the design requirements of the flow control variable spray system,the orifice aperture and spool half cone Angle of the electronic control proportional valve were calculated,and the valve block of the electronic control proportional valve was simplified into a thin wall orifice plate physical model to analyze its flow control characteristics and working characteristics.The structure size of the selected proportional valve block was mapped and modeled in three dimensions.The distribution of pressure field and velocity field inside the valve block was simulated and analyzed by Fluent module in ANSYS software.The simulation results showed that the distribution of flow field inside the valve block was relatively balanced and stable at 50% opening degree.It also provides data support for subsequent system state adjustment and algorithm compensation.In order to solve the problems of complex control parameter adjustment and strong dependence on experience,the artificial bee colony algorithm(ABC)with better optimization performance was used to optimize the PID controller parameters.In order to verify the control effect of the system,MATALAB is used for simulation analysis.The results show that the PID overshoot is 24.5%,the fuzzy PID overshoot is 18.2%,and the ABC-PID control algorithm has no obvious overshoot.Therefore,it is preliminarily concluded that the control accuracy of the ABC-PID control algorithm is better than that of conventional PID and fuzzy PID.The experimental results show that the accuracy error of flow regulation can be controlled within 4.0%,and the overall structure of flow regulation variable spray control system is reasonable.The experimental results showed that the control precision of constant speed was higher than that of variable speed,and the control precision of ABC-PID control strategy was higher than that of other two control strategies under constant speed and variable speed.Field experiments were conducted to further verify the ABC-PID control algorithm,which showed good performance in improving the control precision of dosage,and the accuracy of dosage control was 2.8%,which could provide a new idea for variable application technology. |
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