Research On Droplet Deposition Characteristics Of Large-scale Plant Protection UAV Spraying Operation

Plant protection UAV low-spray-volume spraying technology is characterized by a large one-time operation area,a good pest control effect,and high operating efficiency and pesticide utilization.During the spraying operation,the human-drug separation model fundamentally solves the problem of pesticides harming workers during the pest control process,and satisfies the requirements of modern ecological agriculture for high efficiency and safe development.However,during the spraying operation,the airflow generated by the rotors of UAVs is an unsteady flow field,and the downwashing flow field has a greater impact on the deposition and drift of droplets.In order to achieve the best effect of spraying pesticides,and accurately spraying the plant canopy to evenly cover the front and back surfaces of the blades,not only the safety and stability of the flight performance of the plant protection UAV,but also the matching spray system.The atomization effect,droplet size,UAV airflow field,spray height,spray flow rate,crop characteristics,and environmental conditions.In this paper,under the financial support of Jiangsu Province's agricultural science and technology independent innovation capital project-high-load UAV high-efficiency spraying technology and spray equipment(CX(15)1038),a 60 kg FR-200 oil-powered single rotor wing plant protection UAV For the research platform,the variation of droplet deposition characteristics was studied for the parameters affecting the UAV spray effect.The main research work of this article includes:1.Research on spray system design and atomization effect of Large-scale UAVs.Based on the FR-200 unmanned helicopter vehicle platform,the appropriate spray system components were selected in conjunction with its flight performance parameters,and an associated UAV spray system was designed to basically meet the low-air and low-volume spraying requirements of the UAV.The atomization characteristics of the core components of the UAV spray system were experimentally studied,and the influence of different atomization pressures on the particle size of the droplets,the nozzle flow rate,the atomization angle,and the variation of the spray deposition distribution with the fan nozzle installation spacing were analyzed.The design and development of the UAV-assisted spray system provide a reliable basis.2.Performance analysis of UAV spraying equipment.Excluding other factors such as nozzle spacing and number of nozzles,the design test focused on the influence of dredging air flow from a UAV on the droplet distribution of a single nozzle.The results were compared with the distribution of droplet deposition in the hovering state of the UAV.Two kinds of fan nozzles with larger spray widths were selected.The results show that the droplets deposited by IDK120-015 nozzles are more than the Teejet 110-015 nozzles,but the coefficient of variation is larger and the uniformity of droplet distribution is poorer.The higher the height of the nozzle from the ground,the smaller the amount of droplet deposition,indicating that the UAV rotor sweep airflow has a greater impact on the droplet deposition distribution.3.Heavy load plant protection UAV spray droplet deposition distribution characteristics.The influences of nozzle type,flying height,flight speed and temperature on the droplet deposition distribution of the UAV were analyzed.According to the droplet distribution law,the optimal flying height for UAV spraying operation was 5m,and the flying speed was 7m/s.After the addition of the vegetable oil additive Maifei,it can improve the moisturizing properties of the spray droplets in the draught of the UAV.Reduced droplet evaporation by approximately 17.3%.4.The effect of additives on spray deposition uniformity and drift of UAV.The DCAT11 surface tension meter and DepositScan image processing software from Dataphysics,Germany were used for data analysis.The effects of different additives types and temperatures on the distribution uniformity and anti-drift properties of the FR-200 unmanned helicopter were studied.The lower the surface tension of the liquid,the more uniform the spray distribution of the droplets sprayed by the UAV.Under the effect of cross wind,the drift phenomenon was very obvious when the UAV was not used,and the addition of 5 spray additives could significantly reduce the drift of the droplets.The fly prevention synergist Memphis can reduce the droplet evaporation of approximately 17.3% during the drip spray droplet settling of UAV.