Research On Droplet Deposition Characteristics In Soybean Field By Single-rotor Plant Protection Unmanned Aerial Vehicle

In recent years,the domestic demand for soybeans is increasing year by year,but the soybean yield in our country is far from meeting domestic demand,thereby causing the situation that we have to rely on soybean import a lot,which directly poses a threat to the food security of our country.The field management in the middle and later growing stages of soybeans is especially important for the increase in soybean yield.Therefore,in view of the difficulties,such as it is difficult for traditional field management machinery to work in the middle and later growing stages of soybeans after closing of crop,as well as soybean seedlings pressing and etc,the paper carried out the UVA protection test by using single rotor plant protection UAV in the middle and later stages of soybeans,and optimized the operation parameters of UAV,so as to provide test data and technical support for the application and popularization of field management and UAV pesticide application technology for the soybeans in middle and later growing stages.This paper mainly carried out experimental research from the following three aspects:(1)Research on wind farm distribution characteristics of single rotor plant protection UAV.The wind farm analysis test bed was used to make an experimental analysis of the wind farm distribution under the rotor of electric single rotor plant protection UAV.The test data showed that the wind farm under the rotor of single rotor plant protection UAV presented certain law: the wind speed was positively related to axial distance within the scope of the rotor's wing span at a same height above ground,and the wind speed would gradually increase with the increase in height;the wind speed gradually decreased after it was beyond the scope of wing span until the boundary of wind farm;the wind speed showed a positive correlation with the height above the ground;the wind speed reached the maximum value in the area 1~2.5m below the rotor,that was 12.9m/s;there was a certain eddy phenomenon at the wind farm boundary;the wind farm below 1m would produce turbulence affected by the ground effect,which was not consistent with the law above.(2)Field test in different growth stages of soybeans.The experiment was carried out in the branching stage and fruiting stage of soybeans respectively,of which the carmine solution at a certain concentration was used as the spraying liquid,and the qualitative filter paper was used for the deposition and distribution of collected droplets.The experimental results showed that the characteristic of distribution of droplets was similar to that of the wind field distribution of plant protection UAV.The addition of special auxiliary for UVAtest could facilitate the deposition of droplets and reduce drifting.The optimal operation parameters of electric single rotor plant protection UAV in soybean field were optimized by response surface analysis,namely,V=5m/s,H=2m.(3)Comparison test on the droplet deposition distribution of different UVA models.In this experiment,Mercury one electric single rotor,S40 electric single rotor plant protection UAV,M23 electric four-rotor,and M8 A electric eight-rotor plant protection UAV were used for spray test in soybean field respectively.The droplet deposition distribution of single-rotor and multi-rotor UAV when spraying in soybean field was analyzed,and the experiment results proved that the uniformity,penetrability and etc.of droplet deposition of single-rotor plant protection UAV in soybean field is superior to that of multi-rotor plant protection UAV.