环境风速及飞行参数对多旋翼植保无人机雾滴飘移特性的影响

The influences of wind speed and flight parameters on droplet drift characteristics of multi-rotor plant protection unmanned aerial vehicle

为评估植保无人机低空低容量施药下的喷雾飘移风险,以国内市场主流机型电动多旋翼植保无人机为施药机械,研究不同环境风速及飞行参数(高度和速度)下喷雾雾滴飘移特性,构建雾滴飘移率与飘移距离之间的函数关系,并将测试结果与侧风速度及飞行参数进行相关性分析和回归分析。结果表明:在温度为16.5~25.2℃,相对湿度为21.7%~64.4%的条件下,植保无人机喷雾地面雾滴飘移率与下风向距离的关系满足指数函数λ=a·ebx,相关系数R2均大于0.914;在侧风速度为1.1~7.0 m/s的条件下,雾滴累计飘移率在13.0%~56.2%之间,90%飘移雾滴沉降在喷雾区下风向7.0~27.3 m距离范围内;侧风速度、飞行高度均与雾滴累计飘移率和90%累计飘移距离呈极显著正相关,且3个因素对雾滴飘移率的影响大小为侧风速度>飞行高度>飞行速度,对90%累计飘移距离的影响大小为飞行高度>侧风速度>飞行速度,对喷幅内沉积率的影响大小为飞行高度>侧风速度>飞行速度。研究结果可用于多旋翼植保无人机实际作业中雾滴飘移风险的控制及飘移缓冲距离的确定。

In order to assess the risk of spray drift of plant protection unmanned aerial vehicle(UAV)with the character of low-altitude and low-volume, the influences of wind speed and flight parameters(altitude and speed) on the droplet drift characteristics of multi-rotor plant protection UAV were studied.A functional relationship between droplet drift rate and drift distance was established, and the correlation and regression analysis between the test results and crosswind speed and flight parameters were made. The results showed that the relationship between the droplet drift rate and the downwind distance met the exponential function λ=a·ebx, and the correlation coefficients R2 were greater than 0.914 under the conditions of 16.5-25.2℃ and relative humidity of 21.7%-64.4%. When the crosswind speed was1.1-7.0 m/s, the cumulative drift rate of droplets was between 13.0% and 56.2%, and 90% of the total drift droplets fell within a range of 7.0-27.3 m in the downwind distance. Crosswind speed and flight height were significantly positively correlated with the cumulative droplet drift rate and the 90% value of the total drift distance. The magnitude of influence of three factors on droplet drift rate was crosswind speed>flight height>flight speed. The magnitude of influence on the 90% value of the total drift distance was flight height>crosswind speed>flight speed. The magnitude of the influence on deposition rate was flight height>crosswind speed>flight speed. These results may help controlling the risk of droplet drift and determine the drift buffer distance in pesticide application by the multi-rotor plant protection UAV.