Authors

Abstract

Aiming at the problems of spraying pole-type plant protection machines difficult to get down to the field after row closure of maize in the middle and late stages, uneven droplet distribution of pressure nozzle-type plant protection drone, and difficult to change the droplet particle size, this paper designed a UAV centrifugal spraying system for maize planting protection through the designed centrifugal nozzle combined with a plant protection drone. A single nozzle parameter test was carried out to study the relationship between nozzle speed, flow rate and droplet size. The variable parameter flow rate is set in the range of 300 ml ~ 1000 mL / min, and the nozzle rotation speed is set in the range of 8000 ~ 18000 r / min gradient change. The test results show that the droplet size is related to the liquid supply flow rate and the nozzle rotation speed. According to the theory of optimal biological particle size, the centrifugal nozzle parameter is determined to select the liquid supply flow rate of 1000 mL / min and the nozzle rotation speed of 14000 r / min. The droplet distribution characteristics test under the actual operating conditions was carried out with this parameter, and the important index parameters such as droplet size, droplet density and coverage rate were analyzed to characterize the UAV aerial spraying operation. The experimental results show that the flight speed of the UAV has an important effect on the droplet deposition parameters, which significantly affects the droplet coverage, droplet density and deposition amount of the bottom layer of maize, and the droplet coverage and the droplet deposition amount of each sampling layer tends to decrease with the increase of flight speed, and the coefficient of variation (CV) value of the centrifugal spraying system was the smallest at the flight speed of 1.5m/s, and the effect of droplet deposition was the most uniform. at a flight speed of 1.5m/s. The effect of droplet deposition is the most uniform. This study can provide a reference basis for the optimization of parameters and the correct use of centrifugal plant protection UAV in the middle and late stage plant protection operations of tall crops such as maize.

Abstract in Chinese

针对玉米中后期封行后喷杆式植保机难以下田、压力喷头式植保无人机雾滴分布不均匀、雾滴粒径变化难等问题，本文通过设计的离心喷头结合植保无人机设计了一款用于玉米植保的无人机离心喷施系统。开展了单喷头参数测试，研究了喷头转速、流量与雾滴粒径的关系。将变化参数流量设置在300ml~1000 mL/min，喷头转速设置在8000~18000r/min范围内梯度变化，测试结果表明：雾滴粒径与供液流量、喷头转速均相关，且根据最佳生物粒径理论，确定离心喷头参数选择供液流量为1000mL/min，喷头转速为14000 r/min，以此参数进行了实际作业情况下的雾滴分布特性试验，分析雾滴粒径、雾滴密度、覆盖率等表征无人机航空喷施作业的重要指标参数。试验结果表明：无人机的飞行速度对雾滴沉积特性参数有重要影响，显著影响玉米底层的雾滴覆盖率、雾滴密度和沉积量，各采样层的雾滴覆盖率和雾滴沉积量的变化趋势均为随着飞行速度的增大而减小，在飞行速为1.5m/s时离心喷施系统的变异系数CV值最小，雾滴沉积效果最均匀。该研究可为离心式植保无人机在玉米等高秆作物中后期植保作业的参数优化和正确使用提供参考依据。