植保无人机动态变量施药系统设计与试验

Design and Test of Dynamic Variable Spraying System of Plant Protection UAV

针对我国植保无人机施药系统控制方式单一,施药流量无法根据飞行参数自动调整造成的雾滴分布不均匀、重喷、漏喷等问题,设计了基于ARM架构单片机的施药控制系统,提出基于PWM(脉宽调制)的施药流量控制方法,采用多传感器融合技术,实现施药参数的实时动态监测。设计了基于LabVIEW的地面站控制软件,实现对施药系统的远程控制和作业数据存储。基于3CD-15型单旋翼无人机平台对动态变量施药系统实际作业性能及施药效果进行了测试。试验结果表明,在飞行速度为0.8~5.8 m/s时,该动态变量施药系统可实现施药流量与飞行速度自动匹配,实际流量与理论流量之间平均偏差为1.9%,实际施药作业优选飞行速度为3.91~5.10 m/s,此时有效喷幅为5 m,雾滴覆盖密度为18~41个/cm^2,变异系数为34%~75%,雾滴沉积量为42.1~52.4μg/cm^2。

In order to improve the droplet distribution uniformity and avoid repeating and missing spraying, a spraying flow control method based on pulse width modulation （PWM） was designed, and based on the MCU of STM32F407VET6, a dynamic variable spraying system fused with muhi-sensor was developed. Spraying system was controlled remotely and spraying parameters were detected and saved by ground measurement and control software which was developed by LabVIEW. The tests based on reality field environment were carried out under the condition of different flying speeds to test actual operation performance and spraying effect of dynamic variable spraying system of plant protection UAV. Operation performance was reflected by deviation between practical and theoretical flows. Practical flow of micro diaphragm pump was detected by a flow sensor and theoretical flow was calculated by a derivation formula. Spraying effect was characterized by droplet deposition, which was collected by water sensitive papers and polyester films at targeted flying speed of 1.0 m/s, 2.0 m/s, 3.0 m/s, 4.0 m/s and 5.0 m/s. Rhodamine-B water solution with concentration of 0.1% was used as a substitute for pesticides in the tests. Concentration of Rhodamine-B was measured by fluorescence intensity protractor, droplet coverage density and distribution uniformity were identified through image processing. The results showed that when flying speed was changed from 0.8 m/s to 5. accurately based on the spraying system and control 8 m/s, spraying flow was able to match the speed method, and average deviation between practical and theoretical flows was 1.9% . The optimum flying speed of spraying operation based on 3CD - 15 plant protection UAV was 3.91 - 5.10 m/s, during the variation range of speed, the effective sprinkling width was 5 m, droplet coverage density was 18 -41 per square centimeter, coefficient of variation was 34% - 75% , droplet deposition was 42.1 - 52.4 μg/cm^2. The research result provided method for optimization of flying speed and also theoretical support to improve the quality of aviation operations.