Drift Evaluation of a Quadrotor Unmanned Aerial Vehicle (UAV) Sprayer: Effect of Liquid Pressure and Wind Speed on Drift Potential Based on Wind Tunnel Test

Abstract

Background: Unmanned Aerial Vehicles (UAVs) applied to agricultural plant protection is widely used, and the field of operation is expanding due to their high efficiency and pesticide application reduction. However, the work on pesticide drift lags behind the development of the UAV spraying device. Methods: We compared the spray drift potential at four liquid pressures of 2, 3, 4, and 5 bar ejected from the hydraulic nozzles mounted on a UAV test platform exposed to different wind speeds of 2, 4, and 6 m/s produced by a wind tunnel. The combination of the wind tunnel and the UAV test platform was used to obtain strict test conditions. The droplet size distribution under spray drift pressures was measured by a laser diffraction instrument. Results: Increasing the pressure leads to smaller droplet volume diameters and produced fine droplets of less than 100 µm. The deposition in the drift area was elevated at most of the sampling locations by setting higher pressure and faster wind speed. The deposition ratios were all higher than the flow ratios under three wind speeds after the adjustment of pressures. For most samples within a short drift distance (2–8 m), the drift with the rotor motor off was more than an order of magnitude higher than that with the rotor motor on at a pressure of 3 bar. Conclusions: In this study, the wind speed and liquid pressure all had a significant effect on the UAV spray drift, and the rotor wind significantly inhibited a large number of droplets from drifting further.

Characteristics of unmanned aerial spraying systems and related spray drift: A review

“…In addition, the test platform can adjust the pitch angle from –30 ° to 30 ° . Liu et al (2021) combined the UASS platform with the wind tunnel and placed the platform at the extremity of the wind tunnel in order to build an indoor drift test device. Although the sampling area is not located inside the wind tunnel, this method is a good attempt to reduce disturbances from natural environmental conditions.…”

“…On one hand, the operating efficiency of a single UASS has increased from 2 to 3 hectares per hour to the current 15–20 hectares per hour within the past 5 years ( Chen H. et al, 2021 ). The result of single-machine efficiency implies that more chemicals can be sprayed in a short time ( Wang Z. et al, 2022 ), however more pesticide droplets may also be scattered in the air ( Liu et al, 2021 ). The overall environmental risks due to efficiency improvements need to be assessed.…”

Research on Methods Decreasing Pesticide Waste Based on Plant Protection Unmanned Aerial Vehicles: A Review

“… Ferguson et al (2016) applied three different pressures of 207, 310, and 414 kPa to five types of nozzles and found that the number density of droplets is affected by pressure, with higher pressure leading to the largest density. Liu et al (2021) performed experiments on the liquid distribution performance of a nozzle under four pressures. The experimental results showed that when the pressure was adjusted from 200 to 500 kPa, the value of Dv0.5 ranged from 124.46 to 85.95 μm, and when 400 or 500 kPa liquid was used, the droplets size distribution was more uniform.…”

Aplicação de pesticidas com veículos aéreos não tripulados nas culturas de café, citros e feijão

“…Embora as máquinas agrícolas terrestres desempenhem um papel fundamental na pulverização das lavouras, áreas agrícolas íngremes e montanhosas ou culturas de alto porte, restringem sua utilização no controle de doenças, pragas e plantas daninhas (GUO et al, 2020;LAN;CHEN, 2018;WANG et al, 2022a). As aeronaves tripuladas mesmo que equipadas com tecnologia avançada de pulverização, ainda apresentam limitações de uso, como o elevado risco de deriva (LIU et al, 2021a).…”

“…A velocidade de voo (CHEN et al, 2017;, o volume de calda (CHEN et al, 2018;, a altura de voo (BAE; KOO, 2013; e as pontas de pulverizações mais adequadas ainda são importantes fatores de estudo nesse tipo de pulverização (CHEN et al, 2020a(CHEN et al, , 2020bFAN;. A quantidade de deriva gerada nas aplicações com VANTs também tem sido pesquisadas (GUO et al, 2020;LIU et al, 2021a;TANG et al, 2017;YU et al, 2021). Esses estudos vêm sendo desenvolvidos tanto em cultivos de baixo porte (WANG et al, 2022b;YAN et al, 2021;ZHAO et al, 2022) como em culturas arbóreas .…”