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Abstract: Currently, unmanned aerial vehicles (UAVs) were widely applied to spray for pest and disease control. However, spray effect can be further improved by setting operation parameters more reasonably and scientifically. Therefore, this study attempts to derive the relationship between operation parameters and spray effect. Different growth stages were distinguished by various corn heights. A six-rotor UAV was operated at different heights and velocities to test pesticides spray effects for corns at different growth stages. Different plant canopy coverage rate and penetrating coefficients were obtained, according to which, the effects on droplet deposition rate caused by different UAVs' operation parameters were analyzed. Droplet penetrating coefficients were applied as indexes to evaluate and select UAVs operation parameters for corns at different growth stages respectively. Mathematical models of droplet penetrating coefficients with UAVs operation parameters were established for corns at all growth stages. The determination coefficients (R2) of all models were greater than 0.90 and average relative errors were within 20%, which asserted high forecasting accuracy of droplet penetrating rate. With the help of the models, parameters like operating height away from the bottom of corns and UAVs velocities were further analyzed, which guided the optimization of parameter settings and selection of spray methods for corns at different growth stages.
Keywords: multi-rotor unmanned aerial vehicle, spraying, parameter model, growth stage, corn
DOI: 10.3965/j.ijabe.20171003.2578
(ProQuest: ... denotes formulae omitted.)
1Introduction
From huge bell stage to maturity stage, leaf index of corn is between 60 and 100[1]. Every part of corns is easily attacked by diseases like corn curvalaria leaf spot and smut. Moreover, corns are commonly devastated by pests, such as corn aphid, corn borer and armyworm[2'3] in this period. Therefore, the pivotal task of field management is to protect leaves from damage and premature senility to achieve the high yield target. Currently, utilizing terrain machines to spray pesticides is considered as the primary method of chemical pest control. However, in-field operation through applying large machinery can result in leaf damage or even ear drop, which negatively influences the corn growth and production since ridges have been basically sealed.
Research illustrated that droplet penetrating rate and deposition rate are deeply affected by plant shape, volume, leaf area density and physical characteristics141. After jointing stage, there is a...