To improve the precision spraying strategy and reduce excessive pesticide application in orchards,an air-assisted sprayer integrated with a laser-scanning system was developed to realize the toward-target variable-rat...To improve the precision spraying strategy and reduce excessive pesticide application in orchards,an air-assisted sprayer integrated with a laser-scanning system was developed to realize the toward-target variable-rate spraying.In the spray control system,a method of calculating canopy gridding volumes was designed to ensure that the canopy was divided into a uniform grid size,a variable-rate spray model was used in the flow rate decision software to control the spray output according to the canopy gridding volumes and travel speed,and a method of saving and accessing spray data was used to control the spray delay.The effects of different grid sizes and travel speeds on the spray performance were evaluated by quantifying spray coverage uniformity inside tree canopies.The results showed that spray coverage uniformity declined with increasing grid width from 0.14 to 0.28 m although the mean spray coverage on each target location showed no significant differences.Additionally,there were no significant variations in mean spray coverage at speeds of 1.0,1.2 and 1.4 m/s for a tested tree of 1.6 m width and at any experimental speeds for a tested tree of 1.3 m width,which indicated that the variable-rate sprayer could provide good spray coverage uniformity under various travel speeds with a canopy size limitation.Compared with the same sprayer without the variable-rate spray function,the intelligent sprayer prototype realized effective toward-target spraying and avoided overspraying while providing sufficient spray coverage.展开更多
The interaction between leaves and airflow has a direct effect on the droplet deposition characteristics of the leaf canopy.In order to make clear the mechanism of droplet deposition in terms of the interaction betwee...The interaction between leaves and airflow has a direct effect on the droplet deposition characteristics of the leaf canopy.In order to make clear the mechanism of droplet deposition in terms of the interaction between the droplets and leaves from the point of the leaf aerodynamic response velocity,the leaf movement under different airflow velocities and the influence of the leaf aerodynamic response on droplet coverage ratio were investigated.The effect of the aerodynamic response velocity of a leaf on the droplet deposition of the leaf surface was investigated.The aerodynamic characteristics of the leaf were analyzed theoretically.Boundary layer theory from fluid mechanics was used to develop a model of the leaf aerodynamic response velocity to nonperiodic excitations based on a convolution integral method.Target leaf aerodynamic velocities were detected using a high-speed camera,and the results indicated that the modeled leaf aerodynamic response velocity matched the measured values.At given conditions of spray liquid and leaf surface texture,the spray test showed that the droplet coverage ratio was influenced by the leaf aerodynamic response velocity,the droplet coverage ratio increased and then decreased with the leaf response velocity.Through analyze four droplets deposition state,the highest droplet deposition ratio and best deposition state on the leaf surface occur when the leaf aerodynamic response velocity was less than 0.14 m/s.According to the analysis of droplet deposition states,the uniformity of the droplet size and quantity distribution of droplets on the leaf surface related to the leaf aerodynamic response velocity.The results can provide a basis for the design and optimization of orchard air sprayers.展开更多
基金This study was financially supported by the National KeyResearch and Development Program(2016YFD0200700).
文摘To improve the precision spraying strategy and reduce excessive pesticide application in orchards,an air-assisted sprayer integrated with a laser-scanning system was developed to realize the toward-target variable-rate spraying.In the spray control system,a method of calculating canopy gridding volumes was designed to ensure that the canopy was divided into a uniform grid size,a variable-rate spray model was used in the flow rate decision software to control the spray output according to the canopy gridding volumes and travel speed,and a method of saving and accessing spray data was used to control the spray delay.The effects of different grid sizes and travel speeds on the spray performance were evaluated by quantifying spray coverage uniformity inside tree canopies.The results showed that spray coverage uniformity declined with increasing grid width from 0.14 to 0.28 m although the mean spray coverage on each target location showed no significant differences.Additionally,there were no significant variations in mean spray coverage at speeds of 1.0,1.2 and 1.4 m/s for a tested tree of 1.6 m width and at any experimental speeds for a tested tree of 1.3 m width,which indicated that the variable-rate sprayer could provide good spray coverage uniformity under various travel speeds with a canopy size limitation.Compared with the same sprayer without the variable-rate spray function,the intelligent sprayer prototype realized effective toward-target spraying and avoided overspraying while providing sufficient spray coverage.
基金This work was supported by earmarked funds for the Special project of Rural Vitalization Strategy of Guangdong Academy of Agricultural Sciences(Accession No.TS-1-4)the Guangdong Provincal Modern Agricultural Industry Technology System(Accession No.2019KJ123)+2 种基金the Key-Area Research and Development Program of Guangdong Province(Grant No.2019B020223002)the China Agriculture Research System(CARS-32-14)and the National Key R&D Program of China(Grant No.2018YFD0201101).
文摘The interaction between leaves and airflow has a direct effect on the droplet deposition characteristics of the leaf canopy.In order to make clear the mechanism of droplet deposition in terms of the interaction between the droplets and leaves from the point of the leaf aerodynamic response velocity,the leaf movement under different airflow velocities and the influence of the leaf aerodynamic response on droplet coverage ratio were investigated.The effect of the aerodynamic response velocity of a leaf on the droplet deposition of the leaf surface was investigated.The aerodynamic characteristics of the leaf were analyzed theoretically.Boundary layer theory from fluid mechanics was used to develop a model of the leaf aerodynamic response velocity to nonperiodic excitations based on a convolution integral method.Target leaf aerodynamic velocities were detected using a high-speed camera,and the results indicated that the modeled leaf aerodynamic response velocity matched the measured values.At given conditions of spray liquid and leaf surface texture,the spray test showed that the droplet coverage ratio was influenced by the leaf aerodynamic response velocity,the droplet coverage ratio increased and then decreased with the leaf response velocity.Through analyze four droplets deposition state,the highest droplet deposition ratio and best deposition state on the leaf surface occur when the leaf aerodynamic response velocity was less than 0.14 m/s.According to the analysis of droplet deposition states,the uniformity of the droplet size and quantity distribution of droplets on the leaf surface related to the leaf aerodynamic response velocity.The results can provide a basis for the design and optimization of orchard air sprayers.
