Wind field is one of the important factors affecting the distribution characteristics of aerial spraying droplet deposition.In order to reveal the impact mechanism of droplet deposition distribution by the wind field ...Wind field is one of the important factors affecting the distribution characteristics of aerial spraying droplet deposition.In order to reveal the impact mechanism of droplet deposition distribution by the wind field below agricultural unmanned helicopter rotor,in this study,the wind field distribution below uniaxial single-rotor electric unmanned helicopter rotor was measured by using a wireless wind speed sensor network measurement system for unmanned helicopter.The effects of wind field in three directions(X,Y,Z)below the rotor on droplet deposition distribution were analyzed with the condition of aerial spraying droplet deposition in rice canopy,and the regression model was established via variance and regression analyses of experiment results.The results showed that,the wind field in Y direction had a significant effect on droplet deposition in effective spray area,the wind field in Z direction had an extremely significant effect on droplet deposition in effective spray area,and the corresponding significance(sig.)values were 0.011 and 0.000.Furthermore,the wind field in Z direction had a significant effect on the penetrability and uniformity of droplet deposition in effective spray area,the corresponding sig.values were 0.025 and 0.011 respectively.The wind speed in Y direction at the edge of effective spray area had a significant effect on droplet drift,the sig.value was 0.021.In addition,the correlation coefficient R of the regression model was 0.869 between droplet deposition in effective spray area and the wind speed in Y and Z directions,and 0.915 between the uniformity of droplet deposition in effective spray area and the maximum wind speed in Z direction.The result revealed the influencing mechanism of the wind field below the rotor of uniaxial single-rotor electric unmanned helicopter on the distribution of aerial spraying droplet deposition.The results can provide guidance for the actual production application of aerial spraying to reduce liquid drift and improve the utilization rate of pesticide.展开更多
Considering the difficulty of broadcasting in the small plots and complex terrain in South China,this research aimed to explore a new efficient broadcasting way and figure out advisable operation parameters by using a...Considering the difficulty of broadcasting in the small plots and complex terrain in South China,this research aimed to explore a new efficient broadcasting way and figure out advisable operation parameters by using a hollow 12-axis,rotor-wing Unmanned Aerial Vehicle(UAV)which is typically made up of four groups of solid support structure,with each consisting of three axes and two rotor wings.A 3.7 L reverse pyramid-shape seed hopper with a 60 mm×13 mm rectangular outlet at the bottom was designed to realize self-gravity seeding.Rice seed firstly directly falls on the rotating disc driven by direct-current dynamo before being sown.The disc was located 120 mm above the ground,with a diameter of 350 mm.Under constant flight conditions,parameters of the on-board broadcasting devices(dropping speed referring to speed for the outlet and the broadcasting speed for the disc’s rotation speed)determine the uniformity of air broadcasting.The FUTABA T8FG transmitter and receiver system were employed as the remote control device.When the UAV flies at 3 m/s and 2 m above the ground with an expected seeding of 180 grain/m^(2),the RD(Right Down)knob marked 29 and LD(Left Down)knob marked-24 with a disc rotation speed of 900 r/min,the broadcasting lasts for 15 seconds with a 25%opening(1.95 cm^(2))of rectangular outlet.In order to verify the feasibility of air broadcasting parameters,the project team carried out a field broadcasting test by using a hollow multi-rotor UAV at Zhongluotan Test Base in Guangzhou in July,2014.In the square field plots of 0.09 hm^(2),flying path of air broadcasting operation was designed.The collected sampling data of broadcasting quantity per unit area after the test showed that there were,on average,187.4 grains/m^(2)of the five sampling points with a standard deviation of 22.77,and a coefficient of variation of 12.15%which was far smaller than that of artificial broadcasting.The average yield of field broadcasted by UAV is 7705.5 kg/hm^(2)in 2014,implying that rice air broadcasting by UAV is feasible.展开更多
The wind field produced by the rotor-wing UAV has a significant impact on the distribution of rice pollen,which directly influences hybrid rice breeding.This research aimed to explore the distribution law of rice poll...The wind field produced by the rotor-wing UAV has a significant impact on the distribution of rice pollen,which directly influences hybrid rice breeding.This research aimed to explore the distribution law of rice pollen in the wind field of small UAV.Aviation Beidou Positioning System UB351 positions all sampling nodes for precise corresponding coordinates and spacing information,and draws UVA’s flying trajectories,thus providing accurate data for tests.Wireless sensor network measurement system was used to study the three-direction wind field produced by the rotor-wing UAV under various experimental factors and acquires wind field width and wind speed,and the data were compared with the area ratio and width of pollen distribution.Test of univariate normality was conducted through Shapiro-Wilk test and Kolmogorov-Smimov test.In order to figure out the appropriate flight speed for UAV’s pollination under pollen distribution law,it is also necessary to perform analysis of variances on regression model.The comparison of wind speed in longitudinal(X)and lateral(Y)direction show that as the major force of the horizontal wind field produced by the rotor-wing UAV,the wind from Y-direction forms the widest wind field.Moreover,flight speed mainly influences wind field width.To be specific,the width of horizontal wind field decreases as flight speed increases.Meanwhile,UAV flight speed also exerts significant impact on vertical wind field.Both the pollen distribution width of more than 5 pollen grains and the area ratio reached the maximum when the UAV flight was at 4.53 m/s,which was the most favorable speed to pollination.In addition,pollen quantity is closely associated with both horizontal and vertical wind field.With comparison of the pollen quantity of sampling nodes,it was found that the wind field produced by the rotor-wing UAV exerted asymmetrical impact on pollen distribution.Q-Q plot of SPSS verifies that pollen distribution is against normal distribution.The establishment of a multiple linear regression model of pollen distribution and wind speed in three directions indicates that pollen distribution quantity only shares positive linear relation with the wind field in X-direction.These findings provide a theoretical guidance for rice pollination by using agricultural UAVs.展开更多
The rapid developments of unmanned aerial vehicles(UAV)and vision sensor are contributing a great reformation in precision agriculture.Farmers can fly their UAV spraying pesticides around their crop fields while stayi...The rapid developments of unmanned aerial vehicles(UAV)and vision sensor are contributing a great reformation in precision agriculture.Farmers can fly their UAV spraying pesticides around their crop fields while staying at their remote control room or any place that is separated from their farm land.However,there is a common phenomenon in rice planting management stage that some empty areas are randomly located in farmland.Therefore,a critical problem is that the waste of pesticides that occurs when spraying pesticides over rice fields with empty areas by using the common UAV,because it is difficult to control the flow accuracy based on the empty areas changing.To tackle this problem,a novel vision-based spraying system was proposed that can identify empty areas automatically while spraying a precise amount of pesticides on the target regions.By this approach,the image was preprocessed with the Lucy-Richardson algorithm,then the target area was split from the background with k-means and the feature parameters were extracted,finally the feature parameters were filtered out with a positive contribution which would serve as the input parameters of the support vector machine(SVM)to identify the target area.Also a fuzzy control model was analyzed and exerted to compensate the nonlinearity and hysteresis of the variable rate spraying system.Experimental results proved that the approach was applicable to reducing the amount of pesticides during UAV spraying,which can provide a reference for precision agriculture aviation in the future.展开更多
基金the National Key Technologies Research and Development Program(2016YFD0200700)Guangdong National Natural Science Foundation of China(2015A030313420).
文摘Wind field is one of the important factors affecting the distribution characteristics of aerial spraying droplet deposition.In order to reveal the impact mechanism of droplet deposition distribution by the wind field below agricultural unmanned helicopter rotor,in this study,the wind field distribution below uniaxial single-rotor electric unmanned helicopter rotor was measured by using a wireless wind speed sensor network measurement system for unmanned helicopter.The effects of wind field in three directions(X,Y,Z)below the rotor on droplet deposition distribution were analyzed with the condition of aerial spraying droplet deposition in rice canopy,and the regression model was established via variance and regression analyses of experiment results.The results showed that,the wind field in Y direction had a significant effect on droplet deposition in effective spray area,the wind field in Z direction had an extremely significant effect on droplet deposition in effective spray area,and the corresponding significance(sig.)values were 0.011 and 0.000.Furthermore,the wind field in Z direction had a significant effect on the penetrability and uniformity of droplet deposition in effective spray area,the corresponding sig.values were 0.025 and 0.011 respectively.The wind speed in Y direction at the edge of effective spray area had a significant effect on droplet drift,the sig.value was 0.021.In addition,the correlation coefficient R of the regression model was 0.869 between droplet deposition in effective spray area and the wind speed in Y and Z directions,and 0.915 between the uniformity of droplet deposition in effective spray area and the maximum wind speed in Z direction.The result revealed the influencing mechanism of the wind field below the rotor of uniaxial single-rotor electric unmanned helicopter on the distribution of aerial spraying droplet deposition.The results can provide guidance for the actual production application of aerial spraying to reduce liquid drift and improve the utilization rate of pesticide.
基金the grants of National Key Research and Development Plan(2016YF0200700)Innovation project of modern agricultural equipment and technology in Jiangsu Province(NZXT01201403)+1 种基金Guangdong Natural Science Foundation of China(2015A030313420)National Sparking Plan Project(2015GA780039)。
文摘Considering the difficulty of broadcasting in the small plots and complex terrain in South China,this research aimed to explore a new efficient broadcasting way and figure out advisable operation parameters by using a hollow 12-axis,rotor-wing Unmanned Aerial Vehicle(UAV)which is typically made up of four groups of solid support structure,with each consisting of three axes and two rotor wings.A 3.7 L reverse pyramid-shape seed hopper with a 60 mm×13 mm rectangular outlet at the bottom was designed to realize self-gravity seeding.Rice seed firstly directly falls on the rotating disc driven by direct-current dynamo before being sown.The disc was located 120 mm above the ground,with a diameter of 350 mm.Under constant flight conditions,parameters of the on-board broadcasting devices(dropping speed referring to speed for the outlet and the broadcasting speed for the disc’s rotation speed)determine the uniformity of air broadcasting.The FUTABA T8FG transmitter and receiver system were employed as the remote control device.When the UAV flies at 3 m/s and 2 m above the ground with an expected seeding of 180 grain/m^(2),the RD(Right Down)knob marked 29 and LD(Left Down)knob marked-24 with a disc rotation speed of 900 r/min,the broadcasting lasts for 15 seconds with a 25%opening(1.95 cm^(2))of rectangular outlet.In order to verify the feasibility of air broadcasting parameters,the project team carried out a field broadcasting test by using a hollow multi-rotor UAV at Zhongluotan Test Base in Guangzhou in July,2014.In the square field plots of 0.09 hm^(2),flying path of air broadcasting operation was designed.The collected sampling data of broadcasting quantity per unit area after the test showed that there were,on average,187.4 grains/m^(2)of the five sampling points with a standard deviation of 22.77,and a coefficient of variation of 12.15%which was far smaller than that of artificial broadcasting.The average yield of field broadcasted by UAV is 7705.5 kg/hm^(2)in 2014,implying that rice air broadcasting by UAV is feasible.
基金support by the grants of The National Key Research and Development Plan(2017YFD0701000)Guangdong National Natural Science Foundation of China(2015A030313420)Agricultural standardization research project of Guangdong,China/2016.
文摘The wind field produced by the rotor-wing UAV has a significant impact on the distribution of rice pollen,which directly influences hybrid rice breeding.This research aimed to explore the distribution law of rice pollen in the wind field of small UAV.Aviation Beidou Positioning System UB351 positions all sampling nodes for precise corresponding coordinates and spacing information,and draws UVA’s flying trajectories,thus providing accurate data for tests.Wireless sensor network measurement system was used to study the three-direction wind field produced by the rotor-wing UAV under various experimental factors and acquires wind field width and wind speed,and the data were compared with the area ratio and width of pollen distribution.Test of univariate normality was conducted through Shapiro-Wilk test and Kolmogorov-Smimov test.In order to figure out the appropriate flight speed for UAV’s pollination under pollen distribution law,it is also necessary to perform analysis of variances on regression model.The comparison of wind speed in longitudinal(X)and lateral(Y)direction show that as the major force of the horizontal wind field produced by the rotor-wing UAV,the wind from Y-direction forms the widest wind field.Moreover,flight speed mainly influences wind field width.To be specific,the width of horizontal wind field decreases as flight speed increases.Meanwhile,UAV flight speed also exerts significant impact on vertical wind field.Both the pollen distribution width of more than 5 pollen grains and the area ratio reached the maximum when the UAV flight was at 4.53 m/s,which was the most favorable speed to pollination.In addition,pollen quantity is closely associated with both horizontal and vertical wind field.With comparison of the pollen quantity of sampling nodes,it was found that the wind field produced by the rotor-wing UAV exerted asymmetrical impact on pollen distribution.Q-Q plot of SPSS verifies that pollen distribution is against normal distribution.The establishment of a multiple linear regression model of pollen distribution and wind speed in three directions indicates that pollen distribution quantity only shares positive linear relation with the wind field in X-direction.These findings provide a theoretical guidance for rice pollination by using agricultural UAVs.
基金We acknowledge that the research was financially supported by Research and Demonstration of Key Technologies for Water Saving in Irrigation Areas in Guangdong Province based on UAV(2016-18)Research and Demonstration of Key Technology for Precision Spraying of Agricultural UAV based on Multi-source Information(201803020022).
文摘The rapid developments of unmanned aerial vehicles(UAV)and vision sensor are contributing a great reformation in precision agriculture.Farmers can fly their UAV spraying pesticides around their crop fields while staying at their remote control room or any place that is separated from their farm land.However,there is a common phenomenon in rice planting management stage that some empty areas are randomly located in farmland.Therefore,a critical problem is that the waste of pesticides that occurs when spraying pesticides over rice fields with empty areas by using the common UAV,because it is difficult to control the flow accuracy based on the empty areas changing.To tackle this problem,a novel vision-based spraying system was proposed that can identify empty areas automatically while spraying a precise amount of pesticides on the target regions.By this approach,the image was preprocessed with the Lucy-Richardson algorithm,then the target area was split from the background with k-means and the feature parameters were extracted,finally the feature parameters were filtered out with a positive contribution which would serve as the input parameters of the support vector machine(SVM)to identify the target area.Also a fuzzy control model was analyzed and exerted to compensate the nonlinearity and hysteresis of the variable rate spraying system.Experimental results proved that the approach was applicable to reducing the amount of pesticides during UAV spraying,which can provide a reference for precision agriculture aviation in the future.
