In China,it is difficult for manned aircraft to sow seeds in small and scattered plots,especially in areas including hills,swamps,telegraph poles,windbreaks,and residential areas;in such terrain,the sowing machinery c...In China,it is difficult for manned aircraft to sow seeds in small and scattered plots,especially in areas including hills,swamps,telegraph poles,windbreaks,and residential areas;in such terrain,the sowing machinery cannot function properly.However,unmanned helicopters(UHs)are flexible enough to control and adapt to the complex environments that are not easily accessible by terrain sowing machinery and large agricultural aircraft,which have been widely used in agriculture.In this study,a centrifugal disc-type sowing device for an unmanned helicopter(CDTSDUH)was designed.The factors influencing the seed velocity when the seeds move away from the disc were explored by analyzing the forces of the seed acting on the sowing disc and the wind field of the UHs.The influential factors include the distance from the falling mouth to the center of the disc,the offset angle of the falling mouth,and the rotation speed of the disc.An orthogonal test was designed with the sowing width and the curvature of the sowing area as the indexes.The test results showed that the three factors mentioned above had a greater impact on the sowing width than the curvature of the seeding area.Moreover,the superior parameters of the disc were determined.It was also suggested that the above factor levels had little effect on the offset width of sowing.The results of the test conducted for studying the sowing uniformity of the CDTSDUH indicated that the maximum and minimum difference values among the number of particles of the sampling points in the forward direction was 11 and 8,and the coefficient of variation of the number of particles in each row was more than 20%,indicating less uniformity was achieved when sowing in the lateral(perpendicular to the forward direction)direction,as compared to that in the forward direction.This study determined the ideal values for the radius of particles position,the offsetting angle,and the disc speed of the sowing machinery designed.Furthermore,considering that there are so many factors that influence the manner in which a UH functions,more analysis results and test data of influencing factors need to be acquired by experiments.The uniformity of sowing needs to be further improved.The results provided some theoretical and experimental references for the technology research on the centrifugal disc-type sowing device for UHs.展开更多
Anti-sway performance is one of the most important factors that affect the stability of unmanned aerial vehicles(UAVs).In this study,an anti-sway performance testing method and an evaluation formula for pesticide tank...Anti-sway performance is one of the most important factors that affect the stability of unmanned aerial vehicles(UAVs).In this study,an anti-sway performance testing method and an evaluation formula for pesticide tanks were developed,which could facilitate the design and application of pesticide tank.The detection device mainly comprises a testing stand,a mounting and testing part,and a driving and control part.In the testing method,P(maximum pressure)measured by a barometer and t(fluctuation recovery time)measured by a high-speed camera were used as evaluation indexes.With the aim to determine the optimal position of the pressure detection device and the optimal filling ratio,four representative pesticide tanks were involved in this study.The results showed that the optimal position of the pressure detection device was at the middle position on the tank wall,halfway up from the bottom,and the optimal filling ratio was 0.8.Using P and t as evaluation indexes,a comprehensive evaluation formula was developed based on these tests:S=0.7Pi+0.3ti.Anti-sway performance of pesticide tanks was evaluated by a comprehensive score.A disk pesticide tank with a baffle was determined to be the best among the four types of pesticide tanks,showing a score of 1.The scores of the other three pesticide tanks were 0.500,0.428 and 0.612,respectively.These results indicated that the baffle structure in the pesticide tank and the radian design of the tank wall can effectively improve the anti-sway performance of a pesticide tank.The proposed detection device and test method are simpler and more intuitive compared to other approaches in evaluating the anti-sway performance of pesticide tanks in spraying UAVs,and they can be used as a reference to guide the design of pesticide tanks and the stability evaluation of spraying UAVs.展开更多
The endurance performance(EP)of electric multi-rotors spraying drones(EMSDs)is a key technical indicator that ensures the completion of tasks and improves their usefulness.To improve the EP of current EMSD,a test syst...The endurance performance(EP)of electric multi-rotors spraying drones(EMSDs)is a key technical indicator that ensures the completion of tasks and improves their usefulness.To improve the EP of current EMSD,a test system was designed to determine the EP based on the EMSD test platform,and the performance evaluation method was studied.Firstly,a test model was established to determine the equivalent energy dissipation using the performance-testing platform of the EMSD.Secondly,a multisensory test system was constructed.An attitude sensor,high-power DC power supply,infrared thermal imager,and serial port server were selected.The mounting fixture was designed to meet the universal mounting requirements of drone.In addition,the software LabVIEW was employed to program the code for the controller and the host computer,where functions such as data collection,data processing,communication,and graphical user interface(GUI),were performed reliably in real time.Thirdly,the test method was explored by considering factors such as the power consumption,thermal efficiency ratio,and unit load power consumption rate.In particular,a comprehensive index method and expert consultation weight method were used to evaluate the EP of the EMSD with multiple indexes.Finally,a systematic real-machine test was carried out on the three types of drones that are currently widely used in the market.The results verified the effectiveness and feasibility of the proposed method,which was employed to test and evaluate the EP based on the EMSD performance testing platform.At the same time,it can provide a reference for the development of the EMSD.展开更多
基金supported by the Science and Technology Plan of Guangdong Province of China(Project No.2017B090907031,2017B090903007,2015B020206003,2014B090904073)Innovative Research Team of Guangdong Province Agriculture Research System(2017LM2153)for funding this research.
文摘In China,it is difficult for manned aircraft to sow seeds in small and scattered plots,especially in areas including hills,swamps,telegraph poles,windbreaks,and residential areas;in such terrain,the sowing machinery cannot function properly.However,unmanned helicopters(UHs)are flexible enough to control and adapt to the complex environments that are not easily accessible by terrain sowing machinery and large agricultural aircraft,which have been widely used in agriculture.In this study,a centrifugal disc-type sowing device for an unmanned helicopter(CDTSDUH)was designed.The factors influencing the seed velocity when the seeds move away from the disc were explored by analyzing the forces of the seed acting on the sowing disc and the wind field of the UHs.The influential factors include the distance from the falling mouth to the center of the disc,the offset angle of the falling mouth,and the rotation speed of the disc.An orthogonal test was designed with the sowing width and the curvature of the sowing area as the indexes.The test results showed that the three factors mentioned above had a greater impact on the sowing width than the curvature of the seeding area.Moreover,the superior parameters of the disc were determined.It was also suggested that the above factor levels had little effect on the offset width of sowing.The results of the test conducted for studying the sowing uniformity of the CDTSDUH indicated that the maximum and minimum difference values among the number of particles of the sampling points in the forward direction was 11 and 8,and the coefficient of variation of the number of particles in each row was more than 20%,indicating less uniformity was achieved when sowing in the lateral(perpendicular to the forward direction)direction,as compared to that in the forward direction.This study determined the ideal values for the radius of particles position,the offsetting angle,and the disc speed of the sowing machinery designed.Furthermore,considering that there are so many factors that influence the manner in which a UH functions,more analysis results and test data of influencing factors need to be acquired by experiments.The uniformity of sowing needs to be further improved.The results provided some theoretical and experimental references for the technology research on the centrifugal disc-type sowing device for UHs.
基金Authors wish to thank the Science and Technology Plan of Guangzhou and Guangdong Province of China(Grant No.2015B020206003,201807010111,2017B090907031,2017B090903007)Innovative Research Team of Guangdong Province Agriculture Research System(2017LM2153)for funding this research.
文摘Anti-sway performance is one of the most important factors that affect the stability of unmanned aerial vehicles(UAVs).In this study,an anti-sway performance testing method and an evaluation formula for pesticide tanks were developed,which could facilitate the design and application of pesticide tank.The detection device mainly comprises a testing stand,a mounting and testing part,and a driving and control part.In the testing method,P(maximum pressure)measured by a barometer and t(fluctuation recovery time)measured by a high-speed camera were used as evaluation indexes.With the aim to determine the optimal position of the pressure detection device and the optimal filling ratio,four representative pesticide tanks were involved in this study.The results showed that the optimal position of the pressure detection device was at the middle position on the tank wall,halfway up from the bottom,and the optimal filling ratio was 0.8.Using P and t as evaluation indexes,a comprehensive evaluation formula was developed based on these tests:S=0.7Pi+0.3ti.Anti-sway performance of pesticide tanks was evaluated by a comprehensive score.A disk pesticide tank with a baffle was determined to be the best among the four types of pesticide tanks,showing a score of 1.The scores of the other three pesticide tanks were 0.500,0.428 and 0.612,respectively.These results indicated that the baffle structure in the pesticide tank and the radian design of the tank wall can effectively improve the anti-sway performance of a pesticide tank.The proposed detection device and test method are simpler and more intuitive compared to other approaches in evaluating the anti-sway performance of pesticide tanks in spraying UAVs,and they can be used as a reference to guide the design of pesticide tanks and the stability evaluation of spraying UAVs.
基金We acknowledge that this research work was financially supported by the Science and Technology Plan of Guangdong Province of China(Project No.2014A020208103,2015B020206003,2017B090903007)Innovative Research Team of Guangdong Province Agriculture Research System(2017LM2153)for funding this research.
文摘The endurance performance(EP)of electric multi-rotors spraying drones(EMSDs)is a key technical indicator that ensures the completion of tasks and improves their usefulness.To improve the EP of current EMSD,a test system was designed to determine the EP based on the EMSD test platform,and the performance evaluation method was studied.Firstly,a test model was established to determine the equivalent energy dissipation using the performance-testing platform of the EMSD.Secondly,a multisensory test system was constructed.An attitude sensor,high-power DC power supply,infrared thermal imager,and serial port server were selected.The mounting fixture was designed to meet the universal mounting requirements of drone.In addition,the software LabVIEW was employed to program the code for the controller and the host computer,where functions such as data collection,data processing,communication,and graphical user interface(GUI),were performed reliably in real time.Thirdly,the test method was explored by considering factors such as the power consumption,thermal efficiency ratio,and unit load power consumption rate.In particular,a comprehensive index method and expert consultation weight method were used to evaluate the EP of the EMSD with multiple indexes.Finally,a systematic real-machine test was carried out on the three types of drones that are currently widely used in the market.The results verified the effectiveness and feasibility of the proposed method,which was employed to test and evaluate the EP based on the EMSD performance testing platform.At the same time,it can provide a reference for the development of the EMSD.
