Design And Experiment Of A Wing Retractable Rapeseed Aerial Seeding Device

Rapeseed is an important oilseed economic crop,and there are many planting methods in China,such as artificial sowing,transplanting and mechanical direct seeding.At present,the technical level of rapeseed mechanized planting and transplanting in my country is relatively low,only 35.65% in 2020.My country’s rapeseed industry has an urgent need for light,simple,efficient and highly adaptable seeding technology and equipment.For this reason,based on the quadrotor UAV platform built by the research group,this paper designs and validates a side-wing retractable rapeseed aerial seeding device based on the pneumatic centrifugal seed metering system.This paper systematically summarizes the design,trial production and test process and results of the flank telescopic rapeseed aerial seeding device.The main contents are as follows:(1)According to the agronomic technical requirements for rapeseed sowing,and in accordance with the original design intention of stable and controllable width,efficient and adjustable operation speed,it is determined that the upward convex centrifugal seed metering device is used for seed metering,airflow high-speed seeding,and lateral wing telescopic horizontal The overall design of the seed-guided flying device.Based on the introduction of the basic structure and working principle of the scheme,the overall technical parameters of the core components such as the air-feed centrifugal rapeseed metering system and the seed guiding device had a further clarification.(2)The structure create and parameter analysis about the air-feeding centrifugal rapeseed metering system were carried out.Based on the improvement of the existing upward convex centrifugal seed metering device of the research group,the air pressure balance port of the seed metering port is changed to an air inlet.In order to meet the circular appearance characteristics of the upwardly convex centrifugal collector and the needs of long-distance transportation of seeds and grains by air flow,and at the same time to ensure the compactness of the device,a funnel-shaped seed box with a fan air flow duct is designed,and two inner diameters of 15 mm are arranged.mm air inlet and4 air outlets with an inner diameter of 8 mm,and it is estimated and confirmed that the volume of the seed box is 4.5 L.According to relevant analysis,the total torque required for the smooth operation of the seed metering system is 1.9 N·m.The seed metering drive motor uses a J-5718HB4401 stepper motor,and a WS9250-24-240-X200 microcentrifugal fan is used as the air source.(3)In order to reduce the safety risk of the wide-width seed metering device during the take-off and landing process of the UAV,a rack and pinion flank telescopic seed guide device is proposed and verified.Based on the introduction of the working principle of the side-wing telescopic seed guide device,the structure design and main parameter analysis of the telescopic seed guide device are carried out.The42HS6015A4 stepper motor is selected as the telescopic motor to provide power,and the standard spur gear with the modulus,pressure angle,and number of teeth of 2 mm,20°,and 42 is selected as the transmission gear,and the rack with the number of teeth of 145 is selected correspondingly,and the number of teeth is determined.There are two types of seeding distributors with two points of top in and bottom out and three points of three points in the form of bottom in and top out.(4)The bench test of seed metering performance was carried out.The experimental results show that this method has the best seed metering effect and can obtain good performance when the wind pressure was 3920 Pa and the speed of the seed metering plate was 200 r/min.The coefficient of variation of the total displacement stability remains stable at 80～160 r/min at first,and then rises sharply.On the whole,it will remain between 0.98% and 8.63%.On the contrary,with the increase of seeding speed,the variation coefficient of displacement consistency of each row does not change much.When the variation coefficient of displacement consistency of each row reaches the maximum value of 21.9%,the seeding speed is 80 r/min;when the seeding speed Between 80 and 200 r/min,the coefficient of variation of the displacement consistency of each row will gradually decrease according to the speed of seeding,and then slightly increase according to the speed of seeding.It can be concluded that the displacement of each row is not uniform.(5)The preliminary field test flight test shows that the designed flank telescopic rapeseed aerial seeding device has a stable working width,the width is 3 m when the flight height is 1 m,and the seeds are distributed in multiple rows of ribbons,with an average width of 25 cm.Basically achieve the expected design effect.