DESIGN AND TESTING OF A SOWING DRONE BASED ON RICE PRECISION STRIP SEEDING

In order to solve the problem that the wind field disturbs the trajectory of falling seeds and causes the seeds to be unable to be arranged in equidistant rows when the UAV is spreading rice, a shot seeding device that can sow five rows of pelleted rice seeds at the same time was designed. The unit is centered on an external grooved wheel seed metering device and a seed acceleration unit for row seeding and hole sowing. The airflow simulation of the rotor wind field of the UAV was carried out by simulation software to explore the changes in the wind field of the UAV during operation. The position where the wind field disturbance is minimized is chosen for the seed guide tube arrangement. The position with the least wind field disturbance is chosen to arrange the seed guide tube and combine it with a seed acceleration device to reduce the influence of the UAV wind field airflow on the direction of seed movement. The operational effectiveness of the seeding device with and without wind was verified by an indoor test and an outdoor flight seeding test, respectively. Simulation results show that: when the mouth of the seed guide pipe is 0.9 m away from the paddle, the wind field has the smallest influence on the sowing results. The results of the bench test show that: when the rotational speed is 30-45 r/min, the coefficient of variation of the discharge rate of each row (CVR) and total seed discharge rate stability (CVT) are less than 1.98% and 0.84%, and the seed breakage rate is less than 0.95%, which all conform to the UAV fly sowing industry standards. The outdoor mud box test shows that: when the baffle angle changes by 26%, 58%, and 71%, each slot wheel hole can store 5-10, 3-5 and 1-3 seeds respectively, and the UAV operates at a speed of 2 m/s-3 m/s, the pass rate of hybrid rice is greater than 86%, which meets the agronomic requirements of rice sowing operation.