Authors

Abstract

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.

Abstract in Chinese

为解决无人机在水稻撒播时，普遍存在风场扰动种子下落的轨迹和种子无法成穴排布的问题，设计了一种可同时播种六行颗粒状水稻种子的射种装置。该装置由一个外槽轮式排种装置和种子加速装置为核心，实现了精准行播和穴播的功能。通过仿真软件对无人机进行了旋翼风场的气流仿真模拟，探究风场的变化特性。确定风场扰动最小的位置去布置导种管。加速装置和无人机的气流分析都是为了减少无人机风力对种子运动方向的影响。在室内试验和室外飞行播种试验中，分别验证在无风场和有风场下播种装置的作业效果。仿真结果表明：导种管道口距离桨叶为0.9m时，风场对播种结果影响最小；台架试验结果表明：转速处于30-45r/min时，每行排种率的变异系数小于1.98%、总排量稳定性的变异系数小于0.84%、种子破损率小于0.95%等都符合无人机飞播行业标准；室外泥盒试验表明：挡板角度变化26%、58%、71%时，每个槽轮孔可以分别储存5-10粒、3-5粒、1-3粒种子，且无人机以2m/s-3m/s速度下作业，杂交稻合格率均大于86%，满足水稻直播作业的农艺要求.