The influence of a seeding plate of the air-suction minituber precision seed-metering device on seeding quality

The existing seed-metering device has the problems of low qualified index and high multiple index of minituber mechanized seeding. In this work, a seed-metering device suitable for precision seeding of minituber was designed to solve the above problems and improve the seeding efficiency. By analyzing the motion mechanism of minituber on the seeding plate, it is determined that the diameter of the suction seeding hole, the rotation speed and tilt angle of the seeding plate and the negative pressure value are the main factors affecting the seeding performance of the seed-metering device. The steady-state airflow in the negative pressure chamber was analyzed by computational fluid dynamics. When the diameter of the suction seeding hole is 8 mm and the rotation speed of the seeding plate is 40 r/min, the highest negative pressure value is reached at the suction seeding hole. The CFD-DEM coupling simulation method was used to investigate the stress of minituber and the effect of adsorption of minituber by suction seeding hole under different tilt angles of seeding plate and negative pressures. The coupling simulation results were verified and optimized by bench test, and the movement of the minituber on the seeding plate was observed by a high-speed camera. Design Expert was used to optimize the test results, and it is found that when the tilt angle is 20 degrees and the negative pressure is -6000 Pa, the working effect of the seed-metering device could achieve the multiple index is below 3.5 %, the miss seeding index no more than 1.5 %, the qualified index remained above 94.5 %, and the coefficient of variation is kept under 11 %. This work puts forward new ideas in improving the seeding quality of high-speed precision seed-metering device, and also provides a new design idea for the development of seeding device.