Effects of land slope on seeding performance of a broad width precision no-tillage planter for rapeseed

Abstract: In view of the influence of the change of the land slope on the performance of the broad width precision no-tillage planter for rapeseed, the planter and the air-assisted centralized metering device were taken as the research objects, and the mechanical models between rapeseed and circumscribed arc type hole, rapeseed-air flow and central distributor were built under different land slope. The stochastic process model of the seed feeding rate and seeding rate of the air-assisted centralized metering device was established. The effects of land slope along the working direction and rotation speed of seed feeding device on seed feeding rate were analyzed by EDEM simulation and the corresponding mathematical model was established. EDEM-CFD coupling simulation was used to analyze the influence of the land slope along the working direction on the seeding performance of the central distributor. The simulation results showed that the seed feeding decreased gradually with increase of the land slope angle in the range of -5°-5°. The variation of seed feeding rate could be up to 50% compared with no tilt when the absolute value of land slope angle was in the range of 3°-5°. The uniformity variation coefficient of seed numbers of each seed outlet increased with the increase of land slope angle, and the uniformity variation coefficient ranged from 4.95% to 14.91%. The land slope had a significant effect on the seed feeding rate and the uniformity variation coefficient of seed quality of each seed outlet. The intelligent test platform of planting machines was used to simulate the field working effect of planter under the different land slope. The experiment results indicated that with the increase of absolute value of land slope angle along with the working direction, the angle range of the planter swing front and back, the angle range of the planter swing front or back in one way and the uniformity variation coefficient of the seed quality of each seed outlet all increased gradually. With the increase of the absolute value of the land slope angle, the operations of continuous uphill or downhill had little effects on the variation coefficient of seed feeding rate stability. The uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of it's ranged from 4.76% to 13.85%. With the increase of the angle range of front and back reciprocating swing, the seed feeding rate had obvious changes, the uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of seed quality of each seed outlet ranged from 4.76% to 10.27%. The effect of front or back single swing on seeding performance showed with the increase of the angle range of front or back swing in one way, the variation coefficient of seed feeding rate was slightly higher than that of with no tilt, the uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of seed quality of each seed outlet ranged from 6.76% to10.71%. The average error of seed feeding rate between the theoretical calculated by the simulation model and the bench test was 4.28%. The matching relationship between the seeding quality, the land slope angle along the working direction and the rotation speed of seed feeding device can ensure the planter has the same seeding quality when the planter working on the land with slope similar to that on the flat land, which can provide a reference for the structure optimization of the planter and the air-assisted centralized metering device to meet the seeding operation under different land slopes.