SIMULATION AND OPTIMIZATION OF THE SPOON-WHEEL TYPE MAIZE PRECISION SEED-METERING DEVICE BASED ON VIBRATION

The DEM (discrete element method) simulation and optimization of the shapes and quantity of spoons of spoon-wheel disc in the spoon-wheel seed-metering device under vibrational conditions are investigated in this paper. EDEM (Engineering-DEM) software was adopted to establish DEM models of ‘Zhongyu No.3’ coated maize seeds and the spoon-wheel seed-metering device first, and four additional spoons of various shapes (labeled as K1~K5, respectively) were designed. The test results indicated that the acceleration of seeds in the Y-direction in spoons (K2~5) was all less fluctuating than those in the original spoon (K1), and the multiple rate was the largest in spoon (K5). The ultimate optimal working speed of the spoon-wheel maize precision planter in southwest China was identified as 3 km/h, with 22 spoons and the ideal spoon shape being K3. The bench validation test was executed under vibrational conditions based on the optimal spoon structure and operation settings. The qualified rate exceeded 94.5% at an operating speed of 3~4 km/h, while the multiple rate was less than 4%, the leakage rate was lower than 1.5%, and the variation coefficient was smaller than 25.5%. The variety adaptability test was launched when the working speed was 3 km/h. The qualified rates of various maize varieties were all more than 96.5%; the multiple and leakage rates were both less than 2%, which satisfied the technical requirements of maize precision sowing in southwest China. The qualified rates of various maize varieties were all more than 96.5%, and the multiple and leakage rates were both less than 2%, which satisfied the technical requirements of maize precision sowing in southwest China.