Abstract:In order to solve the problems caused by large soil disturbance, low return flow, poor hole size regularity, poor hole forming effect, high dew rate and low upright degree, a multi-leaf duck bill planting mechanism was designed based on duck bill shape. The composition and working principle of the whole structure were described, and the structure and working parameters of the key components were preliminarily designed through theoretical analysis and the establishment of the mathematical model of motion. The factors affecting the soil cavitation effect were analyzed. With the number of duckbill leaves, the opening and closing angle of duckbill, and the opening and closing speed of duck bill as test factors, and the soil disturbance amount, soil return flow, and the regularity of the cavity size as evaluation indexes, a three-factor and three-level orthogonal combination experiment was designed. A regression mathematical model of the evaluation indexes was established by using Design-Expert software. The response surface of the test results was compared, and the significance of the three factors on the evaluation index was compared. According to the multi-objective parameter optimization of the regression model, when the number of duck bill leaves was4, the opening and closing angle of duckbill was 22 °, and the opening and closing speed of duckbill was 70 r/min, the regularity of soil disturbance amount, soil return flow rate and hole size were 0.559, 0.788 and 7.136, respectively, the soil cavitation effect was the best at this time. According to the optimal test results, the design parameters of the key components were optimized and determined, and the field planting experiment was carried out. The results showed that the average error of evaluation index between planting operation test and coupling simulation test was 2.2%, 2.3% and1.8%, respectively, which met the requirement of error between simulation test and actual test. At the same time, the dew rate and orthostatic qualification rate after planting operation were evaluated, the dew rate was 3.6%, and the orthostatic qualification rate was 96.7%, which met the requirements of the machinery industry standard JB/T 10291—2013《Dryland Planting Machinery》 with the dew rate not higher than 5% and orthostatic degree not less than 93%. The correctness of the design and theoretical analysis of the multi-leaf duckbill planting mechanism was verified.