南瓜种子姿态约束定向组合式排种器设计与试验

Design and Test of Combined Pumpkin Seed Attitude-constrained Directional Seed Metering Device

摘要:

为实现南瓜种子定向播种，提出先调整南瓜种子运动姿态再进行定向的组合式定向方法，设计了一种南瓜种子组合式定向排种器。该定向装置的关键部件包括限位清种板和导向板两部分。基于南瓜种子几何特性确定了限位清种板的结构参数。建立南瓜种子定向过程的运动学方程，明确了南瓜种子定向过程中姿态变化与导向板结构参数的关系，确定了导向板结构参数。利用CFD-DEM耦合法，验证了南瓜种子组合式排种器定向排种的可行性，确定了排种盘转速取值范围。搭建试验台，以平躺吸附率为试验指标，通过单因素试验确定了排种盘型孔直径。以单粒率为试验指标，通过单因素试验确定了负压和排种盘型孔数取值范围。选取负压、排种盘型孔数、排种盘转速为试验因素，以单粒率、定向成功率为试验指标，进行了三因素三水平二次中心组合试验，得出影响排种器单粒率的主次因素为负压、排种盘型孔数、排种盘转速，影响排种器定向成功率的主次因素为排种盘转速、负压、排种盘型孔数。对优化后参数进行田间验证试验，结果表明，当排种盘型孔数为16、负压为10kPa、排种盘转速为4r/min时，单粒率为94.7%，定向成功率为82.7%，南瓜种子落入穴盘的正负偏转角度为18.5°。

Abstract:

In order to realize the directional seeding of pumpkin seeds, a combined direction method was proposed to standardize the movement attitude of pumpkin seeds and then orient them, and a combined directional seed metering device for pumpkin seeds was designed. The key components of the device to realize the direction of pumpkin seeds included two parts: limit clearing plate and deflector plate. Based on the geometric characteristics of pumpkin seeds, the structural parameters of the limit cleaning plate were determined. The kinematic equations of the direction process of pumpkin seeds were established, and the relationship between the attitude change and the structural parameters of the deflector plate during the direction process of pumpkin seeds was clarified, and the structural parameters of the deflector plate were determined. The coupling analysis method of CFD-DEM was used to verify the feasibility of directional seeding of the seed metering device. The value range of rotation speed of seed discs was determined. A test bench was built. With the flat adsorption rate as the test index, the diameter of the hole in the seed discs was determined by a single factor test. The single seed rate was the test indicators, and the value range of negative pressure and the number of holes in the seed discs were determined by the single factor test. The negative pressure, the number of holes in the seed discs and the rotation speed of the seed discs were selected as the test factors, and the single seed rate and directional success rate were the test indicators. A three-factor and three-level secondary center combination test was carried out, and the primary and secondary factors influencing the single seed rate of the seed arranger were the negative pressure, the number of holes in the seed discs and the rotation speed of the seed discs. The primary and secondary factors influencing the directional success rate was the rotation speed of the seed discs, the negative pressure, the number of holes in the seed discs. Field validation experiments were carried out on the optimized data, and the results showed that when the negative pressure was 10kPa, the number of holes in the seed discs was 16, and the rotation speed of the seed discs was 4r/min, the single seed rate was 94.7%, the directional success rate was 82.7%, and the positive and negative deflection angle of the seeds falling into the cave basin was 18.5°.