带式玉米高速导种装置旋夹纳种机理分析与参数优化

Mechanism Analysis and Parameter Optimization of Corn Seeds Receiving by Rotating Clamp of Belt-type High-speed Seed Guiding Device

针对玉米在高速(12~16 km/h)播种时籽粒脱离种盘初速度大,与带式导种装置种腔内壁碰撞弹跳,发生碰撞异位,导致籽粒进入种腔精准度低等问题,以具有纳种机构的带式玉米高速导种装置为研究对象,建立籽粒夹取、转运和排放动力学模型,提出在拨指表面添加人字形纹路的改进方法,明确影响纳种稳定性与籽粒进入种腔精准度的主要因素。利用高速摄像与图像目标追踪技术进行单因素对比试验及多因素优化试验。单因素试验结果表明,播种速度较快时,有人字形纹路拨指轮纳种合格指数和种腔间隔变异系数均明显优于无人字形纹路拨指轮。为获得拨指轮改进后的纳种机构最佳性能参数,以轮心距、拨指轮转速及拨指长度为试验因素,以纳种合格指数与种腔间隔变异系数为评价指标,进行三因素五水平二次正交旋转组合试验,采用多目标优化方法,确定当轮心距为36.8 mm,拨指轮转速为584.97 r/min,拨指长度为10.8 mm时,纳种合格指数为98.23%,种腔间隔变异系数为0.24%。对优化结果进行验证试验,验证结果与优化结果基本一致。在相同条件下进行台架对比试验,结果表明,有带式玉米高速导种装置的作业性能远优于不安装带式玉米高速导种装置的作业性能。

When corn is sown at high speed(12~16km/h),the initial speed of the seeds leaving the dish is high,and the seeds collide with the seed cavity wall of the belt-type seed guide device,resulting in collision and dislocation,which leads to the low precision of the seeds entering the seed cavity.The belt-type high-speed corn seed guide device with seed receiving mechanism was taken as the research object,and the dynamic model of clamping,transportation,and discharge of the seeds was established.The main factors that affect the seed receiving stability and the precision of the seeds entering the seed cavity were identified,and the improvement method of adding herringbone lines on the surface of the finger was put forward.Single-factor comparison tests and multi-factor optimization tests were carried out by using high-speed camera and image target tracking technology.The single factor test showed that the seed acceptance index and variation coefficient of seed cavity spacing of the finger wheel with improved herringbone lines were obviously better than those of the finger wheel without herringbone lines when the sowing speed was fast.In order to obtain the best performance parameters of the improved seeding mechanism,taking the wheel center distance,the rotation speed of the finger wheel,and the finger length as test factors and the qualified index of seed acceptance and the variation of seed cavity spacing as evaluation indexes,a quadratic orthogonal rotation combination test with three factors and five levels was carried out.By using the multi-objective optimization method,it was determined that when the wheel center distance was 36.8mm,the rotating speed of the finger wheel was 584.97r/min,and the finger length was 10.8mm,the qualified index of seed acceptance was 98.23%,and the coefficient of variation of seed cavity spacing was 0.24%.The optimization results were verified,and the verification results were basically consistent with the optimization results.Under the same conditions,the bench comparison test showed that the sowing performance with a high-speed seed guide device was better than that without high-speed seed guide device.