马铃薯切块薯种取种勺设计与仿真优化

Design and Simulation Optimization of Seed Picking Spoon for Cut-potato Tubers

马铃薯切块播种是节约用种成本、打破薯种休眠的有效途径,针对马铃薯播种机传统圆形取种勺对切块薯种适应性较差,导致漏播率高,播种合格率低的问题,对马铃薯播种机取种勺进行了设计与仿真优化。在测定薯种力学特性参数的基础上,利用EDEM软件,选取Hertz-Mindlin接触模型,构建了切块薯种离散元模型。通过对切块薯种取种充种状态进行分析,以传统圆形取种勺为基础,设计了一种切口式马铃薯播种机取种勺,并确定了影响取种效果的主要因素。以切口圆心角、切口深度和切口个数为试验因素,以取种成功率、重种率和空种率为评价指标,开展三因素三水平虚拟仿真正交试验。正交试验结果表明:切口式取种勺取种能力明显优于传统圆形取种勺,当切口圆心角为60°,切口深度为15 mm、切口数量为3个时,其取种效果最优。利用优化后的取种勺进行切块薯种播种验证试验,结果表明:播种取种成功率为82.2%,重种率为7.1%,空种率为10.7%,相比于传统圆形种勺,其重种率降低约12个百分点,取种成功率提升约12.5个百分点。

Cutting potatoes before planting is an effective way to save seed costs and break seed dormancy.Aiming at the problem that the traditional round seed picking spoon of potato planter is poorly adapted to the cut-potato tubers,resulting in high miss-planting rate and low sowing qualification rate,the seed picking spoon of potato planter was designed and simulation optimization.On the basis of determining the mechanical characteristic parameters of potato tubers,a discrete elemental model of cut-potato tubers was constructed by using EDEM software and selecting the Hertz-Mindlin contact model.By analyzing the state of seed picking and seed filling,a notched potato seed picking spoon was designed based on the traditional round seed picking spoon,and the main factors affecting the effect of seed picking were determined.A threefactor,three-levels virtual orthogonal simulation test was carried out using the incision center angle,incision depth and number of incisions as test factors,and the successful seeding rate,reseeding rate and missed seeding rate as evaluation indexes.The results of orthogonal test showed that the seed picking ability of incision type spoon was significantly better than that of traditional round seed picking spoon,and its working effect was optimal when the incision center angle was 60°,the incision depth was 15mm,and the number of the incisions was 3.The optimized seed picking spoon was used to conduct a cut-potato seed planting validation test,which showed that the successful seeding rate was 82.2%,the reseeding rate was 7.1%,and the missed seeding rate was 10.7%.Compared with the traditional round seed picking scoop,its missed seeding rate was reduced by about 12 percentage points and the successful seeding rate was improved by about 12.5 percentage points.