基于离散元法的油莎豆降阻挖掘装置设计与试验

目前油莎豆机械化收获方式以正旋旋耕挖掘为主，但工作过程中存在工作阻力大、碎土率低、埋果率高等问题，本文针对油莎豆旋耕挖掘方式进行反旋运动学分析，建立了旋耕刀与油莎豆团聚体离散元模型，结合EDEM进行挖掘过程离散元仿真试验，确定影响旋耕刀工作阻力和刀轴扭矩的结构参数和取值范围，利用Design-Expert进行试验优化与回归分析，确定旋耕刀的最佳结构参数为：弯折角130°、工作幅宽45mm，在相同参数设置下与正旋旋耕方式进行对比试验，工作阻力降低了8.6%，刀轴扭矩降低了5.9%，证明反旋挖掘具有降阻作用。为检验优化设计的旋耕刀作业性能，以埋果率和土壤破碎率作为试验指标进行对比试验，结果表明：反旋作业方式埋果率1.07%，土壤破碎率93.48%，与标准旋耕刀相比，新型旋耕刀油莎豆块茎埋果率减低了1.2个百分点，土壤破碎率提高了1.3个百分点。

Design and Test of Resistance-reducing Excavation Device of Cyperus edulis Based on Discrete Element Method

At present, the mechanized harvesting method of Cyperus edulis is mainly forward rotary tillage excavation, but there are problems in the work process such as large working resistance, low soil fragmentation rate and high fruit burying rate. The discrete element model of the rotary tiller and the cedar agglomerates was analyzed and established, the discrete element simulation test of the excavation process was carried out combined with EDEM, and the structural parameters and value ranges that affected the rotary tiller''s working resistance and the torque of the tool shaft were determined. Design-Expert experiment optimization and regression analysis were carried out to determine the best structural parameters of the rotary tiller, which were as follows: bending angle of 130°, working width of 45mm, compared with the normal rotary tillage method under the same parameter settings, the working resistance was reduced by 8.6%, the torque of the cutter shaft was reduced by 5.9%, which proved that the anti-rotating excavation had the effect of reducing resistance. In order to test the performance of the optimized rotary tiller, the fruit burying rate and the soil breaking rate were used as the test indicators to conduct a comparative test. The results showed that the reverse rotary operation method had a fruit burying rate of 1.07% and a soil broken rate of 93.48%, which were compared with the standard rotary cultivator. Compared with the new type rotary scalper, the burial rate of tubers of Cyperus edulis was reduced by 1.2 percentage points, and the soil broken rate was increased by 1.3 percentage points, which improved the harvesting efficiency of Cyperus edulis.