桑园立式旋转动力耙优化设计与试验

Optimization Design and Experiment of Vertical Rotary Harrow for Mulberry Plantation

摘要:

桑园耕整地作业是提高桑叶产量的重要基础，根据桑园种植模式和耕整地作业要求，设计了一种适用于桑园的立式旋转动力耙。根据桑园种植模式和耕整地农艺要求确定了动力耙整机结构，通过对耙刀作业过程理论计算和运动学分析，确定耙刀结构参数。利用离散元法对动力耙作业过程进行仿真，分析不同外倾角对耙刀所受扭矩和作业质量的影响以及耙刀作业过程中所受扭矩的变化规律。选取转子转速、前进速度、耙深为试验因素，以碎土率、耙后地表平整度、土壤容重为试验指标，进行了三因素三水平正交旋转组合田间试验。试验结果表明：转子转速和前进速度对碎土率、耙后地表平整度和土壤容重的影响极显著；耕深仅对碎土率的影响显著，对耙后地表平整度和土壤容重均无显著影响。优化计算得到作业参数最优组合：转子转速为350 r/min、前进速度为0.7 m/s、耕深为20 cm，此时碎土率为97.89%，耙后地表平整度为11.04 mm，土壤容重为1.11 g/cm3。以优化得到的作业参数组合进行验证试验，得到碎土率为97.29%，耙后地表平整度为11.53 mm，土壤容重为1.07 g/cm3，与优化得到的结果一致，满足作业要求。

Abstract:

The cultivation and land preparation work in mulberry plantations is the important foundation for improving mulberry leaf yield. Based on the mulberry planting mode and the requirements of cultivation and land preparation work, a vertical rotating rotary harrow suitable for mulberry plantations was designed and optimized. According to the mulberry plantation planting and cultivation requirements to determine the rotary harrow machine structure, through the theoretical analysis of the harrow knife operation process and kinematic analysis, the harrow knife structure parameters were determined. Using the discrete element method to simulate the rotary harrow operation process, and the influence of different camber angles on the torque of the harrow knife and working quality of the machine and the variation law of the torque during the harrow operation were analyzed. Taking rotor speed, forward speed and plowing depth as test factors, and taking soil breakage rate, surface flatness after harrowing and soil weight as test indexes, a three-factor, three-level orthogonal rotary combination field test was carried out to analyze the influence of each factor on the operational effect of rotary harrow. The test results showed that the rotor speed and forward speed on the soil breakage rate, harrowing surface flatness and soil weight was very significant;the effect of plowing depth was only significant on the soil breakage rate, and there was no significant effect on the harrowing surface flatness and soil weight. The optimal combination of operating parameters was calculated as follows: rotor speed was 350 r/min, forward speed was 0.7 m/s, plowing depth was 20 cm, soil fragmentation rate was 97.89%, surface flatness was 11.04 mm after harrowing, and soil capacity was 1.11 g/cm3. The verification test was carried out with the optimized operation parameter combination, and the soil breakage rate was 97.29%, surface flatness after harrowing was 11.53 mm, soil capacity was 1.07 g/cm3, which was consistent with the optimized results, and it met the operational requirements.