Authors

Abstract

The hilly terrain where sugarcane harvesters travel, the harvest object of rough and tough stalks, and the perennial cultivation property are all different from those of other straw crops. In order to reduce the cutting damage of cane stalks caused by complex excitation in field conditions, a method for optimizing dynamic characteristics of vibration transmission system based on implicit parametric modeling of harvester frame was proposed. First, the impact damage effect of the cutter on the cut section of stalk was analyzed by high-speed images. Accordingly, the cutter amplitude RMS and impact velocity (VI) were proposed as parameters to characterize the damage inducibility. Subsequently, a 5-DOF dynamic model of the whole machine was established covering 21 dynamic parameters. With the measured excitation of road spectrum, cane cutting force and engine, the virtual prototype simulation showed that the frame stiffness was the most sensitive to vibration response. Through topology optimization and implicit parametric modeling of such load-bearing frame, a high-rigidity design was derived to improve the vibration transmission characteristics. Comparison of testing results before and after frame optimization illustrated that the bending stiffness and torsional stiffness were increased by 1.95% and 2.84% respectively, and the RMS of operating frequency-response functions with road and engine as path sources were decreased by 21.7% and 27.2% respectively. As a result, the output amplitude RMS and impact velocity VI were reduced by 35.9% and 5.9% respectively, implying corresponding improvements in the cutting quality of cane stalks. This study provided a reference for the development of harvester dynamic systems based on harvesting quality optimization.

Abstract in Chinese

甘蔗收获机的丘陵行进地形、粗韧茎秆割收对象及其宿根种植性状与其它秸秆作物条件不同。为降低蔗地工况复杂激励所致的蔗杆切割损伤，本文提出了一种基于机架隐式参数化建模对蔗杆切割损伤进行优化的方法。首先利用高速摄像图像剖析了刀盘-茎秆互作的冲击损伤效应。据此提出了采用刀盘振幅RMS和冲速（VI）作为诱损性表征参量。随后，基于实测路谱建立了整机5自由度动力学模型，解析发现机架刚度对动力响应的敏感性最大。进而筛选出可映射机架承载式结构特征的21个设计变量，从而建立其隐式参数化模型，并通过拓扑优化衍生出机架高刚性的优化设计。优化前后的对比测试结果表明，其弯曲、扭转刚度分别提高1.95%和2.84%，以路面、发动机为路径源的传振频响函数RMS各降低21.7%和27.2%。综合引起致损振幅RMS和冲速VI降低了35.9%及5.9%，意味着蔗杆切割质量获得相应的改进。该研究可为收获机械的动力学系统开发及收割质量优化提供参考。