大葱收获机挖掘阻力的理论与试验研究

Theoretical and Experimental Study on Excavation Resistance of Green Chinese Onion Harvester

大葱收获机挖掘阻力的研究对大葱收获机设计具有十分重要的作用,目前还未见有大葱收获机挖掘阻力的报道。为此,针对大葱收获机挖掘阻力难以测试的问题,采用理论建模和自主创新的嵌入式测试技术进行了研究。通过对大葱挖掘铲的受力分析及对挖掘土壤的动力学分析,研究了土壤附着力对挖掘过程的影响并建立了挖掘阻力数学模型。为克服传统根茎类作物挖掘力测试系统存在测试构件多、力传递误差大等不足,创新设计了嵌入式连续土壤阻力测试系统。同时,进行了不同挖掘速度和挖掘深度下的挖掘阻力测试试验,并将挖掘阻力理论结果与试验结果进行比较,二者趋于一致,表明对挖掘阻力的研究是正确的。最后,基于大量测试数据,建立了挖掘深度、挖掘速度与挖掘阻力之间的关系图。研究表明:阻力随着挖掘深度和挖掘速度的增加而逐渐增大,挖掘深度对挖掘阻力的影响比挖掘速度对挖掘阻力的影响大得多。因此,在保证将大葱从土壤中顺利挖掘出来的前提下,尽量减小挖掘入土深度,同时兼顾收获效率和大葱损伤率及损失率等因素,尽量提高挖掘速度,以保证大葱收获机的挖掘效率。

The harvest of green onions is a mechanized problem in the production of green Chinese onion in China. The research on the excavation resistance of the onion harvester plays a very important role in green Chinese onion harvester’s design. At present, there is no report on the excavation resistance of the green Chinese onion harvester. Aiming at the difficulties in testing the resistance of onion harvester, the theoretical modeling and independent innovation of embedded testing technology were studied. Through the analysis of the force of the digging shovel and the dynamic analysis of the excavated soil, the influence of soil adhesion on the excavation process was studied and the mathematical model of excavation resistance was established. In order to overcome the shortcomings of traditional rhizome crops excavation resistance test system which has many test components and large force transmission errors, an embedded continuous soil resistance test system was designed. Furthermore, the test of excavation resistance under different excavation speeds and excavation depths was carried out. Through the comparative analysis of the theoretical results of the excavation resistance and the experimental results, it is found that the two tend to be consistent, indicating that the research on the excavation resistance is correct. Finally, based on a large amount of test data, a diagram between excavation depth, excavation speed and excavation resistance is established. The research shows that the resistance increases with the increase of excavation depth and excavation speed. The influence of excavation depth on the excavation resistance is much greater than the excavation speed on the excavation resistance. Under the premise of ensuring the smooth excavation of green Chinese onion from the soil, the depth of excavation should be minimized. At the same time, factors such as harvesting efficiency, damage rate of onion and loss rate should be taken into consideration, and the excavation speed should be increased as much as possible to ensure the excavation efficiency of the green Chinese onion harvester.