设施蔬菜收获机拉拔力学性能EDEM 仿真与试验.

Although China is a vegetable growing country, but the degree of mechanization of vegetable production is low, with China's urbanization and industrialization of the advance, arable land gradually less, so the vegetable cultivation plant more and more people pay attention. Facilities vegetable cultivation is an important way for vegetable cultivation. However, the level of mechanization of vegetable greenhouses is less than 25%, and the comprehensive mechanization level of vegetable production is about 20%, while that of leaf vegetables in China accounts for 30% to 40% of total production. Therefore, the development of efficient and stable facilities vegetable harvesting machinery is the premise to achieve the vegetable plantation and production process automation, and to achieve agriculture, especially vegetable production mechanization is of great significance. In this paper, the height of the vegetable pickling machine can not meet the requirements, the distance of the rhizome exposed is too short, which leads to the phenomenon of vegetable cutting and harvesting. Therefore, the model of the vegetable harvester is established, and the problem of cutting is analyzed. Based on the analysis of the above and below parts of the vegetable stem in the process of drawing, the mathematical parameters of the drawing force were analyzed, and the key factors affecting the pulling force of the vegetables were the height of the vegetables and the height slope. Through the tensile test of the rhizome of the vegetable sample and the compression test of the stem of the vegetable sample, the mechanics parameters of the vegetable were obtained, and the necessary theoretical support was provided for the simulation parameters of the extraction efficiency of the vegetable and the other research. The distinct element method (DEM) is a numerical simulation method for dealing with discontinuous medium problems. And it is widely used in the field of bulk material processing. EDEM software is a general CAE analysis software based on discrete element method, which is commonly used to simulate and analyze particle processing and operating system in industry and agricultural production. At present, its application in crop harvesting has not been reported, but it has been successfully applied in the field of agriculture, especially in the treatment of soil matrix. The discrete element simulation model of vegetable drawing process was established by using discrete element software EDEM, and the optimal drawing force and drawing effect were determined by studying the mechanism of pulling the vegetables. According to the simulation analysis, the relationship between the pulling force of vegetables and the displacement of vegetables and the simulation process of vegetable drawing were obtained. It was determined that the minimum drawing resistance was 26.87 N when the optimum drawing distance was 20 mm. The maximum safe draft load of vegetable rhizome was 37.5 N and the maximum safe compression load of vegetable stem was 84.36 N under the condition of safety factor of 1.1, using small universal testing machine. According to the upper and lower limits of the drawing force and the mathematical parameters of the drawing, the inclination angle of the planting trough to meet the planting of 1~6 vegetables was determined to be 17.8°. And at this angle of inclination, the maximum thrust value of the stem of the vegetable is less than the maximum destructive force of the vegetable 84.36 N. The final working parameters were applied to the single - row prototype test, and the good harvesting effect was obtained, which verified the rationality of the key parameters of the vegetable and vegetable harvest. [ABSTRACT FROM AUTHOR]