Design And Experimental Research On Root Cutting Device Of Chinese Cabbage Harvester

At the present stage,the mechanized harvesting level of Chinese cabbage is low and the harvesting effect is not ideal.This paper focuses on the root cutting operation in the process of Chinese cabbage harvesting,and designs a double-disc root cutting device,which can achieve low-power consumption and high-efficiency root cutting.In this paper,the root cutting process of Chinese cabbage is studied by numerical simulation using explicit dynamics analysis software(LS-DYNA),and the working parameters of the root cutting device are optimized by bench test.The main contents and conclusions of this article are as follows:(1)The geometric parameters were measured and statistically analyzed to support the design of root cutting device for Chinese cabbage at maturity.It was concluded from the experiments that the density of Chinese cabbage roots was close to that of water,and its water content increased from bottom to top;its average values of axial and radial modulus of elasticity were 6.15MPa and 4.36MPa,and its shear strength decreased from bottom to top.(2)By analyzing the root cutting mechanism of Chinese cabbage,the root cutting method and type of the root cutting device were determined,and the type of cutter was selected.Referring to the physical and geometric parameters of Chinese cabbage,the key components of the root cutting device were designed,and the 3D modeling of the root cutting device was modeled using SolidWorks 2020 software.According to the mechanical parameters of Chinese cabbage roots,the simulation model of Chinese cabbage root cutting was established by using SolidWorks and ANSYS software.The root cutting force,root deformation,stress and internal energy of root cutting during the root cutting process of Chinese cabbage were obtained by explicit dynamics analysis.The root cutting simulation experiment was conducted with machine forward speed,cutter rotation speed,cutter tilt angle and cutter overlap amount as independent variables to investigate the influence between each factor and the maximum root cutting force and internal energy of root cutting.(3)An adjustable test bench of Chinese cabbage root cutting was designed and built,which mainly consists of clamping and conveying mechanism,root cutting mechanism,frame and data acquisition system,etc.Through single-factor test,the variation pattern of each factor on the cutting root power was analyzed to determine the factor level of multi-factor test,and then multi-factor test was conducted.It is concluded from the test that the factors affecting the root cutting power in the order of priority are:cutter rotation speed>forward speed>cutter tilt angle>the amount of cutter overlap.The parameters of the regression model were optimized with the lowest root cutting power as the optimization index.The results showed that the lowest root cutting power of Chinese cabbage was achieved at the cutter rotation speed of 200r/min,the forward speed of 0.3m/s,the cutter tilt angle of 10° and the amount of cutter overlap of 20mm,and the optimized test value was 53.2W.(4)The Chinese cabbage root cutting device was processed and assembled,and the field experiments of Chinese cabbage harvesting were carried out in the Chinese cabbage planting base by combining the crawler walking chassis.The test results showed that the qualified rate of Chinese cabbage root cutting device was 87.2%,and the operation loss rate was 7.2%,which met the requirements of Chinese cabbage harvesting.