| Harvesting is the main link in the production of Radix Isatidis.At present,the level of mechanized harvesting of Radix Isatidis is low,and the suitable harvesting machinery and equipment is still blank.In order to improve the level of mechanized harvesting of Radix Isatidis and improve the harvesting efficiency and quality of Radix Isatidis,a swing screen type of Radix Isatidis harvester suitable for single ridge operation was developed in this paper.The two key parts of Radix Isatidis harvester,digging part and separating part,were designed and tested.The main research contents are as follows:(1)The physical characteristics of Radix Isatidis in Tailai County,Qiqihar City,Heilongjiang Province were measured to obtain the root profile shape and size.The physical properties of soil in harvest period were tested,and the size and proportion of soil particle,water content and density in different depths were obtained,which provided basic data for subsequent research.(2)According to the agronomic requirements of Radix Isatidis harvest,the advantages and disadvantages of different types of digging shovel were analyzed and compared.Combined with the design requirements of digging shovel,a V-shaped plane digging shovel with grid bar at the tail was developed based on triangular plane digging shovel and grid bar digging shovel,and the relevant structural parameters were determined.Through the construction of soil compression failure theory model and excavation resistance model,it is concluded that the geometric factors affecting the performance of soil breaking and excavation resistance are as follows: shovel face angle,shovel blade angle,shovel body length and shovel body width.(3)Based on EDEM software and field resistance test,a virtual soil model was established.Taking the digging resistance and broken soil rate as test indexes,and the inclination angle of shovel face,the inclination angle of shovel edge and the length of shovel body as test factors,the virtual simulation test of V-type plane excavator was carried out by using three factors and three levels box Behnken response surface analysis method in the established virtual soil model,and the better combination of structural parameters was obtained as shovel face inclination is 17°,blade angle is 53°,the length of shovel body is 377 mm.(4)Based on the analysis and comparison of the advantages and disadvantages of different separation devices,a swing type of separation device with screen strip plate combination screen surface is developed,and the key components of the device are designed.The kinematic and dynamic analysis methods were used to analyze the movement mechanism of the root soil complex on the screen surface,and the shooting strength,the main factors affecting the harvest effect and the working parameters range of the swing type root soil separation device were determined.(5)Taking the inclination angle of screen surface,crank speed and crank radius as the experimental factors,the open stem rate and damage rate as the evaluation indexes,the field performance test of the experimental prototype was carried out by using the three factor and five level quadratic orthogonal rotation combination experimental design method.Design expert8.0.6 was used to complete variance analysis and significance test on the data,and the regression equation and response surface graph were obtained.The interaction between various factors was analyzed,and the optimal parameter combination was screen surface inclination is 14 °,the crank speed is 412r/min and the crank radius is 23 mm.The results showed that the rate of bright stem was 96.09%,and the rate of damage was 2.54%,which met the requirements of Isatis indigotica. |
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