| Transplantation has a great economic benefit,but the transplanting mechanism is the difficult point and hot spot in the research of the modern agricultural mechanism.The seedling transplanting mechanism of planetary gear system has a well rotation performance,which is suitable for the high-speed transplanting.However,the existing configuration of transplanting mechanism of planetary gear system is fewer and the flexibility of the movement is insufficient as well.Meanwhile,the design method of planetary gear system mechanism in achieving the exact positions and postures is also lacking.After the existing design methods aiming at the mechanism’s positions and postures are synthetically analyzed and compared,the transmission type of linkage mechanism is found to be uncomplicated and the design of linkage mechanism is found to be flexible.Meanwhile,the researchers have achieved abundant research results about linkage mechanism’s configuration and kinematic synthesis.However,the linkage mechanism which is used to achieve the complex motion is difficult to be designed,and the linkage mechanism is just suitable for the working conditions of low revolving speed,which is difficult for the working efficiency to be improved.The planetary gear system mechanism is a mechanism configuration that can have the efficient motion,but the design methods aiming at its positions and postures are still existing problems.In order to accurately realize the trajectory and posture requirements of transplanting mechanism’s output component,the analytical theory in achieving the exact positions and postures design of linkage mechanism is combined with the design of the planetary gear system in this paper’s research.Based on the solution region synthesis of 2R open chain linkage group,a planetary gear system mechanism that can achieve the exact position and posture requirements is designed,and a transplanting mechanism of planetary gear system that can achieve the exact position and posture conditions in transplanting working process is intended to be developed.The main research contents of this paper are as followed:1)The methods that the equation of Burmester curves were established through modern design method of linkage mechanism and the Burmester curves were represented orderly through the angle mapping relation were analyzed.A method to establish the 2R linkage mechanism’s limited solution region,then to restrain the mechanism’s positions and sizes as well as discriminate the mechanism’s movement defect,finally to establish the 2R linkage mechanism’s feasible solution region was put forwarded.2)A transplanting mechanism of planetary gear system was proposed,and the kinematic model of the mechanism was built through the analysis of mechanism’s constitution and working principle.3)Aiming at the transplanting requirements of the rapeseed blanket seedling,the trajectory of the transplanting mechanism was projected,and its kinematical targets were put forwarded.The integrated design software of the transplanting mechanism of planetary gear system was written based on the MATLAB software,in order to carry through the optimization design of the mechanism.The parameters of the mechanism that met the working goals were obtained through software,and the design results could be visually output through software.4)The structure of transplanting mechanism was designed,the 3D model of the mechanism was completed,and the virtual simulation experiment of the mechanism was conducted.A mechanism prototype was produced and a transplanting test bench was built to carry out the transplanting experiment of rapeseed blanket seedling.The images of transplanting mechanism’s actual motion trajectory were captured through the high-speed photography,and the actual motion trajectory of the transplanting mechanism was compared and analyzed with the set theoretical designed trajectory through the high-speed photography analysis software.When the transplanting mechanism passing the finite separated four position points,the attitude angles of transplanting arm were measured as 167.99 °,157.20 °,147.63 ° and 102.95 ° through the software,and the discrepant angles between actually measured angles and theoretically set angles were 2.01 °,2.80 °,2.37 ° and 2.05 °.The test results were all in the error range of the mechanism experiment,so the design method on transplanting mechanism of planetary gear system based on the solution region synthesis of 2R open chain linkage group was verified to be correct.Finally,the actual transplanting effects of transplanting mechanism were test through the transplanting experiment of rapeseed blanket seedling. |
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