| The transplanting of rape seedlings has the characteristics of high survival rate,fast greening,and high yield.The seedling removal device is the key component of the seedling placement machine.In order to solve the problems of poor reliability and unstable performance of seedling extraction,this paper designed a After adapting to the finishing of the compartment,the six-row canola pot seedling placement machine was designed and tested on the seedling extraction device.The specific results are as follows:(1)The penetration resistance test of rape seedlings and pots was carried out to obtain the relationship between penetration resistance and displacement at different water contents.Through the pull resistance test,the ranges of pull resistance and detachment displacement at different water contents were obtained.Provide a mechanical reference for the follow-up design of seedling harvesting claws.(2)The structural design of the seedling picking claw of the seedling picking device is an innovative design of a fork-shaped four-needle seedling picking claw,and the four-linkage chute mechanism is used in conjunction with the cam pusher to achieve seedling picking and unloading.Establish a three-dimensional model to optimize the design of the seedling trajectory using simulation method.Based on the Solidworks motion plug-in,analyze the effects of various parameters on the seedling needle trajectory and angular displacement,and obtain a set of optimal parameter combinations: swing rod length LDE=225mm,support arm length LCD =90 mm,deflection arm length LEF=76mm,drive rod LAB=38mm,deflection arm angle ∠FEG=125°.The length and height of the seedling extraction trajectory are 360 mm and 110 mm respectively.When the seedling extraction trajectory height is 35 mm,the needle insertion into the soil section is similar to the straightness of less than 2 mm,and the angular displacement of the seedling extraction needle is less than 3°.The change of the needle needle displacement during the seedling stage is less than 3°,and the change of the needle needle displacement during the seedling stage is less than 1°.Using ADAMS 2017 software for dynamic simulation,the speed-acceleration curves of the seedling tip and the roller were obtained,which verified that the movement conditions of the seedling harvesting device could meet the requirements of accurate seedling harvesting and stable delivery.(3)In order to meet the smooth implementation of the process of taking seedlings and unloading seedlings,the electric control system of the seedling extraction device was studied,and a control system plan was designed.The photoelectric switch and the electromagnetic relay were used to control the on-off of the DC motor to achieve intermittent extraction of the device.The system can realize the reliable movement of the seedling harvesting process when the seedlings are thrown in.(4)For the seedling collection device and indoor seedling collection test,analyze the influence of each factor on the seedling collection effect through a single factor test,use Design expert 8.0.6 to design a multi-factor orthogonal test table,and complete the analysis of variance through SPSS software.A set of best parameter combination: water content is41.57%,insertion speed is 80mm/s,and soil depth is 35 mm.Under this combination,the success rate of seedling extraction is 95.8%,and the success rate of seedling injection is95.6%.(5)A field test was carried out on the developed rapeseed seedling placement machine.When the tractor was driven in the first gear at low speed and the seedling frequency was 19times/min,the coefficient of variation of plant spacing was 11.6% and the rate of missed planting was 2.2%.The seedling device meets the standard operating requirements for transplanting and transplanting of rape seedlings. |
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