半自动压缩基质型西瓜钵苗移栽机成穴器参数优化

Parameter optimization of opener of semi-automatic transplanter for watermelon seedlings raised on compression substrate

在圆饼状压缩基质型西瓜钵苗移栽时,由于栽植机形成的穴形质量不佳,会造成钵苗倾斜。根据西瓜钵苗的移栽农艺要求,结合旱地移栽机械作业的特点,开展了半自动压缩基质型西瓜钵苗移栽机的成穴器参数优化研究。分析了成穴器的运动机理,建立了栽植穴的参数方程,得出理论成穴深度是影响穴口上部纵长的主要因素;利用离散元法对成穴器成穴过程进行仿真分析,验证成穴器结构参数与运动参数的合理性,探明了小端直径不同的成穴器在不同理论成穴深度的成穴效果;结合田间试验对成穴器参数进行优化,试验结果表明,成穴器小端直径为60 mm,理论成穴深度为65 mm时,所成穴形有利于圆饼状压缩基质型西瓜钵苗栽植;仿真及试验结果表明,穴口上部纵长、穴口上部宽度和有效成穴深度的仿真结果与试验结果之间的误差最小值、最大值和平均值分别为0.34%、12.78%、6.7%;7.23%、20.87%、12.33%;1.79%、17.92%、10.46%。该研究为成穴器的优化改进提供参考。

Aiming at the problems of the poor quality of the hole shape formed by the transplanter will cause the seeding to tilt,when watermelon seedlings raised on pie-shaped compression substrate for transplanting.Opener parameters of hole-forming device in semi-automatic transplanter for watermelon seedlings raised on compression substrate is optimized to meet the agronomic requirements of transplanting compression substrate watermelon seedling and combining the characteristics of dryland transplanting machinery.Through analyzing the movement mechanism of the opener,this paper established the parameter equation of the planting hole.It was concluded that the depth of the hole-forming was the main factor affecting the longitudinal length of the upper part of the hole mouth.The Edinburgh Elasto-Plastic Cohesion Model,which can reflect the elastoplasticity and cohesiveness of soil.The simulation analysis of the hole-forming process of the opener was carried out by using the discrete element method.The rationality of the structure parameters and motion parameters of the opener was verified,and the hole-forming effect of different diameters of the small end of opener was explored at different theoretical depth of hole-forming.According to the simulation results,the diameter of the small end of opener was 60 mm and the theoretical depth of hole-forming was 65 mm.The bottom of the hole was relatively flat,effective depth of hole-forming was 51 mm.The upper longitudinal length of hole and the upper width of hole were relatively small.It was conducive to the growth of coated transplanted crops.In order to verify the accuracy of the above design method and the reliability of the operation of the hole-forming device,a prototype and 3 sets of opener with different small end diameters were trial-manufactured to carry out field experiments,and the upper longitudinal length of hole,upper width of hole and effective depth of hole-forming were measured.The results of the experiment combined with the simulation analysis showed that the upper longitudinal length of hole and the upper width of hole were increased with the increase of the theoretical depth of hole-forming.The upper longitudinal length of hole and the upper width of hole increased with the increase of the diameter of the small end of the opener.The influence of the diameter change of the small end of the opener on the upper longitudinal length of hole was weaker than the change of theoretical depth of hole-forming.The theoretical depth of hole-forming had a significant effect on the upper longitudinal length of hole.The larger the diameter of the small end of the opener,the more the upper width of hole increased as the theoretical depth of hole-forming.The minimum error between simulation result and the test result of upper longitudinal length of hole was 0.34%,the maximum was 12.78%,and the average error was 6.7%.The minimum error between the simulation result and test result of the upper width of hole was 7.23%,maximum was 20.87%,and average error was 12.33%.The minimum error between effective depth of hole-forming simulation results and test results was 1.79%,the maximum was 17.92%,and the average error was 10.46%.The research can provide a reference for the optimization and improvement of the opener.