链夹式移栽机立苗机理分析与试验

针对链夹式移栽机用于油菜移栽时存在的对土壤适应性差、易倒伏等问题,对链夹式移栽机结构、栽植部件工作原理及秧苗在栽植过程中的运动特性进行分析。运动特性分析结果表明,在零速投苗位置,秧苗夹持部位绝对运动轨迹为摆线,而根部轨迹为余摆线,上部为短摆线,即秧苗有向机具前进方向倾斜的趋势,特别是对于较大株高的油菜苗更加明显。针对现有移栽机存在的这一问题,采用对比试验的方法,对投苗角度与立苗率的关系进行研究。改变相关零部件的设计参数,设置了提前投苗、零速位置投苗、滞后投苗3种情形的对比试验。结果表明:提前5°投苗,秧苗的优良率为45.6%、倒伏率5.3%,均优于零速投苗,且明显优于滞后投苗情形下的相应指标。试验结果与运动学分析结果一致。

Theoretical analysis and experiments of transplanting mechanism of chain-clamp transplanter for rapeseed seedlings

During rapeseed seedling transplanting by chain-clamp transplanter,the seedlings are easy to go lodging,which reduces the quality of transplanting.To solve this problem,transplanting mechanism of chain-clamp transplanter is analyzed in this paper.Firstly,the structure of chain-clamp type transplanting machine is specified,and the working principles of transplanting components are analyzed.Secondly,Motion characteristics of rapeseed seedlings during planting process are analyzed.According to the analysis,absolute motion trajectory of the clamping part of seedling clamp is cycloid,locus of seedling root part is trochoid,and the upper part is a short cycloid.This suggests that seedlings have displayed forward tendency.Tests show that,for tall seedlings like rapeseed seedlings,the forward tendency reduced the vertical degree and standing rate.In order to find the method to solve this problem,comparative tests of three kinds of circumstances are carried out,which are dropping seedlings in zero speed position,advanced position and lagging position.The results show that chain-clamp dropping seedlings at 5 degrees before zero speed position bring a better vertical degree and standing rate for seedling than in zero speed position,and much better than that in 5 degrees behind zero speed position.