基于两段收获的弹齿式花生捡拾机构研究

Spring-finger Peanut Pickup Mechanism Based on Two-stage Harvest

为解决花生两段式机械收获过程中因花生捡拾装置存在植株＂壅堆＂与＂抛起＂而造成掉果损失的问题,结合相应的花生收获农艺和植株物理机械特性,针对滑道式弹齿滚筒式捡拾装置,根据弹齿在捡拾、举升、推送和空回4节拍中实现的理想摆动姿态和运动规律,以捡拾装置护板半径最小为主要目标,采用非支配排序遗传算法NSGAII进行了弹齿、曲柄、滑道和护板等多元件整体优化设计和机构参数优化,分析了弹齿、曲柄、护板等构件参数变化对目标函数的影响。根据4个工位中弹齿摆动特点,设计凸轮滑道中心线轨迹方程,运用Matlab编程获得滑道中心线轨迹,并采用非均匀三次B样条曲线对凸轮滑道轮廓线进行平滑处理。通过ADAMS动力学与运动学仿真,获得捡拾过程中齿端运动轨迹,通过分析确定了空回工位采用五次多项式过渡方式。根据设计结果制作弹齿滚筒式花生捡拾装置。通过样机运转试验、花生捡拾性能试验表明,新型弹齿式捡拾装置用于花生捡拾过程中,不存在植株＂壅堆＂与＂抛起＂问题;通过响应面分析法及试验,获得捡拾装置最优工作参数为：前进速度V为48.0 m/min,转速N为53.1 r/min,离地高度H为-7.4 mm。在花生植株含水率15%~17%的两段收获条件下,花生植株捡拾率为98.9%,掉果损失率为2.5%。

In order to reduce the loss of peanut caused by peanut plants stacking and throwing during two-stage peanut harvester working,a spring-finger cylinder pickup was designed by analyzing springfinger swing and movement rule of a sliding spring-finger cylinder pickup in four processes of picking,lifting,pulling,and null swing with peanut harvest agronomic and plant physical and mechanical characteristics parameters,including spring-finger,crank,slide,shield,etc. which were optimized and designed optimally by NSGA-II for minimum shield radius. Equations of cam slide centerline locus were designed by using spring-finger swing characteristic. Cam slide centerline locus was obtained and smoothed by using Matlab and cubic non-uniform B-spline. The end displacement locus of the springfinger was obtained by using ADAMS. The quintic polynomial was used in null swing station with springfinger swing simulation analysis. The experiments of prototype working and collecting peanut plants indicate that,the phenomenon of peanut plants stacking and throwing was disappeared; the optimal working parameters of spring-finger cylinder pickup were obtained by using response surface method： the forward speed was 48. 0 m / min,cylinder rotating speed was 53. 1 r / min,and height above around was-7. 4 mm. The collecting rate and the loss rate were 98. 9% and 2. 5% respectively under peanut plant moisture content of 15% ~ 17% in two-stage harvest.