油菜基质块苗移栽机取苗装置设计与试验

Design and Experiment on Pick-up Device for Rapeseed Substrate Seedling Transplanter

针对现有油菜基质块苗取苗装置在取苗过程易脱苗和基质损失率高等问题,设计了一种往复夹取式取苗装置。根据垂直苗盘取苗、平行铅垂线投苗的取苗臂位置要求,确定了取苗装置各构件尺寸关系,构建了取苗臂的运动学模型,得出其位移方程及相对运动轨迹。以减小取苗轨迹水平间距及取苗轨迹高度为优化目标,基于Matlab软件优化取苗装置各构件参数为:主动杆长度75.10 mm,取苗臂长度335.26 mm,从动杆长度100.42 mm,机架长度171.32 mm,该参数组合下,取苗轨迹水平间距为173.20 mm,取苗轨迹高度为29.56 mm。构建了取苗回程苗块的动力学模型,分析了苗块临界脱苗方程,结合苗块力学特性参数测定试验,得出最小取苗夹持力为7.07 N,确定了末端执行器气缸缸径为20 mm。应用ADAMS软件获得仿真取苗轨迹,运用高速摄影技术测定实际取苗轨迹高度和取苗轨迹水平间距,经对比分析,实际值与理论值、仿真值的相对误差均小于3%,验证了取苗装置设计的合理性。台架试验表明,取苗成功率为93.33%,脱苗率为2.86%,基质损失率为3.75%,满足油菜基质块苗移栽要求。

Rapeseed seedling transplanting is an innovative and efficient transplanting technique.However,falling off and high substrate loss have become the common problem facing rapeseed seedling transplanting fields and causing the transplanting quality of rapeseed seedling decrease.A clipping type seedling pick-up device was developed.According to the position requirements of the pick-up arm,the size relationship between the components of pick-up device was determined.The displacement equation and motion trajectory of pick-up arm were obtained by dynamic analysis.The optimal parameter combination was obtained based on Matlab optimization analysis,so as to reduce the horizontal spacing(ΔxE)and the height(ΔyE)of trajectory,which were as follows:the length of active side-stick was 75.10 mm,the length of pick-up arm was 335.26 mm,the length of negative side-stick was 100.42 mm,and the length of frame was 171.32 mm.And the optimization results were as follows:the horizontal spacing of trajectory was 173.20 mm,and the height of trajectory was 29.56 mm.The critical falling off equations of seedling block was established by dynamic analysis.The mechanical and physical properties of seedling block were obtained by experiment.The following conclusions were obtained through analysis:the minimum clamping force for pick-up device was 7.07 N,and the diameter of the finger cylinder was 20 mm.The virtual trajectory was obtained by ADAMS,and the actual trajectory was obtained by high-speed photography technology.After comparison and analysis,the error between the actual value,optimization result and simulation result were less than 3%,which verified the correctness of the mechanism design.The seedling pick-up was tested through the bench experiment,and the results were as follows:the success rate of seedling pick-up was 93.33%,the rate of seedling falling off was 2.86%,and the rate of substrate loss was 3.75%,which met the requirements of rapeseed substrate seedling pick-up and verified the feasibility of the mechanism design.The research result provided a reference for the design of pick-up device for rape substrate seedling transplanter.