基于DEM-MFBD的辣椒移栽机取投苗装置设计与试验

Optimization Design and Test of Seedling Picking and Throwing Device of Plug Seeding Transplanter Based on DEM-MFBD

针对现有辣椒移栽机取苗成功率低、损伤率高、稳定性差的问题,设计了一种插夹联动式末端执行器,基于整排取苗、间隔投苗的取投苗作业形式设计了气动控制系统,分析了取投苗装置结构及工作原理,建立了末端执行器运动学、动力学模型,以薄皮椒钵苗为研究对象开展力学特性试验,结合取苗过程边界条件确定了末端执行器主要参数范围;通过ADAMS运动轨迹仿真与FluidSIM-P 3.6气动系统仿真分析,验证了取投苗装置结构设计与气动时序的合理性;通过DEM-MFBD联合仿真对取苗情况进行了可视化分析,为末端执行器关键参数优化提供依据。通过单因素试验明确了各关键因素对取苗成功率与基质损失率的作用规律;设计正交试验,通过方差分析、响应面分析与多目标寻优得出最优参数组合为:取苗针间距12.25 mm、取苗针入土角50.37°、取苗针行程14.21 mm。台架验证试验得出:取苗成功率为97.92%、基质损失率为2.21%,与回归模型预测值误差分别为0.49%、3.8%,无茎秆损伤现象,取投苗效果良好。

Aiming at the problem of low seedling picking success rate,high damage rate and poor stability of pepper transplanter,a kind of clamp-puncture end effector and pneumatic system was proposed based on the operation mode of taking seedlings in whole row and throwing seedlings at intervals.The structural configuration and working principle of device was analyzed and the kinematics and dynamic model was established.Based on the physical characteristics of pepper plug seedlings and analysis of boundary condition,the main parameters range of the newly improved end effector was determined.Simulation test based on ADAMS and FluidSIM-P 3.6 were carried out to verify the reasonability of the structure and response time sequence of pneumatic actuator.The coupling simulation test based on EDEM and RecurDyn turned out that the improved structure had a better performance.Aiming at the success rate of seedlings picking and the loss rate of substrate,single factor test and analysis were carried out on the key factors such as needle interval,needle insertion stroke and needle insertion angle.According to the results of single factor test,the orthogonal test,variance analysis and response surface analysis were carried out.The optimal parameters were obtained as follows:needle interval was 12.25 mm,needle insertion angle was 50.37°,needle insertion stroke was 14.21 mm,the seeding picking success rate,substrate loss rate were respectively 97.44%and 2.13%.Bench verification test showed that the success rate of seedling extraction was 97.92%and the matrix loss rate was 2.21%.The relative error between verification result and the predicted value was less than 5%.