非圆齿轮行星轮系传动的栽植机构参数优化与试验

为了进一步优化栽植嘴的轨迹、姿态及其挖出的穴口形状,提高钵苗移栽的立苗率,提出了基于两级非圆齿轮行星轮系传动的栽植机构组合设计思路,运用变性椭圆-共轭非圆齿轮、变性偏心圆-共轭非圆齿轮、变性巴斯噶蜗线非圆齿轮、变性傅里叶非圆齿轮和变性正弦非圆齿轮5类非圆齿轮副,组合设计了25种不同的栽植机构。建立了基于非圆齿轮行星轮系传动的栽植机构通用数学模型,并将通用数学模型代入旋转式钵苗栽植机构多目标优化模型,根据给定的栽植农艺条件,优化得到了满足理想栽植要求的栽植机构类型及其对应的机构参数。选取其中的偏心-椭圆齿轮行星轮系栽植机构与变性椭圆齿轮行星轮系栽植机构进行对比分析,结果表明运用多种非圆齿轮副进行组合设计的栽植机构具有优越性。根据优化得到的栽植机构类型及其对应的参数进行结构设计和样机研制,并进行了运动学高速摄像试验和模拟田间栽植试验。由高速摄像试验得到的轨迹、姿态、速度等指标和理论计算的对比分析,验证了通用数学模型的正确性;由模拟田间栽植试验可得本栽植机构立苗率较高,约为95%。

Parameter Optimization and Experiment of Planting Mechanism Driven by Planetary Non circular Gears

To further optimize the trajectory and pose of planting nozzle as well as the geometrical shape of hole digged out by planting nozzle, which could improve the seedling erectness rate of seedling transplanting, a combinational design of planting mechanism driven by two stage planetary non circular gears was proposed. 25 different kinds of planting mechanisms were designed by using deformed elliptic conjugate non circular gears, deformed eccentric circle conjugate non circular gears, deformed Pascal curve non circular gears, deformed Fourier curve non circular gears and deformed sinusoidal non circular gears. General mathematical model of planting mechanism driven by planetary non circular gears was built, and the general model was substituted into the proposed multi objective parameter optimization model of rotary seedling planting mechanism. According to conditions of planting agriculture, the types of planting mechanism and the corresponding parameters which met the perfect planting requirements were got by optimizing. One kind of planting mechanism driven by planetary eccentric elliptical gears was compared with planting mechanism with planetary deformed elliptic gears. The result showed that the planting mechanism designed by many kinds of non circular gear pairs had better performance. According to the types of planting mechanism and the corresponding parameters which were got by optimization, structural design and prototype development were carried out, then the experiment of kinematics with high speed camera and the experiment of simulating the field planting were carried out. The comparison between the trajectory, pose and speed of planting nozzle obtained from high speed camera experiment and theoretical calculation showed that the structural design was reasonable, the machining precision met the requirements and the test bed can realize expected principle projects. The simulation experiment in field planting shows the planting mechanism has high seedling erectness rate of 95%.