中文摘要：

为了实现棉花移栽自动取苗，针对棉花基质苗茎秆抗拉力远大于取苗力的特点，该文提出高阶混合变性椭圆齿轮行星系夹苗式取苗机构，并建立该机构的运动学数学模型，分析夹苗式取苗工作的运动目标，编写机构优化分析软件，确定一组机构参数：啮合齿轮中心距58 mm，第1级基椭圆的偏心率为0.2，二阶变形椭圆齿轮的主变形系数0.9，第2级基椭圆的偏心率为0.14，一阶变形椭圆齿轮的主变形系数0.18，初始时刻太阳轮标线的安装角为13π/18、行星架OA边与太阳轮标线的夹角为π/2、中间轴A上安装的第2中间轮与第1中间轮标线的夹角为7π/18、行星架AB边相对与第2中间轮标线夹角为35π/36、取苗爪BE边相对于第1行星轮标线夹角π/6、取苗爪BE边与BT边夹角7π/18、取苗爪BT边长度150 mm，工作轨迹的取苗段与苗箱夹角91°、取苗过程行星架转角36°、取苗过程苗与钵盘不干涉、取苗过程取苗爪摆角5°、入苗段与取苗段轨迹夹角为85°、投苗角76°、两取苗爪之间最小距离49 mm。机构的虚拟试验表明，该型取苗机构的工作轨迹和理论计算吻合，满足夹苗式取苗工作要求，取苗爪在取苗段速度较大利于快速取苗，周期速度曲线平滑，该研究结果为棉花基质育苗移栽自动取苗提供了参考。

英文摘要：

Picking seeding tache in plug seedings of cotton transplanting is completed manually at present. As a result, the efficiency of cotton transplanting is limited. In order to realize automatic pick-up in seedlings in cotton transplanting, a new kind of seedling pick-up mechanism was designed which adapts with the characteristics of the stems’ matrix tensile force of the cotton seedlings in nursery medium which is much larger than the fetching seedling force. A new form of planetary gearing system that is composed with blended high-order deformed elliptic gears was introduced. Mechanism kinematics mathematical model was established, the objective of clipping seedling type working with seeding pick-up mechanism were set according to the demand of the clipping seedling type. Working and the demand of coordination between the seeding pick-up mechanism and seeding box, seeding transplanting mechanism, and optimize analysis of software were compiled to determine the parameters of institutions：the center distance of the meshing gear is 58 mm, the eccentricity ratio of first stage second order deformation elliptical gear is 0.2, the major deformation coefficient of first stage second order deformation elliptical gear is 0.9, the eccentricity ratio of second stage single deformation elliptical gear is 0.14, and the major deformation coefficient of second stage single deformation elliptical gear is 0.18. The installation angle of the mark line on the fixed sun gear 1 is 13π/18, the angle of planetary carrier OA and the mark line on the sun gear 1 isπ/2, the first middle gear and the second middle gear are installed on the middle shaft A, the first middle gear that the meshing with sun gear, the angle of mark lines on the second middle gear and the first middle gear is 7π/18. At the initial position, the angle of the planetary carrier AB and the mark line of the second middle gear is 35π/36, the first planetary gear that the meshing with the second middle gear, the first planetary gear and the picking-up seedling claw