中文摘要：

针对水稻钵苗宽窄行Z字形移栽农艺要求,提出了一种差速式水稻钵苗Z字形宽窄行移栽机构,利用差速轮系的不等速传动和空间传动,以空间轨迹实现水稻钵苗Z字形宽窄行移栽。将非均匀B样条曲线理论应用于非圆齿轮节曲线的拟合,并采用坐标变换方法建立了机构齿轮箱轮系的数学模型。将水稻钵苗Z字形宽窄行移栽的轨迹和姿态要求参数化为9个具体的运动学优化目标,编写了基于机构数学模型的可视化参数优化界面,利用该软件界面分析了传动箱非圆齿轮节曲线和齿轮箱非圆齿轮节曲线对轨迹形状的影响,以及斜齿轮螺旋角和取秧夹片长度与轨迹偏移量的关系。通过优化得到取秧段偏移量为3.9 mm,取秧段轨迹有效长度为45.6 mm,移栽机构离地高度为32.6 mm,夹片离从动非圆齿轮牙嵌轴距离6.7 mm的大环扣式移栽轨迹。完成了移栽机构的虚拟仿真与样机试制,利用自制试验台架、工业相机和图像处理软件对机构移栽臂运动轨迹和姿态进了分析,结果与理论数据吻合,验证了移栽机构方案的可行性和结构的合理性。

英文摘要：

For rice seedling transplanting, there are more than 5 kinds of planting patterns in China, including equal row carpet seedling transplanting, wide-narrow row carpet transplanting, equal row pot seedling transplanting, wide-narrow row pot seedling transplanting, and semi-pot seedling transplanting. The zigzag wide-narrow row rice seedlings transplanting is a new method of planting adjacent rows of rice seedling alternately, and distributing wide and narrow rows. This kind of planting method absorbs the merits of traditional equal row pot seedling planting, wide-narrow row carpet seedling planting and zigzag planting. The pattern of zigzag and wide-narrow row pot seedling transplanting can increase the light penetration and ventilation of the paddy-field, which brings some advantages such as reducing the plant diseases and insect pests, increasing lodging resistance ability of rice and improving the rice yield and quality for rice production. In this paper, a variable and differential transplanting mechanism for zigzag wide-narrow row rice pot seedlings was presented. This mechanism consists of2 major parts that are transmission case and gear case. There are 10 gears, including 2 pairs of noncircular gears, 2 pairs of bevel gears as well as one pair of spur gears, employed to transform one input constant rotational speed into 2 output rotational speeds which are used to drive the noncircular gear case. Based on the non-uniform and spatial transmission of differential gear train, this mechanism can achieve a special figure-eight spatial-shaped trajectory, which can meet the kinematic requirements of zigzag wide-narrow row pot seedling transplanting. In order to obtain closed, smooth and continuous pitch curves, non-uniform B-spline curve was applied to fit the pitch curve of non-circular gear, and the mathematical model of gear train in gear case was established based on coordinate transformation theory. Moreover, the trajectory and attitude requirements of the zigzag wide-narrow row pot seedling transplanting were