旱作移栽钵苗高速低损取、投机理及机构优化研究

Dry-farming transplanting is an important agricultural technology to help remain a stable production and increase the yield, the main factor to prevent this technology to be popularized in our country is its low efficiency. It has been researched that the speed of a seedling being taken by the manipulator has a decisive effect on the transplanting efficiency. Currently, the speed of a seedling being taken by a manipulator is about 60~90 per minute for existing transplanting mechanism. However, this speed is relatively low for transplanting, the final object of this project is to reach the ideal speed (90~120 per minute) and decrease the damage to the pot body when a seedling is taken from the seedling plate. In order to achieve this goal, we are going to research on the soil property, seeding mechanism and other relative factors. We will do some deep research on the soil cohesion property of the pot body which is made by soil, mechanical property of coupling between the seeding and the pot body, principle of mechanism of high-speed and multi-objective complex optimization method. We are going to develop a kind of automatic seedling system that behaves well in the condition of high speed with high efficiency and lower damage based on our theory. The theory and research method will provide new ideas for the dry-farming transplanting and improve the efficiency of transplanting, thence have the important scientific significance and bright application prospect.

旱作钵苗移栽是一项重要的稳产增产农艺技术，而制约其在我国大面积推广应用的重要因素是移栽效率低下，提高移栽效率主要取决于钵苗从穴盘中取出投苗的速度。目前机械手取苗速度可以达到60~90株/min，但效率仍偏低，进一步提高取苗速度（单行90~120株/min），且作业过程中钵体损伤小是本项目的研究目标。围绕这一目标，项目拟融合土壤、秧苗、机构等多方面因素，开展钵苗高速低损取、投机理及机构优化的研究工作。主要对秧苗钵体的黏附力学特性、钵苗与高速机械物耦合作用的力学性能、取苗机构高速作业机理及多目标复合优化方法等关键技术进行深入研究，研制一种适合于高速作业的自动取苗系统，实现钵苗的高速低损自动取、投。研究理论和方法将提供旱作移栽技术发展新思路，提升旱作钵苗移栽效率，具有重要的科学意义和应用前景。

旱作钵苗移栽是一项重要的稳产增产农艺技术，而制约其在我国大面积推广应用的重要因素是移栽效率低下，提高移栽效率主要取决于钵苗从穴盘中取苗投苗的速度。目前机械手取苗速度可以达到60~90株/min，但效率仍偏低，进一步提高取苗速度（单行90~120株/min），并降低钵体损伤是本项目的研究目标。本课题针对上述问题，进行了蔬菜穴盘苗自动移栽技术与装置的研究，旨在实现蔬菜自动高效移栽；研究理论和方法将提供旱作移栽技术发展新思路，提升旱作钵苗移栽效率，具有重要的科学意义和应用前景。.结论如下：.1. 通过对辣椒钵苗力学特性研究，采用综合评分法选出辣椒钵苗机械特性较优参数组合为苗龄为40天，基质成分为草炭：蛭石：珍珠岩=3:1:1，钵苗土钵含水率为55%。此时该钵苗的拉拔力大小为3.05N，屈服极限为4.5452N，5N加载压力下2s内的平均蠕变量为0.037mm（蠕变量较小，采用机械式入钵夹取钵苗时，可以不必考虑苗钵的压缩蠕变情况），钵苗与栽植嘴壁面间的摩擦系数为0.5476。.2. 穴盘苗物理力学特性及苗钵拉拔力试验表明：基质FNZ的穴盘苗在苗钵含水率55%时，钵体抗压能力较强（4.70N），抗压力随位移的变化曲线也较为理想。采用机械式入钵取苗，需在保证苗钵具有较好抗压能力的情况下，拉拔力相对较小（需超过2.67N），以避免夹取穴盘苗的过程中损伤苗钵。.3.建立钵苗与鸭嘴相互过程动力学模型，通过编写钵苗运动过程分析软件，对栽植器进行了改进设计，得到了一组满足移栽要求的结构参数：太阳轮和行星轮的中心距即行星架OB长度L1=50mm，连杆BC的长度L2=50mm，取苗臂DC长度L3=120mm，摇杆ED的长度L4=130mm，取苗臂旋转中心DC点至取苗针端点F的距离L5=180mm，OA杆的初始安装角α0=189°，OA杆与AB杆的夹角α1=262°，连杆BC与X轴方向上的夹角α2=163°，FC杆与CG杆的夹角α3=60°，FC杆与CD杆的夹角α4=214°，E点的坐标位置XE=76mm和YE=68mm，利用SoldWorks2014完成了自动移栽装置的虚拟装配与运动仿真，验证了其理论分析的正确性。改进后的栽植机构在运转转速120r/min左右时能够保证移栽作业的顺利完成。