基于瓜类蔬菜柔嫩特性的斜插式自适应嫁接新机构机理及关键技术研究

Grafting seedling technique is an effective sustainable biological cultivation method to overcome the continuous cropping obstacle. Grafting can well improve the plant’s ability of resistance to soil borne disease, and overcome the continuous cropping obstacle. Due to the labor shortage, the automatic grafting for melons vegetables is in urgent need, but because the special structure of melons vegetables’ grafting stock stem, the diameter difference between grafting scion and stock stem is larger. Especially because the tender and easy to damage of grafting seedling, it is in urgent need to study the mechanisms related with characteristics of melons vegetables and grafting mechanism. This research project based on the inclined-inserting grafting method for melons vegetables, propose flexible concept in design mechanical structure. Main research contents are as follows: the geometrical and mechanical characteristics of grafting stock and scion, the flexible removing trajectory and mechanisms design for stock growing point, the dynamic analysis and modeling of suction for scion locating, the flexible alignment and parameter optimization for stock clamping, the mechanism and parameter optimization for process of inclined-inserting grafting, and the development and test optimization for melons vegetables inclined-inserting grafting machine system. The research of this project can provide new mechanisms for development of melons vegetables grafting machine and technical support. This project can raise the level for automation and intellectualization of melons vegetables grafting.

嫁接育苗技术是一种有效克服连作障碍的可持续性生物栽培方法，通过嫁接能较好地提高植株抗土传病害的能力，克服连作障碍影响。由于劳动力紧张，瓜类蔬菜的机械自动化嫁接非常急需，但由于瓜类蔬菜砧木茎杆的结构特殊、接穗与砧木茎差较大，特别是由于嫁接苗柔嫩，易损伤，迫切需要针对瓜类蔬菜的特性研究有关的机构与嫁接机理。本项目以瓜类蔬菜为对象，基于斜插嫁接法，提出在机构设计中融合柔性概念。主要研究内容为砧木与接穗几何与力学特性，砧木生长点柔性去除轨迹与机构设计，接穗苗气吸定位的动力学分析与模型建立，砧木柔性校直夹持及参数优化，斜插式插接过程机理与参数优化，斜插式瓜类蔬菜嫁接装置系统研制与试验优化。通过项目的研究为瓜类蔬菜嫁接机的研制提瓜新机构与技术支撑，提高瓜类蔬菜嫁接的自动化与智能化程度。

蔬菜嫁接是克服连茬病害的最有效途径，由于嫁接蔬菜比较柔嫩、且不规则，给机械嫁接带来了较大的困难。针对这些问题，项目以瓜类蔬菜为研究对象，以不损伤或少损伤嫁接苗为目标，对斜插式蔬菜嫁接机的关键机构进行了研究。首先测定了嫁接适期的接穗和砧木的几何特性和力学特性，获得了砧木和接穗的外部特征参数，砧木茎秆和接穗子叶的力学特性，为嫁接机各机构的设计研究提供基础。为解决嫁接过程中由于砧木弯曲而导致嫁接苗损伤的问题，提出了一种具有自动对中功能的交替组合式砧木夹持机构，试验结果表明，砧木夹持机构的夹持成功率为98.33%，且对砧木苗无损伤。设计了一种气吸式接穗夹持机构，通过CFD分析软件对气吸机构内部的流场进行了仿真分析，结果表明在吸头为H型吸嘴，真空度为3kPa，孔深为1mm参数条件下，气吸机构的吸附成功率为97.78%，无接穗苗损伤现象。模仿人手去除砧木生长点的方式，提出了一种基于砧木苗特点的生长点仿形去除机构并进行了试验研究，结果发现生长点去除机构的去除成功率达95.56%。通过分析幼苗内部髓腔结构，设计了砧木苗打孔机构，砧木与接穗的断根机构，通过试验研究，确定了砧木苗打孔最佳角度为40°，砧木断根机构的成功率为98.89%，接穗断根机构的成功率为96.67%。最后，对嫁接机械装置进行总体设计与结构整体组装，通过试验得到所设计斜插式嫁接机的嫁接成功率为91.39%，满足嫁接要求。通过此项目的研究，取得了嫁接过程的基础数据和新机构，有助于提高我国瓜类蔬菜嫁接的机械化水平。