小粒径种子精量排种系统设计基础理论与方法

There are numerous species and large scale of planting of small particle size seeds in China, such as rapeseed, vegetable seeds, which causes urgent demand for mechanized precision metering. To solve the current situation that the small particle size seeds possess the characteristics of large differences in the geometry of each dimension, the study on precision metering technique is very backward, the theory of metering system design is imperfect, and the design method is obsolete and miscellaneous. The mechanical and physical characteristics of each dimension will be tested for excavating common scale and mechanical property of representative small particle size seeds. Based on the random process, fuzzy mathematics theory, and gas-solid coupling simulation, the dependence relationship between the seeds group and single seed will be proved and the coupling of gaseous state, solid state, and the liquid state will be analyzed under the conditions of different flow fields. The reliability design and optimization design will be applied to design series mechanism and parallel mechanism of the seeding metering process and establish a digital model in order to analyze the interference-free and cooperative constraint mechanism of the series-parallel mechanism.The migration trajectory of the small seeds and the freedom constraint mechanism of movement for seeds will be revealed, meanwhile, the short-range metering path of high precision can be explored, respectively. On the basis of the above research, the knowledge base and expert system for the agronomic requirement will be supplied to precision metering the basic theory of precision metering for small particle size seeds of variable scale could be established, and the global optimization solution and intelligent design method would be provided for the functional modules of the seed metering process. The loss-less and short-range metering, and high-efficiency intelligent design of small particle size precision metering will be achieved, which can provide systematic basic theory and high-efficiency design method for quantifiable and predictable precision metering of small particle size seeds.

我国油菜、蔬菜等小粒径作物种类多、种植规模大，对机械化精量播种需求迫切。项目针对小粒径种子机械物理特性差异性大、精量播种技术研究滞后、排种系统设计理论体系不健全、设计方法落后等问题，开展小粒径精量播种理论与方法的基础研究。测试代表性小粒径种子各维度机械物理特性测试，挖掘共性属性；基于随机过程、模糊数学和气固耦合仿真，探明单粒种子与种群间依存关系及不同场作用下的气固液耦合机制；应用可靠性设计、多目标优化设计等开展排种过程串并联机构设计及数字化建模，解析串并联机构免干涉和协同约束机制，揭示种子运移轨迹及自由度约束机制；探究高精度短程排种路径，构建小粒径精量播种基础理论；建立面向精量播种农艺要求的精量排种系统设计的知识库和专家系统，提供面向排种过程功能模块的全局最优化求解和智能化设计方法；实现小粒径精量低损短程排种并高效智能设计，为小粒径作物精量播种的可量化与可预测提供基础理论与高效设计方法。

本项目针对油菜、小白菜、芝麻、谷子等小粒径种子精量播种技术研究滞后、缺乏排种系统设计基础理论体系与方法等影响精量播种功能实现和性能提升的难题，开展小粒径精量播种理论与方法的基础研究。利用聚类分析及高速摄影技术等开展小粒径种子机械物理特性参数的共性尺度及其机械属性的测试与挖掘；基于随机过程理论、运动学与动力学、气固耦合仿真，分析了充种、囊种、携种、匀种、导种、投种等环节气力式小粒径种子精量排种系统、气送式小粒径种子高速精量排种系统、导种气送式小粒径种子精量穴播集排系统、小粒径种子勺式精量穴播排种系统内种子迁移中的位移、速度、受载等随机变量的随机过程，并建立了在不同排种环节的共性耦合作用机制，分析确定穹顶状上弧板所处球体半径为245mm时，有利于提高了种子流分配均匀性，减少种子流无序运移；应用赫兹理论、耦合仿真，开展种子运移机制与短程路径规划研究，提出了小粒径种子迁移轨迹路径规划的短程控制策略，开发了取消护种和清种环节的小粒径种子勺式精量穴播排种器；应用高速摄影技术、多目标优化设计，开展了排种过程的串并联机构交互机制及其数字化建模；综合上述研究，项目研究建立了小粒径种子精量排种系统设计基础理论与方法，优化排种系统并创制新型播种装置，实现低损短程排种并高效智能设计，发表与种群依存关系、精量播种过程耦合分析、串并联机构优化设计及参数建模、小粒径种子运移自由度约束机制及迁移轨迹、高精度短程路径的规划、精量排种系统设计的基础理论与方法等内容相关的本学科领域高水平学术论文13篇，其中EI收录文章12篇；获授权专利6项，其中发明专利5项；培养研究生10人；开发了小粒径精量排种装置10台套，构建了智能精量播种机测试平台、研制了小粒径种子兼用精量联合播种机8种机型，通过省级农机推广鉴定5个机型并已应用于生产实际。