大蒜半喂入切根作业机理研究及机构优化

Mechanized root cutting is the necessary process during garlic mechanized harvesting，which is also the weakest link of garlic combine harvest technology in China. According to the problem of low cutting root rate and the high damage ratio in garlic half feed root cutting, this project intends to carry out the research on dynamic characteristics of root cutting and mechanism of operation quality, exploration the control strategy of operation quality and the method of mechanism optimization design. This project intends to apply the theory of multi-body system dynamics combine with the simulation sensor detection and control technology, it can build the simulation model of rigid flexible coupling system for garlic lines – root cutting mechanism；This project uses the method of dynamic simulation analysis, high-speed photography analysis and bench test analysis. This method can research the kinematics and dynamics behavior of the operation procedure, analyze the interaction relationship between garlic lines – root cutting mechanism. Eventually, it can proven internal relations of operation quality and cutting mechanism parameters , reveals the root quality formation mechanism; Applying kinds of research methods including multi – objective digital simulation optimization, Response Surface experimental optimization and experimental verification, the comprehensive optimization method on garlic half feed root cutting device are to be explored to established the parameterized model of simulation system and the prediction model of operation qualities. Comprehensive optimization scheme of the root cutting device will be study. The optimal combination of structural parameters and operating parameters will be achieved finally. The research results will provide theoretical basis and new ideas for the research and development of garlic half feed root cutting technique.

机械化切根是大蒜机械化收获的必要工序，也是我国大蒜联合收获技术最薄弱环节。针对大蒜半喂入切根作业过程中根系切净率低、鳞茎损伤率高等问题，本项目拟开展切根动力学特性和作业质量产生机理研究，探索作业质量控制策略和机构优化设计方法。拟运用多体系统动力学理论，融合仿真传感检测与控制技术，组建大蒜株系-切根机构刚柔耦合系统动力学仿真模型；动力学仿真分析、高速摄影分析与台架试验分析等相结合，研究作业过程运动学和动力学行为特性，分析蒜株-切根机构相互作用关系，探明作业质量与切根机构特征参数的内在联系，揭示切根作业质量形成机制；综合运用多目标数字仿真优化、响应面试验优化与台架验证试验等技术方法，建立仿真系统参数化模型与切根作业质量预测数学模型，研究切根机构综合优化方案，实现切根机构结构参数和作业参数最优组合。研究结论为大蒜半喂入切根技术提升和机构优化提供理论依据和新思路。

切根技术是实现我国大蒜全程机械化收获的主要短板，也是制约我国大蒜机械化收获技术发展的主要因素。目前，有关大蒜半喂入切根机构作业过程的认知尚未达到理论水平，对切根作业机理研究和认识还很粗浅，机构优化方法不足，严重制约了机构创新水平和作业质量。本项目以我国大蒜主产区典型品种为研究对象，获取了主产区适收期典型大蒜品种的株系基本信息、根系空间分布规律、株系几何形态特征、株系基础力学特性参数等。确定了适用于大蒜联合收获的大蒜切根作业工艺流程，完成了切根机构的优化设计并构建了切根机构虚拟样机模型及切根试验台。研究了大蒜株系柔性体描述和建模方法并构建了大蒜株系柔性体模型。针对构建的切根机构虚拟样机仿真模型、大蒜株系柔性体模型，模拟机械化切根实际作业过程，构建了能有效描述切根作业过程的大蒜株系-切根机构刚柔耦合系统动力学仿真模型，并开展了切根作业过程动力学仿真分析，研究了切根作业过程鳞茎、根系以及切根机构的受力和运动行为特征。运用理论分析法开展了根系浮动切割作业过程中力学特性研究，推导出切根作业过程鳞茎碰撞动力学方程，明确了影响鳞茎碰撞损伤的影响因素；探析了根系滑切作业原理并建立了刀刃切割阻力力学模型，揭示了根系群切割阻力形成致因。运用高速摄影分析法，揭示了鳞茎挤压变形、碰撞破损以及根系群扰动、根系断裂等力学行为的产生过程。运用刚柔耦合系统多目标数字仿真分析法，探明了切根机构不同结构参数和运动参数对切根作业性能的影响。系统开展了多因素多指标响应面试验和正交试验研究，建立了能预测切净率、伤蒜率等作业指标的多因素数学模型，探明了各因素显著性水平、主次作用顺序与影响规律，试验测定与台架验证相结合，通过多目标综合优化获得切根机构综合优化方案。本研究可弥补我国大蒜机械化切根基础理论研究的不足，为我国大蒜半喂入切根技术创新和机构研发提供理论依据和新方法。