番茄穴盘苗顶推-夹茎组合式低损自动取苗机理与机构研究

This project aims to solve some key issues of the automatic pick-up mechanism, such as the root injury, the stem injury and the bowl injury of tomato plug seedling in the process of transplanting. To achieve this, the research proposed a seedling pick-up method based on bowl-plug separate by push and snatch at stem with flexible fingers. By considering the mechanical properties and mechanical damage characteristics of the tomato plug seeding, the change regulation about damage mechanics characteristic of the bowl pushing machine and clamp injury of the seeding stem is developed, and the low damage critical condition between the bowl-plug separate and seedling pick-up is also revealed. After that, the injury criteria for both seeding stem and bowl of the tomato plug seedling is established, all of this can provide the theory basis for low damage seedling pick-up on jacking-gripping type. Based on above low damage automatic mechanism of jacking bowl and clamping stem, the theoretical analysis and experimental study of seedling pick-up mechanism with gripping stem type are proposed. Firstly, the kinematic model of the automatic mechanism is set up. Compounding the human computer interaction and fuzzy optimization,kinematic parameters are then optimized by solving the multi-objective programming problem according to satisfaction degree. Meanwhile, the optimal parameters and the ideal trajectory that meet the requirements of the seedling plant are obtained. Moreover, the accuracy of the model is verified by virtual simulation, and a seedling pick-up test-bed with combined type for seedling picking-up test is built, then the kinematics and dynamics performance test is carried out. Finally, the main structural parameters and working parameters of the seedling pick-up mechanism are optimized by utilizing the orthogonal experiment ,the kinematic model is also modificatoried. The methods and conclusions of this project have great significance in a theoretical and experimental basis for developing the tomato automatic transplanter with high efficiency and low damage.

项目以新疆番茄穴盘苗为研究对象，针对目前自动取苗过程中存在的伤根、伤茎及伤钵问题，提出基于钵-盘顶推分离与柔性夹指夹茎取苗的组合式取苗方法。项目从番茄穴盘苗物理力学特性和机械损伤特性研究入手，研究穴盘苗钵体顶推损伤与茎杆夹持损伤力学特性规律，分析钵-盘顶推低损分离与夹茎取苗的临界条件，研究建立番茄穴盘苗茎杆与钵体损伤判别标准，为低损顶推分离及夹茎取苗研究提供理论依据。基于顶推-夹茎式低损自动取苗机理研究，重点开展夹茎取苗机构理论与试验研究。分析机构运动学模型，研究基于满意度原理的取苗机构多目标优化模型，人机交互优化取苗机构运动学参数，获得满足取苗工作要求的理想取苗轨迹与优化参数组合，仿真验证理论模型准确性。搭建组合式取苗试验台，进行机构运动学与动力学特性测试和取苗旋转正交组合试验，优化结构参数与工作参数，修正理论模型。项目研究可为穴盘苗高效低损自动移栽机的研发提供理论依据和试验基础。

项目通过对适栽期番茄穴盘苗物理形态特性及其力学特性规律研究，提出一种斜夹直拔取苗作业方式，建立了夹茎式取苗机构的运动学理论模型，设计基于二阶椭圆齿轮行星轮系的取苗机构，对取苗机构作业性能进行试验测试，验证了夹茎式取苗机构理论分析的准确性，为番茄穴盘苗高效低损伤自动取苗技术的研究提供了新的思路与参考。主要研究内容有：. 1）适栽期番茄穴盘苗形态特性与力学特性分析. 对适栽期番茄穴盘苗物理形态特性进行测定与分析，获得穴盘苗生长统计数据。试验获得了番茄穴盘苗茎秆在外力作用下的力学参数变化规律及其破坏损伤规律，为番茄穴盘苗取苗机构的参数设计提供重要参考和依据。 . 2）高效低损伤取苗机理与机构理论研究. 基于二阶椭圆齿轮节曲线规律及其传动特性研究，提出了一种基于二阶椭圆齿轮行星轮系夹茎式取苗机构以及顶推苗盘破结设计方案，并对其运动特性进行了分析，建立取苗机构运动学模型，通过人机交互获得了满足自动取苗作业要求的理想取苗轨迹与机构参数，得到机构主要参数变化对取苗机构作业轨迹以及作业性能的影响规律，为后续取苗机构的进一步优化和改进提供重要的依据。建立夹苗器凸轮机构数学模型，为夹苗器凸轮机构的设计奠定基础。通过三维建模与运动学仿真分析对取苗机构理论分析进行的验证。该研究可为夹茎式高效低损伤取苗机构的参数化设计提供重要的理论依据。. 3）试验研究. 试制取苗机构物理样机并搭建自动取苗试验台。利用高速摄像试验获取夹苗片尖点运行轨迹，与Adams仿真分析得到的轨迹对比分析。取苗试验表明夹茎式取苗机构工作性能可靠、稳定，取苗成功率较高，伤苗率低，验证了取苗机构理论分析的准确性以及机构实际应用的可行性。. 该项目的实施可为开展自动移栽机取苗装置的研发提供一定的理论基础和技术参考。项目发表论文11篇，其中EI 3篇，申请专利11项（其中实用新型9项已授权），培养研究生2名。