基于三维重建的果树固有特性研究
摘要
对果树振动特性研究一直是国内外的一个研究重点，国外在对激振参数与采净率之间关系的研究中发现不同的振动参数组合对采收效率有极大影响，国内对树枝进行激振试验，建立枝干加速度与激振频率之间的数学关系式，发现树枝在冲击式激振下的动态响应要大于在正弦式激振下的动态响应。国外通过建立双摆模型研究激振能量在树枝间的传递发现当测试点远离激振点位置时，树枝的动态响应逐渐增大。为了更加直观的进行试验研究，国内外将三维重建技术进行研究并应用。研究的重点在于枝干提取，研究出了基于双目视觉、点云配准、数码相机等三维重建关键技术，国内通过三维实体建模进行模态和频率谐响应分析，得出激振频率24Hz为较好振幅。这类研究成果为果树振动特性的研究奠定了理论基础。
关键词：振动特性，激振参数，枝干提取，三维重建
Research on Fruit Tree #39;s Intrinsic Characteristics Based on 3D Reconstruction
Abstract
Research on vibration characteristics of fruit trees has always been a research focus at home and abroad. In the study of the relationship between vibration parameters and extraction rate in foreign countries, it has been found that different combinations of vibration parameters have a great influence on the harvesting efficiency, and the domestic branches are stimulated. The vibration test establishes a mathematical relationship between the acceleration of the trunk and the excitation frequency and finds that the dynamic response of the tree under impact excitation is greater than that under sinusoidal excitation. In the foreign countries, the establishment of the double pendulum model to study the transmission of excitation energy among the branches revealed that the dynamic response of the branches gradually increases when the test point is far from the excitation point. In order to carry out experimental research more intuitively, domestic and foreign research and application of 3D reconstruction technology will be conducted. The research focuses on branch extraction. The key technologies of 3D reconstruction based on binocular vision, point cloud registration, and digital camera have been researched. The modal and frequency harmonic response analysis has been performed through 3D solid modeling in China, and the excitation frequency is 24Hz. For better amplitude. This type of research laid a theoretical foundation for the study of vibration characteristics of fruit trees.
Key words: Vibration characteristics, Excitation parameters, Branch extraction, 3D reconstruction
- 课题研究目的和意义
我国林果产业位居世界榜首。林果采收作业是林果生产中最耗时、最费力的一个环节，其所用劳动力占整个生产过程的35%-45%[1-2]。目前的采收技术多采用机械振动激振果树使其落果，其优势在于振动式收获能够快速有效地分离成熟果实，适合大面积、规模化果品生产。林果采收振动系统动态特性研究可通过动力学建模和实验分析两种手段获得[3-4]。为了提高振动系统的采收效率和果实的采净率，国外已逐步深入对动态特性参数与振动传递的实验研究。现有的研究大多着眼于激振与采净效果之间的关系，而没有细化研究激振能量在树干处的动态响应特性，以及振动响应与激振频率的具体关系及其原因，同时对于果树本身专有的一个特性研究并不充分。
