桑属植物的生物物理机械特性分析及机械采摘桑叶的作用机理与运动规律研究

Mulberry field area in Guangxi province was ranked as No.1 in China. The current situation was that mechanization level of mulberry leaves picking in the field was still relatively low, which resulted in low labor productivity and huge labor intensity. Therefore, mulberry leaves picking machine was appointed as the research object. The means of basic physical mechanics, theoretical mechanics, material mechanics, biomechanics, multi-flexible-body dynamics, continuous topological structure design as well as decomposition-coordination optimization design would applied to do the research as followed: Do the research about biomechanical properties of mulberry ramulus and cutting performance of petiole, function principle and motion regularity of picking mulberry leaves mechanically. A series of model such as the relation model of elastoplastic constitutive of Moraceae, the mathematical model of positioning mechanics based on Great Flexibility Theory, the cutting model of petiole based on Elastic Wave Theory, the mechanism kinematics and dynamics model of key components as well as the mathematical model of decomposition-coordination optimization design were set up. Experiments would carry out to test the validity of theoretical analysis mentioned above. From the research, the mechanical damage and fracture mechanism of leaves stalk was revealed as well as function principle between kinematic parameters and running time, motion regularity of mulberry ramulus restricted to the structure and coordination and consistency principle of associated mechanism were revealed. The research achievement would have great theoretical and actual guiding significance in improvement on design technology of mulberry leaves picking machine. It would provide the important theoretical reference for cutting machines of other similar soft plants. The achievement would also supply technical support for mulberry leaves picking mechanization progress.

广西桑园面积位居全国第一，当前现状是桑叶采摘的机械化水平较低，劳动强度大，生产率低。为此本项目以桑叶采摘机为研究对象，采用基础物理力学、理论力学、材料力学、生物力学、多柔体动力学、连续拓扑结构设计以及分解协调优化等方法，进行桑枝生物物理机械特性和叶柄切割力学性能研究；机械采摘桑叶的作用机理和机构运动规律研究；建立桑属植物的弹塑性本构关系模型；大柔度理论桑枝定位数学模型；弹性波理论叶柄切割力学模型；关键机构的运动学和动力学仿真模型；机构分解协调优化数学模型等，并通过试验来验证理论分析结果，揭示叶柄断裂的机械破坏机理，桑枝的运动参数与时间的作用机理，桑枝在限定条件下的运动规律及关联机构运动协调一致性机理。本项目的研究成果对于完善桑叶采摘机设计的技术理论具有重要的理论意义和实际指导作用，同时对于其他柔性植物叶柄的机械切割理论研究具有较大的理论参考价值，为推动桑叶采摘的机械化进程提供技术支持。

广西桑园面积位居全国第一，当前现状是桑叶采摘的机械化水平较低，劳动强度大，生产率低。为此本项目以桑叶采摘机为研究对象，采用基础物理力学、理论力学、材料力学、生物力学、多柔体动力学、连续拓扑结构设计以及分解协调优化等方法，进行桑枝生物物理机械特性和叶柄切割力学性能研究，包括叶柄拉伸、剪切、弯曲等力学性能，揭示叶柄断裂的机械破坏机理，建立了桑属植物的弹塑性本构关系模型；采集桑属植物种植数据，建立桑树侧枝的位置分布与主干定位位置的关系模型和叶柄结点与桑枝直径、有效采摘长度的函数关系模型，为采桑机关键结构设计提供理论依据；进行关键机构的运动学和动力学仿真，揭示了桑枝的运动参数与时间的作用机理；根据桑枝在限定条件下的运动规律及关联机构运动协调一致性机理，建立关键机构的分解协调一致性优化模型进行采桑机械结构多目标优化，在关键结构上，取得最优设计方案，如桑枝的喂入角约100°，桑枝行走速度10mm/s，刀具水平运动速度54mm/s，采摘机构重量由1.1582kg减至0.6014kg，减轻重量为48%。输送能力由每分钟输送19株提高至25株，输送能力提高30.5%，保证了物流的畅通，提高了桑叶采摘的效率。本项目的研究成果对于完善桑叶采摘机设计的技术理论有重要的理论意义和实际指导作用，研究的理论成果和技术手段将为推动机械采摘桑叶设备的研究做出有益的探索，对于其他柔性植物叶片的采摘理论研究具有重要的理论参考价值，为推动桑叶采摘的机械化进程提供技术支持，具有较大的经济意义和现实意义。