沙棘果实-果柄系统振动采收机理分析与仿真

沙棘在西部广泛种植,用于水土保持和防风固沙。其果实营养丰富、有较高经济价值,但采收非常困难,影响其经济价值。为改变人工采摘的状况,有必要进行沙棘的机械化采收研究。为此,研究了沙棘果实与果柄脱离的振动采摘机理,建立了双自由度受迫振动物理模型,推导出动力学方程,并采用数理微分方程求解得到沙棘果实-果柄系统稳态受迫振动输出解及采摘惯性力。同时,通过贝塞尔函数曲线模拟果实的几何形状,得出果实几何轮廓曲线方程,并利用Pro/E的函数功能画出沙棘果实的三维模型,将模型导入有限元分析软件ANSYS进行了模态分析。结果表明:理论计算的果实-果柄系统的位移、速度和加速度响应与有限元仿真分析的结果比较相符,频率在18~46Hz范围内时,果实部分产生共振且主振型最大,故果实的最佳采摘频率范围可确定为18~46Hz。该研究为沙棘振动采摘装备的开发提供理论基础。

Mechanism Analysis an dSimulation of Vibration Har vesting of the Sea Buckthorn Fruit-stalk System

Sea buckthorn is an ideal plant for ecological management and was thus planted widely in the western of Chi -na .Its fruit is rich in nutrition , and has high economic value , but sea buckthorn fruit is very difficult to be harvested .In order to change the situation mainly by manual picking , it is necessary to study the mechanized harvesting of sea buck-thorn .In this paper , the mechanism of fruit-stalk detachment by vibration was studied ,and a two degree of freedom forced vibration physical model is established and derive the kinetic equation .The steady forced vibration solution and the inertia detachment force of the fruit-stalk system were obtained by solving mathematical differential equations .Mean-while , the geometric outline of fruit , of fruit is simulated by Bessel's function curve , and the geometric curve equation of the fruit were used to draw the 3D model of the fruit in Pro/E.Afterwards, the fruit model was introduced into the finite element analysis software ANSYS to carry out Modal analysis .The results show that the displacement , velocity and accel-eration of the fruit-stalk system were in conformity with the results of finite element simulation analysis .When the fre-quency is in the range of 18~46 Hz, the part of the fruit is resonant and the main mode is the largest .This will provide the theoretical basis for the development of the vibration picking equipment for sea buckthorn fruit .