大型核桃树振动响应特性与落果试验研究

Experimental Study on Vibration Response Characteristics and Fruit Drop of Large Walnut Tree

为确定大型核桃树的振动响应特性,探究大型果树机械化摇振采收方法,以南疆大型核桃树为研究对象,利用ANSYS进行有限元分析获取各分枝振动响应特性;应用自主研发摇振收获设备进行扫频试验及落果试验研究,对各主枝进行共振频率检测,通过各分枝上的传感器获取的频率-加速度幅值曲线,确定曲线峰值对应的共振频率;最后,进行摇振落果试验,对比各主枝在不同共振频率下的落果情况。结果表明:大型果树同一主枝及其上侧枝共振频率相同,各主枝共振频率在22~26 Hz之间;同一主枝上的各检测点加速度响应曲线整体呈现先增加后减小的趋势,距离激振位置越远,加速度响应幅值越大;在共振条件下收获,能够获得更高的落果率。为此,提出一种基于大型核桃树主枝共振频率的摇振采收方法,通过获取主枝处的共振频率,以各主枝共振频率进行多次摇振收获作业,实现共振条件下以较低激振能量获得最大振动响应收获,可有效提高收获效率和采净率。研究结果可为大型果树摇振采收方法提供理论基础。

In order to determine the vibration response characteristics of large walnut trees and explore the mechanized shaking harvesting method of large fruit trees,taking large walnut trees in Southern Xinjiang as the research object,finite element analysis using ANSYS was used to obtain the vibration response characteristics of each branch.Application of independent research and development of vibration wave frequency sweep test and fruit harvesting equipment test and research,to resonant frequency detection,the main branch by the frequency of the sensors on each branch-acceleration amplitude curve,determine the curve peak corresponding resonance frequency,then shaking fruit drop of vibration experiment,comparing the major branch fruit under different resonant frequencies The results showed that the same main branch and its upper and lateral branches had the same resonant frequency,and the resonant frequency of each main branch was between 22 and 26 Hz.The acceleration response curves of each detection point on the same main branch show an overall trend of increasing first and then decreasing.The acceleration response amplitude increases with the distance from the excitation position.Under the resonance condition can obtain higher harvest fruit drop rate Based on this,puts forward a kind of based on large trees a central resonance frequency of the vibration wave collecting methods,through access to a central place of the resonance frequency,vibration wave to harvest many times at the main branch resonant frequency assignment,implementation under the condition of resonance vibration energy gain maximum at a relatively low response to harvest,harvest and improve efficiency and the net rate effectively This study can provide a theoretical basis for the method of vibration harvesting of large fruit trees.