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选取海棠果树为材料,通过激振果树主干不同的位置和施加不同力采集树体各个位置的加速度信号,并将采集的加速度信号通过Matlab进行FFT变换得到果树的共振频率。FFT转换得到的海棠果树的前四阶共振频率分别为3.0、8~9、16~17、23~25 Hz。激振过程中,能量在无分叉主干部分能量衰减率为-1.5%~3%,能量在直径较大和偏离角度较小树枝分流较大。当冲击点距离地面40~60 cm位置和激振力为900 N时,落果率最佳。
Select the fruit tree of crabapple as material, and acquire the acceleration signal of each position of tree by exciting different position of fruit tree trunk and exerting different forces, and get the resonance frequency of fruit tree by FFT transform of the collected acceleration signal. The first four order resonance frequencies of Begonia mangium fruits obtained by FFT conversion are respectively 3.0, 8 ~ 9, 16 ~ 17,23 ~ 25 Hz. During the excitation process, the energy decay rate of the energy in the unbranched main part is -1.5% -3%, and the energy is larger in the branch with the larger diameter and smaller deviation angle. When the point of impact is 40 ~ 60 cm from the ground and the exciting force is 900 N, the fruit drop rate is the best.