果树冲击振动动态特性的研究

The Research of Fruit Trees Dynamic Characteristics with Impact Vibration

【目的】研究果树冲击时枝条阻尼比与直径的关系,树干、树枝的加速度动态响应,获得果树共振频率,确定较合适的采摘激振频率,为林果振动采摘收获机的参数优化提供必要的理论基础.【方法】将树干、树枝视为弹性、阻尼系统,建立果树简谐振动微分方程,并在室内进行振动台架试验,获得动态响应信号,通过对数衰减法计算得到不同测点处的树干或树枝的阻尼比以及对应的动态响应.【结论】由各测点加速度响应曲线可知,25 Hz左右为最优激振频率,树枝或树干的阻尼比随着直径的减小而增大,且近似成线性关系.

【Objective】 This paper study the relation of damping ratio with the diameter of the trunk,branches acceleration dynamic response of fruit trees to obtain the resonance frequency,to determine which pick excitation frequency,to provide the necessary theoretical basis for the optimization parameters fruit picking vibration harvester.【Method】 The trunk,branches were regarded as elasticity,damping system,establishment of an inter-harmonic vibration differential equation and indoor vibration test bed,the dynamic response of the signal obtained by the logarithmic decrement method calculated at different points of the trunk or branches of damping ratio.【Conclusion】 Acceleration response curve of each measuring point shows that the optimal excitation frequency is in around 25 Hz,branch or trunk damping ratio increases with decreasing diameter and approximately linear relationship.