黑加仑干枝的试验模态分析

为研究黑加仑振动采收时果枝的运动规律，该文根据果树在田间的实际情况，假设果枝为固定支撑的悬臂梁结构，采用步进式正弦激励，单点激振多点测量的方法进行试验模态分析，使用加权最小二乘法，提取果枝的模态参数。研究结果表明：在4～30 Hz范围内，黑加仑干枝存在1个或2个共振频率，干枝的无阻尼固有频率为11.8±4.54 Hz，阻尼比、模态质量和模态刚度差异较大，均值分别为7.08%、0.0686 kg和394.8 N/m。该研究为黑加仑采收系统的研制提供有关参数和设计依据。

Modal experiment analysis on blackcurrant branches

In order to investigate the movement characteristics of blackcurrant branches during harvesting operation, a series of experimental modal analysis were performed by using the stepping sinusoidal excitation, one-point excitation and multi-point acceleration response method based on the assumption of bush branches as cantilever structure fixed a support to match with the actual situation of the bush in the farm. And the least square complex exponent method was employed to fit the modal parameters of the branches. The results indicated there existed one or two resonance frequencies in the range of 4 to 30 Hz on the blackcurrant branches under natural frequency of 11.8±4.54 Hz. The wide distributions of data were shown in the damping ratio, the modal mass and the modal stiffness of the branches and the average value was 7.08%, 0.0686 kg and 394.8 N/m, respectively. These results provide design parameters and basis for the blackcurrants harvesting system.