基于5R并联机构的二自由度树冠振动装置设计与试验

Design and Experiment of Two⁃degree⁃of⁃freedom Canopy Shaking Equipment Based on 5R Parallel Mechanism

振动式采收是一种高效的林果机械化采收形式。在现有的激振形式中,非圆周激励可以使果树产生有效的振动,实现整体采收效果。为进一步提高果实的采收效率,针对非圆周激励中不同类型旋轮线轨迹进行深入研究。通过SolidWorks、ANSYS、ADAMS等软件建立果树柔性体模型。将不同轨迹参数的旋轮线位移载荷导入ADAMS,施加于果树模型激振点。比较不同轨迹的旋轮线位移载荷下果树模型的振动响应,确定3支线1号外旋轮线轨迹E为最优激振轨迹。根据最优激振轨迹,设计了由平面5R并联机构驱动的二自由度树冠振动装置。以油茶树为激振对象,确定频率6 Hz、振幅90 mm为激振参数,设计并搭建样机进行试验。试验结果表明,7×7交错分布的激振杆布局方式的激振效果最优,该布局下树冠平均合成加速度响应为22.38 m/s^(2),激振加速度传递效率为77.63%,验证了二维激振轨迹的有效性。

Vibratory harvesting is an efficient form of mechanized harvesting of tree fruits.In the existing excitation form,non⁃circular excitation can produce effective vibrations in fruit trees,which can achieve an overall harvesting effect.In order to further improve the harvesting efficiency of fruits,the trajectories of different types of cycloid in non⁃circular excitation were researched in depth.Fruit tree flexible body models were built through SolidWorks,ANSYS,ADAMS and other software.The cycloid displacement loads of different trajectory parameters were imported into ADAMS,being applied to the excitation point of fruit tree model.By comparing the responses of the tree model to the cycloid displacement loads of different trajectories,the 3⁃branch No.1 epitrochoid trajectory E was determined as the optimal excitation trajectory.According to the optimal excitation trajectory,a two⁃degree⁃of⁃freedom canopy shaking equipment driven by a 5R parallel mechanism was designed.The Camellia oleifera tree was used as the shaking object,and the excitation frequency of 6 Hz and amplitude of 90 mm were determined.An experiment prototype was designed and built.Experimental results showed that the shaking rod layout with 7×7 staggered distribution was the optimal layout,and the average synthetic acceleration of the canopy under this layout was 22.38 m/s^(2).The excitation acceleration transmission efficiency under the shaking rod layout was 77.63%,which verified the effectiveness of the two⁃dimensional excitation trajectory.