齿带式油菜捡拾器仿形减振装置设计与试验

Design and Experiment of Profiling and Damping Device for Rapeseed Tooth-belt Pickup

针对现有油菜捡拾器在复杂田块作业时作业稳定性低的问题,设计了一种用于铰接式齿带捡拾器的地面仿形减振装置。通过建立仿形减振系统动力学模型,确定了影响地面仿形稳定性的关键结构与作业参数。以仿形弹簧刚度、系统阻尼比和捡拾器前进速度为试验因素,以铰接点处的峰值角度均差和仿形稳定性变异系数为评价指标,进行了基于响应面法的三因素三水平BoxBenhnken组合试验,得到影响峰值角度均差的因素影响力由大到小依次为阻尼比、弹簧刚度、前进速度,影响仿形稳定性变异系数的因素影响力由大到小依次为前进速度、弹簧刚度、阻尼比。通过软件寻优得到角度均差和仿形稳定性变异系数最小条件下的最佳参数组合为:弹簧刚度9.7 N/mm、阻尼比0.38、前进速度0.95 m/s,对应的理论角度均差为2.3°、仿形稳定性变异系数为6.2%。田间对比试验表明,挂接仿形减振装置的捡拾器平均捡拾损失率4.53%,平均含杂率3.22%,分别比未挂接减振装置的同一捡拾器降低了30.73%和27.64%,作业效果提升明显。

Rapeseed is one of the most important oil crops in China.Obstruction exists in mechanized combine harvesting because of the biological characteristics of rapeseed.In recent years,the two stage-harvesting is widely adopted due to the advantages in well-adapted ability of rapeseed variety and high quality of the harvested rapeseed,but there are still some problems in the pick-up stage especially the low operation efficiency and quality due to the instability when working on the uneven terrain.Aiming at the problem of low operating stability of existing rapeseed pickers during the high-speed operation in complex fields,a profiling-damping device for articulated toothed-belt pickup was designed.By establishing the kinematic model of the profiling and vibration reduction system,the key structures and operating parameters that affected the stability of profiling were determined.And the specific parameters which could play important roles in the operation process were analyzed.The spring stiffness coefficient k,system damping ratioξand forward speed vf were selected as the test factors,and the variation coefficient of peak angle of hinged point was selected as the test index based on the response surface method of three factors and three levels BoxBenhnken combination test.The order of the factors affecting the average degree deviation was obtained from large to small as follows:damping ratio,stiffness coefficient and forward speed.The order of the factors affecting the stability of profiling was obtained from large to small as follows:forward speed,stiffness coefficient and damping ratio.The optimum parameter combination under the minimum average degree deviation and profiling stability variation coefficient was found as follows:stiffness coefficient of 9.7 N/mm,damping ratio of 0.38 and forward speed of 0.95 m/s.Field comparison tests were carried out using the approximate optimal parameters combination,the results showed that the average loss ratio of the pickup harvester with the profiling-damping device was 4.53%and the average impurity ratio was 3.22%.The loss and impurity ratio were 30.73%and 27.64%lower than the one that without the device respectively and the operation quality was significantly improved.The research results can provide references for improving the profiling and operation stability and quality.