秸秆捡拾打捆机振动去土作业参数优化

Optimization of working parameters on soil removal of stover pickup baler by vibration

为解决秸秆捡拾打捆后含土率高的问题,该文提出通过振动方式去除粘附和夹杂在黄贮秸秆中的土壤,以提高秸秆的后续利用价值。通过试验台设计和高速摄像分析,发现了秸秆振动去土规律;以土壤去除率和秸秆损失率为指标,以摘穗后整株铺放和切碎铺放的秸秆为研究对象,对各参数进行了单因素试验,建立了振动去土试验边界条件;通过三元正交多项式回归试验,在振动频率、振幅和振动时长三因素下,分析了2种秸秆物料的土壤去除率和秸秆损失率的变化规律。获得了黄贮秸秆振动去土的最优组合为:整株铺放秸秆振幅15 mm、振动频率4.5 Hz、振动时长14 s,切碎铺放秸秆振幅20 mm、振动频率4 Hz、振动时长12 s,并通过台架试验进一步验证了最优组合,试验结果与预测值误差较小,参数模型可靠。该研究为改进黄贮秸秆捡拾打捆机的作业机理、优化关键零部件设计、提高综合作业质量,提供了理论基础和试验参考。

Yellow silage corn stover is taken as a kind of important feedstuff for animal husbandry.Corn stover pickup balers are used to collect the stover and bundle it into straw bale in the harvest process of yellow silage corn stover.But in Northeast China,the soil has strong adhesiveness when it is in high moisture content.And when the moisture content is low,the soil disperses into fine particles which are easily carried in the miscellaneous branches of stover.It is a fleeting moment when stover is gathered and transported into baler.Soil adhered to stover and carried by the branches can’t be removed in this short process.As a result,high soil content reduces feed quality of yellow silage corn stover.In order to solve the problem of high soil content of yellow silage corn stover,the paper proposed to remove the soil adhered and included in stover by means of vibration.The soil removal mechanism of stover pickup baler by vibration was fitted on the bottom of the machine.It is connected between the pickup unit and the cutting and rubbing unit.Stover can be picked up and delivered to the vibrating conveying screen to remove the soil.Then,the stover would be robbed,cut and bundled.The operating principle of the test-bed was clarified through the design of the test-bed and analysis of high-speed camera.Collision between stover and screen and internal friction of stover could release soil in the stover.Stover thickness,vibration time,vibration amplitude and vibration frequency were 4 influencing factors acting on performance of soil removal in the tests.Taking the soil removal rate and the stover loss rate as indices,single factor experiments were conducted to determine the value range of each parameter on the whole-plant stover(long stover)and chopped stover(short stover)on the ground respectively.The result showed that the soil removal rate and the stover loss rate increased with the increase of vibration time,vibration amplitude,and vibration frequency.But the soil removal rate and the stover loss rate dropped with the increase of stover thickness.It was given that the focus ranges of values of all parameters were vibration time from 10 to 14 s,vibration amplitude from 10 to 20 mm,vibration frequency from 4 to 6 Hz for long stover,and vibration time from 12 to 16 s,vibration amplitude from 10 to 20 mm,vibration frequency from 4 to 6 Hz for short stover.Through the three-factor orthogonal polynomial regression test,the author found the change laws of the soil removal rate and the stover loss rate determined by vibration frequency,vibration amplitude and vibration time.Four regression equations were induced according to experiment and analysis above.Then,a comprehensive index indicating soil removal rate and stover loss rate toward the optimum synchronously was made to evaluate the effect of soil removal.By analyzing the regression equations and the comprehensive index,an optimal solution was obtained.The optimal combination of soil removal from corn stover by vibration was as follows:For the long stover,the vibration amplitude was 15 mm,the vibration frequency was 4.5 Hz,and the vibration time was 14 s;for the short stover,the vibration amplitude was 20 mm,the vibration frequency was 4 Hz,and the vibration time was 12 s.Verification tests were conducted on the test-bed to verify the results above.Through calculating with the regression equations,the soil removal rate and the stover loss rate of long stover were 4.71%and 0.34%,respectively,and for short stover,the calculating results were 4.44%and 1.42%respectively.In the verification tests,the results were 4.80%and 0.38%for long stover and 4.72%and 1.53%for short stover.By comparing the simulated and the experimental result,it was found that the relative errors of the soil removal rate and the stover loss rate were acceptable.It was believed that the result of mathematical model matched the test result well.This study provides references not only for removing soil from stover by vibration,but also for the improvement of corn stover pickup baler design.