Design And Experiment On Flexible Low-Loss Fresh Corn Picking Device

With the adjustment of China’s corn industry policy,the situation of grain and corn market is not optimistic,and cultivating new market demand has become an important subject of agricultural scientific research.Fresh corn is a kind of crop with high economic benefit.It can be used not only as food economic crop,but also as fruit and vegetable and feed crop.It is of great practical significance to develop fresh corn planting and harvesting.In nutritional diet,fresh corn has good palatability,rich nutrition,unique flavor,variety,known as "longevity food";in the aspect of market economy,fresh corn has the characteristics of short production cycle,high market price and high economic benefit,which promote the jade of our country.The rice industry develops at a high speed.The grain moisture content of fresh-eating maize is higher at harvest stage,and the requirement of ear-picking device is more stringent.At present,there are some problems such as high grain breaking rate,high impurity content and high power consumption in corn picking devices adopted at home and abroad.In view of the lack of non-destructive picking technology of fresh corn in China,the key technology of flexible ear picking is emphatically broken through.Develop fresh corn harvest test-bed to solve the problem of mechanization of fresh corn harvest.Based on the analysis of the mechanism of ear damage,a flexible and low loss picking mechanism of fresh corn was designed in order to reduce the breaking rate of the ear,reduce the power consumption of the ear,reduce the length of the spike stalk,and reduce the loss of harvest.The main tasks are as follows:(1)Summarize the research status of corn harvesting machinery at home and abroad,understand the technical characteristics and working performance of various models,and understand the limitation and deficiency of the existing ear-picking devices in fresh corn harvesting,so as to lay a foundation for the research in this paper.(2)On the basis of analyzing the mechanism of ear damage in the process of heading,a flexible and low-loss cutting bench for fresh corn was designed according to the design requirements of fresh corn harvesting platform.The flexible and low loss ear picking of fresh corn was realized by using circular flexible plucking belt clamping and feeding corn stem,combined with sliding cutting stem roller and cutting ear stalk at the same time,so as to reduce the tensileforce needed for ear picking and reduce the length of ear stalk.The structure design of the key parts of the picking device is completed.The diameter,effective working length,sliding angle and length of the roller knife are determined,and the finger length of the ring flexible tappet belt is also determined in this paper,which includes the diameter,the effective working length,the sliding angle of the roller knife and the length of the roller knife.Degree,dial pitch and circumferential speed.(3)According to the different installation modes of slide-cut roller,the multi-body dynamics simulation analysis was completed by using ANSYS coupled ADAMS.The relative installation mode of blade was determined,and the contact force between roller knife and stem was 610 N,which was easy to cause stem break.The indirect contact force between the roller knife and the stem is 425 N,and the three-point bending clamping can be formed to achieve continuous and effective stem pulling.At the same time,the stem can be effectively prevented and ear impurity content can be reduced.Therefore,slide-cut type stem roller uses blade staggered installation mode.(4)The number of sliding-cutting broaching roller blades further affects the picking-up ability and shear failure strength of stem-pulling rollers.The kinematic analysis and sequential analysis of different roller numbers are carried out by using ADAMS software,and the optimum number of rollers is determined to be 6,Thus,ear impurity content was guaranteed,the picking mechanism was continuously and effectively pulled,and there was no action redundancy,low loss and high efficiency to complete the fresh corn picking operation.(5)In order to explore the reliability of clamping and pulling stem under the actual working condition,the statics analysis of the pull-down stem roll is completed by using ANSYS Workbench software platform,and the stress,strain and deformation images of the roller under load are obtained.It is determined that the design of sliding-cut stem-pulling roller meets the strength requirement.At the same time,coupling the statics analysis of the slide-cut stem roller,the 6-order prestressed modal analysis of the pull-stem roller is carried out,and the intrinsic frequency values of each order of the mechanical system are obtained,and the resonance will not be caused in the working process of the sliding-cut type stem-pulling roller.According to the mode diagram,when the drawing roller cuts down and pulls the stem,it is easy to cause the force roller knife and its adjacent roll knife.The torsion deformation occurs,and the welding strength between the roller knife and the roller knife can be strengthened properly during the actual machining.(6)In order to determine the optimum working parameters of flexible low loss ear picking device for fresh corn,the optimal test level of clearance at the outlet end of the picking plate was31.25 mm and the optimal test level was 22.58 mm by using the orthogonal combination test of two factors and five levels.Secondly,the orthogonal rotary combination test of three factors and five levels is used to determine the selection of the optimal horizontal combination of each factor: therotation speed of sliding-cut type stem-pulling roller is 535r/min,the angle of sliding-cut-type stem-pulling roller is 22.82°,and the advancing speed is 2.51m/s.The corresponding evaluation indexes were as follows: ear impurity content was 0.5%,the grain fragmentation rate was 0.33%,The power consumption is 2.1kw.Finally,the traditional hexagonal drawing stem roller and the sliding cutting type stem pulling roller are selected to compare and verify the soil trough.The results showed that ear impurity content,grain fragmentation rate,and power consumption of fresh corn picking device with sliding cutting stem roller were 2.13%,3.22% and 1.07 kw lower than those with traditional six-edge sliding cutting stem roller.