Study On The Mechanism And Key Technology Of Corn Ear Picking With Vertical Roller

The vertical roller corn harvester has the characteristics of orderly stalk conveying,short contact time between the ears and the ear picking roller group,the stalks after picking the ears are easy to realize centralized chopping,convenient recovery of chopped materials,and the size of the header is small.Studies have shown that the vertical corn harvesting method meets the requirements of mechanized harvesting of corn with whole plastic film mulching on double ridges in arid regions.It can fill the gap of the current mechanized harvesting of corn with whole plastic film mulching on double ridges,and improve the cultivation enthusiasm and profit of users.It is of great significance to carry out research on the mechanism and key technology of harvesting ear picking of vertical roller corn to improve the ear picking quality and adaptability of corn stalk.During the harvest,due to the limitation of ear picking gap,the vertical roller has a large degree of compression on the stem.Under normal conditions,the working performance is better,but in the case of thick stems,inconsistent sizes,and high water content,the stem is easy to be pulled off and the picking roller is blocked.In order to realize the low-loss ear picking of the vertical roller header and solve the adaptability of the corn stalk diameter,the physical and mechanical characteristics of the corn plants and ears were studied.A vertical roller gap adaptive ear picking device was designed.Through simulation analysis and experimental research,the mechanism of the corn ear stalk and harvest plant clamping and transportation and ear picking was revealed.A full-membrane double-ridge furrow and stem combined harvester suitable for corn production in the northwest arid region was developed,which provided theoretical support for the performance improvement of corn ear and stem combined harvesting.Mainly conducted in-depth research in the following aspects:(1)The physical parameters of maize plant,the bending resistance of maize plant,the compression and extension of stem,and the mechanical test and analysis of ear picking process were carried out.The load displacement curves of the stalk stretching,compression and ear picking were obtained,and the effect of moisture content on the mechanical properties of corn grain was analyzed.(2)The feeding process of corn plant gripping and self-adaptive gripping and conveying mechanism of corn plant attitude in vertical header were expounded,and the gap gripping and conveying device was designed.Through the analysis of the structure of the crop divider and the suitable row spacing of the plant,the alignment method of the header is determined to be the center of the small ridge;Through the theoretical analysis of the clamping conveying state and the simulation analysis of the adaptive plant attitude,the optimization and improvement method of the clamping conveying device is determined.And the arrangement plan of the cutting table was determined: the clamping and conveying device was symmetrically arranged on the left and right,the guide section was gathered and fed,and the double-row clamping chain with P = 15.875 was selected.The interval between the clamping and conveying channels was 127 mm,the width of the channel was 39 mm,The diameter of the wheel is 335 mm.(3)This paper reveals the mechanism of gap adaptive corn ear picking in vertical header,and designs a gap adaptive vertical corn ear picking device.In this paper,the principle of corn vertical ear plucking device and the mechanical damage factors of ear plucking device are analyzed.According to the statistical data of corn plants,the structural parameters of the ear plucking parts are determined: the base circle diameter of the ear plucking roller is 76 mm,the upper section of the ear plucking roller is 400 mm,the lower section is 200 mm,the height of the convex edge(tooth)of the ear plucking roller is 6 mm,and the gap of the roller group is 15-22 mm.According to the module(M = 3)and number of teeth of transmission gear(Z = 31),the ear picking gap is designed as 17 mm.A gap adaptive ear plucking device is designed,in which the lower gap is fixed and the upper gap is dynamically adjustable.By using ADAMS software,the rigid soft hybrid model of ear plucking device and corn plant was established.The relationship between ear plucking time and ear collision force with time was analyzed by using the method of sensor and script control.By changing the inclination angle of the vertical roller group,the picking time and collision force of the ear at different angles of the header were simulated and calculated,and the minimum collision force of the ear was obtained when the inclination angle of the header was 15°.From the analysis of the movement of plucking ear,it is an effective measure to increase the width of ear conveyor belt and adopt flexible material conveyor belt to reduce the loss of harvest.(4)Research on the test-bed of gap self-adaptive corn harvester.A gap self-adaptive vertical corn ear plucking performance test-bed was built.By adjusting the rotation speed of the variable frequency motor,the feeding speed of the plant conveyor,the rotation speed of snapping roller,and the installation angle of retaining rod were changed to realize the adjustment of the influencing factors in the test process.The central composite response surface method was used to design the quadratic rotation orthogonal combination test.The feeding speed of the plant conveyor,the rotation speed of snapping roller and the installation angle of retaining rod were taken as the influencing factors,and the loss rate of corn ear,loss rate of corn kernels,broken rate of corn kernels and stem breaking rate were taken as the evaluation indexes to study the harvesting performance of the header.Using Design-Expert 8.0.6 software to deal with the test results,the regression model between the influencing factors and the evaluation indexes is established,and the influence law of the influencing factors on the test indexes is analyzed.The optimum combination of parameters was obtained as follows: the feeding speed was 3.84 km/h,the rotation speed of ear snapping roller was 1160 r/min,the installation angle of retaining rod was 73°,and the indoor bench test was carried out with the optimum combination of parameters.The results showed that under the optimized combination of parameters,the loss rate of corn ear was 1.86%,the loss rate of corn kernels was 0.32%,the broken rate of corn kernels was 0.25%,and the stem breaking rate was 1.12%.The results show that the gap adaptive ear plucking device meets the requirements of ear plucking header of corn harvester and can realize the adaptability of stem diameter of corn plant.At the same time,the gap adaptive ear plucking device significantly improves the passing performance of corn plant in the vertical header and meets the design requirements of the vertical corn harvesting header.(5)Development and field test of corn combine harvester reaping both corn ear and stalk for whole plastic film mulching on double ridges.On the basis of indoor bench test,a new type of corn combine harvester reaping both corn ear and stalk for whole plastic film mulching on double ridges was developed,which is suitable for corn production in northwest arid regions.The field test of the prototype was carried out.The field test results are similar to the bench test results,and meet the operation quality requirements of corn combine harvester.