| Rape is oil crops,forage crops,energy crops,honey plant,also is landscape plant that has a high economic efficiency.More than 90% of rapeseed is concentrated mainly in Yangtze River Basin in China,where is the main produce area of winter rapeseed.The contradiction of crops for rotation is very outstanding.Seedling transplanting could alleviate the contradiction between the summer harvest and the autumn planting,could fully use light and temperature conditions to increase production.Mechanization transplanting for rapeseed pot seedling can alleviate labor intensity of manpower and shorten reviving time of rapeseed pot seedling.In order to realize mechanization transplanting for rapeseed pot seedling,a model was established based on ADAMS for optimizing structural parameters of the transplanting mechanism and a pneumatic pick-up mechanism for rape pot seedling that can work well with double five-bar transplanting mechanism was designed in this paper.The main research contents of this paper were as follows:1)The matching study of height between transplanting trajectory and rape pot seedling in suitable planting stage was carried out.The result showed that the seedling height had significant differences between some rape varieties in the same time.But the height of different rape varieties during various periods was subjected to normal distribution.The average height was 185 mm.It could meet the demands of rapeseed transplanting when the height of the planting locus was 230 mm.2)A multifunctional rape pot seedling transplanter was developed,which determined the key parts of the machine are the transplanting mechanism and the picking-up mechanism.The structure,working principle and process,structural and performance parameters of the rape transplanter were introduced.3)A model had established based on ADAMS for optimizing structural parameters of the transplanting mechanism,the consistency verification experiment of optimal planting trajectory had carried out by using high speed photography system.The results showed that the length of DG and CH were 300 mm and 305 mm,shortened by 23.3% and 25.6%.When the tractor's speed was 0.3m/s,the transplanting frequency was 60 seedlings per minute and the transplanting depth was 80 mm,the deviation between diving and unearthed was 1.3mm,the width of vertical direction was 10 mm,the range of deflection angle was-9.8°~14.5°,the percentage of crank AD rational degree was 11.7%,the locus height was 225 mm.The length of GH had great influence on planting process,the duckbill-type planting unit's attitude had nothing to do with tractor's speed and planting frequency.4)A pick-up mechanism had designed based on pneumatic principle.The structure of pneumatic pick-up mechanism was finished,which compared three types of conveyor belt,seedling cup type and pneumatic.A driving system of the pneumatic pick-up mechanism was designed.The pneumatic cylinder was driven in proper order by two position three way magnetic exchange valve.The results showed that air consumption calculation for the pneumatic system was 1.378T-1(L/min),while it was 3.708T-1(L/min)when the pneumatic system worked for six lines.5)A model had established based on ADAMS for optimizing structural parameters of the pneumatic pick-up mechanism.The regularity of how the structure parameters changed in vaule influence work locus of the pick-up mechanism was analyzed in a convenient way and the correctness of theoretical analysis was verified by using high speed photography system.The optimal parameter combination of pneumatic pick-up mechanism as follows:the length of AD was 220 mm,the length of AC was 170 mm,the length of DE was 160 mm,the length of OE was 413 mm.The height of seeding pick-up trajectory was 130 mm.When the height of seeding pick-up trajectory was 80 mm,the deviation of trajectory straightness was less than 2mm and deviation angle of seeding pick-up needle was less than 4°at picking-up seedings stage,in addition,deviation angle of seeding pick-up needle was less than 1°at dropping seedings stage.6)The field test of transplanting mechanism and the prototype test of pneumatic seeding pick-up mechanism had been done.The field test demonstrated that qualified percentage of the depth and length of the hole were 90.7% and 84%,the Coefficient of variation were 7.1% and 6.6% respectively,which can meet the demand of the seeding transplanting process.the prototype test showed that the picking-up seeding and dropping seding success rate were 93.0% and 89.5%,which was verified the feasibility of pneumatic pick-up mechanism. |
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