| As the main oil-bearing crop grown in China,the export of peanut accounts for more than 20%of the world’s peanut exports.Cultivating and growing good peanut varieties not only helps solve the oil problem,but also creates foreign exchange income.Peanut plot breeding takes the experimental plot as the sowing unit.Due to the small area and small quantity of the plot,it is difficult to use field machinery for sowing.Artificial seeding not only has high labor intensity,but also can not guarantee the accuracy of the experiment.Therefore,it is increasingly urgent to develop a peanut plot breeding and sowing machine.According to the agronomic requirements of precise sowing in peanut plot breeding,a combined seeding mechanism was designed.The specific contents are as follows:(1)According to the characteristics of various peanut varieties in the plot breeding test,three varieties of Huayu 23,Baisha(large)and Silihong were selected with great differences in their external dimensions.The triaxial dimensions were calculated,and the average triaxial sizes of the three varieties were 18.12mm × 8.55mm × 8.34mm,16.24mm× 8.03mm × 7.50mm,and 14.23mm × 8.54mm × 8.37mm,respectively.(2)Based on the shape characteristics of different peanut varieties,a combined seeding mechanism was designed,which used inclined disc seed distribution and horizontal grid plate seeding.Through uniform seed distribution and uniform speed seeding,single seed precision sowing can be realized.(3)Through the analysis of the force and motion state of peanut seed kernel in the seeding mechanism,the hole of the inclined disc was determined to be elliptical hole with a length of 20 mm and a width of 10 mm,and the outer edge was rounded.The diameter of the horizontal grid is 290 mm,and 36 grids are set.Discrete element simulation software EDEM was used to carry out seed planting simulation test,and variance analysis was carried out on the test results.The specific structural parameters of the seed planting device were determined as the radius of the tilted disk 107 mm,the rotation speed 13 r/min and the inclination Angle 18°.The rotational speeds of the two plates were calculated as n1 ≤48 r/min and 35 r/min≤ n2≤46 r/min respectively.(4)By analyzing the widely used processors and sensors,STM32 single-chip microcomputer is selected as the central processor,slot photoelectric sensor and angle control precision servo motor to constitute the hardware part of the control system;the programming software keil is used for programming.PID parameter tuning is used to eliminate the deviation in the process of servo motor motion,and improve the fast response ability.(5)Three factors and three levels response surface analysis experiment was designed,and the significant factors were found out by variance analysis and regression analysis of test data by design expert software.Matlab software was used to optimize the test indexes.The swash plate radius was 110mm,the swash plate speed was 12R/min,and the disk speed was 35r/min.The results showed that when the theoretical seed spacing was 20cm and the advancing speed of seeding platform was 0.42m/s,the qualified rate of seed spacing of Huayu 23 was 98.66%,the rate of hole and repeat sowing was 0.67%,and the rate of damaged seed was 0.21%;the qualified rate of seed spacing of Baisha(large)was 98.21%,the rate of hole and repeat sowing was 0.90%,and the rate of seed damage was 0.4 The qualified rate of seed spacing was 98.45%,the rate of hole and repeat sowing was 0.77%,and the rate of damaged seed was 0,which met the agronomic requirements of precision sowing in plot breeding. |
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