| Peanut single grain precision sowing technology has the advantages of strong seedlings and plants,cost saving and efficiency,etc.Traditional peanut mechanized sowing mostly uses double grain sowing with low sowing accuracy,which to a certain extent limits the promotion and application of peanut single grain precision sowing technology.This paper combines the existing research results,and through theoretical analysis,numerical simulation and experimental research,designs an air-suction roller precision dibbler for peanut,explores the interaction between the structural parameters of the dibbler,the working parameters and the seeding quality,reveals the seeding mechanism of the dibbler,and solves the problems of low seeding accuracy and unstable seeding performance of the dibbler for peanut mechanized sowing.The main conclusions are as follows:(1)According to the agronomic seeding requirements of peanut,the overall design of the air-suction roller precision dibbler for peanut was determined,the structural composition and working principle of the dibbler were elaborated,and the structural parameters of key components of the dibbler were determined by establishing a mathematical model analysis.The kinetic theoretical analysis of seed carrying,primary seeding and seed cover separation processes was carried out to determine the assembly parameters of relevant components,and the influence of the two types of contact and non-contact separation methods on the seeding process was analyzed.(2)Numerical simulations of the different assembly parameters of the cavity seeder were carried out using EDEM software.The single-factor simulation showed that: the smaller the choke block assembly angle,the less contact separation in the seed cover separation process,and the probability of contact separation was 61° for choke block assembly angle > 46° for choke block assembly angle > 31° for choke block assembly angle;the seeding process was more stable within 12.5°～20° for choke block assembly angle,and the appropriate increase of choke block assembly angle was not only helpful to reduce the initial kinetic energy during seed separation,but also to reduce the initial kinetic energy of the seeds.The seeding rate is significantly higher than that of 15° and 20° when the assembly angle of the seed guide mechanism is 10°.Within reasonable parameters,reducing the assembly angle of the seed guide mechanism can be an effective means to improve the seeding performance of the cavity seeder.(3)A bench test of air-suction roller precision dibbler for peanut was carried out to further optimize the seeding performance of the seeder.A three-factor,three-level combination test was conducted on a dibbler test stand with the seed guide assembly angle,the dibbler cover assembly angle,and the forward speed of the machine as test factors,and the single seeding pass,miss,and reseed rates as test evaluation indexes.The test results showed that with the optimized combination of 11.18° for the seed guide mechanism,17.10° for the cover,and 3.85 km/h for the operation speed,the qualification rate of single seeding was 95.37%.The results of the verification and comparison tests were found to meet the requirements of the relevant standards,and the advantages of seeding after optimization were more obvious than those before optimization.(4)The field performance test of air-suction roller precision dibbler for peanut was carried out.The machine speed was set to 3.05,3.45,3.85,4.25 and 4.65 km/h,and the single seeding rate was 91.87%,93.64%,94.17%,91.23% and 89.51%;the missed seeding rate was 3.56%,3.08%,3.02%,4.75% and 6.32%;the reseeding rate was 4.57%,3.28%,2.81%,4.02%,4.17%.The compliance index gradually decreased compared with the bench test,but the trend was basically the same as that of the bench test,and the qualification rate of single grain hole sowing was more than 89%,the omission rate was less than 6%,and the reseeding rate was less than 5%,which met the requirements of single grain precision sowing of peanut. |
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