Research On Pneumatic Vibration Precision Metering Device For Super Rice

Mechanized sowing is an essential part of rice planting's mechanization, current riceseed-metering devices in rearing seedlings are mainly for ordinary rice can realize2~5particleper transplant rice seedlings area, but Super rice's tiller ability compared with conventional riceis much stronger, so its planting requirement rises to accurate seeding from2~5particle pertransplant rice seedlings area to2±1particle per transplant rice seedlings area, which requiresnot only to control the number of seeds on each seedling area, but also need to control thegermination position after sowing. Current rice seed-metering devices neither can meet therequirements of carpets of rearing Super rice's seedlings, nor can meet the machine-requirementsof guaranteeing Super rice's2±1plants per seedlings area, that greatly limits the promotion ofsuper rice planting to be mechanization. In response to this problem, this paper proposed apneumatic vibration precision metering device to meet the mechanized planting's agronomicrequirements for Super rice. The contents and conclusions of this paper were listed as follows:1) Domestic and foreign research statuses of rice seeding devices had been studied, byanalyzing their characteristics, and pointed out the existing precision seeding devices can notmeet the requirements of Super rice's accurate seedling-nursery. According to Super rice'sagronomic requirements of mechanized cultivation, and combined with Super rice seed'sgeometry to analysis the sense of directional sort of Super rice and proposed a pneumaticvibration precision metering device for Super rice. This device can achieve directional sort ofrice, and obtain seed current to be uniform and orderly to meet the number and location of theprecise germination requirements in per unit area.2) Based on the physical characteristic of Super rice seed's surface, using the characteristicthat along its long shaft the awns grow in all directions from glumes to the glumes tip to researchthe steering mechanism of rice based on the guide plate of high friction coefficient. Through theanalysis of rice turning parameters, further proposed the directed sequencing program based onthe curved guide plate, and write VB program to obtain the parameters' range meeting the requirements of directional ordering.By analyzing the kinematics and dynamics of rice'smovement on vibration plate (in the section of the curved guide plate), obtaining the theoreticalformulas of the characteristics of its movement, speed and displacement, and write VB programto simulate the relationship between the values of movement characteristics and get the range ofparameters.3) Through analyzing the theory of cardboard forced oscillation on the metering device, andused ANSYS software to carry out modal analysis of metering device model to obtain the mostsuitable frequency, about4.5H z.By harmonic response analysis of the structure ofseed-metering device, the distributions of displacements on the vertical and horizontal of thevibrating plate's surface can be obtained. Through pilot testing of vibrating plate under allfrequency responses, the result is basically same with the ANSYS calculations. By harmonicresponse analysis of different thickness of vibration plates of the metering device models, thebest theoretical thickness of vibration board is3mm.4) By analyzing rice's hops on the vibration plate to get the acceleration condition ofjumping. Using acceleration sensors, data acquisition and analysis apparatus and otherequipments to test the vibration plate, and got the vibration characteristics of the vibration platebeyond different angles of the vibrating plate and air pressures. When combined with thetheoretical analysis of rice's leaping, the regional of the board where seed doesn't leap and thecombination of parameters which make the rice leap small can be obtained. And it also provideda theoretical basis and practical guidance for the arrangement of the curved guide plates.5) Pneumatic vibration precision metering device for super rice was designed, and theorthogonal test of metering device's structure parameters was carried out: angle of the vibrationplateα,vibration direction angleε, rice's angle of friction along the line21, angle of frictionretrograde22and the curvature of the curved guide plateρ. Through range analysis, getting theinfluence of each factor about the rate of directional order and obtain the best level of thecombination of factors:α=15°, ε=10°,22=57.5°, ρ=2.65.By taking the verification test under the best level of combination, rice seed's actual sowingeffect in seeder assembly line was showed as below: the seed-metering device basically realized uniform and orderly seeds flow, directed sequencing was87.3%, the number of rice on a plantingplate was around1850meeting the requirement of blanket seedlings which acquires no less than1400~1700seeds per plate, and seeding efficiency could reach100plates per hour, rice velocitywas0.017m/s.6) At last, there was a conclusion for the paper and the contents for further research wereput forward.