| The air suction soybean planter doing field operation requires to ensure the qualified grain spacing and the qualified seeding rate.And the missed seeding rate and the rebroadcast rate need to be controlled below the value of an eligible sowing rate.Soybean sowing machine can't deal with missed seeding and over seeding in a single field operation.It needs manual operation later.Once there is a large area of missed seeding and over seeding,it will not only waste labor and material resources,but also affect soybean yields.As a result,the air suction soybean seeder as one of the most important parts for the work of soybean sowing machinery,whose main tasks are adsorbing seeds and discharging seeds.it has a high requirement for the sucking performance of the air suction soybean seeder.In this paper,the sucking performance of the air suction soybean seeder is studied.The monitoring system of suction seeder and the structure and material of suction holes are studied.In view of the difficulties in collecting seed sucking conditions and the accuracy of the existing monitoring system,which cannot meet the needs of monitoring,Seeding Monitoring System based on Photoelectric Sensor(SMSPS)is designed in this paper.Aiming at the phenomenon that the sowing machinery have missed and multi seeding because of the traditional air suction seeder has insufficient sucking ability,this paper presents a method for changing the original structure and material by a separate design of the suction holes of the seed disks.(1)Through combining the signals obtained by the photoelectric sensor and the photoelectric rotary encoder,signal state in three cases of normal seed-suction,missed seed-suction and multi seed-suction are defined.In this way,the suction holes of the seed tray are determined and obtained,and a comparison test is made with the commonly used Seeding Monitoring System based on Image Processing(SMSIP)of the seeder test bench under 6 working conditions.The result of accuracy analysis shows that the maximum relative error of SMSPS is 0.31% compared with SMSIP,and the result of fluctuation analysis shows that the amplitude of SMSPS and SMSIP is close,and the maximum relative deviation between them is not more than 1%.Through the comparison of data obtained by SMSPS and high speed camera,shows that the maximum relative error of SMSPS monitoring seed sucking amount of a single suction hole is 16.67%,the minimum relative error is 0.The results indicate that SMSPS has certain reliability for monitoring the sucking amount of single suction hole.(2)By extracting and fitting the contour curve of the soybean placed randomly,a segment of the intercept curve is around the central axis to ensure that the radius of the bottom hole of the suction hole is rotated,and the arc surface of the suction hole is obtained.The flexible material silicon rubber is selected as the material for making holes.The experiment was carried out with taking different curves,hardness of silicone rubber and negative pressure of seeding chamber as factors,and taking the leakage rate,seed suction rate and seeding rate of seeding apparatus as indicators.The experimental results show that the best performance is achieved when the highest order of curve is 5,the hardness of the suction hole made by silicone rubber is 30 HA,and the suction chamber has a negative pressure of 2.32 kPa.(3)Through the bench test,compare the seeder plate which has the flexible suction hole with the tradition seeder plate,under the 6 experimental conditions,the seeder plate with flexible suction holes has lower leakage rate and multiple seed uptake rate,and the qualified rate of seed sucking was higher.The test shows that the seeder plate with flexible suction holes can improve the seed suction performance of the air suction seeder to a certain extent.Based on theoretical analysis and bench test,field trials were carried out: 1)the monitoring results of the SMSPS with the results of manual counting was compared,and the accuracy of the system in field work was analyzed.The average relative error of the missed suction and multi suction is 3.87% and 8.42%,and the maximum relative error is 10.34% and 20%,respectively.2)the field performance of suction seeder was tested by the SMSPS,and the performance of two types of seed plate was compared.The seeder plate with flexible suction holes has a certain enhancement effect on the seed suction.The results of bench test and field experiment show that the design of seed suction performance monitoring system can meet the requirement of monitoring the suction performance of air suction seeder,and the seed plate with flexible suction hole can also improve the seed suction performance of the air suction seeder. |
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