Design And Experiment Of Wheat Seed Flow Multi-channel Parallel Detection Device With Refracting Thin-surface Light

Real-time seed flow detection technology is important to enhance the intelligence level of wheat seeders.With the increase of operation speed and seeding frequency of wheat seeder,the difficulty of real-time wheat seeding detection is improved.To solve the problem that it is difficult to accurately count wheat seeds in high-frequency seeding,based on the idea of changing high flux into low flux multi-channel parallel detection,and using the principle of convex lens refraction and non-contact photoelectric induction,this paper designed a wheat seed flow multi-channel parallel detection device with refracting thinsurface light.and the bench test and field test were carried out respectively.The specific research contents and conclusions are as follows:(1)The structural design of wheat seed flow multi-channel parallel detection device with refracting thin-surface light was carried out.According to the physical characteristics of wheat seeds,based on the existing sensing principle of the research group,a method of "LED lamp beads + narrow slits" to generate a thin-surface light layer combined with the principle of convex lens refraction to expand the effective detection area was proposed,the multi-channel parallel detection sensing principle was confirmed,the structure of the seed flow diversion and the size of the thin-surface LED narrow slit were designed,and the focal length of the convex lens and the key parameters of the sensing element was determined.For the purpose of investigating the uniformity and stability of the shunt structure under different inclination conditions,the shunt structure simulation test and bench test were carried out.The results showed that when the inclination angle of the shunt structure is less than 10°,the variation coefficient of shunt consistency in each pipe is less than 6.67% and9.39% respectively in simulation and bench test.Moreover,the shunt uniformity of the shunt structure is good.(2)A multi-channel signal synchronous acquisition system of the detection device was designed.The system synchronously collected the seed signals of four channels and processed them into signals that can be recognized by the microcontroller,and then the microcontroller synchronously converted each channel of the seed signals into sowing information,thus realizing the synchronous acquisition and processing of multi-channel seed signals.In order to verify the working performance of the system,the system function test,the microcontroller interrupt high concurrent processing performance test and the blind area test were carried out.The results showed that: all modules of the multi-channel signal synchronous acquisition system can work normally;the microcontroller can meet the demand of wheat high-frequency sowing counting;the device has no detection blind area and the counting is normal.The support of LED lamp beads with different narrow slit widths were selected,and the bench test of the effect of different narrow slit widths on the accuracy of the device was carried out,and the optimal narrow slit width was 0.5mm.(3)Bench and field tests of the detection device were carried out.To preliminarily verify the detection performance of the device,the bench test of the device was carried out,and the results showed that the detection accuracy was higher than 77.03% when the seeding frequency reached 320 Hz.To improve the detection accuracy,the error law of the detection device was analyzed,an accuracy compensation model was constructed,and the bench test of the device using the compensation model was carried out.The results showed that the detection accuracy was still higher than 95% when the seeding frequency reached700Hz;the detection accuracy declined significantly when the seeding frequency was higher than 700 Hz.Field tests on wheat seed flow were conducted,and the results showed that the detection accuracy of the device was higher than 95.28% when the seeding frequency reached 320 Hz,at the same time,the device was not affected by light,vibration,dust and other factors during the field tests,and no blockage occurred.