Abstract:In order to realize the mechanized planting of mini-tuber and solve the problem of large seed filling, a vibrating feeding pneumatic disc seed-metering device for mini-tuber was designed. The seed-metering device was composed of metering plate, air chamber, frame and vibrating seed feeding device. Seeding-filling performance was the key factor that influenced the properties of metering device. In order to improve the seed-filling performance of the pneumatic disc seed-metering device, Lishu No.6 mini-tuber was adopted as sowing object, the method of UDEC was used as research technique, meanwhile, variance yields of average normal stress was considered as the optimizing targets. Through single factor experiment, the vibration frequency and vibration amplitude were numerically simulated respectively. It can be found that the experimental phenomenon and effect were in consistent with the simulation ones. Results showed that vibration frequency and vibration amplitude increased variance yields of average normal stress of seeds, hence disturbance of seeds was enhanced. Based on the three-factor five-level quadratic orthogonal rotating combination test method, the influence of vibration frequency, vibration amplitude and layer height on sowing performance were explored. The regression equations of the three factors and five levels were fitted through the processing by Design-Expert 8.0.6 (experimental design expert) software. Based on the results of examination, it can be found that the fitting of the equation was good, and the best parameter combination was the operating speed of 2.4km/h, negative pressure of 6kPa,vibration frequency of 6.5~6.9Hz, vibration amplitude of 20~21mm and layer height of 70mm. Under the optimal condition, the qualified index was greater than 95, and the multiple index as well as the missing index was less than 2.5. It showed that the vibrating feeding pneumatic disc seed-metering device met the standard and requirements by comparing the results with the national standard. The research approach was suitable for the exploitation of mini-tuber seed-metering, and it provided a theoretical reference for the design of pneumatic disc seed-metering device.
