EXPERIMENTAL RESEARCH ON PERFORMANCE OF MULTI-MODE SEED METERING DEVICE

The paper, combined with structural characteristics of mechanical seed metering devices and air-suction seed metering devices, designs a multi-mode seed metering device. According to installation of seed holding rings and application of negative pressure, three modes (mechanical mode, air-suction mode and combination of air-suction mode and mechanical mode) can be realized. JPS-12 seed metering performance test benches and high-speed camera are used for indoor tests. According to results, under the mechanical mode, advancing speed has a significant effect on seed metering performance. At a low speed, the qualification rate is maintained at about 96%; with advancing speed increased, the qualification rate decreases significantly. Seed spacing variation coefficient gradually increases with speed increased and stabilizes at about 30%. Under the air suction mode, negative pressure and advancing speed have a significant effect on qualification rate and miss seeding rate. With negative pressure increased, qualification rate increases while miss seeding rate decreases. Negative pressure has no significant effect on seed spacing variation coefficient, but advancing speed has a significant effect on seed spacing variation coefficient. With speed increased, seed spacing variation coefficient increases significantly. Under the multi-mode, advancing speed and negative pressure have a significant effect on qualification rate and miss seeding rate. Negative pressure has no significant effect on seed spacing variation coefficient, but advancing speed has a significant effect on seed spacing variation coefficient. Upon comparison of three modes, when speed is 6 km/h, qualification rate of air suction mode is close to multimode, which is significantly higher than that of mechanical mode. When speed is 8-12 km/h, qualification rate of multi-mode is significantly higher than that of air suction work. With negative pressure increased, gap between them gradually decreases.