Mechanism modeling and experimental analysis of seed throwing with rice pneumatic seed metering device with adjustable seeding rate

Abstract Rice seeding in hill is beneficial to the growth of rice in the field and the increase of rice yield. However, rice seed metering device usually uses multiple rice seeds for sowing, which is difficult to form a hill. To improve the performance of rice seeding in hill, the seed throwing mechanism of the rice pneumatic seed metering device with adjustable seeding rate was study, and the trajectory of seed throwing was analyzed theoretically. The equation of seed throwing trajectory was established. The distribution of sucking holes on the sucking plate was optimized by using asynchronous seed throwing method. The distribution mechanism of seed throwing was studied, and the theoretical trajectory area of seed throwing was established. The actual trajectory area of seed throwing was established by high-speed photography. The theoretical area and actual trajectory area of seed throwing were compared by experiments. The influence factor of errors between the actual and theoretical seed trajectory areas were analyzed. The performance of seed throwing in hill was tested under different positive pressure and different rotational speeds. The optimum qualification rates of different seeding rates were 97.34%, 90.36% and 87.36% respectively. These were 10–17% higher than the original qualification rates of seed throwing. The experimental results showed that the optimized sucking holes on sucking plate could effectively improve the performance of seeding in hill of seed metering device. This study provided a theoretical basis for the seed throwing mechanism of the rice pneumatic seed metering device, and improved the qualification rate of seed throwing.