A discrete element model of the edible sunflower seed was constructed, addressing the lack of an accurate model for edible sunflower seeds in the simulation process of seeding, cleaning, and transportation, and it was calibrated and verified through actual and simulation tests. Taking the edible sunflower seed as the research object, the range of its simulation parameter values was preliminarily determined through actual tests. Using the seed repose angle as the test index, the simulation parameters of the seed were calibrated through the Plackett—Burman test, the steepest climb test, and the Box–Behnken test. The suspension velocity of the seed model was determined by the Fluent–EDEM coupling simulation test, and the reliability of the discrete element model of the edible sunflower seed was verified. The simulated test results showed that the seed repose angle obtained by the optimization test was 35.823°, which exhibited a relative error of 0.103% in comparison to the average values obtained from the actual test. The simulated suspension velocity of the seed was 6.98 m/s. with a deviation of 0.55 m/s from the average suspension velocity obtained through the actual test. The discrete element model of the edible sunflower seed is accurate and reliable, offering guidance for improving the design of machinery used for seeding and harvesting edible sunflowers.

To address the issues of bulky structure and complex transmission systems in current transplanters, a compact, electric-driven automatic transplanter was designed. Using pepper plug seedlings as the test subject, this study investigated plug tray dimensions and planting patterns. According to the design requirement that the width of the single-row transplanter must be less than 62.5 cm, a three-dimensional transplanter model was constructed. The transplanter comprises a coaxially installed dual-layer seedling conveying device and a sector-expanding automatic seedling picking and depositing device. The structural dimensions, drive configurations, and driving forces of the transplanter were also determined. Finally, the circuit and pneumatic system were designed, and the transplanter was assembled. Both bench and field tests were conducted to select the optimal working parameters. The test results demonstrated that the seedling picking and depositing mechanism met the required operational efficiency. In static seedling picking and depositing tests, at three transplanting speeds of 120 plants/min, 160 plants/min, and 200 plants/min, the success rates of seedling picking and depositing were 100%, 100%, and 97.5%, respectively. In the field test, at three transplanting speeds of 80 plants/min, 100 plants/min, and 120 plants/min, the transplanting success rates were 94.17%, 90.83%, and 88.33%, respectively. These results illustrate that the compact, electric-driven seedling conveying and picking and depositing devices meet the operational demands of automatic transplanting, providing a reference for the miniaturization and electrification of transplanters.