Parameter optimization of key components in seed-metering device for pre-cut seed stems of Pennisetum hydridum

To address the issues of missed seeding and seed stem jamming-factors that contribute to unstable performance in Pennisetum hydridum planting device, this study optimize the key components of the pre-cut stem planting device and evaluated its operational performance, thereby improving planting quality. Based on the results of preliminary experiments and discrete element method (DEM) simulation analysis, the critical components of the seed-metering device and their key influencing parameters were identified. Single-factor experiments were conducted to determine the appropriate parameter range. These were followed by a quadratic regression orthogonal rotation combination design for parameter optimization and the development of a response model for influencing factors. Finally, validation tests were performed to assess the effectiveness of the optimized parameters. The parameter optimization revealed that the optimal working parameter combination for the seed-metering device was: seed-cleaning rubber roller rotation speed (A) at 62.2 r/min, seed-filling rubber roller rotation speed (B) at 23 r/min, and conveyor belt operating speed (C) at 0.045 m/s. Under these conditions, the theoretically qualified seeding rate (Y₁) reached 92.5%, the missed seeding rate (Y₂) was 2.13%, and the reseeding rate (Y₃) was 5.37%. Validation experiment confirmed that Y₁ = 91.8%, Y₂ = 2.5%, Y₃ = 5.7%, with a relative error of 0.76%. The single-factor experimental results indicated that as A and B increased, Y₁ initially rose and then declined; as C increased, Y₁ gradually decreased. The interaction factor analysis of the orthogonal experimental results showed that the order of influence on seeding quality was: A > B > C. The verification tests confirmed the reliability of the optimized parameter scheme, providing both theoretical basis and technical support for improving the operational performance of the Pennisetum hydridum seed-metering equipment.