Design and experimental study of a novel seed guide device based on Bézier curves

To improve the seed-hole formation quality and uniformity in multiple-seeds-per-hole sowing, a seed-converging grooved (SCG) seed guide tube based on the principle of Bézier curves was proposed. The key structural parameters of the SCG seed guide tube were designed, and the collision behavior of multiple seeds inside the seed guide tube as well as the mechanism of seed-hole formation were analyzed. The seed guiding process was comprehensively analyzed and numerically investigated using the discrete element method (DEM). The results showed that the Bézier curve can effectively reduce collisions, while the seed-converging groove constrains seed motion in the z -direction, enabling seed convergence and improving seed-hole formation performance. Single-factor experiments were conducted to identify the significant factors affecting seed guiding performance and to determine their appropriate value ranges. A Box–Behnken design was then employed to establish regression equations between the performance indices and the influencing factors, and to analyze the effects of these factors on the experimental indices. Multi-objective optimization indicated that when the inner diameter of the seed guide tube is 25.6 mm, the horizontal length is 148.7 mm, and the vertical length is 474.9 mm, the Qualified index of hole diameter and the Qualified index of hole distance reach 93.3% and 94.4%, respectively. The seed guiding performance of the proposed SCG seed guide tube is significantly better than that of the Bézier seed guide tube and the conventional seed guide tube, and it meets the sowing requirements for quinoa.