Parameter Optimization of Companion Particles and Anti-Blocking Mechanism for Sesame Seed Metering in a Binary Sesame–Companion Particle System

Sesame seeds are small, irregularly shaped, and poorly flowable, often causing insufficient filling and unstable discharge in external fluted-roller seed-metering devices. This study developed a sesame–companion-particle binary seed-metering system to improve metering stability. The discrete element method (DEM) was used to simulate particle motion, and the model was validated through YOLO11-based machine-vision experiments. Response surface methodology was then applied to evaluate the effects of mass mixing ratio, companion-particle density ratio B, and particle diameter on seed-metering performance. The normalized cumulative discharge trajectories from the experiments and simulations showed high agreement, with mean Pearson correlation coefficients exceeding 0.99 for sesame seeds, sorghum particles, and total particles. The recommended parameter combination was a sesame-to-companion-particle mass mixing ratio of 9.102:1, B = 1.315 (ρc = 1222.95 kg·m−3), and a companion-particle diameter of 1.636 mm. Under this combination, the proportion of strong force chains was 14.25 percentage points lower than the maximum among the investigated conditions. Appropriate matching of companion-particle parameters can restructure interparticle contacts, weaken strong force chains near the seed outlet, and improve sesame seed-metering stability and discharge-composition uniformity.