## 4 Conclusions  
Physical experiments enable the measurement of the material property parameters associated with Sesbania seeds. These parameters encompass the triaxial size, thousand-seed weight, density, Poisson's ratio, and elastic modulus of the seeds, as well as the coefficients of restitution, static friction, and rolling friction between the seeds and materials such as PMMA, SAE 304 stainless steel, PLA, and 6061 aluminum alloy. Based on these material property parameters of Sesbania seeds, the DEM of the seeds can be constructed. With the physical stacking angle as the target, the Box-Behnken experimental method, with three factors and three levels, was employed to perform the stacking simulation experiment. This process facilitated the calibration of the contact characteristic parameters between Sesbania seeds. After calibration, the coefficient of restitution, coefficient of static friction, and coefficient of rolling friction between the seeds were determined to be 0.168,  
Figure 11: Computer vision seeding device experimental platform: (1) conveyor belt; (2) image acquisition device; (3) seed-metering device; and (4) numerical control table. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Experiment Indices** & **Simulation Values** & **Experiment Values** & **Relative Error** \\ \hline Replay-seeding rate/\% & 11.81 & 12.55 & 5.90 \\ Missed-seeding rate/\% & 7.09 & 7.53 & 5.84 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison between bench experiment and simulation experiment. 0.339, and 0.083, respectively. The calibrated simulation stacking angle was 34.9\({}^{\circ}\), exhibiting a percentage error of only 1.16% relative to the physical stacking angle. With the replay-seeding and missed-seeding rates as test indicators, the sowing simulation test results were compared against the bench experiment results. The results indicate that the replay-seeding and missed-seeding rates in the simulation test were 11.81% and 7.09%, respectively, whereas the corresponding rates in the bench experiment were 12.55% and 7.53%. The discrepancies in relative terms between the simulation outcomes and the results from the seeder bench experiments were minor. These results met the technical requirements, confirming that the calibrated simulation parameters for Sesbania seeds can be applied in the seeder simulation experiment. Through the parameter measurement of Sesbania seeds, it was found that, when compared with the Vigna and Glycine genera, the coefficients of restitution between Sesbania seeds are lower. In contrast, the coefficient of friction is higher. This suggests that Sesbania seeds exhibit weaker fluidity. These considerations provide valuable references for the simulation and optimization of the Sesbania precision seeder. In addition to fulfilling the agronomic requirements for Sesbania sowing, the design of the seeder must also account for seed damage resulting from the operation of its parts and the influence of seed stacking during the seed-carrying process. Seeds can be categorized based on their damage status, and discrete-element modeling can be performed for each category, following the methodologies established for intact seeds [29]. However, this study did not investigate the question of damaged seeds. Future research could involve the statistical analysis of the proportions of various types of damaged seeds within Sesbania seeds and incorporate corresponding discrete-element models into EDEM, in proportion, to enhance the optimization of the seeder design. Additionally, the damage mechanisms relevant to seeds under the forces applied could be investigated, allowing for further refinement of the seeder structure through force simulations conducted in EDEM's post-processing module [30]. Conceptualization, S.C. and Y.L. ; methodology, S.C.; software, S.C.; validation, S.C. and B.W. ; formal analysis, S.C.; investigation, S.C. and B.W. ; resources, Y.L., B.W. and X.H. ; data curation, S.C.; writing--original draft preparation, S.C.; writing--review and editing, S.C., Y.L. and M.S.