## 3 Results and Discussion
### BPNN-MOPSO Efficient Parameter Optimization Results and Experimental Verification  
The efficient parameter optimization of the device was carried out for the three types of seeds (tomato, pepper, and bok choi seeds) not having participated in the seeding performance experiments. Using the BPNN-MOPSO algorithm, the device parameters for tomato, pepper, and bok choi seeds were optimized. The Pareto optimal sets were obtained, and the corresponding Pareto optimal frontiers are shown in Figure 14. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Parameter**} & \multicolumn{3}{c}{**Indices**} \\ \cline{3-8}
**Seed Type** & & **Hole** & **Vacuum** & **Rotational** & **Missing** & **Reseeding** & **Qualified** \\  & & **Diameter** & **Pressure** & **Speed** & **Index** & **Index** & **Index** \\  & & **(mm)** & **(kPa)** & **(rpm)** & **(\%)** & **(\%)** & **(\%)** \\ \hline Cabbage & Experimental value & 1.00 & 10.0 & 12 & 3.39 & 9.64 & 86.97 \\  & Optimized value & 1.00 & 11.6 & 18 & 5.20 & 6.28 & 88.52 \\  & Experimental value & 0.60 & 6.0 & 14 & 11.72 & 3.65 & 84.63 \\  & Optimized value & 0.77 & 4.3 & 14 & 11.70 & 2.24 & 86.06 \\ Radish & Experimental value & 1.00 & 10.0 & 10 & 10.94 & 0.00 & 89.06 \\  & Optimized value & 0.98 & 10.6 & 10 & 8.76 & 1.59 & 89.65 \\  & Experimental value & 0.80 & 8.0 & 14 & 11.20 & 5.99 & 82.81 \\  & Optimized value & 0.71 & 6.2 & 10 & 11.96 & 3.36 & 84.68 \\ Chinese & Experimental value & 0.60 & 10.0 & 14 & 10.94 & 4.95 & 84.11 \\ cabbage & Optimized value & 0.70 & 9.0 & 14 & 10.48 & 5.19 & 84.33 \\  & Experimental value & 1.00 & 6.0 & 10 & 7.03 & 12.50 & 80.47 \\ Sesame & Optimized value & 0.85 & 6.3 & 14 & 10.52 & 6.46 & 83.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 20: Comparison of the optimal experimental and optimized results. Figure 13: Comparison of optimal experimental and optimized values of \(QI\) (qualified index). Each Pareto optimal frontier includes 100 non-dominated solutions. In Figure 14a, the values of \(M\)Is and \(R\)Is distribute within the interval [5,17] and [1,17], respectively. The solution with the minimum \(M\)I (5.04%) simultaneously has the maximum \(RI\) (16.85%), so the corresponding \(QI\) (78.11%) might not be satisfactory. Therefore, the 100 non-dominated solutions for each seed type were scored by Equations (16)-(18) to determine the optimal solution. The solution with the highest score was recorded as the optimized result. The results are shown in Table 21.  
The bench experiments were carried out to verify the optimization results in Table 21, and the verification results are shown in Table 22.  
According to Table 22, the predicted qualified indices for tomato, pepper, and bok choi seeds are all greater than 80%, which are 85.50%, 85.52%, and 84.87%, respectively. All the absolute errors are less than 3%. The verification results prove the accuracy of the established BPNN predictive model and the effectiveness of the MOPSO algorithm for searching for the optimal solution, showing that the parameter optimization method based on the BPNN/MOPSO combination simplifies the parameter optimization process effectively, improves optimization efficiency, and shortens research time. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Parameter**} & \multicolumn{3}{c}{**Indices**} \\ \cline{2-7}
**Seed** & \begin{tabular}{c} **Hole** \\ **Diameter** \\ **(mm)** \\ \end{tabular} & \begin{tabular}{c} **Vacuum** \\ **Pressure** \\ **(kPa)** \\ \end{tabular} & \begin{tabular}{c} **Rotational** \\ **Speed** \\ **(rpm)** \\ \end{tabular} & \begin{tabular}{c} **Missing** \\ **Index** \\ **(\%)** \\ \end{tabular} & \
\begin{tabular}{c} **Reseeding** \\ **Index** \\ **(\%)** \\ \end{tabular} &
\begin{tabular}{c} **Qualified** \\ **Index** \\ **(\%)** \\ \end{tabular} \\ \hline Tomato & 0.75 & 5.6 & 13.7 & 11.85 & 2.66 & 85.50 \\ Pepper & 1.00 & 10.4 & 18.0 & 11.54 & 2.94 & 85.52 \\ Bok choi & 0.67 & 8.6 & 14.0 & 10.72 & 4.41 & 84.87 \\ \hline \hline \end{tabular}
\end{table}