# Design and Experimental Study of the General Mechanical Pneumatic Combined Seed Metering Device
## 4 Seed Performance Test
### Multivariate Test
#### 4.4.3 Parameter Optimization  
By exploiting the software's optimization function for the optimization analysis, it found the operating performance could be the best when the cleaning air velocity was 16.7 m/s, the seeding drum speed was 13.7 r/min, and the hole cone angle reached 35.6\({}^{\circ}\). On that basis, the qualified seeding index was 97.94%, the replay index reached 0.03%, and the missed broadcast index was 2.03%.  
To verify the credibility of the optimization results, based on the optimal working parameters, the bench verification test was performed and repeated five times. The test results are listed in Table 4.  
As indicated from the results, the average qualified index was 98.10%, the average replay index was 0%, and the missed index was 1.90%. The test results were basically consistent with the optimized results.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Experimental Factor**} & \multicolumn{4}{c}{**Experimental Index**} \\ \cline{2-7}
**Experimental** & **Clearing** & **Speed of** & **Cone Angles** & **Qualified** & **Replay Index** & **Missing Index** \\
**Number** & **Airflow** & **Velocity** & **Feeding Drum** & **Holes** & **A/\%** & **D/\%** & **M/\%** \\  & **\(X_{1}\)/m/s** & **\(X_{2}\)/r-min\({}^{-1}\)** & **\(X_{3}\)/\({}^{\circ}\)** & **A**/\% & **A**/\% & **A**/\% \\ \hline  
1.682\) & \(0\) & \(0\) & \(82.92\) & \(5.71\) & \(11.37\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Protocols and results.  
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Variance**} & \multicolumn{6}{c}{**Qualified Index A/\%**} & \multicolumn{6}{c}{**Replay Index D/\%**} & \multicolumn{6}{c}{**Missing Index M/\%**} \\ \cline{2-13}  & **Sum of** & **Degree** & **Mean** & **Square** & **F Value** & **Sum of** & **Degree** & **Mean** & **Square** & **F Value** & **Sum of** & **Degree of** & **Mean** & **Square** & **F Freedom** & **Mean Square** & **F Value** & **\(p\) Value** \\ \hline Model & 602.82 & 9 & 72.54 & 13.20 & 0.0002 & 131.26 & 9 & 14.56 & 7.09 & 0.0026 & 271.57 & 9 & 30.17 & 5.65 & 0.0061 \\ X\({}_{1}\) & 31.54 & 1 & 31.54 & 5.74 & 0.0056 & 37.54 & 1 & 37.54 & 18.24 & 0.0016 & 0.26 & 1 & 0.28 & 0.009 & 0.8256 \\ X\({}_{2}\) & 81.51 & 1 & 85.51 & 14.83 & 0.0002 & 10.86 & 1 & 10.86 & 5.28 & 0.0445 & 23.87 & 1 & 0.3287 & 6.16 & 0.0025 \\ X\({}_{3}\) & 7.99 & 1 & 7.29 & 1.42 & 0.2612 & 7.30 & 1 & 7.30 & 3.55 & 0.0090 & 8.015 \(\times 10^{-1}\) & 1 & 8.018\(\times 10^{-1}\) & 1 & 8.015 \(\times 10^{-1}\) & 0.9697 \\ X\({}_{3}\)X\({}_{2}\) & 1.63 & 1 & 1.63 & 0.30 & 0.9891 & 9.68 & 1 & 0.68 & 4.70 & 0.0553 & 3.37 & 1 & 3.37 & 0.63 & 0.4455 \\ X\({}_{3}\)X\({}_{3}\) & 1.97 & 1 & 1.97 & 0.36 & 0.5627 & 0.084 & 1 & 0.084 & 0.041 & 0.8493 & 2.87 & 1 & 2.87 & 0.54 & 0.4801 \\ X\({}_{3}\) & 0.019 & 1 & 0.019 & 3.459 \(\times 10^{-3}\) & 0.9543 & 2.16 & 1 & 2.16 & 1.05 & 0.3294 & 1.78 & 1 & 1.78 & 0.33 & 0.5767 \\ X\({}_{2}\)\({}^{2}\) & 190.82 & 1 & 190.82 & 34.72 & 0.0002 & 20.10 & 1 & 23.20 & 9.82 & 0.0106 & 56.84 & 1 & 86.581 & 16.27 & 0.0024 \\ X\({}_{2}\)\({}^{2}\) & 298.01 & 1 & 298.01 & 54.22 & -0.0001 & 29.10 & 1 & 29.30 & 1.144 & 0.0037 & 140.87 & 1 & 140.807 & 26.39 & 0.0004 \\ X\({}_{2}\)\({}^{2}\) & 139.41 & 1 & 19.491 & 25.36 & 0.0005 & 26.82 & 1 & 26.82 & 13.03 & 0.0048 & 43.93 & 1 & 43.93 & 8.23 & 0.0167 \\ \hline Residual & 54.96 & 10 & 5.50 & & 20.58 & 10 & 2.06 & & 53.37 & 10 & 5.34 & & & & & \\ Lack off & 44.72 & 5 & 8.94 & 4.37 & 0.0658 & 16.80 & 5 & 3.36 & 4.44 & 0.0639 & 38.39 & 5 & 7.68 & 2.56 & 0.1625 \\ Pure Error & 10.24 & 5 & 2.05 & & 3.79 & 5 & 0.76 & & 14.89 & 5 & 3.00 & & & & \\ Cor Total & 007.78 & 19 & & 151.54 & 19 & & & 324.94 & 19 & & & & & & \\ \hline \multicolumn{11}{c}{Note significant (0.01 \(<\)_c \(<\) 0.05), highly significant (_c \(<\) 0.01)} \\ \hline \hline \end{tabular}
\end{table}
Table 3: Analysis of variance.