## 4 Calibration Test of Plug Seedling Pot Simulation Model
### Regression Model Interactive Response Analysis  
A response surface analysis diagram and corresponding contour map of different factors were obtained using Design-Expert software, as shown in Figure 9. The response surface graph is a curved surface of the three-dimensional space formed by the response value to the static friction coefficient between the pot and steel, the collision restitution coefficient between the pot and the pot, and the bond radius of each test factor. From the response surface analysis graph, the impact of the interaction of various factors on the collision impact force between the pot and the steel plate can be clearly seen. If the curve is steeper, this factor significantly impacts the impact force between the pot and the steel plate, represented by the change in the response value. The contour map shows that the \begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **No.** \\ **Friction X\({}_{2}\)** \\ \end{tabular} & \
\begin{tabular}{c} **The Pot-Pot Restitution** \\ **Coefficient X\({}_{4}\)** \\ \end{tabular} &
\begin{tabular}{c} **Band Radius X\({}_{9}\)/mm** \\ **Collision between the Pot and** \\ **the Steel Plate/N** \\ \end{tabular} \\ \hline
1 & 0 & 1 & 1 & 14.95 \\
2 & 0 & 0 & 0 & 14.24 \\
3 & 1 & 1 & 0 & 11.59 \\
4 & 0 & 1 & \(-\)1 & 13.24 \\
5 & 1 & 0 & \(-\)1 & 9.04 \\
6 & \(-\)1 & 1 & 0 & 11.56 \\
7 & \(-\)1 & 0 & \(-\)1 & 13.25 \\
8 & 0 & \(-\)1 & 1 & 14.98 \\
9 & \(-\)1 & \(-\)1 & 0 & 14.84 \\
10 & 0 & 0 & 0 & 12.89 \\
11 & 0 & 0 & 0 & 12.88 \\
12 & 0 & 0 & 0 & 12.85 \\
13 & \(-\)1 & 0 & 1 & 14.98 \\
14 & 0 & 0 & 0 & 14.67 \\
15 & 1 & \(-\)1 & 0 & 11.59 \\
16 & 1 & 0 & 1 & 13.25 \\
17 & 0 & \(-\)1 & \(-\)1 & 13.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Box–Behnken experimental design and results of significant contact parameters. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **Source of Variation** \\ \end{tabular} & \begin{tabular}{c} **Mean Square** \\ \end{tabular} & \begin{tabular}{c} **Degree of Freedom** \\ \end{tabular} & \
\begin{tabular}{c} **Sum of Square** \\ \end{tabular} &
\begin{tabular}{c} _p Value_ \\ \end{tabular} \\ \hline Model & 34.71 & 9 & 3.86 & 0.0316 * \\ X\({}_{2}\) & 10.49 & 1 & 10.49 & 0.0105 * \\ X\({}_{4}\) & 1.35 & 1 & 1.35 & 0.2535 \\ X\({}_{9}\) & 11.07 & 1 & 11.07 & 0.0092 * \\ X\({}_{2}\)X\({}_{4}\) & 2.69 & 1 & 2.69 & 0.1229 \\ X\({}_{2}\)X\({}_{9}\) & 1.54 & 1 & 1.54 & 0.2264 \\ X\({}_{4}\)X\({}_{9}\) & 0.000625 & 1 & 0.000625 & 0.9794 \\ X\({}_{2}\)\({}^{2}\) & 7.00 & 1 & 7.00 & 0.0254 * \\ X\({}_{4}\)\({}^{2}\) & 0.13 & 1 & 0.13 & 0.7073 \\ X\({}_{9}\)\({}^{2}\) & 0.72 & 1 & 0.72 & 0.3946 \\ Residual & 6.12 & 7 & 0.87 & \\ Lack of fit & 3.02 & 3 & 1.01 & 0.3890 \\ Pure error & 3.10 & 4 & 0.77 & \\ Sum & 40.83 & 16 & & \\ \hline \hline \end{tabular} Note. * indicates extremely significant (\(p<0.01\)), * indicates significant (\(0.01<p<0.05\)).  
\end{table} 
Table 9: Variation analysis of [PERSON]–Behnken design quadratic model. greater the curvature of the contour is, the more significant the interaction between the two parameters. As shown in Figure 9a, the static friction coefficient between the pot and steel and the impact restitution coefficient between the pot and the steel plate significantly impact the force between the pot and the steel plate. The curve slope changes significantly, indicating that the static friction coefficient between the pot and steel and the impact restitution coefficient between the pot and the steel plate has a significant impact on the impact force between the pot and the steel plate. The curvature of the contour line is large, which indicates that the interaction of the pot and steel static friction coefficient and bond radius is significant. As shown in Figure 9c, the impact restitution coefficient between the pot and the pot and bond radius significantly impacts the impact force of the pot and the steel plate.