## 3 Parameter Optimization and Performance Test
### Experiment on Stability of Seeding Dropping Duration under Multi-Planting Frequency
#### 3.3.2 Test Results and Analysis  
The test results and the calculation of the variation coefficient are shown in Table 3.  
The test results showed that:  
1. When the drive motor speed was low (60\({}^{\circ}\)-80\({}^{\circ}\)/s, corresponding to a planting frequency of 50\(\sim\)67 plants/(min - row)), the coefficient of variation of the seedling dropping duration was larger. The main reason was that the frictional sliding process of the potted seedlings differed at the same seedling plate opening speed due to friction and the frictional sliding distance, and the difference had a large uncertainty, while the slower the opening speed, the larger the difference, which led to a large variation in the potted seedling dropping duration.
2. With the increase in the drive motor speed (90\({}^{\circ}\)-150\({}^{\circ}\)/s, corresponding to a planting frequency of 75-128 plants/(min - row)), the opening speed of the seedling carrying plate was accelerated, and the pot seedlings lost the support of the seedling carrying plate and fell in a short period of time. The difference in the sliding duration caused  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Test Times and**} & \multicolumn{8}{c}{**Rotation Speed Grouping/(\({}^{\circ}\)/s)**} & \\ \multicolumn{1}{c}{**Calculation Results/(s)**} & **60** & **70** & **80** & **90** & **100** & **110** & **120** & **130** & **140** & **150** \\ \hline
1 & 0.6 & 0.66 & 0.55 & 0.53 & 0.42 & 0.42 & 0.48 & 0.41 & 0.43 & 0.43 \\
2 & 0.59 & 0.64 & 0.45 & 0.55 & 0.52 & 0.4 & 0.46 & 0.45 & 0.38 & 0.44 \\
3 & 0.6 & 0.61 & 0.53 & 0.5 & 0.49 & 0.46 & 0.47 & 0.43 & 0.45 & 0.43 \\
4 & 0.69 & 0.61 & 0.57 & 0.45 & 0.47 & 0.46 & 0.4 & 0.41 & 0.45 & 0.43 \\
5 & 0.55 & 0.53 & 0.52 & 0.48 & 0.43 & 0.43 & 0.46 & 0.44 & 0.38 & 0.39 \\
6 & 0.51 & 0.55 & 0.55 & 0.45 & 0.46 & 0.48 & 0.4 & 0.41 & 0.43 & 0.44 \\
7 & 0.56 & 0.53 & 0.55 & 0.51 & 0.49 & 0.42 & 0.44 & 0.39 & 0.39 & 0.43 \\
8 & 0.71 & 0.55 & 0.56 & 0.47 & 0.5 & 0.46 & 0.39 & 0.41 & 0.41 & 0.43 \\
9 & 0.73 & 0.56 & 0.62 & 0.43 & 0.47 & 0.4 & 0.44 & 0.46 & 0.39 & 0.37 \\
10 & 0.63 & 0.67 & 0.57 & 0.49 & 0.49 & 0.48 & 0.45 & 0.39 & 0.44 & 0.4 \\ Average duration/s & 0.62 & 0.59 & 0.55 & 0.49 & 0.47 & 0.44 & 0.44 & 0.42 & 0.42 & 0.42 \\ Variation & & & & & & & & & & \\ coefficient/\% & 11.76 & 9.08 & 7.95 & 7.77 & 6.54 & 6.96 & 7.24 & 5.72 & 6.84 & 5.68 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Test results of seedling uniformity under multiple planting frequencies.  
by individual differences in the pot seedlings was compressed, which reduced the uncertainty in the process of falling seedlings, and the duration of falling seedlings was stabilized.
3. By observing the test process, it was found that when the speed of the drive motor was large (140\({}^{\circ}\)-150\({}^{\circ}\) s, corresponding to a planting frequency of 117-125 plants/ (min \(\cdot\) row)), although the coefficient of variation of the dropping seedling duration did not change significantly, the installation angle of the drive cam at each position was found to change to varying degrees after the test. Preliminary analysis indicated that the reason for this was that the effect of contact with the seedling carrier plate increased as the drive cam speed increased. Since the cam and drive shaft were fixed by a top wire, they could not withstand large impact loads. Therefore, the drive cam had a small angle offset during contact, and because of the difference in the installation tightness, the cam offset angles at each position were different. Moreover, as the test was only carried out at the No. 3 position, and no continuous drop test was performed at each position, thus the drop time caused by the change in the installation position of the drive cam could not be reflected.