# Performance Testing and Evaluation of Drum-Type Stem-Separation Device for Pepper Harvester
## 3 Results and Discussion  
Table 4 presents the performance test results for each factor level according to the speed of the three-shaft drum stem-separation device. When operating from factor level 1 to factor level 6 using the three-shaft drum, the SSE of the AR legend increased, and the PTR and DR of the AR legend decreased. At factor level 6, the average SSE was 76.8%, the average PTR was 20.9%, and the average DR was 2.3%, thus showing the highest efficiency. In this study, to select the optimal drum rotation speed, the rotation speeds of A, B, and C using the three-shaft drum with a factor level of 6 were set to 0.9, 2.7, and 1.3 m/s, respectively, as this showed the highest efficiency. In the four-shaft drum, the rotation speeds of A, B, and C were the same as that of the three-shaft drum, and the rotation speed of D was set to 1.3 m/s, which is the same as C. The conveyor speed was 0.5 m/s. Table 5 lists the field performance test results for AR Legend and Jeokyoung. In the non-moving status during non-picking operation, the average SSEs of AR Legend and Jeokyoung with the three-shaft drum were 70.0% and 69.3%, respectively; the average PTRs were 26.9% and 27.7%, respectively; and the average DRs were 3.1% and 3.0%, respectively, which means the results were similar regardless of pepper species. The average SSEs of AR Legend and Jeokyoung with the four-shaft drum were 64.0% and 72.3%, respectively; the average PTRs were 25.5% and 17.8%, respectively; and the average DRs were 10.5% and 9.9%, respectively, which means that the average PTR of Jeokyoung was lower than that of AR Legend. The overall DR with the four-shaft drum was slightly higher compared to that with the three-shaft drum, but the average PTR decreased, thus confirming that the four-shaft drum is more suitable for stem separation. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Drum type** & **Level** & **AVE/SD** & **SSE 1 (\%)** & **PTR 2 (\%)** & **DR 3 (\%)** \\ \hline \multirow{8}{*}{3-shaft} & 1 & AVE 4 ** & 51.6 & 45.1 & 3.3 \\  & & SD 5  & 2.8 & 2.7 & 0.5 \\  & & AVE & 59.1 & 38.7 & 2.2 \\  & & SD & 3.4 & 3.8 & 1.4 \\  & & AVE & 53.9 & 42.5 & 3.6 \\  & & SD & 6.3 & 7.1 & 0.8 \\  & & AVE & 57.7 & 38.8 & 3.4 \\  & & SD & 6.2 & 4.1 & 2.1 \\  & & AVE & 64.1 & 33.0 & 2.9 \\  & & SD & 7.2 & 7.9 & 0.7 \\  & & AVE & 76.8 & 20.9 & 2.3 \\  & & SD & 8.2 & 8.5 & 1.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Experiment results of field test based on drum type and rotational speed level. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Operating Status** & **Drum Type** & **Variety** & **AVE 1/SD 2** & **SSE 3** & **PTR 4** & **DR 5** & **GAR 6** \\  & & & & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline \multirow{8}{*}{Non-picking operation} & \multirow{8}{*}{Non-moving} & \multirow{8}{*}{3} & AR Legend & AVE & 70.0 & 26.9 & 3.1 & - \\  & & & SD & 8.2 & 8.5 & 1.3 & - \\  & & & Jeokyoung & AVE & 69.3 & 27.7 & 3.0 & - \\  & & & SD & 5.4 & 4.8 & 1.1 & - \\ \cline{1-1}  & & & & & 64.0 & 25.5 & 10.5 & - \\ \cline{1-1}  & & & & SD & 2.9 & 3.2 & 1.4 & - \\ \cline{1-1}  & & & Jeokyoung & AVE & 72.3 & 17.8 & 9.9 & - \\ \cline{1-1}  & & & SD & 6.3 & 6.2 & 2.1 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Experiment results of field test based on moving operation of drum type and variety of pepper used for each picking part status. In the non-moving status during picking operation, the average SSEs with the three-shaft drum were 86.0% and 90.1%, respectively; the average PTRs were 9.3% and 6.2%, respectively; and the average DRs were 4.7% and 3.7%, respectively. Compared to the three-shaft drum, the average SSE with the four-shaft drum increased by 4.1%, the average PTR decreased by 3.1%, and the average DR increased by 1%, which means that the four-shaft drum had higher performance than the three-shaft drum.