## 3 Results and Discussion
### Descriptive Statistics
#### 3.2.1 CoM Descriptive Statistics
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Measurement** & **n** & **Mean** & **Sd** & **Median** & **Min** & **Max** & **Range** & **Skew** & **Kurt** \\ \hline AdM\_CoM\_0\_Xx & 11 & 105.65 & 0.08 & 105.67 & 105.53 & 105.75 & 0.22 & \(-\)0.29 & \(-\)1.70 \\ AdM\_CoM\_1\_Xx & 11 & 98.78 & 0.20 & 98.79 & 98.48 & 99.06 & 0.58 & \(-\)0.15 & \(-\)1.60 \\ AdM\_CoM\_2\_Xx & 11 & 98.34 & 0.14 & 98.33 & 98.20 & 98.64 & 0.44 & 0.87 & \(-\)0.49 \\ AdM\_CoM\_0\_Yy & 11 & 256.67 & 0.05 & 256.68 & 256.60 & 256.74 & 0.13 & \(-\)0.06 & \(-\)1.76 \\ AdM\_CoM\_1\_Yy & 11 & 310.56 & 0.00 & 310.56 & 310.55 & 310.56 & 0.01 & 0.03 & \(-\)1.41 \\ AdM\_CoM\_2\_Yy & 11 & 310.24 & 0.10 & 310.26 & 310.05 & 310.39 & 0.34 & \(-\)0.28 & \(-\)0.74 \\ AdM\_CoM\_0\_2\_Zz & 11 & 214.53 & 0.15 & 214.52 & 214.30 & 214.81 & 0.52 & 0.36 & \(-\)0.69 \\ AdM\_CoM\_1\_Zz & 11 & 238.99 & 0.09 & 238.98 & 238.88 & 239.22 & 0.34 & 0.99 & 0.21 \\ AdM\_CoM\_2\_Zx & 11 & 237.95 & 0.20 & 237.93 & 237.70 & 238.40 & 0.71 & 0.71 & \(-\)0.08 \\ CvM\_CoM\_0\_Xx & 11 & 112.84 & 0.00 & 112.84 & 112.84 & 112.84 & 0.00 & 0.17 & \(-\)1.60 \\ CvM\_CoM\_1\_Xx & 11 & 109.63 & 0.09 & 109.69 & 109.47 & 109.74 & 0.27 & \(-\)0.36 & \(-\)1.58 \\ CvM\_CoM\_2\_Xx & 11 & 109.51 & 0.18 & 109.52 & 109.28 & 109.80 & 0.52 & 0.14 & \(-\)1.48 \\ CvM\_CoM\_0\_Yy & 11 & 317.08 & 0.00 & 317.08 & 317.07 & 317.08 & 0.01 & 0.51 & \(-\)0.69 \\ CvM\_CoM\_1\_Yy & 9 & 310.54 & 0.11 & 310.57 & 310.26 & 310.60 & 0.34 & \(-\)1.93 & 2.25 \\ CvM\_CoM\_2\_Yy & 10 & 310.25 & 0.14 & 310.31 & 309.93 & 310.36 & 0.44 & \(-\)1.35 & 0.34 \\ CvM\_CoM\_0\_2\_Zx & 11 & 265.82 & 0.16 & 265.80 & 265.60 & 266.12 & 0.52 & 0.69 & \(-\)0.73 \\ CvM\_CoM\_1\_Zz & 11 & 263.93 & 0.09 & 263.96 & 263.77 & 264.04 & 0.26 & \(-\)0.34 & \(-\)1.40 \\ CvM\_CoM\_2\_Zz & 11 & 262.46 & 0.07 & 262.46 & 262.31 & 262.56 & 0.25 & \(-\)0.43 & \(-\)0.95 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: CoM descriptive statistics for Arm I—AdM and Arm I—CvM. Figure 13: Measurements of CoM axis X.  
from 0 kg to 1 kg, and a slight decrease in the median position when changing the load from 1 kg to 2 kg. The highest range is for measurements in the direction of the Y axis for CvM_CoM_2_Yy, namely range 0.44 mm and standard deviation sd of 0.14 mm. For measurements in the direction of the Z axis (Figure 15), for Arm I--AdM, there is a significant increase in the median position when changing the load from 0 kg to 1 kg and slightly decreasing in the median position when changing the load from 1 kg to 2 kg. Arm I--CvM shows a slight decrease in the median position when changing the load from 0 kg to 1 kg and a slight decrease in the median position when changing the load from 1 kg to 2 kg. The range in the direction of the Z axis is the largest for measurement AdM_CoM_2_Zz, namely the range up to 0.71 mm and the standard deviation sd of 0.20 mm. Figures 13-15 show that both Arm I--AdM and Arm I--CvM, without load, will reach a different position than when measuring with load. The resulting increase in the position of the robotic arm in the Z axis direction using Arm I--AdM with respect to Arm I--CvM, is caused by springing of the Arm I--AdM structure. Figure 14: Measurements of CoM axis Y.  
Figure 15: Measurements of CoM axis Z. From Table 8 and Figure 17, for Arm I--AdM, measurements in the Y axis direction, an increase in the median value can be observed as the load increases and the range and standard deviation sd change slightly. For Arm I--CvM in the direction of the Y axis, it is possible to observe an increase in the median and the mean with increasing load, while the range and standard deviation sd is higher at higher loads. Failure to meet the condition of normal distribution of measured values is also confirmed by anomalies in Figure 17, at the same time, the stress caused by the construction of Arm I--AdM needs to be considered.