## 3 Results
### Identification of Real Performance Parameters
Figure 8: Trajectories of shoulder flexion–extension—load 2.2 kg. Figure 7: Case 1 -Exclusive series of exercises per joint (**a**) on the \(x\)-axis, (**b**) on the \(y\)-axis, and (**c**) on the \(z\)-axis. Table 8 shows the positioning accuracy, which represents the ability to reach or approach the programmed value of a given location in the ERMIS trajectories, and the degree of closeness between the different readings at the same point, representing the repeatability. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Loading Conditions** & **Movement** & \(x\)**-axis (mm)** & \(y\)**-axis (mm)** & \(z\)**-axis (mm)** \\ \hline
2.2 kg &
\begin{tabular}{c} Shoulder abduction–adduction \\ Shoulder flexion–extension \\ \end{tabular} & 11.9 & 17.6 & 9.8 \\
4.2 kg &
\begin{tabular}{c} Shoulder flexion–extension \\ \end{tabular} & 3.6 & 5.6 & 8.5 \\ \cline{2-5}
4.2 kg &
\begin{tabular}{c} Shoulder abduction–adduction \\ Shoulder flexion–extension \\ \end{tabular} & 23.0 & 11.0 & 39.0 \\
13.6 & \begin{tabular}{c} Shoulder flexion–extension \\ \end{tabular} & 13.6 & 15.3 & 24.8 \\ \cline{2-5} Healthy subject & \
\begin{tabular}{c} Shoulder abduction–adduction \\ Shoulder flexion–extension \\ \end{tabular} & 17.2 & 18.0 & 6.8 \\ \cline{2-5}  &
\begin{tabular}{c} Shoulder flexion–extension \\ \end{tabular} & 6.4 & 5.2 & 5.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Absolute error in trajectories under loading conditions. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Conditions** & **Movement** & \(x\)**-axis (mm)** & \(y\)**-axis (mm)** & \(z\)**-axis (mm)** \\ \hline \multirow{8}{*}{**Without load**} & Case 1 & 595.1\(-\)595.4 & 180.4\(-\)181.2 & 194.6\(-\)194.2 \\ \cline{2-5}  & Case 3 & 486.0\(-\)488.3 & 0.0\(-\)13.1 & 150.9\(-\)144.9 \\ \cline{2-5}  & Shoulder abduction–adduction & 547.5\(-\)547.5 & 158.6\(-\)159.2 & 426.5\(-\)426.3 \\ \cline{2-5}  & Shoulder flexion–extension & 267.6\(-\)268.1 & 482.3\(-\)482.0 & 402.9\(-\)402.8 \\ \cline{2-5}  & Arm flexion–extension & 234.5\(-\)234.0 & 375.8\(-\)372.9 & 172.1\(-\)173.7 \\ \cline{2-5}  & Internal and external shoulder rotation & 265.2\(-\)253.2 & 544.8\(-\)565.2 & 453.8\(-\)453.1 \\ \hline \multirow{2}{*}{**2.2 kg**} & Shoulder abduction–adduction & 169.0\(-\)161.2 & 519.7\(-\)529.9 & 357.3\(-\)358.6 \\ \cline{2-5}  & Shoulder flexion–extension & 260.7\(-\)260.3 & 373.6\(-\)372.1 & 345.2\(-\)347.8 \\ \hline \multirow{2}{*}{**4.2 kg**} & Shoulder abduction–adduction & 82.7\(-\)74.8 & 608.5\(-\)609.0 & 358.1\(-\)375.7 \\ \cline{2-5}  & Shoulder flexion–extension & 173.3\(-\)169.1 & 452.6\(-\)447.0 & 366.5\(-\)362.8 \\ \hline \multirow{2}{*}{**Healthy subject**} & Shoulder abduction–adduction & 164.1\(-\)159.0 & 527.5\(-\)534.3 & 359.8\(-\)359.6 \\ \cline{2-5}  & Shoulder flexion–extension & 255.8\(-\)257.2 & 376.9\(-\)376.8 & 345.2\(-\)346.1 \\ \hline \end{tabular}
\end{table} 
Table 7: RMS values of the ERMIS exoskeleton. Figure 9: Movement of shoulder abduction–adduction—2.2 kg load (**a**) on the \(x\)-axis, (**b**) on the \(y\)-axis, and (**c**) on the \(z\)-axis. The use of this methodology allowed for the easier implementation of the tasks. The results obtained allowed the design to be carried out and refined to obtain the prototype specifications within the TRLs.