## 2 Materials and Methods
### Design Process
#### 2.2.2 Establishing the Functional Technology Matrix of the Rehabilitation Chair
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Functions**} & \multicolumn{3}{c}{**Technology Element Score**} & \multicolumn{2}{c}{**Technical Index Scores**} & \multicolumn{2}{c}{**Technical Index Factors**} \\ \hline \multirow{4}{*}{F1} & T1(1) & T1(2) & T1(3) & & & \\  & T1(1) & 0 & 2 & 3 & 5 & 0.42 \\  & T1(2) & 2 & 0 & 3 & 5 & 0.42 \\  & T1(3) & 1 & 1 & 0 & 2 & 0.16 \\  & T2(1) & T2(2) & T2(3) & & & \\  & T2(1) & 0 & 1 & 1 & 2 & 0.17 \\ F2 & T2(2) & 3 & 0 & 3 & 6 & 0.50 \\  & T2(3) & 3 & 1 & 0 & 4 & 0.33 \\  & T3(1) & T3(2) & T3(3) & & & \\ F3 & T3(1) & 0 & 1 & 3 & 4 & 0.33 \\  & T3(2) & 3 & 0 & 3 & 6 & 0.50 \\  & T3(3) & 1 & 1 & 0 & 2 & 0.17 \\  & T4(1) & T4(2) & T4(3) & & & \\ F4 & T4(1) & 0 & 3 & 3 & 6 & 0.50 \\  & T4(2) & 1 & 0 & 3 & 4 & 0.33 \\  & T4(3) & 1 & 1 & 0 & 2 & 0.17 \\  & T5(1) & T5(2) & T5(3) & & & \\ F5 & T5(1) & 0 & 3 & 2 & 5 & 0.45 \\  & T5(2) & 1 & 0 & 1 & 2 & 0.18 \\  & T5(3) & 2 & 3 & 0 & 4 & 0.36 \\  & T6(1) & T6(2) & T6(3) & & & \\ F6 & T6(1) & 0 & 1 & 2 & 3 & 0.23 \\  & T6(2) & 3 & 0 & 2 & 5 & 0.38 \\  & T6(3) & 3 & 2 & 0 & 5 & 0.38 \\  & T7(1) & T7(2) & T7(3) & & & \\ F7 & T7(1) & 0 & 3 & 2 & 5 & 0.42 \\  & T7(2) & 1 & 0 & 1 & 2 & 0.16 \\  & T7(3) & 2 & 3 & 0 & 5 & 0.42 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Evaluation of applicability index coefficients of the functional elements of the modular rehabilitation chair. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{3}{c}{**Compatibility**} \\ \cline{2-5}  & **T1(1)** & **T1(2)** & \(\ldots\) & **Tn(m)** \\ \hline T1(1) & 0/1 2  & 0/1 2  & 0/1 & \(\ldots\) & 0/1 \\ T1(2) & 0/1 & 0/1 & \(\ldots\) & 0/1 \\ \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) \\ Tn(m) 1  & 0/1 & \(\ldots\) & 0/1 \\ T1(2) & 0/1 & 0/1 & \(\ldots\) & 0/1 \\ \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) \\ Tn(m) 1  & 0/1 & \(\ldots\) & 0/1 \\ T1(2) & 0/1 & 0/1 & \(\ldots\) & 0/1 \\ \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) & \(\ldots\) \\ Tn(m) 1  & 0/\[Q=\{q1,q2,qn,\ldots,qm\} \tag{2}\]  
Here, qn is the nth feasible solution and m is the number of feasible solutions. Step 7: Determine a feasible functional solution for the rehabilitation chair. As shown in Table 8, the pathways with higher technical excellence index coefficient scores in Tables 5-7 were subjected to technical compatibility matrix analysis, with compatibility as 1 and incompatibility as 0. The feasible options for the rehabilitation chair function were obtained as follows:  
1. Massage Function: roller, worm gear worm gear, strut. 2. Stretching Function: sleeve type expansion slider, telescopic slider. 3. Chest Expansion Function: screw, mandrel. 4. Arm Lift Function: support piece, rotating section. 5. Flexion Function: folded movable rod end, retaining pin. 6. Leg Lift Function: wooden knockout head, hinge rod. 7. Pedal Function: turntable, foot pedal. Step 8: Functional structure design of the rehabilitation chair  
According to the above technical elements, combined with the functions obtained from user research, including back massage, leg flexion and extension, chest expansion movement, arm lifting, leg bending, leg lifting, and footrest movement, the rehabilitation chair functional program is designed. This is shown in Figures 4-6. Figure 4: Backrest massage program.