## 3 Results and Discussion
### Results of a Delphi Survey of Experts  
Based on the risk factors identified in the initial survey, a more detailed assessment was conducted through expert panel evaluation. Four distinct groups of experts provided ratings for severity, probability, and overall risk scores. Table 3 presents the descriptive statistics of their assessments, organized by nine risk factors (collision, deviation, battery discharge, explosion-proof performance, sensors, work environment, unauthorized access, external acceleration, and other). For each risk factor, severity (S), probability (P), and risk score (R) are presented as sub-items, with mean-standard deviation (M \(\pm\) SD) and median (Me) values for each expert group (Group 1: \(n\) = 5, Group 2: \(n\) = 5, Group 3: \(n\) = 4, Group 4: \(n\) = 5) and the overall mean (\(n\) = 19). The descriptive statistics of their assessments (Table 3) and visualization of results (Figures 3 and 4) reveal interesting patterns in how different stakeholders perceive safety risks. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Risk Factor** & **Group** & \begin{tabular}{c} **Severity** \\ **M \(\pm\) SD (Me)** \\ \end{tabular}  & \ \begin{tabular}{c} **Probability** \\ **M \(\pm\) SD (Me)** \\ \end{tabular}  & \begin{tabular}{c} **Risk Score** \\ **M \(\pm\) SD (Me)** \\ \end{tabular}  \\ \hline \multirow{4}{*}{Collision} & group1 & 3.6 \(\pm\) 1.02 (4) & 3.2 \(\pm\) 1.17 (3) & 11 \(\pm\) 4.56 (9) \\  & group2 & 3.4 \(\pm\) 0.8 (4) & 3 \(\pm\) 0.89 (3) & 10.4 \(\pm\) 4.08 (12) \\  & group3 & 3 \(\pm\) 1.22 (2.5) & 3 \(\pm\) 1 (3) & 8 \(\pm\) 1.41 (8) \\  & group4 & 5 \(\pm\) 0 (5) & 4 \(\pm\) 0.63 (4) & 20 \(\pm\) 3.16 (20) \\  & average & 3.75 \(\pm\) 1.15 (4) & 3.3 \(\pm\) 1.03 (4) & 12.35 \(\pm\) 5.81 (10) \\ \hline \multirow{4}{*}{Path deviation} & group1 & 2.4 \(\pm\) 0.8 (3) & 3.8 \(\pm\) 1.47 (4) & 8.8 \(\pm\) 4.62 (10) \\  & group2 & 3.2 \(\pm\) 0.4 (3) & 2.6 \(\pm\) 1.02 (3) & 8.6 \(\pm\) 4.32 (9) \\  & group3 & 2.25 \(\pm\) 0.43 (2) & 2.5 \(\pm\) 0.5 (2.5) & 5.5 \(\pm\) 0.87 (6) \\  & group4 & 4.6 \(\pm\) 0.49 (5) & 4.4 \(\pm\) 1.2 (5) & 20 \(\pm\) 5.48 (20) \\  & average & 3.11 \(\pm\) 1.09 (3) & 3.33 \(\pm\) 1.38 (3) & 10.73 \(\pm\) 7 (9) \\ \hline \multirow{4}{*}{Battery discharge} & group1 & 3.8 \(\pm\) 0 (5) & 2.6 \(\pm\) 0.8 (1) & 10.2 \(\pm\) 4 (5) \\  & group2 & 2.8 \(\pm\) 1.02 (2) & 2.2 \(\pm\) 0.63 (2) & 6.2 \(\pm\) 2.93 (4) \\  & group3 & 3.5 \(\pm\) 0.83 (3.5) & 2.5 \(\pm\) 0.5 (1.5) & 9.25 \(\pm\) 0.83 (5.5) \\  & group4 & 4 \(\pm\) 0.4 (5) & 3.2 \(\pm\) 0.89 (2) & 13.4 \(\pm\) 4.71 (10) \\  & average & 3.53 \(\pm\) 1.26 (5) & 2.63 \(\pm\) 0.77 (2) & 9.76 \(\pm\) 4.03 (5) \\ \hline \multirow{4}{*}{Explosion prevention} & group1 & 5 \(\pm\) 0.49 (3) & 1.6 \(\pm\) 0.89 (2) & 8 \(\pm\) 2.58 (8) \\  & group2 & 2.4 \(\pm\) 1.5 (2) & 2 \(\pm\) 0.8 (1) & 5.2 \(\pm\) 4.03 (2) \\ \cline{1-1}  & group3 & 3.75 \(\pm\) 1.12 (2.5) & 1.5 \(\pm\) 1.09 (3) & 5.25 \(\pm\) 5.43 (7.5) \\ \cline{1-1}  & group4 &  
Figure 4: Comparison of risk scores across expert groups using a spider diagram. Figure 3: Visualization of risk factors. (**a**) Risk map of risk factors. (**b**) Heatmap of risk assessment by expert group. The analysis of expert assessments reveals several notable patterns. Academic experts (Group 4) consistently rated risks higher than other groups, particularly for collision (mean risk score 20.0) and path deviation (mean risk score 20.0). This higher risk assessment might reflect their theoretical understanding of potential hazards and broader knowledge of worst-case scenarios from various applications. In contrast, robot developers (Group 3) generally provided lower risk assessments, possibly due to their intimate understanding of the technology's capabilities and built-in safety features. The risk visualization in Figure 3 provides two complementary perspectives on these assessments. The risk map (Figure 3a) plots each factor's severity against probability, with color intensity indicating the overall risk level.