# Robots in Partially Known and Unknown Environments:
## 5 Experiments and Results
### OfflineRMP Analysis
#### 5.2.2 OfflineRMP Results
Table 7 shows comparisons in terms of smoothness and time; the bold numbers highlight the best time between the four approaches, and the underlined numbers highlight the best smoothness. The hybrid approach achieves the best results in terms of smoothness in five of the nine instances; in the four remaining, the best result is obtained by PRM. The measured smoothness favors the paths with more turns but that are less abrupt. The execution times of OfflineRMP highly surpass those of other approaches such as PRM and two-phase ACO, and better the times from the hybrid approach for every instance, considering that OfflineRMP uses the original resolution. It is important to remark that the shortest paths mostly produce uneven routes. Also, our approach was able to obtain these short paths in very low computation times. Moreover, here, we also include a comparison of the performance of OfflineRMP against the RRT approach [13]. For this, we first executed the RRT approach, known for being able to obtain solutions quickly. Then, we applied the simulated annealing approach to the solution obtained by RRT. Table 8 shows, for each problem instance, the average number of points obtained by the RRT solution (nPoints) and their corresponding average length. We also list the average length, length after post-processing, smoothness, and iteration of the best solution obtained by simulated annealing applied to the initial RRT solution. For the RRT experiments, we considered a neighbor threshold = 200 and a maximum number of iterations = 20 \(\times\)_Resolution_. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Instance** & \multicolumn{3}{c}{**OfflineRMP**} & \multicolumn{1}{c}{**Two-Phase ACO**[21]} & **PRM**[12] & **Hybrid**[3] \\ \hline back\_and\_forth & **4806.4** & **4806.4** \(\pm\)**0.0** & 6222.5 & 4896.2 & 4841.7 \\ corridor\_wavy & **2488.2** & **2502.9 \(\pm\)**8.6** & 3547.7 & 2698.8 & 2665.7 \\ bugtrap1 & **748.4** & **749.8 \(\pm\)**2.1** & 1002.9 & 770.1 & 751.1 \\ clasps & **3596.1** & 3600.8 \(\pm\)**5.5** & 4921.7 & 3710.7 & 3615.4 \\ complex & **2781.0** & 2786.6 \(\pm\) 4.7 & 3521.1 & 2813.0 & **2784.0** \\ potholes & 2021.8 & 2032.4 \(\pm\) 20.4 & 2061.7 & 1953.3 & **1948.2** \\ rockpile & 2045.7 & 2137.6 \(\pm\) 29.7 & 2668.4 & 2040.4 & **2032.4** \\ var\_density & 1586.5 & 1597.3 \(\pm\) 5.1 & 1721.5 & 1593.9 & **1579.5** \\ square\_spiral & **4118.4** & **4119.6 \(\pm\)**1.2** & 5422.9 & 4205.0 & 4133.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Average path length comparison with the literature. Bold numbers show the best results in each problem instance. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**OfflineRMP**} & \multicolumn{1}{c}{**Two-Phase ACO**[21]} & \multicolumn{2}{c}{**PRM**[12]} & \multicolumn{2}{c}{**Hybrid**[3]} \\ \cline{2-9}
**Instance** & **Smoothness** & **Time [s]** & **Smoothness** & **Time [s]** & **Smoothness** & **Time [s]** & **Smoothness** & **Time [s]** \\ \hline back\_and\_forth & 108.2 & **1.0** & 145.5 & 60.8 & 168.9 & 633.8 & **170.6** & 15.2 \\ corridor\_wavy & 105.6 & **3.0** & 140.9 & 55.9 & 167.2 & 66.3 & **169.8** & 8.5 \\ bugtrap1 & 132.4 & **0.5** & 139.3 & 18.0 & 166.8 & 61.0 & **174.2** & 7.1 \\ clasps & 119.0 & **1.4** & 142.2 & 63.3 & 162.4 & 852.6 & **168.6** & 14.2 \\ complex & 134.5 & **2.6** & 147.7 & 66.8 & **171.7** & 581.3 & 168.0 & 35.5 \\ potholes & 71.0 & **0.5** & 174.1 & 75.8 & 176.3 & 847.0 & **177.4** & 4.7 \\ rockpile & 88.2 & **1.1** & 143.5 & 91.1 & **169.3** & 192.5 & 163.9 & 11.3 \\ var\_density & 116.6 & **0.7** & 165.4 & 85.1 & **172.2** & 500.6 & 168.9 & 7.2 \\ square\_spiral & 112.4 & **12.1** & 150.5 & 62.4 & **168.6** & 745.6 & 164.6 & 52.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Smoothness and time comparison with the literature. Bold numbers show the best results in each problem instance. From Table 8, the first important result is that the RRT algorithm did not obtain any solution for the corridor_way instance.