## 4 Simulation
### Results of Simulation  
For the performance evaluation of the proposed washout algorithm, simulation was performed based on the human sensation model. The simulation used the vehicle dynamic data generated in situations such as left/right, uphill/downhill, slalom and rapid acceleration and deceleration driving and the cutoff frequency of both the high-frequency and low-frequency filters is 0.01 Hz and the calculation period is 2 ms. The reason why the cutoff frequency is set to 0.01 Hz is that the response characteristics of the human sensation model function are best between 0.01 Hz and 0.1 Hz. Figures 11-13 show simulation configurations to derive the motion sensation of the real vehicle, the motion sensation of the classical washout algorithm and the motion sensation of the proposed washout algorithm, respectively. The input data required for the simulation are generated by KAAS (KATECH Automotive Driving Simulator), a vehicle driving simulator developed by KATECH (Korea Automotive Technology Institute) [4; 5]. Table 4 represents correlation coefficient between the motion sensation of the actual vehicle and motion sensation of classical washout algorithm and proposed washout algorithm. The closer the correlation coefficient value is to one, the more similar it can be to the actual motion sensation. Figure 11: Simulation diagram for the motion sensation in actual vehicle. Figure 12: Simulation diagram for the motion sensation by the classical washout algorithm. The specific gravity gain was set to 0.6 and 0.9, and the simulation is performed with various values up to 0.2, 0.5, 0.7 and 1 for the scale parameter \(k\) of the subregion scale method. In most situations, it can be seen that the sense of motion is improved compared to the classical washout algorithm, and in particular, performance of the rotational motion sensation of the new tilt coordination algorithm can be improved by applying the specific force gain and subregion scale method. That is, while improving the translational motion sensation, it is possible to guarantee a certain level of rotational motion sensation. Figures 14-17 are graphs that express the sense of translation and rotation of the x and y axes in the case of left and right turn driving, rapid acceleration and deceleration driving, slope road driving and slalom driving, respectively. The black line represents the  
\begin{table}
\begin{tabular}{c|c|c|c|c|c|c|c|c|c|c} \hline \hline  & \multirow{2}{*}{\ \begin{tabular}{c} **Classical** \\ **Washout** \\ **Algorithm** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **New Tilt** \\ **Coordination** \\ **Algorithm** \\ \end{tabular}  } & \multicolumn{6}{c|}{**Proposed Washout Algorithm**} \\ \cline{3-11}  & & & \multicolumn{6}{c|}{specific force gain (\(\alpha=0.6\))} & \multicolumn{6}{c}{specific force gain (\(\alpha=0.9\))} \\ \cline{3-11}  & & & \multicolumn{6}{c|}{subregion scale parameter} & \multicolumn{6}{c}{subregion scale parameter} \\ \cline{3-11}  & & \multicolumn{6}{c|}{\(k=0.2\)} & \multicolumn{6}{c|}{\(k=0.5\)} & \multicolumn{6}{c|}{\(k=0.7\)} & \multicolumn{6}{c|}{\(k=1\)} & \multicolumn{6}{c|}{\(k=0.2\)} & \multicolumn{6}{c|}{\(k=0.5\)} & \multicolumn{6}{c|}{\(k=0.7\)} & \multicolumn{6}{c|}{\(k=1\)} \\ \hline \multicolumn{11}{c}{Left-Right Turn} \\ \hline surge & 0.7683 & 0.8802 & 0.8709 & 0.8724 & 0.8729 & 0.8730 & 0.8798 & 0.8814 & 0.8819 & 0.8821 \\ \hline sway & 0.7550  
motion sensation felt by the actual vehicle, the green line represents the classical washout algorithm and the blue line represents the proposed washout algorithm. Figure 14: Motion sensation in the case of left–right turn driving. (**a**) Motion sensation of surge direction. (**b**) Motion sensation of sway direction. (**c**) Motion sensation of roll direction. (**d**) Motion sensation of pitch direction. Figure 15: Cont. Figure 16: Motion sensation in the case of slope road (uphill/downhill) driving. (**a**) Motion sensation of surge direction. (**b**) Motion sensation of sway direction. (**c**) Motion sensation of surge direction.