# A Supervised Neural Network Control for Magnetorheological Damper in an Aircraft Landing Gear
## 7 Conclusions  
This paper presents an application of supervised neural network control for a landing gear equipped with an MR damper in various landing scenarios. Experimental environments for drop tests of the landing gear were set up for different aircraft masses and sink speeds based on the dSPACE platform, which provides real-time control by models in Simulink. The hybrid controller, which has demonstrated high performance among the existing techniques in both the simulation and experiments, was set as the target model of the supervised learning and was provided with the exact mass of the aircraft and the measured ground reaction force. The neural network controller receives only the system's state variables as input and does not require any information on the aircraft mass or strut force. In the actual operating situations of the aircraft landing gear, only the model-dependent estimates of the aircraft mass and forces are available for control, which degrades the performance of the existing controller. On the other hand, the proposed artificial neural network controller reproduces the behavior of a hybrid controller, which shows the best performance under ideal ground experiment conditions, using only the system state variable information. Therefore, the proposed controller could maintain superior performance to the existing controllers and proved this through comparative experiments. The main results show that the proposed controller exhibits similar landing performance to the hybrid controller with exact information. There is a small difference of 1-3% in shock absorber efficiency between the two controllers. Moreover, the proposed controller produces better shock absorber efficiency by up to 6% than the hybrid controller without exact information. In the future, a robust controller based on sliding model control will be designed to improve the robustness of the MR damper. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & \multicolumn{3}{c}{**Hybrid Control Without**} & \multicolumn{3}{c}{**Intelligent Control**} \\ \cline{3-8}  & & \(\begin{array}{c}\mathbf{F}_{\mathbf{T}}^{max}\\ (\mathbf{k}\mathbf{N})\end{array}\) & \(\begin{array}{c}\mathbf{s}^{max}\\ (\mathbf{m})\end{array}\) & \(\begin{array}{c}\mathbf{\eta}\text{ (\%)}\end{array}\) & \(\begin{array}{c}\mathbf{F}_{\mathbf{T}}^{max}\\ (\mathbf{k}\mathbf{N})\end{array}\) & \(\begin{array}{c}\mathbf{s}^{max}\\ (\mathbf{m})\end{array}\) & \(\begin{array}{c}\mathbf{\eta}\text{ (\%)}\end{array}\) \\ \hline \multirow{3}{*}{\(m_{1}=150\) kg} & \(v=1\,\mathrm{m/s}\) & 3.89 & 0.146 & 71.2 & 3.60 & 0.142 & **74.9** \\ \cline{2-8}  & \(v=2\,\mathrm{m/s}\) & 5.91 & 0.144 & 73.8 & 5.75 & 0.144 & **76.6** \\ \cline{2-8}  & \(v=3\,\mathrm{m/s}\) & 9.27 & 0.146 & 78.5 & 9.06 & 0.154 & **78.9** \\ \hline \multirow{3}{*}{\(m_{1}=170\) kg} & \(v=1\,\mathrm{m/s}\) & 3.99 & 0.149 & 76.5 & 3.61 & 0.147 & **82.1** \\ \cline{2-8}  & \(v=2\,\mathrm{m/s}\) & 5.93 & 0.152 & 79.8 & 5.83 & 0.153 & **82.3** \\ \cline{2-8}  & \(v=3\,\mathrm{m/s}\) & 9.55 & 0.160 & 81.4 & 8.95 & 0.167 & **81.6** \\ \hline \multirow{3}{*}{\(m_{1}=190\) kg} & \(v=1\,\mathrm{m/s}\) & 4.06 & 0.152 & 82.5 & 3.60 & 0.155 & **87.9** \\ \cline{2-8}  & \(v=2\,\mathrm{m/s}\) & 6.17 & 0.156 & 84.6 & 5.97 & 0.162 & **84.7** \\ \cline{2-8}  & \(v=3\,\mathrm{m/s}\) & 9.71 & 0.170 & 82.2 & 9.32 & 0.176 & **82.6** \\ \cline{2-8}  & \(v=1\,\mathrm{m/s}\) & 4.13 & 0.164 & 84.3 & 3.81 & 0.160 & **90.0** \\ \cline{2-8}  & \(v=2\,\mathrm{m/s}\) & 6.25 & 0.160 & 87.1 & 5.96 & 0.171 & **87.5** \\ \cline{2-8}  & \(v=3\,\mathrm{m/s}\) & 9.88 & 0.178 & 83.7 & 9.48 & 0.183 & **84.2** \\ \hline \multirow{3}{*}{\(m_{1}=230\) kg} & \(v=1\,\mathrm{m/s}\) & 4.24 & 0.172 & 83.7 & 4.39 & 0.162 & **88.3** \\ \cline{2-8}  & \(v=2\,\mathrm{m/s}\) & 6.61 & 0.170 & 89.0 & 6.46 & 0.173 & **89.6** \\ \cline{1-1} \cline{2-8}  & \(v=3\,\mathrm{m/s}\) & 9.82 & 0.186 & 85.5 & 9.95 & 0.186 & **86.2** \\ \hline \end{tabular}
\end{table}