## 4 Application of Operating Model to the Simulator
### Design of Interlock and Warning Systems  
To prevent the malfunction by the TBM operator, the simulator must include interlock and warning systems. TBMs are generally designed to have various interlocks, which can only be changed by the manufacturer. Of the many interlock systems in a real TBM, the simulator includes only those essential to its primary purpose of training apprentices in the operation procedures. There are two types of interlock systems in this simulator: mandatory and elective. Operators cannot change the mandatory system during the simulation. Table 5 lists the mandatory systems. This mandatory system prevents operators from implementing locked operations and displays a pop-up message if they attempt to violate the interlocks. Figure 5 shows the example of a mandatory interlock system associated with shield jack operation. Because the cutterhead is not rotating at that moment, the operator cannot press the push button for shield jack extension with the pop-up message. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Stage** & **Part** & **Interlock System** \\ \hline \multirow{4}{*}{Pre-excavation} & Pump and motors & All pumps and motors must be in operation before starting excavation. \\ \cline{2-3}  & Lubrication and & \\  & cooling systems & Lubrication and cooling systems must be in operation before starting excavation. \\ \hline \multirow{4}{*}{Excavation} & Belt conveyor and cutterhead & The belt conveyor must be in operation before starting cutterhead rotation. \\ \cline{2-3}  & Cutterhead and shield jack & Cutterhead rotation must be in operation before starting shield jack extension. \\ \cline{2-3}  & Screw gate and conveyor & The crew gate must be open before starting screw conveyor rotation. \\ \cline{2-3}  & Cutterhead motors should be selected before starting cutterhead rotation. \\ \cline{2-3}  & Cutterhead & The cutterhead rotation direction must be set either clockwise or \\  & Counterclockwise before starting cutterhead rotation. If it is necessary to change \\  & the rotation direction, the cutterhead should be stopped. \\ \cline{2-3}  & The cutterhead rotation speed must be set before starting cutterhead rotation. \\ \hline \multirow{4}{*}{Excavation} & Shield jacks must be selected before starting shield jack extension. \\ \cline{2-3}  & Shield jack & The shield jack speed must be set before starting shield jack extension. \\ \cline{2-3}  & Shield jack & Shield jacks can be selected by grouping modes (upper, lower, left, and right). \\ \cline{2-3}  & At least one grouping mode should be selected for the excavation. \\ \cline{2-3}  & The shield jack must be set in either extension or retraction mode. If it is \\  & necessary to change the mode, the shield jack should be stopped first. \\ \hline \multirow{4}{*}{Screw conveyor} & The screw conveyor rotation direction must be set to either normal (clockwise) or reverse (counterclockwise) before starting screw conveyor rotation. If it is \\ \cline{2-3}  & necessary to change the rotation direction, the screw conveyor should be \\ \cline{2-3}  & Stopped. \\ \cline{2-3}  & Screw gate & The screw gate opening ratio can be controlled in either open or closed mode. \\ \cline{2-3}  & Screw gate, shield jack, and screw \\ \cline{2-3}  & conveyor & Before closing the screw gate, shield jacks and the screw conveyor must be \\ \cline{2-3}  & Cutterhead and screw gate & Before stopping cutterhead rotation, the screw gate must be closed. \\ \cline{2-3}  & Belt conveyor and cutterhead & Before stopping the belt conveyor, the cutterhead rotation must be stopped. \\ \cline{2-3}  & All parts must be stopped before turning off all pumps and/or motors. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Mandatory interlock systems applied in the simulator. The elective interlock system is closely related to the warning system, which can be divided into seven types depending on the TBM parts (Table 6). The warning system can be activated according to the state of the elective interlock system.