
\begin{figure}[b]
\centering
\subfloat[Keypad]{\label{fig:keypad}\includegraphics[width=0.2\textwidth]{keypad}}
\subfloat[Volunteer driving the wheelchair]{\label{fig:volunteer}\includegraphics[width=0.8\textwidth]{volunteer}}
\caption[Virtual reality wheelchair simulator]{A volunteer driving the wheelchair in the VR simulator environment using a keypad as the access device}
\label{fig:VRsimulator}
\end{figure}