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\input{common_latex/common_latex_packages}
\input{common_latex/common_latex_definitions}
\input{common_latex/common_latex_memo_format}
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\begin{document}

\begin{labcover}
\labtitle{Aquaticus Human Platform - The MOKAI}
\vspace{0.1in}
\labdate{August 2018}
\vspace{0.1in}
\labauth{Michael Benjamin, mikerb@mit.edu}
\labauth{Michael Novitzky, novitzky@mit.edu}
\labauth{Paul Robinette, paulrobi@mit.edu}
\labauth{Caileigh Fitzgerald, caileigh@mit.edu}
\labauth{Department of Mechanical Engineering}
\labauth{MIT, Cambridge MA 02139}
\labtoc{small}
\end{labcover}

\wikidoc{file=Memo.AQMokai}
\wikidoc{auth=mikerb@mit.edu}

%====================================================================
\section{MOKAI Overview}
%====================================================================

The MOKAI is a commercially available platform available to the public
from a company in upstate New York dedicated to making this
platform. At the outset of the Aquaticus project, MOKAI graciously
donated a platform to MIT for initial tests. Currently there are five
platforms with spares in the Aquaticus project. "MOKAI" is short for
{\em motorized kayak} and is driven by a small gas engine.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.65\textwidth]{figures/mokai.png}
  \caption{The MOKAI is a commercial platform, typically used by fishermen
    and recreational boaters on lakes or rivers. This image and video
    is one of many found on line at YouTube or Vimeo.}
  \label{fig_mokai}
  \urlvideo{https://vimeo.com/148966001}{1:22}
\end{figure}
\vspace{0.1in}

\noindent
The boat is controlled by a single small joystick and uses waterjet
propulsion. The lack of spinning propeller allows the boat to get into
shallow water easily, but also makes it a safer platform for our
experiments, and allows the boat to be easily place flat on a dock without
having to worry about keeping a propeller off the ground.

%====================================================================
\subsection{Mechanical Modifications to the MOKAI for Aquaticus}

A number of mechanical modifications were made to the MOKAI to better
suit our uses for the competition. We discuss these first, and later
discuss further modifications to add instrumentation. The key
mechanical modificications:

\begin{packed_itemize}
\item A cover for the air intake openings on engine section
\item A windshield
\item Artificial capping of the top speed
\end{packed_itemize}

%--------------------------------------------------------------------
\subsubsection{The Engine Covers}

The MOKAI has been modified with covers over the air intake openings
on the stern. Due to the high amount of maneuvering and sharp turns in
Aquaticus, too much water was getting into the engine, causing
stalling. This was essentially fixed with the covers during the summer
of 2017. The summer of 2018 was a noticeably smooth year for MOKAI
engine operation. 

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.65\textwidth]{figures/mokai_cover.png}
  \caption{The MOKAI has been modified with covers over the air intake
    openings on the stern.}
  \label{fig_mokai_cover}
  \urlvideo{https://vimeo.com/222021219}{0:46}
\end{figure}
\vspace{0.1in}

%--------------------------------------------------------------------
\subsubsection{The MOKAI Windshield}

Not surprisingly, the MOKAI does not come with a windshield. For
normal recreational boating users this may make sense. For Aquaticus
there is a substantial amount of instrumentation and electronic
equipment on board, and operators quickly become wet, as in the below
video.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.65\textwidth]{figures/mokai_cutter.png}
  \caption{Initially, without the MOKAI windshield, operators as shown in
    this video became quite wet in a short amount of time.}
  \label{fig_mokai_cutter}
  \urlvideo{https://vimeo.com/178681034}{1:119}
\end{figure}
\vspace{0.1in}

\noindent
The windshield was added in late 2017 and we haven't looked back. It
has made a huge difference in our ability to safely instrument the
boat. The windshield was purchases from "Painless Tom", one of several
MOKAI hobbysts found on line. They look like this:

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.65\textwidth]{figures/mokai_windshields.png}
  \caption{The MOKAI windshields.}
  \label{fig_mokai_windshields}
\end{figure}
\vspace{0.1in}


%--------------------------------------------------------------------
\subsubsection{Capping the Top Speed Limit by Reprogramming the Joystick}

The third major mechanical modification was actually made to the
software configuration of the joystick, to limit the top thrust
commanded to the boat. This was done for a few reasons. (1) The
unmodified MOKAIs were much much faster than the robots, making the
humans relatively super enabled, which is not particularly
desirable for a human-robot collaboration. (2) The unmodified MOKAIs
are very LOUD, which is not great for being good neighbors at the
sailing pavilion, and for allowing voice-to-text to operate
smoothly. (3) The faster MOKAIs can make some pretty aggressive
turns, which aggrevated the problem of getting water into the engines
and higher splashing around our electronic components.


%====================================================================
\section{Instrumenting the MOKAI}
%====================================================================

The MOKAI has an onboard computer and is on the same network as the
robots. Part of this is (1) safety, so we can talk to the players, and
the MOKAI position is known to the robots for collision avoidance, (2)
data collection, so we can later analyze human decision making and
activities, and (3) communication to the robots, to support on-board
voice-to-text, and incoming text to voice from the robots.

%====================================================================
\subsection{The MOKAI Computer}

The MOKAI computer is a Raspberry PI computer in a water-tight
box. This is the same computer and housing as used on the robot
platforms. It is referred as the PABLO, or payload autonomy box.
The PABLO is powered by an on-board battery stored in a separate
water-tight box connected by water resistant cables.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.65\textwidth]{figures/pablo_mokai.png}
  \caption{The MOKAI computer is a Raspberry PI in side water-tight
  box with external wet connectors for power, Ethernet and USB.}
  \label{fig_mokai_pablo}
\end{figure}
\vspace{0.1in}

\noindent
The PABLO computer is running MOOS, but not any of the IvP autonomy
software. Modules include

\begin{packed_itemize}
\item The MOOSDB 
\item The pShare app for connection to the shoreside computer
\item The iGPS app for reading vehicle position, heading speed
\item The uFldNodeBroker app for auto-connecting to the shoreside
\item The iOS5000 app for reacing compass information
\item The pNodeReporter app for building and sharing full node reports
  to the shoreside and to all robots
\item The iZephyrHRM app for talking to the player heart-rate monitor
\item The iMumbleClient app for sharing audio between players and the
  shoreside
\item The iButtonBox app for interfacing with the button box (see
  below)
\item The pLogger app for logging all data to a single log file
\item The pRecord app for capturing raw audio files
\item The uSpeechRec app for recording speech and performing
  speech-to-text
\end{packed_itemize}



%====================================================================
\subsection{Video/Audio Capture of the Player}

A stand-alone GoPro camera is mounted on all MOKAIs, facing the
player, to capture data about the player not otherwise available,
such as the degree to which he/she is looking around the playing
field, or at their own notes.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.85\textwidth]{figures/mokai_gopro_fig.png}
  \caption{A GoPro camera is mounted in each MOKAI facing the player
    (left).  Example video from a competition is shown on the right.}
  \label{fig_mokai_gopro}
\end{figure}
\vspace{0.1in}

\noindent
Currently (Aug18) the data is offloaded by person, in between each
competition.  Synchronizing to the other logged data is also done
manually. 

%====================================================================
\subsection{Networking Hardware}

All MOKAIs are on the local network, for sharing position information,
and for sharing audio via Voice Over IP (VOIP). Each vehicle uses a
Ubiquiti Networks Bullet 5 GHz High Power 802.11n Outdoor Radio
System, mounted under the starboard side of the boat as shown in
Figure \ref{fig_mokai_network}. The radio is connected to an antenna
mounted on the bow of the boat as shown. Power and data come from
the Ethernet cable coming out of the PABLO box.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.7\textwidth]{figures/mokai_networking.png}
  \caption{Each MOKAI is configured with a Bullet radio, connected to an
    antenna mounted on the bow, and connected via Ethernet cable to the
    onboard PABLO computer box. The radio is powered over Ethernet from
    the same battery poweringthe PABLO computer.}
  \label{fig_mokai_network}
\end{figure}
\vspace{0.1in}

%====================================================================
\subsection{Marine Radio Communications}

Players in the MOKAI are equipped with a marine radio for
communicating to the shoreside operators and nearby motorboat safety
operator if they need.  The marine radio is mounted in the boat on the
port side, roughly at the operator knee level as shown in Figure
\ref{fig_mokai_radio} below. The radio is connected to an RF antenna
mounted on the bow of the boat. A push-button is part of the cable
from the radio to the operator headset. When the player wishes to
talk, he/she pushes the button to talk.

\vspace{0.1in}
\begin{figure}[H]
  \centering
  \includegraphics[width=0.7\textwidth]{figures/mokai_radio_fig.png}
  \caption{Each MOKAI is configured with a marine radio mounted in the
    boat as shown on the left. One line goes to the operator headset.
  The other line goes to an RF antenna mounted on the bow.}
  \label{fig_mokai_radio}
\end{figure}
\vspace{0.1in}

\noindent
The player wears a headset with a microphone as shown in the figure.
The headset gear has two lines. One goes to the marine radio, and the
other goes to the button box, discussed below, for VOIP communications.

\vspace{0.1in}
\noindent
Note: Communications to their teammate will happen
over VOIP so it will be logged in the PABLO and shoreside operators
can listen in, and the opposing team cannot evesdrop on their
conversation. The marine radio is mounted in the boat on the port




\end{document}



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